Internet DRAFT - draft-ietf-idr-bgp-model

draft-ietf-idr-bgp-model







Interdomain Routing                                      M. Jethanandani
Internet-Draft                                            Kloud Services
Intended status: Standards Track                                K. Patel
Expires: 6 January 2024                                           Arrcus
                                                                S. Hares
                                                                  Huawei
                                                                 J. Haas
                                                        Juniper Networks
                                                             5 July 2023


             YANG Model for Border Gateway Protocol (BGP-4)
                      draft-ietf-idr-bgp-model-17

Abstract

   This document defines a YANG data model for configuring and managing
   BGP, including protocol, policy, and operational aspects, such as
   RIB, based on data center, carrier, and content provider operational
   requirements.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 6 January 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components



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   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Goals and approach  . . . . . . . . . . . . . . . . . . .   3
     1.2.  Note to RFC Editor  . . . . . . . . . . . . . . . . . . .   5
     1.3.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     1.4.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Model overview  . . . . . . . . . . . . . . . . . . . . . . .   6
     2.1.  BGP protocol configuration  . . . . . . . . . . . . . . .   6
     2.2.  Policy configuration overview . . . . . . . . . . . . . .   9
     2.3.  BGP RIB overview  . . . . . . . . . . . . . . . . . . . .  10
       2.3.1.  Local Routing . . . . . . . . . . . . . . . . . . . .  12
       2.3.2.  Pre updates per-neighbor  . . . . . . . . . . . . . .  12
       2.3.3.  Post updates per-neighbor . . . . . . . . . . . . . .  12
       2.3.4.  Pre route advertisements per-neighbor . . . . . . . .  12
       2.3.5.  Post route advertisements per-neighbor  . . . . . . .  12
   3.  Relation to other YANG data models  . . . . . . . . . . . . .  12
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
     5.1.  URI Registration  . . . . . . . . . . . . . . . . . . . .  15
     5.2.  YANG Module Name Registration . . . . . . . . . . . . . .  15
   6.  YANG modules  . . . . . . . . . . . . . . . . . . . . . . . .  16
   7.  Structure of the YANG modules . . . . . . . . . . . . . . . .  17
     7.1.  BGP module and submodules . . . . . . . . . . . . . . . .  19
       7.1.1.  BGP module  . . . . . . . . . . . . . . . . . . . . .  19
       7.1.2.  BGP capabilities submodule  . . . . . . . . . . . . .  40
       7.1.3.  BGP common submodule  . . . . . . . . . . . . . . . .  49
       7.1.4.  BGP common multiprotocol submodule  . . . . . . . . .  65
       7.1.5.  BGP common structure submodule  . . . . . . . . . . .  73
       7.1.6.  BGP neighbors submodule . . . . . . . . . . . . . . .  77
     7.2.  BGP notification module . . . . . . . . . . . . . . . . .  81
     7.3.  BGP types module  . . . . . . . . . . . . . . . . . . . .  98
     7.4.  BGP community types module  . . . . . . . . . . . . . . . 109
     7.5.  BGP policy module . . . . . . . . . . . . . . . . . . . . 118
     7.6.  RIB modules and submodules  . . . . . . . . . . . . . . . 136
       7.6.1.  BGP RIB types module  . . . . . . . . . . . . . . . . 136
       7.6.2.  BGP RIB submodule . . . . . . . . . . . . . . . . . . 140
       7.6.3.  BGP RIB attributes submodule  . . . . . . . . . . . . 154
       7.6.4.  BGP RIB tables submodule  . . . . . . . . . . . . . . 161
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . . 169
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 169
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . 169
     10.1.  Normative references . . . . . . . . . . . . . . . . . . 169
     10.2.  Informative references . . . . . . . . . . . . . . . . . 174



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   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . . 175
     A.1.  Creating BGP Instance . . . . . . . . . . . . . . . . . . 175
     A.2.  Neighbor Address Family Configuration . . . . . . . . . . 176
     A.3.  IPv6 Neighbor Configuration . . . . . . . . . . . . . . . 178
     A.4.  VRF Configuration . . . . . . . . . . . . . . . . . . . . 180
     A.5.  BGP Policy - Match Prefix and Set Community . . . . . . . 182
     A.6.  BGP Policy - Match Next-hop and Set Community . . . . . . 186
   Appendix B.  How to add a new AFI and Augment a Module  . . . . . 188
   Appendix C.  How to deviate a module  . . . . . . . . . . . . . . 191
   Appendix D.  Complete configuration tree diagram  . . . . . . . . 192
   Appendix E.  Complete policy tree diagram . . . . . . . . . . . . 218
   Appendix F.  BGP YANG Model AS_PATH Regular Expressions . . . . . 221
     F.1.  AS_PATH Regular Expressions in Implementations  . . . . . 221
     F.2.  Why not use standard POSIX regular expressions? . . . . . 221
     F.3.  BGP YANG AS_PATH Regular Expressions  . . . . . . . . . . 222
     F.4.  Matching AS_PATH Segment Types in AS_PATH Regular
           Expressions . . . . . . . . . . . . . . . . . . . . . . . 223
     F.5.  BGP YANG AS_PATH Regular Expressions ABNF . . . . . . . . 224
     F.6.  Example BGP YANG AS_PATH Regular Expressions  . . . . . . 224
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 224

1.  Introduction

   This document describes a YANG 1.1 [RFC7950] data model for the BGP-4
   [RFC4271] protocol, including various protocol extensions, policy
   configuration, as well as defining key operational state data,
   including a Routing Information Base (RIB).  The model is intended to
   be vendor-neutral, in order to allow operators to manage BGP
   configuration in heterogeneous environments with routers supplied by
   multiple vendors.  The model is also intended to be readily mapped to
   existing implementations to facilitate support from as large a set of
   routing hardware and software vendors as possible.  This module does
   not support previous versions of BGP, and cannot support establishing
   and maintaining state information of neighbors with previous versions
   of BGP.

1.1.  Goals and approach

   The model covers the base BGP features that are deployed across major
   implementations and the common BGP configurations in use across a
   number of operator network deployments.  In particular, this model
   attempts to cover BGP features defined in BGP [RFC4271], BGP
   Communities Attribute [RFC1997], BGP Extended Communities Attributes
   [RFC4360], IPv6 Extended Communities Attributes [RFC5701], BGP Large
   Communities Attributes [RFC8092], BGP Route Reflection [RFC4456],
   Multiprotocol Extensions for BGP-4 [RFC4760], Autonomous System
   Confederations for BGP [RFC5065], BGP Route Flap Damping [RFC2439],
   Graceful Restart Mechanism for BGP [RFC4724], BGP Prefix Origin



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   Validation [RFC6811], and Advertisement of Multiple Paths in BGP
   [RFC7911].  It attempts to make the model extensible by using
   identities for well known standard community types, and the use of
   "raw" string to support new and experimental type definitions.

   Along with configuration of base BGP features, this model also
   addresses policy configuration, by providing "hooks" for applying
   policies, and also defining BGP-specific policy features.  The BGP
   policy features are intended to be used with the general routing
   policy model defined in A YANG Data Model for Routing Policy
   Management [RFC9067].

   The model conforms to the NMDA [RFC8342] architecture.  It has
   support for securing BGP sessions using TCP-AO [RFC5925] or TCP-MD5,
   and for configuring Bidirectional Forward Detection (BFD) [RFC5880]
   for fast next hop liveliness checking.

   For the base BGP features, the focus of the model described in this
   document is on providing configuration and operational state
   information relating to:

   *  The global BGP instance, and neighbors whose configuration is
      specified individually, or templated with the use of peer-groups.

   *  The address families that are supported by peers, and the global
      configuration which relates to them.

   *  The policy configuration "hooks" and BGP-specific policy features
      that relate to a neighbor - controlling the import and export of
      NLRIs.

   *  BGP RIB contents.

   As mentioned earlier, any configuration items that are deemed to be
   widely available in existing major BGP implementations are included
   in the model.  Additional, more esoteric, configuration items that
   are not commonly used, or only available from a single
   implementation, are omitted from the model with an expectation that
   they will be available in companion modules that augment or extend
   the current model.  This allows clarity in identifying data that is
   part of the vendor-neutral base model.

   Where possible, naming in the model follows conventions used in
   available standards documents, and otherwise tries to be self-
   explanatory with sufficient descriptions of the intended behavior.
   Similarly, configuration data value constraints and default values,
   where used, are based on recommendations in current standards
   documentation, or those commonly used in multiple implementations.



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   Since implementations can vary widely in this respect, this version
   of the model specifies only a limited set of defaults and ranges with
   the expectation of being more prescriptive in future versions based
   on actual operator use.

1.2.  Note to RFC Editor

   This document uses several placeholder values throughout the
   document.  Please replace them as follows and remove this note before
   publication.

   RFC XXXX, where XXXX is the number assigned to this document at the
   time of publication.

   2023-07-05 with the actual date of the publication of this document.

1.3.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

1.4.  Abbreviations

       +==============+===========================================+
       | Abbreviation |                                           |
       +==============+===========================================+
       | AFI          | Address Family Identifier                 |
       +--------------+-------------------------------------------+
       | BFD          | Bidirectional Forward Detection           |
       +--------------+-------------------------------------------+
       | NLRI         | Network Layer Reachability Information    |
       +--------------+-------------------------------------------+
       | NMDA         | Network Management Datastore Architecture |
       +--------------+-------------------------------------------+
       | RIB          | Routing Information Base                  |
       +--------------+-------------------------------------------+
       | SAFI         | Subsequent Address Family Identifier      |
       +--------------+-------------------------------------------+
       | VRF          | Virtual Routing and Forwarding            |
       +--------------+-------------------------------------------+

                                 Table 1






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2.  Model overview

   The BGP model is defined across several YANG modules and submodules,
   but at a high level is organized into six elements:

   *  base protocol configuration -- configuration affecting BGP
      protocol-related operations, defined at various levels of
      hierarchy.

   *  multi-protocol configuration -- configuration affecting individual
      address-families within BGP Multiprotocol Extensions for BGP-4
      [RFC4760].

   *  neighbor configuration -- configuration affecting an individual
      neighbor within BGP.

   *  neighbor multi-protocol configuration -- configuration affecting
      individual address-families for a neighbor within BGP.

   *  policy configuration -- hooks for application of the policies
      defined in A YANG Data Model for Routing Policy Management
      [RFC9067] that act on routes sent (received) to (from) peers or
      other routing protocols and BGP-specific policy features.

   *  operational state -- variables used for monitoring and management
      of BGP operations.

   These modules also make use of standard Internet types, such as IP
   addresses and prefixes, autonomous system numbers, etc., defined in
   Common YANG Data Types [RFC6991].

2.1.  BGP protocol configuration

   The BGP protocol configuration model is organized hierarchically,
   much like the majority of router implementations.  That is,
   configuration items can be specified at multiple levels, as shown
   below.

   module: ietf-bgp

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw bgp
          +--rw global!
          |  +--rw as                         inet:as-number
          |  +--rw identifier?                yang:dotted-quad
          |  +--rw distance
          |  |     ...



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          |  +--rw confederation
          |  |     ...
          |  +--rw graceful-restart {bt:graceful-restart}?
          |  |     ...
          |  +--rw use-multiple-paths
          |  |     ...
          |  +--rw route-selection-options
          |  |     ...
          |  +--rw afi-safis
          |  |     ...
          |  +--rw apply-policy
          |  |     ...
          |  +--ro statistics
          |        ...
          +--rw neighbors
          |  +--rw neighbor* [remote-address]
          |  |     ...
          |  +---n established
          |  |     ...
          |  +---n backward-transition
          |  |     ...
          |  +---x clear {bt:clear-neighbors}?
          |        ...
          +--rw peer-groups
          |  +--rw peer-group* [name]
          |        ...
          +--ro rib
             +--ro attr-sets
             |     ...
             +--ro communities
             |     ...
             +--ro ext-communities
             |     ...
             +--ro ipv6-ext-communities
             |     ...
             +--ro large-communities
             |     ...
             +--ro afi-safis
                   ...

   Users may specify configuration at a higher level and have it apply
   to all lower-level items, or provide overriding configuration at a
   lower level of the hierarchy.  Overriding configuration items are
   optional, with neighbor-specific configuration being the most
   specific or lowest level, followed by peer-group, and finally global.
   Global configuration options reflect a subset of the peer-group or
   neighbor-specific configuration options which are relevant to the
   entire BGP instance.



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   The model makes the simplifying assumption that most of the
   configuration items are available at all levels of the hierarchy.
   That is, very little configuration is specific to a particular level
   in the hierarchy, other than obvious items such as "group-name" only
   being available for the peer group-level config.  A notable exception
   is for sub-address family configuration where some items are only
   applicable for a given AFI-SAFI combination.

   In order to allow common configuration to be applied to a set of
   neighbors, all neighbor configuration options are available within a
   peer-group.  A neighbor is associated with a particular peer-group
   through the use of a peer-group leaf (which provides a reference to a
   configured item in the peer-group list).

   Address-family configuration is made available in multiple points
   within the model - primarily within the global container, where
   instance-wide configuration can be set (for example, global protocol
   parameters, the BGP best-path route selection options, or global
   policies relating to the address-family); and on a per-neighbor or
   per-peer-group basis, where address-families can be enabled or
   disabled, and policy associated with the parent entity applied.
   Within the afi-safi container, generic configuration that applies to
   all address-families (e.g., whether the AFI-SAFI is enabled) is
   presented at the top-level, with address-family specific containers
   made available for options relating to only that AFI-SAFI.  Within
   the current revision of the model a generic set of address-families,
   and common configuration and state options are included - further
   work is expected to add additional parameters to this area of the
   model.

   The model supports ipv4-unicast and ipv6-unicast address-families and
   defers the remaining AFI/SAFI to other or future drafts:



















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           +--rw bgp
             +--rw global!
                +--rw afi-safis
                   +--rw afi-safi* [afi-safi-name]
                      +--rw afi-safi-name              identityref
                      |
                      +--rw ipv4-unicast
                      |     ...
                      +--rw ipv6-unicast
                      |     ...
                      +--rw ipv4-labeled-unicast
                      |     ...
                      +--rw ipv6-labeled-unicast
                      |     ...
                      +--rw l3vpn-ipv4-unicast
                      |     ...
                      +--rw l3vpn-ipv6-unicast
                      |     ...
                      +--rw l3vpn-ipv4-multicast
                      |     ...
                      +--rw l3vpn-ipv6-multicast
                      |     ...
                      +--rw l2vpn-vpls
                      |     ...
                      +--rw l2vpn-evpn
                      |     ...

2.2.  Policy configuration overview

   The BGP policy configuration model augments the generic YANG routing
   policy model described in A YANG Data Model for Routing Policy
   Management [RFC9067], which represents a condition-action policy
   framework for routing.  This model adds BGP-specific conditions
   (e.g., matching on the community attribute), and actions (e.g.,
   setting local preference) to the generic policy framework.

   Policies that are defined in the routing-policy model are referenced
   in multiple places within the model:

   *  within the global instance, where a policy applies to all address-
      families for all peers.

   *  on a global AFI-SAFI basis, where policies apply to all peers for
      a particular address-family.

   *  on a per-peer-group or per-neighbor basis - where the policy
      applies to all address-families for the particular group or
      neighbor.



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   *  on a per-afi-safi basis within a neighbor or peer-group context,
      where the policy is specific to the AFI-SAFI for a a specific
      neighbor or group.

   module: ietf-bgp-policy

     augment /rt-pol:routing-policy/rt-pol:defined-sets:
       +--rw bgp-defined-sets
             ...
     augment /rt-pol:routing-policy/rt-pol:policy-definitions
               /rt-pol:policy-definition/rt-pol:statements
               /rt-pol:statement/rt-pol:conditions:
       +--rw bgp-conditions
             ...
     augment /rt-pol:routing-policy/rt-pol:policy-definitions
               /rt-pol:policy-definition/rt-pol:statements
               /rt-pol:statement/rt-pol:actions:
       +--rw bgp-actions
             ...

2.3.  BGP RIB overview

   The RIB data model represents the BGP RIB contents.  The model
   supports five logical RIBs per address family.

   An abridged version of the tree shows the RIB portion of the tree
   diagram.
























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   module: ietf-bgp

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw bgp
          +--ro rib
             +--ro afi-safis
                +--ro afi-safi* [name]
                   +--ro name            identityref
                   +--ro ipv4-unicast
                   |  +--ro loc-rib
                   |  |  +--ro routes
                   |  |     +--ro route* [prefix origin path-id]
                   |  |           ...
                   |  +--ro neighbors
                   |     +--ro neighbor* [neighbor-address]
                   |        +--ro neighbor-address    inet:ip-address
                   |        +--ro adj-rib-in-pre
                   |        |     ...
                   |        +--ro adj-rib-in-post
                   |        |     ...
                   |        +--ro adj-rib-out-pre
                   |        |     ...
                   |        +--ro adj-rib-out-post
                   |              ...
                   +--ro ipv6-unicast
                      +--ro loc-rib
                      |  +--ro routes
                      |     +--ro route* [prefix origin path-id]
                      |           ...
                      +--ro neighbors
                         +--ro neighbor* [neighbor-address]
                            +--ro neighbor-address    inet:ip-address
                            +--ro adj-rib-in-pre
                            |     ...
                            +--ro adj-rib-in-post
                            |     ...
                            +--ro adj-rib-out-pre
                            |     ...
                            +--ro adj-rib-out-post
                                  ...










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2.3.1.  Local Routing

   The loc-rib is the main BGP routing table for the local routing
   instance, containing best-path selections for each prefix.  The key
   for the loc-rib will correspond either to a route in the adj-rib-in-
   post table, described below, or a route redistributed from another
   protocol.

2.3.2.  Pre updates per-neighbor

   The adj-rib-in-pre table is a per-neighbor table containing the NLRI
   updates received from the neighbor before any local input policy
   rules or filters have been applied.  This can be considered the 'raw'
   updates from a given neighbor.

2.3.3.  Post updates per-neighbor

   The adj-rib-in-post table is a per-neighbor table containing the
   routes received from the neighbor that are eligible for best-path
   selection after local input policy rules have been applied.

   The "best-path" leaf is attached to the route selected by the BGP
   Decision Process Section 9.1 of [RFC4271].  Such routes may be
   present in the loc-rib table, described above, when local
   configuration determines that the BGP best-path will be used for that
   destination.

2.3.4.  Pre route advertisements per-neighbor

   The adj-rib-out-pre table is a per-neighbor table containing routes
   eligible for sending (advertising) to the neighbor before output
   policy rules have been applied.

2.3.5.  Post route advertisements per-neighbor

   The adj-rib-out-post table is a per-neighbor table containing routes
   eligible for sending (advertising) to the neighbor after output
   policy rules have been applied.

3.  Relation to other YANG data models

   The BGP model augments the Routing Management model A YANG Data Model
   for Routing Management [RFC8349] which defines the notion of routing,
   routing protocols, and RIBs.  The notion of Virtual Routing and
   Forwarding (VRF) is derived by using the YANG Schema Mount [RFC8528]
   to mount the Routing Management module under the YANG Data Model for
   Network Instances [RFC8529].




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   Similarly, it augments the A YANG Data Model for Routing Policy
   Management [RFC9067] to add in BGP-specific conditions and actions to
   the generic policy model.

4.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].  The NETCONF Access Control Model (NACM) [RFC8341]
   provides the means to restrict access for particular NETCONF or
   RESTCONF users to a preconfigured subset of all available NETCONF or
   RESTCONF protocol operations and content.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  Some of the subtrees and data nodes
   and their sensitivity/vulnerability are described here.

   *  The attribute 'as'.  If a user is allowed to change this
      attribute, it will have the net effect of bringing down the entire
      routing instance, causing it to delete all the current routing
      entries, and learning new ones.

   *  The attribute 'identifier'.  If a user is allowed to change this
      attribute, it will have the net effect of this routing instance
      re-advertising all its routes.

   *  The attribute 'distance'.  If a user is allowed to change this
      attribute, it will cause the preference for routes, e.g. external
      vs internal to change.

   *  The attribute 'enabled' in the 'confederation' container.  This
      attribute defines whether a local-AS is part of a BGP
      confederation.

   *  Finally, there are a whole set of route selection options such as
      'always-compare-med', 'ignore-as-path-length' that affect the way
      the system picks up a particular route.  Being able to change will
      adversely affect how the route selection happens.





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   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  Some of the subtrees and data
   nodes and their sensitivity/vulnerability are:

   *  The list of neighbors, and their attributes.  Allowing a user to
      read these attributes, in particular the address/port information
      may allow a malicious user to launch an attack at the particular
      address/port.

   *  The 'rib' container.  This container contains sensitive
      information such as attribute sets, communities, extended
      communities, IPv6 extended communities, and large communities.
      Being able to read the contents of this container will allow a
      malicious user to understand how the system decide how to route a
      packet, and thus try to affect a change.

   Some of the RPC operations in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control access to these operations.  These are the
   operations and their sensitivity/vulnerability:

   *  The model allows for routes to be cleared using the 'clear' RPC
      operations, causing the entire RIB table to be cleared.

   *  The model allows for statistics to be cleared by the 'clear' RPC
      operation, causing all the individual statistics to be cleared.

   *  The model also allows for neighbors that have been learnt by the
      system to be cleared by using the 'clear' RPC operation.

   BGP OPSEC [RFC7454] describes several policies that can be used to
   secure BGP.  In particular, it recommends securing the underlying TCP
   session and to use the Generalized TTL Security Mechanism (GTSM)
   [RFC5082] capability to make it harder to spoof a BGP session.  This
   module allows implementations that want to support the capability to
   configure a TTL value, under a feature flag.  It also defines a
   container 'secure-session' that contains a choice of using
   TCP-Authentication Option (TCP-AO) [RFC5925], or Protection of BGP
   Sessions via the TCP MD5 Signature Option [RFC2385].  The support for
   MD5 has been made available for legacy reasons.  However, because of
   vulnerabilities in MD5 as described in MD5 and HMAC-MD5 Security
   Considerations [RFC6151], operators are strongly encouraged to use
   TCP-AO or other methods to secure their BGP session.






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5.  IANA Considerations

   This document registers six URIs and six YANG modules.

5.1.  URI Registration

   Following the format in the IETF XML registry [RFC3688] [RFC3688],
   the following registration is requested to be made:

               URI:urn:ietf:params:xml:ns:yang:ietf-bgp
               URI:urn:ietf:params:xml:ns:yang:ietf-bgp-policy
               URI:urn:ietf:params:xml:ns:yang:iana-bgp-community-types
               URI:urn:ietf:params:xml:ns:yang:iana-bgp-notification
               URI:urn:ietf:params:xml:ns:yang:iana-bgp-rib-types
               URI:urn:ietf:params:xml:ns:yang:iana-bgp-types

   Registrant Contact: The IESG.  XML: N/A, the requested URI is an XML
   namespace.

5.2.  YANG Module Name Registration

   This document registers six YANG modules in the YANG Module Names
   registry YANG [RFC6020].




























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            name: ietf-bgp
            namespace: urn:ietf:params:xml:ns:yang:ietf-bgp
            prefix: bgp
            reference: RFC XXXX

            name: ietf-bgp-policy
            namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-policy
            prefix: bp
            reference: RFC XXXX

            name: iana-bgp-community-types
            namespace: urn:ietf:params:xml:ns:yang:iana-bgp-community-types
            prefix: bct
            reference: RFC XXXX

            name: iana-bgp-notification
            namespace: urn:ietf:params:xml:ns:yang:iana-bgp-notification
            prefix: bn
            reference: RFC XXXX

            name: iana-bgp-types
            namespace: urn:ietf:params:xml:ns:yang:iana-bgp-types
            prefix: bt
            reference: RFC XXXX

            name: iana-bgp-rib-types
            namespace: urn:ietf:params:xml:ns:yang:iana-bgp-rib-types
            prefix: brt
            reference: RFC XXXX


6.  YANG modules

   The modules comprising the BGP configuration and operational model
   are described by the YANG modules and submodules in the sections
   below.

   The main module, ietf-bgp.yang, includes the following submodules:

   *  ietf-bgp-capabilities - defines the groupings that are common to
      the BGP Capabilities feature.

   *  ietf-bgp-common - defines the groupings that are common across
      more than one context (where contexts are neighbor, group,
      global).






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   *  ietf-bgp-common-multiprotocol - defines the groupings that are
      common across more than one context, and relate to multi-protocol
      BGP.

   *  ietf-bgp-common-structure - defines groupings that are shared by
      multiple contexts, but are used only to create structural
      elements; i.e., containers (leaf nodes are defined in separate
      groupings).

   *  ietf-bgp-neighbor - groupings with data specific to the neighbor
      context.

   *  ietf-bgp-rib - grouping for representing BGP RIBs.

   *  ietf-bgp-rib-attributes - common data definitions for BGP
      attributes used in BGP RIB tables.

   *  ietf-bgp-rib-tables - structural data definitions for BGP routing
      tables.

   Additionally, the above modules include the following modules:

   *  iana-bgp-community-types - common type and identity definitions
      for BGP Communities.

   *  ietf-bgp-policy - BGP-specific policy data definitions for use
      with [RFC9067] (described in more detail Section 2.2).

   *  iana-bgp-types - common type and identity definitions for BGP,
      including BGP policy.

   *  iana-bgp-rib-types - common type and identity definitions for BGP
      RIB.

7.  Structure of the YANG modules

   The YANG model can be subdivided between the main module for base
   items, types, and policy module.  It references:

   *  BGP Communities Attribute [RFC1997]

   *  Route Refresh Capability for BGP-4 [RFC2918]

   *  NOPEER Community for BGP [RFC3765]

   *  BGP Extended Communities Attributes [RFC4360]

   *  BGP/MPLS IP Virtual Private Networks (VPNs) [RFC4364]



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   *  BGP MED Considerations [RFC4451]

   *  BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN
      [RFC4659]

   *  Graceful Restart Mechanism for BGP [RFC4724]

   *  Multiprotocol Extentions for BGP-4 [RFC4760]

   *  Virtual Private LAN Service (VPLS) Using BGP for Auto-Discovery
      and Signaling [RFC4761]

   *  Autonomous System Configuration for BGP [RFC5065]

   *  The Generalized TTL Security Mechanism (GTSM) [RFC5082]

   *  IPv6 Address Specific BGP Extended Community Attribute [RFC5701]

   *  Bidirectional Forward Detection (BFD) [RFC5880]

   *  Bidirectional Forward Detection for IPv4 and IPv6 (Single Hop)
      [RFC5881]

   *  Bidirectional Forwarding Detection (BFD) for Multihop Paths
      [RFC5883]

   *  The TCP Authentication Option [RFC5925]

   *  BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs
      [RFC6514]

   *  BGP Support for Four-Octet Autonomous System (AS) Number Space
      [RFC6793]

   *  Advertisement of Multiple Paths in BGP [RFC7911]

   *  BGP Large Communities Attributes [RFC8092]

   *  YANG Key Chain [RFC8177]

   *  Carrying Label Information in BGP-4 [RFC8277]

   *  A YANG Data Model for Routing Policy [RFC9067]

   *  YANG Data Model for Bidirectional Forward Detection [RFC9314]

   *  Transmission Control Protocol [RFC9293]




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   *  YANG Model for Transmission Control Protocol (TCP) Configuration
      [I-D.ietf-tcpm-yang-tcp]

7.1.  BGP module and submodules

7.1.1.  BGP module

   <CODE BEGINS> file "ietf-bgp@2023-07-05.yang"
   module ietf-bgp {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-bgp";
     prefix bgp;

     /*
      * Import and Include
      */

     import ietf-routing {
       prefix rt;
       reference
         "RFC 8349: A YANG Data Model for Routing Management
          (NMDA Version).";
     }
     import ietf-routing-policy {
       prefix rt-pol;
       reference
         "RFC 9067: A YANG Data Model for Routing Policy.";
     }
     import iana-bgp-notification {
       prefix bn;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types.";
     }



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     include ietf-bgp-capabilities {
       revision-date 2023-07-05;
     }
     include ietf-bgp-common {
       revision-date 2023-07-05;
     }
     include ietf-bgp-common-multiprotocol {
       revision-date 2023-07-05;
     }
     include ietf-bgp-common-structure {
       revision-date 2023-07-05;
     }
     include ietf-bgp-neighbor {
       revision-date 2023-07-05;
     }
     include ietf-bgp-rib {
       revision-date 2023-07-05;
     }
     include ietf-bgp-rib-attributes {
       revision-date 2023-07-05;
     }
     include ietf-bgp-rib-tables {
       revision-date 2023-07-05;
     }

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This module describes a YANG model for BGP protocol
        configuration. It is a limited subset of all of the
        configuration parameters available in the variety of vendor
        implementations, hence it is expected that it would be augmented
        with vendor-specific configuration data as needed. Additional
        modules or submodules to handle other aspects of BGP
        configuration, including policy, VRFs, VPNs, and additional
        address families are also expected.

        This model supports the following BGP configuration level
        hierarchy:



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         BGP
           |
           +-> [ global BGP configuration ]
             +-> AFI / SAFI global
           +-> peer group
             +-> [ peer group config ]
             +-> AFI / SAFI [ per-AFI overrides ]
           +-> neighbor
             +-> [ neighbor config ]
             +-> [ optional pointer to peer-group ]
             +-> AFI / SAFI [ per-AFI overrides ]

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     /*
      * Identity
      */

     identity bgp {
       base rt:routing-protocol;
       description
         "BGP protocol.";
     }



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     /*
      * Groupings
      */

     grouping bgp-errors-common {
       description
         "BGP NOTIFICATION state that is common in the sent and received
          direction.";

       leaf last-notification {
         type yang:date-and-time;
         description
           "The timestamp indicates the time that a BGP
            NOTIFICATION message was last handled.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            4.5.";
       }
       leaf last-error {
         type identityref {
           base bn:bgp-notification;
         }
         description
           "The last NOTIFICATION error for the peer on this
            connection.  If no identity is registered for the
            Error code / Error subcode, this leaf contains the most
            applicable identity for the BGP NOTIFICATION base code.

            The last-error-code and last-error-subcode will always have
            the information received in the NOTIFICATION PDU.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            4.5.";
       }
       leaf last-error-code {
         type uint8;
         description
           "The last NOTIFICATION Error code for the peer on
            this connection.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            4.5.";
       }
       leaf last-error-subcode {
         type uint8;
         description
           "The last NOTIFICATION Error subcode for the peer on
            this connection.";



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         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            4.5.";
       }
     }
     grouping bgp-errors-common-data {
       description
         "BGP NOTIFICATION data state that is common in the sent and
          received direction.";

       leaf last-error-data {
         type binary {
           length "0..65535";
         }
         description
           "Content of the BGP NOTIFICATION PDU's Data field.  This data
            is NOTIFICATION Error code / Error subcode specific.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            4.5.";
       }
     }

     grouping bgp-encapsulated-errors-common {
       description
         "BGP NOTIFICATION state that is common in the sent and received
          direction that has been encapsulated in a CEASE/HARD RESET
          NOTIFICATION.

          Note that these leaves are only present when carrying the RFC
          8538 encapsulated NOTIFICATION state. In this case,
          the last-error-data leaf will carry the encapsulated Data.";

       leaf last-encapsulated-error {
         type identityref {
           base bn:bgp-notification;
         }
         description
           "The last RFC 8538 encapsulated NOTIFICATION error for the
            peer on this connection.  If no identity is registered for
            the Error code / Error subcode, this leaf contains the most
            applicable identity for the BGP NOTIFICATION base code.

            The last-encapsulated-error-code and
            last-encapsulated-error-subcode will always have the
            encapsulated information received in the CEASE/HARD RESET
            NOTIFICATION PDU's encapsulated ErrCode and Subcode
            fields.";



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         reference
           "RFC 8538: Notification Message Support for BGP Graceful
            Restart, Section 3.1.";
       }
       leaf last-encapsulated-error-code {
         type uint8;
         description
           "The last RFC 8538 encapsulated NOTIFICATION Error code for
            the peer on this connection.";
         reference
           "RFC 8538: Notification Message Support for BGP Graceful
            Restart, Section 3.1.";
       }
       leaf last-encapsulated-error-subcode {
         type uint8;
         description
           "The last RFC 8538 encapsulated NOTIFICATION Error subcode
            for the peer on this connection.";
         reference
           "RFC 8538: Notification Message Support for BGP Graceful
            Restart, Section 3.1.";
       }
     }

     /*
      * Containers
      */

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol" {
       when "derived-from-or-self(rt:type, 'bgp')" {
         description
           "This augmentation is valid for a routing protocol
            instance of BGP.";
       }
       description
         "BGP protocol augmentation of ietf-routing module
          control-plane-protocol.";
       container bgp {
         description
           "Top-level configuration for the BGP router.";
         container global {
           presence "Enables global configuration of BGP";
           description
             "Global configuration for the BGP router.";
           leaf as {
             type inet:as-number;
             mandatory true;



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             description
               "Local autonomous system number of the router.  Uses
                the 32-bit as-number type from the model in RFC 6991.";
           }
           leaf identifier {
             type yang:dotted-quad;
             description
               "BGP Identifier of the router - an unsigned 32-bit,
                non-zero integer that should be unique within an AS.
                The value of the BGP Identifier for a BGP speaker is
                determined upon startup and is the same for every local
                interface and BGP peer.";
             reference
               "RFC 6286: AS-Wide Unique BGP ID for BGP-4. Section 2.1";
           }
           container distance {
             description
               "Administrative distances (or preferences) assigned to
                routes received from different sources (external, and
                internal).";
             leaf external {
               type uint8 {
                 range "1..255";
               }
               description
                 "Administrative distances for routes learned from
                  external BGP (eBGP).";
             }
             leaf internal {
               type uint8 {
                 range "1..255";
               }
               description
                 "Administrative distances for routes learned from
                  internal BGP (iBGP).";
             }
           }
           container confederation {
             description
               "Configuration options specifying parameters when the
                local router is within an autonomous system which is
                part of a BGP confederation.";
             leaf enabled {
               type boolean;
               description
                 "When this leaf is set to true it indicates that
                  the local-AS is part of a BGP confederation.";
             }



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             leaf identifier {
               type inet:as-number;
               description
                 "Confederation identifier for the autonomous system.";
             }
             leaf-list member-as {
               type inet:as-number;
               description
                 "Remote autonomous systems that are to be treated
                  as part of the local confederation.";
             }
           }
           container graceful-restart {
             if-feature "bt:graceful-restart";
             description
               "Parameters relating the graceful restart mechanism for
                BGP.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP.";
             uses graceful-restart-config;
           }
           uses global-group-use-multiple-paths;
           uses route-selection-options;
           container afi-safis {
             description
               "List of address-families associated with the BGP
                instance.";
             list afi-safi {
               key "name";
               description
                 "AFI,SAFI configuration available for the
                  neighbor or group.";
               uses mp-afi-safi-config;
               uses state;
               container graceful-restart {
                 if-feature "bt:graceful-restart";
                 description
                   "Parameters relating to BGP graceful-restart";
                 reference
                   "RFC 4724: Graceful Restart Mechanism for BGP.";
                 uses mp-afi-safi-graceful-restart-config;
               }
               uses route-selection-options;
               uses structure-add-paths;
               uses global-group-use-multiple-paths;
               uses mp-all-afi-safi-list-contents;
             }
           }



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           uses rt-pol:apply-policy-group;
           uses state;
         }

         container neighbors {
           description
             "Configuration for BGP neighbors.";

           list neighbor {
             key "remote-address";
             description
               "List of BGP neighbors configured on the local system,
                uniquely identified by remote IPv[46] address.";

             leaf remote-address {
               type inet:ip-address;
               description
                 "The remote IP address of this entry's BGP peer.";
             }

             leaf peer-group {
               type leafref {
                 path "../../../peer-groups/peer-group/name";
               }
               description
                 "The peer-group with which this neighbor is
                  associated.";
             }

             leaf local-address {
               type inet:ip-address;
               config false;
               description
                 "The local IP address of this entry's BGP connection.";
             }

             leaf local-port {
               type inet:port-number;
               config false;
               description
                 "The local port for the TCP connection between
                  the BGP peers.";
             }

             leaf remote-port {
               type inet:port-number;
               config false;
               description



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                 "The remote port for the TCP connection
                  between the BGP peers.  Note that the
                  objects local-addr, local-port, remote-addr, and
                  remote-port provide the appropriate
                  reference to the standard MIB TCP
                  connection table.";
             }

             leaf peer-type {
               type bt:peer-type;
               config false;
               description
                 "The type of peering session associated with this
                  neighbor.";
               reference
                 "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                            Section 1.1 for iBGP and eBGP.
                  RFC 5065: Autonomous System Configuration
                            for Confederation internal and external.";
             }

             leaf identifier {
               type yang:dotted-quad;
               config false;
               description
                 "The BGP Identifier of this entry's BGP peer.
                  This entry MUST be 0.0.0.0 unless the
                  session state is in the openconfirm or the
                  established state.";
               reference
                 "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                            Section 4.2, 'BGP Identifier'.";
             }

             leaf dynamically-configured {
               type empty;
               config false;
               description
                 "When present, this peer has been created
                 dynamically.";
             }

             leaf enabled {
               type boolean;
               default "true";
               description
                 "Whether the BGP peer is enabled. In cases where the
                  enabled leaf is set to false, the local system should



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                  not initiate connections to the neighbor, and should
                  not respond to TCP connections attempts from the
                  neighbor. If the state of the BGP session is
                  Established at the time that this leaf is set to
                  false, the BGP session should be ceased.

                  A transition from 'false' to 'true' will cause
                  the BGP Manual Start Event to be generated.
                  A transition from 'true' to 'false' will cause
                  the BGP Manual Stop Event to be generated.
                  This parameter can be used to restart BGP peer
                  connections. Care should be used in providing
                  write access to this object without adequate
                  authentication.";
               reference
                 "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                  Section 8.1.2.";
             }

             uses neighbor-group-config;

             container graceful-restart {
               if-feature "bt:graceful-restart";
               description
                 "Parameters relating the graceful restart mechanism for
                  BGP";
               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP.";
               uses graceful-restart-config;
               leaf peer-restart-time {
                 type uint16 {
                   range "0..4096";
                 }
                 config false;
                 description
                   "The period of time (advertised by the peer) that the
                    peer expects a restart of a BGP session to take.";
               }

               leaf peer-restarting {
                 type boolean;
                 config false;
                 description
                   "This flag indicates whether the remote neighbor is
                    currently in the process of restarting, and hence
                    received routes are currently stale.";
               }




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               leaf local-restarting {
                 type boolean;
                 config false;
                 description
                   "This flag indicates whether the local neighbor is
                    currently restarting. The flag is cleared after all
                    NLRI have been advertised to the peer, and the
                    End-of-RIB (EOR) marker has been cleared.";
               }

               leaf mode {
                 type enumeration {
                   enum helper-only {
                     description
                       "The local router is operating in helper-only
                        mode, and hence will not retain forwarding state
                        during a local session restart, but will do so
                        during a restart of the remote peer";
                   }
                   enum bilateral {
                     description
                       "The local router is operating in both helper
                        mode, and hence retains forwarding state during
                        a remote restart, and also maintains forwarding
                        state during local session restart";
                   }
                   enum remote-helper {
                     description
                       "The local system is able to retain routes during
                        restart but the remote system is only able to
                        act as a helper";
                   }
                 }
                 config false;
                 description
                   "This leaf indicates the mode of operation of BGP
                    graceful restart with the peer";
               }
             }

             container prefix-limit {
               description
                 "Parameters relating to the prefix limit for the
                  AFI-SAFI";

               uses prefix-limit-config-common;

               uses prefix-limit-state-common;



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             }

             container afi-safis {
               description
                 "Per-address-family configuration parameters associated
                  with the neighbor";
               uses bgp-neighbor-afi-safi-list;
             }

             leaf session-state {
               type enumeration {
                 enum idle {
                   description
                     "Neighbor is down, and in the Idle state of the
                      FSM.";
                 }
                 enum connect {
                   description
                     "Neighbor is down, and the session is waiting for
                      the underlying transport session to be
                      established.";
                 }
                 enum active {
                   description
                     "Neighbor is down, and the local system is awaiting
                      a connection from the remote peer.";
                 }
                 enum opensent {
                   description
                     "Neighbor is in the process of being established.
                      The local system has sent an OPEN message.";
                 }
                 enum openconfirm {
                   description
                     "Neighbor is in the process of being established.
                      The local system is awaiting a NOTIFICATION or
                      KEEPALIVE message.";
                 }
                 enum established {
                   description
                     "Neighbor is up - the BGP session with the peer is
                      established.";
                 }
               }
               //  notification does not like a non-config statement.
               //  config false;
               description
                 "The BGP peer connection state.";



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               reference
                 "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                  Section 8.1.2.";
             }
             leaf last-established {
               type yang:date-and-time;
               config false;
               description
                 "This timestamp indicates the time that the BGP session
                  last transitioned in or out of the Established state.
                  The value is the timestamp in seconds relative to the
                  Unix Epoch (Jan 1, 1970 00:00:00 UTC).

                  The BGP session uptime can be computed by clients as
                  the difference between this value and the current time
                  in UTC (assuming the session is in the Established
                  state, per the session-state leaf).";
               reference
                 "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                  Section 8.";
             }

             uses bgp-capabilities;

             container errors {
               config false;
               description
                 "Information about BGP NOTIFICATION messages, sent and
                  received for this neighbor.";

               container received {
                 description
                   "BGP NOTIFICATION message state received from this
                    neighbor.";
                 uses bgp-errors-common;
                 uses bgp-encapsulated-errors-common;
                 uses bgp-errors-common-data;
               }
               container sent {
                 description
                   "BGP NOTIFICATION message state sent to this
                    neighbor.";
                 uses bgp-errors-common;
                 uses bgp-encapsulated-errors-common;
                 uses bgp-errors-common-data;
               }
             }




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             container statistics {
               config false;
               description
                 "Statistics per neighbor.";

               leaf established-transitions {
                 type yang:zero-based-counter32;
                 description
                   "Number of transitions to the Established state for
                    the neighbor session. This value is analogous to the
                    bgpPeerFsmEstablishedTransitions object from the
                    standard BGP-4 MIB";
                 reference
                   "RFC 4273: Definitions of Managed Objects for
                    BGP-4, bgpPeerFsmEstablishedTransitions,
                    RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                    Section 8.";
               }
               container messages {
                 description
                   "Counters for BGP messages sent and received from the
                    neighbor";
                 leaf total-received {
                   type yang:zero-based-counter32;
                   description
                     "Total number of BGP messages received from this
                      neighbor";
                   reference
                     "RFC 4273: Definitions of Managed Objects for
                      BGP-4, bgpPeerInTotalMessages.";
                 }
                 leaf total-sent {
                   type yang:zero-based-counter32;
                   description
                     "Total number of BGP messages sent do this
                      neighbor";
                   reference
                     "RFC 4273: Definitions of Managed Objects for
                      BGP-4, bgpPeerOutTotalMessages.";
                 }
                 leaf updates-received {
                   type yang:zero-based-counter32;
                   description
                     "Number of BGP UPDATE messages received from this
                      neighbor.";
                   reference
                     "RFC 4273: Definitions of Managed Objects for
                      BGP-4, bgpPeerInUpdates.";



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                 }
                 leaf updates-sent {
                   type yang:zero-based-counter32;
                   description
                     "Number of BGP UPDATE messages sent to this
                      neighbor";
                   reference
                     "RFC 4273: Definitions of Managed Objects for
                      BGP-4, bgpPeerOutUpdates.";
                 }
                 leaf erroneous-updates-withdrawn {
                   type yang:zero-based-counter32;
                   config false;
                   description
                     "The number of BGP UPDATE messages for which the
                      treat-as-withdraw mechanism has been applied based
                      on erroneous message contents.";
                   reference
                     "RFC 7606: Revised Error Handling for BGP UPDATE
                      Messages, Section 2.";
                 }
                 leaf erroneous-updates-attribute-discarded {
                   type yang:zero-based-counter32;
                   config false;
                   description
                     "The number of BGP UPDATE messages for which the
                      attribute discard mechanism has been applied based
                      on erroneous message contents.";
                   reference
                     "RFC 7606: Revised Error Handling for BGP UPDATE
                      Messages, Section 2.";
                 }
                 leaf in-update-elapsed-time {
                   type yang:gauge32;
                   units "seconds";
                   description
                     "Elapsed time (in seconds) since the last BGP
                      UPDATE message was received from the peer.
                      Each time in-updates is incremented,
                      the value of this object is set to zero (0).";
                   reference
                     "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                      Section 4.3
                      RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                      Established state.";
                 }
                 leaf notifications-received {
                   type yang:zero-based-counter32;



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                   description
                     "Number of BGP NOTIFICATION messages indicating an
                      error condition has occurred exchanged received
                      from this peer.";
                   reference
                     "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                      Section 4.5.";
                 }
                 leaf notifications-sent {
                   type yang:zero-based-counter32;
                   description
                     "Number of BGP NOTIFICATION messages indicating an
                      error condition has occurred exchanged sent to
                      this peer.";
                   reference
                     "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                      Section 4.5.";
                 }
                 leaf route-refreshes-received {
                   type yang:zero-based-counter32;
                   description
                     "Number of BGP ROUTE-REFRESH messages received from
                      this peer.";
                   reference
                     "RFC 2918: Route Refresh Capability for BGP-4.";
                 }
                 leaf route-refreshes-sent {
                   type yang:zero-based-counter32;
                   description
                     "Number of BGP ROUTE-REFRESH messages sent to
                      this peer.";
                   reference
                     "RFC 2918: Route Refresh Capability for BGP-4.";
                 }
               }
               container queues {
                 description
                   "Counters related to queued messages associated with
                    the BGP neighbor";
                 leaf input {
                   type yang:gauge32;
                   description
                     "The number of messages received from the peer
                      currently queued";
                 }
                 leaf output {
                   type yang:gauge32;
                   description



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                     "The number of messages queued to be sent to the
                      peer";
                 }
               }
               action clear {
                 if-feature "bt:clear-statistics";
                 description
                   "Clear statistics action command.

                    Execution of this command should result in all the
                    counters to be cleared and set to 0.";

                 input {
                   leaf clear-at {
                     type yang:date-and-time;
                     description
                       "Time when the clear action needs to be
                        executed.";
                   }
                 }
                 output {
                   leaf clear-finished-at {
                     type yang:date-and-time;
                     description
                       "Time when the clear action command completed.";
                   }
                 }
               }
             }
           }

           notification established {
             leaf remote-address {
               type leafref {
                 path "../../neighbor/remote-address";
               }
               description
                 "IP address of the neighbor that went into established
                  state.";
             }
             description
               "The established event is generated
                when the BGP FSM enters the established state.";
           }

           notification backward-transition {
             leaf remote-addr {
               type leafref {



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                 path "../../neighbor/remote-address";
               }
               description
                 "IP address of the neighbor that changed its state from
                  established state.";
             }
             container notification-received {
               description
                 "If the backwards transition was caused by receiving a
                  BGP NOTIFICATION message, this is the information
                  received in the NOTIFICATION PDU.";

               uses bgp-errors-common;
               uses bgp-encapsulated-errors-common;
             }
             container notification-sent {
               description
                 "If the backwards transition was caused by sending a
                  BGP NOTIFICATION message, this is the information
                  sent in the NOTIFICATION PDU.";

               uses bgp-errors-common;
               uses bgp-encapsulated-errors-common;
             }
             description
               "The backward-transition event is
                generated when the BGP FSM moves from a higher
                numbered state to a lower numbered state.";
           }
           action clear {
             if-feature "bt:clear-neighbors";
             description
               "Clear neighbors action.";

             input {
               choice operation {
                 default operation-admin;
                 description
                   "The type of operation for the clear action.";
                 case operation-admin {
                   leaf admin {
                     type empty;
                     description
                       "Closes the Established BGP session with a BGP
                        NOTIFICATION message with the Administrative
                        Reset error subcode.";
                     reference
                       "RFC 4486 - Subcodes for BGP Cease Notification



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                        Message.";
                   }
                 }
                 case operation-hard {
                   leaf hard {
                     type empty;
                     description
                       "Closes the Established BGP session with a BGP
                        NOTIFICATION message with the Hard Reset error
                        subcode.";
                     reference
                       "RFC 8538, Section 3 - Notification Message
                        Support for BGP Graceful Restart.";
                   }
                 }
                 case operation-soft {
                   leaf soft {
                     type empty;
                     description
                       "Re-sends the current Adj-Rib-Out to this
                        neighbor.";
                   }
                 }
                 case operation-soft-inbound {
                   leaf soft-inbound {
                     if-feature "bt:route-refresh";
                     type empty;
                     description
                       "Requests the Adj-Rib-In for this neighbor to be
                        re-sent using the BGP Route Refresh feature.";
                   }
                 }
               }

               leaf clear-at {
                 type yang:date-and-time;
                 description
                   "Time when the clear action command needs to be
                    executed.";
               }
             }
             output {
               leaf clear-finished-at {
                 type yang:date-and-time;
                 description
                   "Time when the clear action command completed.";
               }
             }



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           }
         }

         container peer-groups {
           description
             "Configuration for BGP peer-groups";

           list peer-group {
             key "name";
             description
               "List of BGP peer-groups configured on the local system -
                uniquely identified by peer-group name";

             leaf name {
               type string;
               description
                 "Name of the BGP peer-group";
             }

             uses neighbor-group-config;
             uses structure-dynamic-peers;

             container graceful-restart {
               if-feature "bt:graceful-restart";
               description
                 "Parameters relating the graceful restart mechanism for
                  BGP";
               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP.";
               uses graceful-restart-config;
             }

             container prefix-limit {
               description
                 "Parameters relating to the prefix limit for the
                  AFI-SAFI";

               uses prefix-limit-config-common;
             }

             container afi-safis {
               description
                 "Per-address-family configuration parameters
                  associated with the peer-group.";
               list afi-safi {
                 key "name";
                 description
                   "AFI, SAFI configuration available for the



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                    neighbor or group";
                 reference
                   "RFC 4724: Graceful Restart Mechanism for BGP.";
                 uses mp-afi-safi-config;
                 container graceful-restart {
                   if-feature "bt:graceful-restart";
                   description
                     "Parameters relating to BGP graceful-restart";
                   uses mp-afi-safi-graceful-restart-config;
                 }
                 uses structure-add-paths;
                 uses bgp-neighbor-use-multiple-paths;
                 uses mp-all-afi-safi-list-contents;
               }
             }
           }
         }

         uses rib;
       }
     }
   }
   <CODE ENDS>

7.1.2.  BGP capabilities submodule

   <CODE BEGINS> file "ietf-bgp-capabilities@2023-07-05.yang"
   submodule ietf-bgp-capabilities {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";

     }
     import iana-routing-types {
       prefix iana-rt-types;
       reference
         "RFC 8294: Common YANG Data Types for the Routing Area.";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";



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     }

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com,
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This sub-module contains groupings that used for BGP
        Capabilities within the BGP module.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping bgp-capabilities-common {
       description
         "BGP Capabilities that are used commonly by the
          advertised-capabilities and received-capabilities lists in the



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          bgp-capabilities grouping.";

       leaf code {
         type uint8 {
           range 1..255;
         }
         description
           "BGP Capability Code";
         reference
           "RFC 5492: Capabilities Advertisement with BGP-4, Section
            4.";
       }
       leaf index {
         type uint8;
         description
           "Multiple BGP Capabilities with a given Capability Code may
            be advertised in a BGP OPEN message.  This index permits
            multiple such Capabilities to be represented in the YANG
            model.  It is RECOMMENDED that this index start at one (1)
            and increase by one for each additional instance of the
            Capability.";
         reference
           "RFC 5492: Capabilities Advertisement with BGP-4, Section
            4.";
       }
       leaf name {
         type identityref {
           base bt:bgp-capability;
         }
         description
           "When known, name carries the bgp-capability identity for the
            AFI/SAFI combination as used in the BGP YANG modules.";
       }

       container value {
         description
           "Some BGP Capabilities carry a Capability-specific Capability
            Value.";
         reference
           "RFC 5492: Capabilities Advertisement with BGP-4, Section
            4.";

         container mpbgp {
           when "../../name = 'bt:mp-bgp'";
           description
             "Multi-Protocol BGP-specific values.";
           reference
             "RFC 4760: Multiprotocol Extensions for BGP-4, Section 8.";



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           leaf afi {
             type iana-rt-types:address-family;
             description
              "Address Family Identifier carried in the Multiprotocol
               Extensions Capability.";
             reference
               "RFC 4760: Multiprotocol Extensions for BGP-4, Section
                8.";
           }
           leaf safi {
             type iana-rt-types:bgp-safi;
             description
              "Subsequent Address Family Identifier carried in the
               Multiprotocol Extensions Capability.";
             reference
               "RFC 4760: Multiprotocol Extensions for BGP-4, Section
                8.";
           }
           leaf name {
             type identityref {
               base bt:afi-safi-type;
             }
             description
               "When known, name carries the BGP AFI-SAFI identity for
                the AFI/SAFI combination as used in the BGP YANG
                modules.";
           }
         }

         container graceful-restart {
           when "../../name = 'bt:graceful-restart'";
           description
             "BGP Graceful Restart-specific values.";
           reference
             "RFC 4724: Graceful Restart Mechanism for BGP.";

           leaf flags {
             type bt:graceful-restart-flags;
             description
               "Restart Flags advertised by the Graceful Restart
                Capability";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }

           leaf unknown-flags {
             type bits {



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               bit unknown-2 {
                 position 2;
                 description
                   "Bit 2 was received but is currently RESERVED.";
               }
               bit unknown-3 {
                 position 3;
                 description
                   "Bit 3 was received but is currently RESERVED.";
               }
             }
             description
               "When a bit is exchanged in the Graceful Restart Flags
                field that is unknown to this module, their bit position
                is rendered using the associated unknown bit.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }

           leaf restart-time {
             type bt:graceful-restart-time-type;
             description
               "The period of time (advertised by the peer) that the
                peer expects a restart of a BGP session to take.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }

           list afi-safis {
             description
               "List of AFI/SAFIs advertised by the BGP Graceful Restart
                Capability and their AFI/SAFI-specific Flags.";
             leaf afi {
               type iana-rt-types:address-family;
               description
                 "Address Family advertised in the BGP Graceful Restart
                  Capability.";
               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP, Section
                  3.";
             }
             leaf safi {
               type iana-rt-types:bgp-safi;
               description
                 "Subsequent Address Family advertised in the BGP
                  Graceful Restart Capability.";



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               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP, Section
                  3.";
             }
             leaf afi-safi-flags {
               type bt:graceful-restart-flags-for-afi;
               description
                 "Flags for Address Family advertised per-AFI/SAFI in
                  the BGP Graceful Restart Capability.";
               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP, Section
                  3.";
             }
             leaf afi-safi-unknown-flags {
               type bits {
                 bit unknown-1 {
                   position 1;
                   description
                     "Bit 1 was received but is currently RESERVED.";
                 }
                 bit unknown-2 {
                   position 2;
                   description
                     "Bit 2 was received but is currently RESERVED.";
                 }
                 bit unknown-3 {
                   position 3;
                   description
                     "Bit 3 was received but is currently RESERVED.";
                 }
                 bit unknown-4 {
                   position 4;
                   description
                     "Bit 4 was received but is currently RESERVED.";
                 }
                 bit unknown-5 {
                   position 5;
                   description
                     "Bit 5 was received but is currently RESERVED.";
                 }
                 bit unknown-6 {
                   position 6;
                   description
                     "Bit 6 was received but is currently RESERVED.";
                 }
                 bit unknown-7 {
                   position 7;
                   description



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                     "Bit 7 was received but is currently RESERVED.";
                 }
               }
               description
                 "When a bit is exchanged in the Graceful Restart Flags
                  for Address Family field that is unknown to this
                  module, their bit position is rendered using the
                  associated unknown bit.";
               reference
                 "RFC 4724: Graceful Restart Mechanism for BGP, Section
                  3.";
             }
           }
         }

         container asn32 {
           when "../../name = 'bt:asn32'";
           description
             "Four-byte AS Number-specific values.";
           reference
             "RFC 6793: BGP Support for Four-Octet Autonomous System
              (AS) Number Space, Section 3.";

           leaf as {
             type inet:as-number;
             description
               "Four-byte AS Number carried by the Support for 4-octet
                AS number capability.";
             reference
               "RFC 6793: BGP Support for Four-Octet Autonomous System
                (AS) Number Space, Section 3.";
           }
         }

         container add-paths {
           when "../../name = 'bt:add-paths'";
           description
             "BGP add-paths-specific values.";
           reference
             "RFC 7911: Advertisement of Multiple Paths in BGP.";

           list afi-safis {
             description
               "List of AFI/SAFIs advertised by the BGP ADD-PATH
                Capability and their AFI/SAFI-specific mode.";
             leaf afi {
               type iana-rt-types:address-family;
               description



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                 "Address Family Identifier for an instance of the BGP
                  ADD-PATH Capability.";
               reference
                 "RFC 7911: Advertisement of Multiple Paths in BGP,
                  Section 4.";
             }
             leaf safi {
               type iana-rt-types:bgp-safi;
               description
                 "Subsequent Address Family Identifier for an instance
                  of the BGP ADD-PATH Capability.";
               reference
                 "RFC 7911: Advertisement of Multiple Paths in BGP,
                  Section 4.";
             }
             leaf mode {
               type enumeration {
                 enum receive {
                   value 1;
                   description
                     "The sender of the capability is able to receive
                      multiple paths from its peer.";
                   reference
                     "RFC 7911: Advertisement of Multiple Paths in BGP,
                      Section 4.";
                 }
                 enum send {
                   value 2;
                   description
                     "The sender of the capability is able to send
                      multiple paths to its peer.";
                   reference
                     "RFC 7911: Advertisement of Multiple Paths in BGP,
                      Section 4.";
                 }
                 enum receive-send {
                   value 3;
                   description
                     "The sender of the capability is able both receive
                      and send multiple paths for its peer.";
                   reference
                     "RFC 7911: Advertisement of Multiple Paths in BGP,
                      Section 4.";
                 }
               }
               description
                 "Send/Receive value for a per-AFI/SAFI instance of the
                  ADD-PATH Capability.";



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               reference
                 "RFC 7911: Advertisement of Multiple Paths in BGP,
                  Section 4.";
             }
           }
         }
       }
     }

     grouping bgp-capabilities {
       description
         "Structural grouping used to include BGP Capabiliites for BGP
          neghbors.";

       container capabilities {
         config false;
         description
           "BGP Capabilities per-neighbor.";
         reference
           "RFC 5492: Capabilities Advertisement with BGP-4.";

         list advertised-capabilities {
           key "code index";
           description
             "List of advertised BGP capabilities, per-peer.
              Identified by the Capability Code and an index.  The
              index covers the case where the same BGP Capability
              may be advertised more than once.";

           uses bgp-capabilities-common;
         }

         list received-capabilities {
           key "code index";
           description
             "List of received BGP capabilities, per-peer.
              Identified by the Capability Code and an index.  The
              index covers the case where the same BGP Capability
              may be advertised more than once.";

           uses bgp-capabilities-common;
         }

         leaf-list negotiated-capabilities {
           type identityref {
             base bt:bgp-capability;
           }
           description



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             "Negotiated BGP capabilities.";
         }
       }
     }
   }
   <CODE ENDS>

7.1.3.  BGP common submodule

   <CODE BEGINS> file "ietf-bgp-common@2023-07-05.yang"
   submodule ietf-bgp-common {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import iana-bgp-community-types {
       prefix bct;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import ietf-interfaces {
       prefix if;
       reference
         "RFC 7223: A YANG Data Model for Interface Management.";
     }
     import ietf-key-chain {
       prefix key-chain;
       reference
         "RFC 8177: YANG Data Model for Key Chains.";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }
     import ietf-routing-policy {
       prefix rt-pol;
       reference
         "RFC 9067: A YANG Data Model for Routing Policy.";
     }
     import ietf-yang-types {
       prefix yang;



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       reference
         "RFC 6991: Common YANG Data Types.";
     }
     import ietf-bfd-types {
       prefix bfd-types;
       reference
         "RFC 9127: YANG Data Model for Bidirectional Forward
          Detection.";
     }
     import ietf-tcp {
       prefix tcp;
       reference
         "I-D.ietf-tcpm-yang-tcp: Transmission Control Protocol (TCP)
          YANG Model.";
     }
     include ietf-bgp-common-structure {
       revision-date 2023-07-05;
     }

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com,
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This sub-module contains common groupings that are common across
        multiple contexts within the BGP module. That is to say that
        they may be application to a subset of global, peer-group, or
        neighbor contexts.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself



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        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping neighbor-group-timers {
       description
         "Config parameters related to timers associated with the BGP
          peer";
       leaf connect-retry-interval {
         type uint16 {
           range "1..max";
         }
         units "seconds";
         default "120";
         description
           "Time interval (in seconds) for the ConnectRetryTimer. The
            suggested value for this timer is 120 seconds.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
            Section 8.2.2.";
       }
       leaf hold-time {
         type uint16 {
           range "0 | 3..65535";
         }
         units "seconds";
         default "90";
         description
           "Time interval (in seconds) for the HoldTimer established
            with the peer.  When read as operational data (ro), the
            value of this object is calculated by this BGP speaker,
            using the smaller of the values in hold-time that was
            configured (rw) in the running datastore and the Hold Time
            received in the OPEN message.

            This value must be at least three seconds
            if it is not zero (0).



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            If the Hold Timer has not been established
            with the peer this object MUST have a value
            of zero (0).

            If the configured value of hold-time object was
            a value of (0), then when read this object MUST have a
            value of (0) also.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.2,
            RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 10.";
       }
       leaf negotiated-hold-time {
         type uint16;
         config false;
         description
           "The negotiated hold-time for the BGP session";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.2,
            RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 10.";
       }
       leaf keepalive {
         type uint16 {
           range "0..21845";
         }
         units "seconds";
         description
           "When used as a configuration (rw) value, this Time interval
            (in seconds) for the KeepAlive timer configured for this BGP
            speaker with this peer.  A reasonable maximum value for this
            timer would be one-third of the configured hold-time.

            In the absence of explicit configuration of the keepalive
            value, operationally it SHOULD have a value of one-third of
            the negotiated hold-time.

            If the value of this object is zero (0), no periodic
            KEEPALIVE messages are sent to the peer after the BGP
            connection has been established.

            The actual time interval for the KEEPALIVE messages is
            indicated by operational value of keepalive.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.4,
            RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 10.";
       }
       leaf min-as-origination-interval {
         type uint16 {
           range "0..max";



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         }
         units "seconds";
         description
           "Time interval (in seconds) for the MinASOriginationInterval
            timer. The suggested value for this timer is 15 seconds.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            9.2.1.2,
            RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 10.";
       }
       leaf min-route-advertisement-interval {
         type uint16 {
           range "0..max";
         }
         units "seconds";
         description
           "Time interval (in seconds) for the
            MinRouteAdvertisementInterval timer.
            The suggested value for this timer is 30
            seconds for EBGP connections and 5
            seconds for IBGP connections.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
            9.2.1.1,
            RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 10.";
       }
     }

     grouping bgp-neighbor-use-multiple-paths {
       description
         "Multi-path configuration and state applicable to a BGP
          neighbor";
       container use-multiple-paths {
         description
           "Parameters related to the use of multiple-paths for the same
            NLRI when they are received only from this neighbor";
         leaf enabled {
           type boolean;
           default "false";
           description
             "Whether the use of multiple paths for the same NLRI is
              enabled for the neighbor.";
         }
         container ebgp {
           description
             "Multi-path configuration for eBGP";
           leaf allow-multiple-as {
             type boolean;



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             default "false";
             description
               "Allow multi-path to use paths from different neighboring
                ASes. The default is to only consider multiple paths
                from the same neighboring AS.";
           }
         }
       }
     }

     grouping neighbor-group-config {
       description
         "Neighbor level configuration items.";
       leaf peer-as {
         type inet:as-number;
         description
           "AS number of the peer.";
       }
       leaf local-as {
         type inet:as-number;
         description
           "The local autonomous system number that is to be used when
            establishing sessions with the remote peer or peer group, if
            this differs from the global BGP router autonomous system
            number.";
       }
       leaf remove-private-as {
         type bt:remove-private-as-option;
         description
           "When this leaf is specified, remove private AS numbers from
            updates sent to peers.";
       }
       container route-flap-damping {
         if-feature "bt:damping";
         leaf enable {
           type boolean;
           default "false";
           description
             "Enable route flap damping.";
         }
         leaf suppress-above {
           type decimal64 {
             fraction-digits 1;
           }
           default "3.0";
           description
             "This is the value of the instability metric at which
              route suppression takes place. A route is not installed



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              in the forwarding information base (FIB), or announced
              even if it is reachable during the period that it is
              suppressed.";
         }
         leaf reuse-above {
           type decimal64 {
             fraction-digits 1;
           }
           default "2.0";
           description
             "This is the value of the instability metric at which a
              suppressed route becomes unsuppressed if it is reachable
              but currently suppressed. The value assigned to
              reuse-below must be less than suppress-above.";
         }
         leaf max-flap {
           type decimal64 {
             fraction-digits 1;
           }
           default "16.0";
           description
             "This is the upper limit of the instability metric. This
              value must be greater than the larger of 1 and
              suppress-above.";
         }
         leaf reach-decay {
           type uint32;
           units "seconds";
           default "300";
           description
             "This value specifies the time desired for the instability
              metric value to reach one-half of its current value when
              the route is reachable. This half-life value determines
              the rate at which the metric value is decayed. A smaller
              half-life value makes a suppressed route reusable sooner
              than a larger value.";
         }
         leaf unreach-decay {
           type uint32;
           units "seconds";
           default "900";
           description
             "This value acts the same as reach-decay except that it
              specifies the rate at which the instability metric is
              decayed when a route is unreachable. It should have a
              value greater than or equal to reach-decay.";
         }
         leaf keep-history {



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           type uint32;
           units "seconds";
           default "1800";
           description
             "This value specifies the period over which the route
              flapping history is to be maintained for a given route.
              The size of the configuration arrays described below is
              directly affected by this value.";
         }
         description
           "Routes learned via BGP are subject to weighted route
            dampening.";
       }
       leaf-list send-community {
         if-feature "bct:send-communities";
         type identityref {
           base "bct:send-community-feature";
         }
         description
           "When supported, this tells the router to propagate any
            prefixes that are attached to these community-types.";
       }
       leaf description {
         type string;
         description
           "An optional textual description (intended primarily for use
            with a peer or group";
       }

       container timers {
         description
           "Timers related to a BGP neighbor";
         uses neighbor-group-timers;
       }

       container transport {
         description
           "Transport session parameters for the BGP neighbor";
         uses neighbor-group-transport-config;
       }

       leaf treat-as-withdraw {
         type boolean;
         default "false";
         description
           "Specify whether erroneous UPDATE messages for which the NLRI
            can be extracted are treated as though the NLRI is withdrawn
            - avoiding session reset";



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         reference
           "RFC 7606: Revised Error Handling for BGP UPDATE Messages.";
       }

       container logging-options {
         description
           "Logging options for events related to the BGP neighbor or
            group";
         leaf log-neighbor-state-changes {
           type boolean;
           default "true";
           description
             "Configure logging of peer state changes.  Default is to
              enable logging of peer state changes.

              Note: Documenting demotion from ESTABLISHED state is
                    desirable, but documenting all backward transitions
                    is problematic, and should be avoided.";
         }
       }

       uses structure-neighbor-group-route-reflector;
       uses structure-neighbor-group-as-path-options;
       uses structure-add-paths;
       uses bgp-neighbor-use-multiple-paths;
       uses rt-pol:apply-policy-group;
     }

     grouping neighbor-group-transport-config {
       description
         "Configuration parameters relating to the transport protocol
          used by the BGP session to the peer.";

       leaf local-address {
         type union {
           type inet:ip-address;
           type if:interface-ref;
         }
         description
           "Set the local IP (either IPv4 or IPv6) address to use for
            the session when sending BGP update messages. This may be
            expressed as either an IP address or reference to the name
            of an interface.";
       }

       leaf tcp-mss {
         type tcp:mss;
         description



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           "Maximum Segment Size (MSS) desired on this connection.
            Note, the 'effective send MSS' can be smaller than
            what is configured here.";
          reference
            "RFC 9293: Transmission Control Protocol (TCP)
                       Specification.";
       }

       leaf mtu-discovery {
         type boolean;
         default "true";
         description
           "Turns path mtu discovery for BGP TCP sessions on (true) or
            off (false).";
         reference
           "RFC 1191: Path MTU discovery.";
       }

       container ebgp-multihop {
         description
           "eBGP multi-hop parameters for the BGP peer-group";
         leaf enabled {
           type boolean;
           default "false";
           description
             "When enabled, the referenced group or neighbors are
              permitted to be indirectly connected - including cases
              where the TTL can be decremented between the BGP peers";
         }
         leaf multihop-ttl {
           type uint8;
           description
             "Time-to-live value to use when packets are sent to the
              referenced group or neighbors and ebgp-multihop is
              enabled";
         }
       }

       leaf passive-mode {
         type boolean;
         default "false";
         description
           "Wait for peers to issue requests to open a BGP session,
            rather than initiating sessions from the local router.";
       }

       leaf ttl-security {
         if-feature "bt:ttl-security";



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         type uint8;
         default "255";
         description
           "BGP Time To Live (TTL) security check.";
         reference
           "RFC 5082: The Generalized TTL Security Mechanism (GTSM),
            RFC 7454: BGP Operations and Security.";
       }

       container secure-session {
         must "enabled = 'false' or " +
              "(enabled = 'true' and options)" {
           error-message "When secure-session is enabled " +
             "secure-session options MUST be set";
         }
         description
           "Container for describing how a particular BGP session
            is to be secured.";

         leaf enabled {
           type boolean;
           default "false";
           description
             "When set to true, session is secured with the
              configured options.";
         }

         container options {
           description
             "Options for securing the BGP session.";
           choice option {
             case ao {
               leaf ao-keychain {
                 type key-chain:key-chain-ref;
                 description
                   "Reference to the key chain that will be used by this
                    model. Applicable for TCP-AO and TCP-MD5 only";
                 reference
                   "RFC 8177: YANG Data Model for Key Chains.";
               }
               description
                 "Uses TCP-AO to secure the session. Parameters for
                  those are defined as a grouping in the TCP YANG
                  model.";
               reference
                 "RFC 5925: The TCP Authentication Option.";
             }




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             case md5 {
               leaf md5-keychain {
                 type key-chain:key-chain-ref;
                 description
                   "Reference to the key chain that will be used by this
                    model. Applicable for TCP-AO and TCP-MD5 only";
                 reference
                   "RFC 8177: YANG Data Model for Key Chains.";
               }
               description
                 "Uses TCP-MD5 to secure the session. Parameters for
                  those are defined as a grouping in the TCP YANG
                  model.";
               reference
                 "RFC 5925: The TCP Authentication Option.";
             }

             case ipsec {
               leaf sa {
                 type string;
                 description
                   "Security Association (SA) name.";
               }
               description
                 "Currently, the IPsec/IKE YANG model has no
                  grouping defined that this model can use. When
                  such a grouping is defined, this model can import
                  the grouping to add the key parameters
                  needed to kick of IKE.";
             }

             description
               "Choice of authentication options.";
           }
         }
       }

       container bfd {
         if-feature "bt:bfd";
         uses bfd-types:client-cfg-parms;
         description
           "BFD client configuration.";
         reference
           "RFC 9127: YANG Data Model for Bidirectional Forwarding
            Detection.";
       }
     }




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     grouping graceful-restart-config {
       description
         "Configuration parameters relating to BGP graceful restart.";
       leaf enabled {
         type boolean;
         default "false";
         description
           "Enable or disable the graceful-restart capability.";
       }
       leaf restart-time {
         type bt:graceful-restart-time-type;
         description
           "Estimated time (in seconds) for the local BGP speaker to
            restart a session. This value is advertise in the graceful
            restart BGP capability.  This is a 12-bit value, referred to
            as Restart Time in RFC4724.  Per RFC4724, the suggested
            default value is <= the hold-time value.";
         reference
           "RFC 4724: Graceful Restart Mechanism for BGP.";
       }
       leaf stale-routes-time {
         type uint32;
         description
           "An upper-bound on the time that stale routes will be
            retained by a router after a session is restarted. If an
            End-of-RIB (EOR) marker is received prior to this timer
            expiring, stale-routes will be flushed upon its receipt - if
            no EOR is received, then when this timer expires stale paths
            will be purged. This timer is referred to as the
            Selection_Deferral_Timer in RFC4724";
         reference
           "RFC 4724: Graceful Restart Mechanism for BGP.";
       }
       leaf helper-only {
         type boolean;
         default "true";
         description
           "Enable graceful-restart in helper mode only. When this leaf
            is set, the local system does not retain forwarding its own
            state during a restart, but supports procedures for the
            receiving speaker, as defined in RFC4724.";
         reference
           "RFC 4724: Graceful Restart Mechanism for BGP.";
       }
     }

     grouping global-group-use-multiple-paths {
       description



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         "Common grouping used for both global and groups which provides
          configuration and state parameters relating to use of multiple
          paths";
       container use-multiple-paths {
         description
           "Parameters related to the use of multiple paths for the
            same NLRI";
         leaf enabled {
           type boolean;
           default "false";
           description
             "Whether the use of multiple paths for the same NLRI is
              enabled for the neighbor. This value is overridden by any
              more specific configuration value.";
         }
         container ebgp {
           description
             "Multi-Path parameters for eBGP";
           leaf allow-multiple-as {
             type boolean;
             default "false";
             description
               "Allow multi-path to use paths from different neighboring
                ASes.  The default is to only consider multiple paths
                from the same neighboring AS.";
           }
           leaf maximum-paths {
             type uint32;
             default "1";
             description
               "Maximum number of parallel paths to consider when using
                BGP multi-path. The default is use a single path.";
           }
         }
         container ibgp {
           description
             "Multi-Path parameters for iBGP";
           leaf maximum-paths {
             type uint32;
             default "1";
             description
               "Maximum number of parallel paths to consider when using
                iBGP multi-path. The default is to use a single path";
           }
         }
       }
     }




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     grouping route-selection-options {
       description
         "Configuration and state relating to route selection options";
       container route-selection-options {
         description
           "Parameters relating to options for route selection";
         leaf always-compare-med {
           type boolean;
           default "false";
           description
             "Compare multi-exit discriminator (MED) value from
              different ASes when selecting the best route.  The default
              behavior is to only compare MEDs for paths received from
              the same AS.";
         }
         leaf ignore-as-path-length {
           type boolean;
           default "false";
           description
             "Ignore the AS path length when selecting the best path.
              The default is to use the AS path length and prefer paths
              with a shorter length.";
         }
         leaf external-compare-router-id {
           type boolean;
           default "true";
           description
             "When comparing similar routes received from external BGP
              peers, use the router-id as a criterion to select the
              active path.";
         }
         leaf advertise-inactive-routes {
           type boolean;
           default "false";
           description
             "Advertise inactive routes to external peers.  The default
              is to only advertise active routes.";
           reference
             "I-D.ietf-idr-best-external: Advertisement of the best
              external route in BGP.";
         }
         leaf enable-aigp {
           type boolean;
           default "false";
           description
             "Flag to enable sending / receiving accumulated IGP
              attribute in routing updates";
           reference



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             "RFC 7311: AIGP Metric Attribute for BGP.";
         }
         leaf ignore-next-hop-igp-metric {
           type boolean;
           default "false";
           description
             "Ignore the IGP metric to the next-hop when calculating BGP
              best-path. The default is to select the route for which
              the metric to the next-hop is lowest";
         }
         leaf enable-med {
           type boolean;
           default "false";
           description
             "Flag to enable sending/receiving of MED metric attribute
              in routing updates.";
         }
         container med-plus-igp {
           leaf enabled {
             type boolean;
             default "false";
             description
               "When enabled allows BGP to use MED and IGP values
                defined below to determine the optimal route.";
             reference
               "RFC 4451: BGP MED Considerations.";
           }
           leaf igp-multiplier {
             type uint16;
             default 1;
             description
               "Specifies an IGP cost multiplier.";
             reference
               "RFC 4451: BGP MED Considerations.";
           }
           leaf med-multiplier {
             type uint16;
             default 1;
             description
               "Specifies a MED multiplier.";
             reference
               "RFC 4451: BGP MED Considerations.";
           }
           description
             "The med-plus-igp option enables BGP to use the sum of
              MED multiplied by a MED multiplier and IGP cost multiplied
              by IGP cost multiplier to select routes when MED is
              required to determine the optimal route.";



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         }
       }
     }

     grouping state {
       description
         "Grouping containing common counters relating to prefixes and
          paths";

       container statistics {
         config false;
         description
           "Global level statistics.";

         leaf total-paths {
           type yang:gauge32;
           description
             "Total number of BGP paths (BGP routes) within the
              context";
         }

         leaf total-prefixes {
           type yang:gauge32;
           description
             "Total number of BGP prefixes (destinations) received
              within the context";
         }
       }
     }
   }
   <CODE ENDS>

7.1.4.  BGP common multiprotocol submodule

   <CODE BEGINS> file "ietf-bgp-common-multiprotocol@2023-07-05.yang"
   submodule ietf-bgp-common-multiprotocol {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import iana-bgp-types {
       prefix bt;
     }
     import ietf-routing-types {
       prefix rt-types;
       reference
         "RFC 8294: Common YANG Data Types for the Routing Area.";



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     }
     import ietf-routing-policy {
       prefix rt-pol;
     }

     // meta

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This sub-module contains groupings that are related to support
        for multiple protocols in BGP. The groupings are common across
        multiple contexts.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";



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     }

     grouping prefix-limit-config-common {
       description
         "Common configuration for prefix-limit feature.";

       leaf max-prefixes {
         type uint32;
         description
           "Maximum number of prefixes that will be accepted from the
            neighbor";
       }
       leaf warning-threshold-pct {
         type rt-types:percentage;
         description
           "Threshold on number of prefixes that can be received from
            a neighbor before generation of warning messages or log
            entries. Expressed as a percentage of max-prefixes";
       }
       leaf teardown {
         type boolean;
         default false;
         description
           "When 'true', tear down the BGP session when the maximum
            prefix limit is exceeded.  When 'false', only log a
            warning when the maximum prefix limit is exceeded.";
       }
       leaf idle-time {
         type union {
           type uint32;
           type enumeration {
             enum forever {
               description
                 "Idle the peer until manually reset.";
             }
           }
         }
         units "seconds";
         description
           "Time interval in seconds after which the BGP session is
            re-established after being torn down due to exceeding the
            max-prefix limit.";
       }
     }

     grouping prefix-limit-state-common {
       description
         "Common operational state for prefix-limit feature.";



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       leaf prefix-limit-exceeded {
         type boolean;
         config false;
         description
           "'true' when the prefix-limit has been exceeded for this
            scope.";
       }
     }


     grouping mp-afi-safi-graceful-restart-config {
       description
         "BGP graceful restart parameters that apply on a per-AFI-SAFI
          basis";
       leaf enabled {
         type boolean;
         must ". = ../../../../graceful-restart/enabled";
         default "false";
         description
           "This leaf indicates whether graceful-restart is enabled for
            this AFI-SAFI.";
         reference
           "RFC 4724: Graceful Restart Mechanism for BGP.";
       }
     }

     grouping mp-afi-safi-config {
       description
         "Configuration parameters used for all BGP AFI-SAFIs";
       leaf name {
         type identityref {
           base bt:afi-safi-type;
         }
         description
           "AFI,SAFI";
       }
       leaf enabled {
         type boolean;
         default "false";
         description
           "This leaf indicates whether this AFI,SAFI is enabled for
            the neighbor or group";
       }
     }

     grouping mp-all-afi-safi-list-contents {
       description
         "A common grouping used for contents of the list that is used



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          for AFI-SAFI entries";
       // import and export policy included for the afi/safi
       uses rt-pol:apply-policy-group;
       container ipv4-unicast {
         when "../name = 'bt:ipv4-unicast'" {
           description
             "Include this container for IPv4 Unicast specific
              configuration";
         }
         description
           "IPv4 unicast configuration options";
         // include common IPv[46] unicast options
         uses mp-ipv4-ipv6-unicast-common;
         // placeholder for IPv4 unicast specific configuration
       }
       container ipv6-unicast {
         when "../name = 'bt:ipv6-unicast'" {
           description
             "Include this container for IPv6 Unicast specific
              configuration";
         }
         description
           "IPv6 unicast configuration options";
         // include common IPv[46] unicast options
         uses mp-ipv4-ipv6-unicast-common;
         // placeholder for IPv6 unicast specific configuration
         // options
       }
       container ipv4-labeled-unicast {
         when "../name = 'bt:ipv4-labeled-unicast'" {
           description
             "Include this container for IPv4 Labeled Unicast specific
              configuration";
         }
         description
           "IPv4 Labeled Unicast configuration options";
         uses mp-all-afi-safi-common;
         // placeholder for IPv4 Labeled Unicast specific config
         // options
       }
       container ipv6-labeled-unicast {
         when "../name = 'bt:ipv6-labeled-unicast'" {
           description
             "Include this container for IPv6 Labeled Unicast specific
              configuration";
         }
         description
           "IPv6 Labeled Unicast configuration options";



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         uses mp-all-afi-safi-common;
         // placeholder for IPv6 Labeled Unicast specific config
         // options.
       }
       container l3vpn-ipv4-unicast {
         when "../name = 'bt:l3vpn-ipv4-unicast'" {
           description
             "Include this container for IPv4 Unicast L3VPN specific
              configuration";
         }
         description
           "Unicast IPv4 L3VPN configuration options";
         // include common L3VPN configuration options
         uses mp-l3vpn-ipv4-ipv6-unicast-common;
         // placeholder for IPv4 Unicast L3VPN specific config options.
       }
       container l3vpn-ipv6-unicast {
         when "../name = 'bt:l3vpn-ipv6-unicast'" {
           description
             "Include this container for unicast IPv6 L3VPN specific
              configuration";
         }
         description
           "Unicast IPv6 L3VPN configuration options";
         // include common L3VPN configuration options
         uses mp-l3vpn-ipv4-ipv6-unicast-common;
         // placeholder for IPv6 Unicast L3VPN specific configuration
         // options
       }
       container l3vpn-ipv4-multicast {
         when "../name = 'bt:l3vpn-ipv4-multicast'" {
           description
             "Include this container for multicast IPv6 L3VPN specific
              configuration";
         }
         description
           "Multicast IPv4 L3VPN configuration options";
         // include common L3VPN multicast options
         uses mp-l3vpn-ipv4-ipv6-multicast-common;
         // placeholder for IPv4 Multicast L3VPN specific configuration
         // options
       }
       container l3vpn-ipv6-multicast {
         when "../name = 'bt:l3vpn-ipv6-multicast'" {
           description
             "Include this container for multicast IPv6 L3VPN specific
              configuration";
         }



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         description
           "Multicast IPv6 L3VPN configuration options";
         // include common L3VPN multicast options
         uses mp-l3vpn-ipv4-ipv6-multicast-common;
         // placeholder for IPv6 Multicast L3VPN specific configuration
         // options
       }
       container l2vpn-vpls {
         when "../name = 'bt:l2vpn-vpls'" {
           description
             "Include this container for BGP-signalled VPLS specific
              configuration";
         }
         description
           "BGP-signalled VPLS configuration options";
         // include common L2VPN options
         uses mp-l2vpn-common;
         // placeholder for BGP-signalled VPLS specific configuration
         // options
       }
       container l2vpn-evpn {
         when "../name = 'bt:l2vpn-evpn'" {
           description
             "Include this container for BGP EVPN specific
              configuration";
         }
         description
           "BGP EVPN configuration options";
         // include common L2VPN options
         uses mp-l2vpn-common;
         // placeholder for BGP EVPN specific configuration options
       }
     }

     // Common groupings across multiple AFI,SAFIs

     grouping mp-all-afi-safi-common {
       description
         "Grouping for configuration common to all AFI,SAFI";
       container prefix-limit {
         description
           "Parameters relating to the prefix limit for the AFI-SAFI";

         uses prefix-limit-config-common;

         uses prefix-limit-state-common;
       }
     }



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     grouping mp-ipv4-ipv6-unicast-common {
       description
         "Common configuration that is applicable for IPv4 and IPv6
          unicast";
       // include common afi-safi options.
       uses mp-all-afi-safi-common;
       // configuration options that are specific to IPv[46] unicast
       leaf send-default-route {
         type boolean;
         default "false";
         description
           "If set to true, send the default-route to the neighbor(s)";
       }
     }

     grouping mp-l3vpn-ipv4-ipv6-unicast-common {
       description
         "Common configuration applied across L3VPN for IPv4
          and IPv6";
       // placeholder -- specific configuration options that are generic
       // across IPv[46] unicast address families.
       uses mp-all-afi-safi-common;
     }

     grouping mp-l3vpn-ipv4-ipv6-multicast-common {
       description
         "Common configuration applied across L3VPN for IPv4
          and IPv6";
       // placeholder -- specific configuration options that are
       // generic across IPv[46] multicast address families.
       uses mp-all-afi-safi-common;
     }

     grouping mp-l2vpn-common {
       description
         "Common configuration applied across L2VPN address
          families";
       // placeholder -- specific configuration options that are
       // generic across L2VPN address families
       uses mp-all-afi-safi-common;
     }

     // Config groupings for common groups

     grouping mp-all-afi-safi-common-prefix-limit-config {
       description
         "Configuration parameters relating to prefix-limits for an
          AFI-SAFI";



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     }
   }
   <CODE ENDS>

7.1.5.  BGP common structure submodule

   <CODE BEGINS> file "ietf-bgp-common-structure@2023-07-05.yang"
   submodule ietf-bgp-common-structure {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import ietf-routing-policy {
       prefix rt-pol;
       reference
         "RFC 9067: A YANG Data Model for Routing Policy Management.";
     }
     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }
     include ietf-bgp-common-multiprotocol;

     // meta

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This sub-module contains groupings that are common across
        multiple BGP contexts and provide structure around other
        primitive groupings.




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        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping structure-neighbor-group-route-reflector {
       description
         "Structural grouping used to include route reflector
          configuration and state for both BGP neighbors and peer
          groups";
       container route-reflector {
         description
           "Route reflector parameters for the BGP peer-group";
         reference
           "RFC 4456: BGP Route Reflection.";
         leaf cluster-id {
           type bt:rr-cluster-id-type;
           description
             "Route Reflector cluster id to use when local router is
              configured as a route reflector.  Commonly set at the
              group level, but allows a different cluster id to be set
              for each neighbor.";
           reference
             "RFC 4456: BGP Route Reflection: An Alternative to
                        Full Mesh.";
         }



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         leaf client {
           type boolean;
           default "false";
           description
             "Configure the neighbor as a route reflector client.";
           reference
             "RFC 4456: BGP Route Reflection: An Alternative to
                        Full Mesh.";
         }
       }
     }

     grouping structure-neighbor-group-as-path-options {
       description
         "Structural grouping used to include AS_PATH manipulation
          configuration and state for both BGP neighbors and peer
          groups";
       container as-path-options {
         description
           "AS_PATH manipulation parameters for the BGP neighbor or
            group";
         leaf allow-own-as {
           type uint8;
           default "0";
           description
             "Specify the number of occurrences of the local BGP
              speaker's AS that can occur within the AS_PATH before it
              is rejected as looped.";
         }
         leaf replace-peer-as {
           type boolean;
           default "false";
           description
             "Replace occurrences of the peer's AS in the AS_PATH with
              the local autonomous system number";
         }
         leaf disable-peer-as-filter {
           type boolean;
           default "false";
           description
             "When set to true, the system advertises routes to a peer
              even if the peer's AS was in the AS path.  The default
              behavior (false) suppresses advertisements to peers if
              their AS number is in the AS path of the route.";
         }
       }
     }




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     grouping structure-add-paths {
       description
         "Structural grouping used to include ADD-PATHs configuration
          and state.";
       container add-paths {
         if-feature "bt:add-paths";
         description
           "Parameters relating to the advertisement and receipt of
            multiple paths for a single NLRI (add-paths)";
         reference
           "RFC 7911: Advertisements of Multiple Paths in BGP.";
         leaf receive {
           type boolean;
           default "false";
           description
             "Enable ability to receive multiple path advertisements for
              an NLRI from the neighbor or group";
         }
         choice send {
           description
             "Choice of sending the max. number of paths or to send
              all.";
           case max {
             leaf max {
               type uint8;
               description
                 "The maximum number of paths to advertise to neighbors
                  for a single NLRI";
             }
           }
           case all {
             leaf all {
               type empty;
               description
                 "Send all the path advertisements to neighbors for a
                  single NLRI.";
             }
           }
         }
         leaf eligible-prefix-policy {
           type leafref {
             path "/rt-pol:routing-policy/rt-pol:policy-definitions/"
                + "rt-pol:policy-definition/rt-pol:name";
           }
           description
             "A reference to a routing policy which can be used to
              restrict the prefixes for which add-paths is enabled";
         }



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       }
     }

     grouping structure-dynamic-peers {
       description
         "Structural grouping to contain dyamic BGP peers. Dynamic
          peers are configured from a list of IP prefixes matching the
          IP source address of the dynamic peer.";

       container dynamic-peers {
         description
           "Configuration and operational state for dynamically
            configured peers.";

         list dynamic-peer-list {
           key "prefix";
           description
             "List of peers by IP prefix for this configuration scope
              that are dynamically configured.";

           leaf prefix {
             type inet:ip-prefix;
             description
               "Prefix for dynamic peer at this configuration scope.";
           }
         }
       }
     }
   }
   <CODE ENDS>

7.1.6.  BGP neighbors submodule

   <CODE BEGINS> file "ietf-bgp-neighbor@2023-07-05.yang"
   submodule ietf-bgp-neighbor {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types.";
     }

     import iana-bgp-types {
       prefix bt;



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       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     // Include the common submodule

     include ietf-bgp-common;
     include ietf-bgp-common-multiprotocol;
     include ietf-bgp-common-structure;

     // meta

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This sub-module contains groupings that are specific to the
        neighbor context of the BGP module.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {



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       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping bgp-neighbor-afi-safi-list {
       description
         "List of address-families associated with the BGP neighbor";
       list afi-safi {
         key "name";
         description
           "AFI, SAFI configuration available for the neighbor or
            group";
         uses mp-afi-safi-config;
         leaf active {
           type boolean;
           config false;
           description
             "This value indicates whether a particular AFI-SAFI has
              been successfully negotiated with the peer. An AFI-SAFI
              may be enabled in the current running configuration, but
              a session restart may be required in order to negotiate
              the new capability.";
         }
         container prefixes {
           config false;
           description
             "Prefix counters for the AFI/SAFI in this BGP session";
           leaf received {
             type yang:zero-based-counter32;
             description
               "The number of prefixes received from the neighbor";
           }
           leaf sent {
             type yang:zero-based-counter32;
             description
               "The number of prefixes advertised to the neighbor";
           }
           leaf installed {
             type yang:gauge32;
             description
               "The number of advertised prefixes installed in the
                Loc-RIB";
           }
         }
         container graceful-restart {
           if-feature "bt:graceful-restart";



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           description
             "Parameters relating to BGP graceful-restart";
           reference
             "RFC 4724: Graceful Restart Mechanism for BGP.";
           uses mp-afi-safi-graceful-restart-config;
           leaf received {
             type boolean;
             config false;
             description
               "This leaf indicates whether the neighbor advertised the
                ability to support graceful-restart for this AFI-SAFI";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }
           leaf advertised {
             type boolean;
             config false;
             description
               "This leaf indicates whether the ability to support
                graceful-restart has been advertised to the peer";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }
           leaf local-forwarding-state-preserved {
             type boolean;
             config false;
             description
               "This leaf indicates whether the local router has
                or would advertise the Forwarding State bit in its
                Graceful Restart capability for this AFI-SAFI.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }
           leaf forwarding-state-preserved {
             type boolean;
             config false;
             description
               "This leaf indicates whether the neighbor has advertised
                the Forwarding State bit in its Graceful Restart
                capability for this AFI-SAFI.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                3.";
           }
           leaf end-of-rib-received {



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             type boolean;
             config false;
             description
               "This leaf indicates whether the neighbor has advertised
                the End-of-RIB marker for this AFI-SAFI.";
             reference
               "RFC 4724: Graceful Restart Mechanism for BGP, Section
                2.";
           }
         }
         uses mp-all-afi-safi-list-contents;
         uses bgp-neighbor-use-multiple-paths;
       }
     }
   }
   <CODE ENDS>

7.2.  BGP notification module

   <CODE BEGINS> file "iana-bgp-notification@2023-07-05.yang"
   module iana-bgp-notification {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:iana-bgp-notification";
     prefix bn;

     // meta

     organization
       "IANA";
     contact
       "Internet Assigned Numbers Authority

        Postal: ICANN
                12025 Waterfront Drive, Suite 300
                Los Angeles, CA 90094-2536
                United States of America
        Tel:    +1 310 301 5800
        <mailto:iana@iana.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This YANG module is maintained by IANA and contains definitions
        of identities used to represent BGP NOTIFICATION Error
        code/Error Subcode tuples.  These values reflect the



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        'BGP Error (Notification) Codes' and 'BGP Error Subcodes'
        registry at IANA.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }


     identity bgp-notification {
       description
         "Base identity for BGP NOTIFICATION state.";
     }

     identity message-header-error {
       base bgp-notification;
       description
         "All errors detected while processing the Message Header MUST
          be indicated by sending the NOTIFICATION message with the
          Error Code Message Header Error.

          The value of the 'Message Header Error' Error code is 1.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.1.";
     }




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     identity message-header-unspecific {
       base message-header-error;
       description
         "If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.";
     }

     identity message-header-connection-not-synchronized {
       base message-header-error;
       description
         "If the Marker field of the message header is not as expected,
          then a synchronization error has occurred and the Error
          Subcode MUST be set to Connection Not Synchronized.

          The value of the 'Conection Not Synchronized Error' subcode is
          1.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.1.";
     }

     identity message-header-bad-message-length {
       base message-header-error;
       description
         "If at least one of the following is true:

          - if the Length field of the message header is less than 19 or
            greater than 4096, or

          - if the Length field of an OPEN message is less than the
            minimum length of the OPEN message, or

          - if the Length field of an UPDATE message is less than the
            minimum length of the UPDATE message, or

          - if the Length field of a KEEPALIVE message is not equal to
            19, or

          - if the Length field of a NOTIFICATION message is less than
            the minimum length of the NOTIFICATION message,

          then the Error Subcode MUST be set to Bad Message Length.  The
          Data field MUST contain the erroneous Length field.

          The value of the 'Bad Message Length' Error subcode is 2.";



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       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.1.";
     }

     identity message-header-bad-message-type {
       base message-header-error;
       description
         "If the Type field of the message header is not recognized,
          then the Error Subcode MUST be set to Bad Message Type.  The
          Data field MUST contain the erroneous Type field.

          The value of the 'Message Header Error' Error subcode is 3.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.1.";
     }

     identity open-message-error {
       base bgp-notification;
       description
         "All errors detected while processing the OPEN message MUST be
          indicated by sending the NOTIFICATION message with the Error
          Code 'OPEN Message Error'.

          The value of the 'OPEN Message Error' Error code is 2.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-message-unspecific {
       base open-message-error;
       description
         "From Section 4.5:
          If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.

          From Section 6.2:
          If one of the Optional Parameters in the OPEN message is
          recognized, but is malformed, then the Error Subcode MUST be
          set to 0 (Unspecific).";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.
          RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-unsupported-version-number {
       base open-message-error;



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       description
         "If the version number in the Version field of the received
          OPEN message is not supported, then the Error Subcode MUST be
          set to Unsupported Version Number.  The Data field is a
          2-octet unsigned integer, which indicates the largest,
          locally-supported version number less than the version the
          remote BGP peer bid (as indicated in the received OPEN
          message), or if the smallest, locally-supported version number
          is greater than the version the remote BGP peer bid, then the
          smallest, locally-supported version number.

          The value of the 'Unsupported Version Number' Error subcode is
          1.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-bad-peer-as {
       base open-message-error;
       description
         "If the Autonomous System field of the OPEN message is
          unacceptable, then the Error Subcode MUST be set to Bad Peer
          AS.  The determination of acceptable Autonomous System numbers
          is outside the scope of this protocol.

          The value of the 'Bad Peer AS' Error subcode is 2.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-bad-bgp-id {
       base open-message-error;
       description
         "From RFC 4271, Section 6.2:
          If the BGP Identifier field of the OPEN message is
          syntactically incorrect, then the Error Subcode MUST be set to
          Bad BGP Identifier.  Syntactic correctness means that the BGP
          Identifier field represents a valid unicast IP host address.

          This was updated by RFC 6286:
          For a BGP speaker that supports the AS-wide Unique BGP
          Identifier, the OPEN message error handling related to the BGP
          Identifier is modified as follows:

          If the BGP Identifier field of the OPEN message is zero, or if
          it is the same as the BGP Identifier of the local BGP speaker
          and the message is from an internal peer, then the Error
          Subcode is set to 'Bad BGP Identifier'.



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          The value of the 'Bad BGP Identifier' Error subcode is 3.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.
          RFC 6286: Autonomous-System-Wide Unique BGP Identifier for
          BGP-4., Section 2.2.";
     }

     identity open-unsupported-optional-parameter {
       base open-message-error;
       description
         "If one of the Optional Parameters in the OPEN message is not
         recognized, then the Error Subcode MUST be set to Unsupported
         Optional Parameters.

         The value of the 'Unsupported Optional Parameter' Error subcode
         is 4.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-unacceptable-hold-time {
       base open-message-error;
       description
         "If the Hold Time field of the OPEN message is unacceptable,
          then the Error Subcode MUST be set to Unacceptable Hold Time.
          An implementation MUST reject Hold Time values of one or two
          seconds.  An implementation MAY reject any proposed Hold Time.
          An implementation that accepts a Hold Time MUST use the
          negotiated value for the Hold Time.

          The value of the 'Unacceptable Hold Time' Error subcode is
          6.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.2.";
     }

     identity open-unsupported-capability {
       base open-message-error;
       description
         "If a BGP speaker that supports a certain capability determines
          that its peer doesn't support this capability, the speaker MAY
          send a NOTIFICATION message to the peer and terminate peering
          (see Section 'Extensions to Error Handling' for more details).
          For example, a BGP speaker may need to terminate peering if it
          established peering to exchange IPv6 routes and determines
          that its peer does not support Multiprotocol Extensions for
          BGP-4 [RFC4760].  The Error Subcode in the NOTIFICATION
          message is then set to Unsupported Capability.  The message



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          MUST contain the capability or capabilities that cause the
          speaker to send the message.

          The value of the 'Unsupported Capability' Error subcode is
          7.";
       reference
         "RFC 5492: Capabilities Advertisement with BGP-4, Section 3.";
     }

     identity open-role-mismatch {
       base open-message-error;
       description
         "If the BGP Role Capability is advertised, and one is also
          received from the peer, the Roles MUST correspond to the
          relationships in Table 2. If the Roles do not correspond, the
          BGP speaker MUST reject the connection using the Role Mismatch
          Notification (code 2, subcode 11).";
       reference
         "RFC 9234: Route Leak Prevention and Detection Using Roles in
          UPDATE and OPEN Messages, Section 4.2.";
     }

     identity update-message-error {
       base bgp-notification;
       description
         "All errors detected while processing the UPDATE message MUST
          be indicated by sending the NOTIFICATION message with the
          Error Code UPDATE Message Error.

         The value of the 'UPDATE Message Error' Error code is 3.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-unspecific {
       base update-message-error;
       description
         "If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.";
     }

     identity update-malformed-attribute-list {
       base update-message-error;
       description



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         "Error checking of an UPDATE message begins by examining the
          path attributes.  If the Withdrawn Routes Length or Total
          Attribute Length is too large (i.e., if Withdrawn Routes
          Length + Total Attribute Length + 23 exceeds the message
          Length), then the Error Subcode MUST be set to Malformed
          Attribute List.

          If any attribute appears more than once in the UPDATE message,
          then the Error Subcode MUST be set to Malformed Attribute
          List.

          The value of the 'Malformed Attribute List' Error subcode is
          1.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-unrecognized-well-known-attribute {
       base update-message-error;
       description
         "If any of the well-known mandatory attributes are not
          recognized, then the Error Subcode MUST be set to Unrecognized
          Well-known Attribute.  The Data field MUST contain the
          unrecognized attribute (type, length, and value).

          The value of the 'Unrecognized Well-known Attribute' Error
          subcode is 2.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-missing-well-known-attribute {
       base update-message-error;
       description
         "If any of the well-known mandatory attributes are not present,
          then the Error Subcode MUST be set to Missing Well-known
          Attribute.  The Data field MUST contain the Attribute Type
          Code of the missing, well-known attribute.

          The value of the 'Missing Well-known Attribute' Error subcode
          is 3.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-attribute-flags-error {
       base update-message-error;
       description



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         "If any recognized attribute has Attribute Flags that conflict
          with the Attribute Type Code, then the Error Subcode MUST be
          set to Attribute Flags Error.  The Data field MUST contain the
          erroneous attribute (type, length, and value).

          The value of the 'Attribute Flags Error' Error subcode is 4.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-attribute-length-error {
       base update-message-error;
       description
         "If any recognized attribute has an Attribute Length that
          conflicts with the expected length (based on the attribute
          type code), then the Error Subcode MUST be set to Attribute
          Length Error.  The Data field MUST contain the erroneous
          attribute (type, length, and value).

          The value of the 'Attribute Length Error' Error subcode is
          5.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-invalid-origin-attribute {
       base update-message-error;
       description
         "If the ORIGIN attribute has an undefined value, then the Error
          Sub-code MUST be set to Invalid Origin Attribute.  The Data
          field MUST contain the unrecognized attribute (type, length,
          and value).

          The value of the 'Invalid ORIGIN Attribute' Error subcode is
          6.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity update-invalid-next-hop-attribute {
       base update-message-error;
       description
         "If the NEXT_HOP attribute field is syntactically incorrect,
          then the Error Subcode MUST be set to Invalid NEXT_HOP
          Attribute.  The Data field MUST contain the incorrect
          attribute (type, length, and value).  Syntactic correctness
          means that the NEXT_HOP attribute represents a valid IP host
          address.



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          The value of the 'Invalid NEXT_HOP Attribute' Error subcode is
          8.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity open-optional-attribute-error {
       base update-message-error;
       description
         "If an optional attribute is recognized, then the value of this
          attribute MUST be checked.  If an error is detected, the
          attribute MUST be discarded, and the Error Subcode MUST be set
          to Optional Attribute Error.  The Data field MUST contain the
          attribute (type, length, and value).

          The value of the 'Optional Attribute Error' Error subcode is
          9.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity open-invalid-network-field {
       base update-message-error;
       description
         "The NLRI field in the UPDATE message is checked for syntactic
         validity.  If the field is syntactically incorrect, then the
         Error Subcode MUST be set to Invalid Network Field.

         The value of the 'Invalid Network Field' Error subcode is 10.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity open-malformed-as-path {
       base update-message-error;
       description
         "The AS_PATH attribute is checked for syntactic correctness.
          If the path is syntactically incorrect, then the Error Subcode
          MUST be set to Malformed AS_PATH.

          If the UPDATE message is received from an external peer, the
          local system MAY check whether the leftmost (with respect to
          the position of octets in the protocol message) AS in the
          AS_PATH attribute is equal to the autonomous system number of
          the peer that sent the message.  If the check determines this
          is not the case, the Error Subcode MUST be set to Malformed
          AS_PATH.




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          The value of the 'Malformed AS_PATH' Error subcode is 11.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.3.";
     }

     identity hold-timer-expired-error {
       base bgp-notification;
       description
         "If a system does not receive successive KEEPALIVE, UPDATE,
          and/or NOTIFICATION messages within the period specified in
          the Hold Time field of the OPEN message, then the NOTIFICATION
          message with the Hold Timer Expired Error Code is sent and the
          BGP connection is closed.

          The value of the 'Hold Timer Expired' Error code is 4.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.5.";
     }

     identity timer-expired-unspecific {
       base hold-timer-expired-error;
       description
         "If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.";
     }


     identity fsm-error {
       base bgp-notification;
       description
         "Any error detected by the BGP Finite State Machine (e.g.,
          receipt of an unexpected event) is indicated by sending the
          NOTIFICATION message with the Error Code Finite State Machine
          Error.

          The value of the 'Finite State Machine Error' Error code is
          5.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.6.
          RFC 6608: Subcodes for BGP Finite State Machine Error.";
     }

     identity fsm-error-unspecified {
       base fsm-error;



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       description
         "If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.
          RFC 6608: Subcodes for BGP Finite State Machine Error, Section
          3.";
     }

     identity fsm-error-unexpected-in-opensent {
       base fsm-error;
       description
         "If a BGP speaker receives an unexpected message (e.g.,
          KEEPALIVE/ UPDATE/ROUTE-REFRESH message) on a session in
          OpenSent state, it MUST send to the neighbor a NOTIFICATION
          message with the Error Code Finite State Machine Error and the
          Error Subcode 'Receive Unexpected Message in OpenSent State'.
          The Data field is a 1-octet, unsigned integer that indicates
          the type of the unexpected message.

          The value of the 'Receive Unexpected Message in OpenSent
          State' Error subcode is 1.";
       reference
         "RFC 6608: Subcodes for BGP Finite State Machine Error, Section
          4.";
     }

     identity fsm-error-unexpected-in-openconfirm {
       base fsm-error;
       description
         "If a BGP speaker receives an unexpected message (e.g.,
          OPEN/UPDATE/ ROUTE-REFRESH message) on a session in
          OpenConfirm state, it MUST send a NOTIFICATION message with
          the Error Code Finite State Machine Error and the Error
          Subcode 'Receive Unexpected Message in OpenConfirm State' to
          the neighbor.  The Data field is a 1-octet, unsigned integer
          that indicates the type of the unexpected message.

          The value of the 'Receive Unexpected Message in OpenConfirm
          State' Error subcode is 2.";
       reference
         "RFC 6608: Subcodes for BGP Finite State Machine Error, Section
          4.";
     }

     identity fsm-error-unexpected-in-established {



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       base fsm-error;
       description
         "If a BGP speaker receives an unexpected message (e.g., OPEN
          message) on a session in Established State, it MUST send to
          the neighbor a NOTIFICATION message with the Error Code Finite
          State Machine Error and the Error Subcode 'Receive Unexpected
          Message in Established State'.  The Data field is a 1-octet,
          unsigned integer that indicates the type of the unexpected
          message.

          The value of the 'Receive Unexpected Message in Established
          State' Error subcode is 3.";
       reference
         "RFC 6608: Subcodes for BGP Finite State Machine Error, Section
          4.";
     }

     identity cease {
       base bgp-notification;
       description
         "In the absence of any fatal errors (that are indicated in this
          section), a BGP peer MAY choose, at any given time, to close
          its BGP connection by sending the NOTIFICATION message with
          the Error Code Cease.  However, the Cease NOTIFICATION message
          MUST NOT be used when a fatal error indicated by this section
          does exist.

          The value of the 'Cease' Error code is 6.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 6.7.";
     }

     identity cease-max-prefixes {
       base cease;
       description
         "From RFC 4271, Section 6.7:
          A BGP speaker MAY support the ability to impose a
          locally-configured, upper bound on the number of address
          prefixes the speaker is willing to accept from a neighbor.
          When the upper bound is reached, the speaker, under control of
          local configuration, either (a) discards new address prefixes
          from the neighbor (while maintaining the BGP connection with
          the neighbor), or (b) terminates the BGP connection with the
          neighbor.  If the BGP speaker decides to terminate its BGP
          connection with a neighbor because the number of address
          prefixes received from the neighbor exceeds the
          locally-configured, upper bound, then the speaker MUST send
          the neighbor a NOTIFICATION message with the Error Code



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          Cease.

          From RFC 4486:
          If a BGP speaker decides to terminate its peering with a
          neighbor because the number of address prefixes received from
          the neighbor exceeds a locally configured upper bound (as
          described in [BGP-4]), then the speaker MUST send to the
          neighbor a NOTIFICATION message with the Error Code Cease and
          the Error Subcode 'Maximum Number of Prefixes Reached'.  The
          message MAY optionally include the Address Family information
          [BGP-MP] and the upper bound in the 'Data' field, as shown in
          Figure 1, where the meaning and use of the <AFI, SAFI> tuple
          is the same as defined in [BGP-MP], Section 7.

          The value of the 'Maximum Number of Prefixes Reached' Error
          subcode is 1.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-admin-shutdown {
       base cease;
       description
         "If a BGP speaker decides to administratively shut down its
          peering with a neighbor, then the speaker SHOULD send a
          NOTIFICATION message with the Error Code Cease and the Error
          Subcode 'Administrative Shutdown'.

          The value of the 'Administrative Shutdown' Error subcode is
          2.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-peer-deconfigured {
       base cease;
       description
         "If a BGP speaker decides to de-configure a peer, then the
          speaker SHOULD send a NOTIFICATION message with the Error Code
          Cease and the Error Subcode 'Peer De-configured'.

          The value of the 'Peer De-configured' Error subcode is 3.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }



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     identity cease-admin-reset {
       base cease;
       description
         "If a BGP speaker decides to administratively reset the peering
          with a neighbor, then the speaker SHOULD send a NOTIFICATION
          message with the Error Code Cease and the Error Subcode
          'Administrative Reset'.

          The value of the 'Administrative Reset' Error subcode is 4.";
        reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-connection-rejected {
       base cease;
       description
         "If a BGP speaker decides to disallow a BGP connection (e.g.,
          the peer is not configured locally) after the speaker accepts
          a transport protocol connection, then the BGP speaker SHOULD
          send a NOTIFICATION message with the Error Code Cease and the
          Error Subcode 'Connection Rejected'.

          The value of the 'Connection Rejected' Error subcode is 5.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-other-configuration-change {
       base cease;
       description
         "If a BGP speaker decides to administratively reset the peering
          with a neighbor due to a configuration change other than the
          ones described above, then the speaker SHOULD send a
          NOTIFICATION message with the Error Code Cease and the Error
          Subcode 'Other Configuration Change'.

          The value of the 'Other Configuration Change' Error subcode is
          6.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-connection-collision {
       base cease;
       description



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         "If a BGP speaker decides to send a NOTIFICATION message with
          the Error Code Cease as a result of the collision resolution
          procedure (as described in [BGP-4]), then the subcode SHOULD
          be set to 'Connection Collision Resolution'.

          The value of the 'Connection Collision Resolution' Error
          subcode is 7.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-out-of-resources {
       base cease;
       description
         "If a BGP speaker runs out of resources (e.g., memory) and
          decides to reset a session, then the speaker MAY send a
          NOTIFICATION message with the Error Code Cease and the Error
          Subcode 'Out of Resources'.

          The value of the 'Out of Resources' Error subcode is 8.";
       reference
         "RFC 4486: Subcodes for BGP Cease Notification Message, Section
          4.";
     }

     identity cease-hard-reset {
       base cease;
       description
         "[RFC 8538] defines a new subcode for BGP Cease NOTIFICATION
          messages, called the Hard Reset subcode.  The value of this
          subcode is [9].  In this document, a BGP Cease NOTIFICATION
          message with the Hard Reset subcode is referred to as a 'Hard
          Reset message' or simply as a 'Hard Reset'.

          The value of the 'Hard Reset' Error subcode is 9.";
       reference
         "RFC 8538: Notification Message Support for BGP Graceful
          Restart, Section 3.";
     }

     identity cease-bfd-down {
       base cease;
       description
         "When a BGP session is terminated due to a BFD session going
          into the Down state, the BGP Speaker SHOULD send a
          NOTIFICATION message with the Error Code Cease and the Error
          Subcode 'BFD Down'.



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          The value of the 'BFD Down' Error subocde is 10.";
       reference
         "draft-ietf-idr-bfd-subcode-05: A BGP Cease Notification
         Subcode For Bidirectional Forwarding Detection (BFD), Section
         2.";
     }

     identity route-refresh-message-error {
       base bgp-notification;
       description
         "The ROUTE-REFRESH Message Error code was defined in RFC 7313.

         The value of the 'ROUTE-REFRESH Message Error' Error code is
         7.";
       reference
         "RFC 7313: Enhanced Route Refresh Capability for BGP-4, Section
          5.";
     }

     identity route-refresh-reserved {
       base route-refresh-message-error;
       description
         "If no appropriate Error Subcode is defined, then a zero
          (Unspecific) value is used for the Error Subcode field.

          The value of the 'Unspecific Error' subcode is 0.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.5.
          RFC 7313: Enhanced Route Refresh Capability for BGP-4, Section
          6.";
     }

     identity route-refresh-invalid-message-length {
       base route-refresh-message-error;
       description
         "If the length, excluding the fixed-size message header, of the
          received ROUTE-REFRESH message with Message Subtype 1 and 2 is
          not 4, then the BGP speaker MUST send a NOTIFICATION message
          with the Error Code of 'ROUTE-REFRESH Message Error' and the
          subcode of 'Invalid Message Length'.  The Data field of the
          NOTIFICATION message MUST contain the complete ROUTE-REFRESH
          message.

          The value of the 'Invalid Message Length' Error subcode is
          1.";
       reference
         "RFC 7313: Enhanced Route Refresh Capability for BGP-4, Section
          5.";



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     }
   }
   <CODE ENDS>

7.3.  BGP types module

   <CODE BEGINS> file "iana-bgp-types@2023-07-05.yang"
   module iana-bgp-types {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:iana-bgp-types";
     prefix bt;

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Types.";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Types.";
     }

     // meta

     organization
       "IANA";
     contact
       "Internet Assigned Numbers Authority

        Postal: ICANN
                12025 Waterfront Drive, Suite 300
                Los Angeles, CA 90094-2536
                United States of America
        Tel:    +1 310 301 5800
        <mailto:iana@iana.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This module contains general data definitions for use in BGP.
        It can be imported by modules that make use of BGP attributes.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.



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        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP-4).";
     }

     /*
      * Features.
      */

     feature add-paths {
       description
         "Advertisement of multiple paths for the same address prefix
          without the new paths implicitly replacing any previous
          ones.";
       reference
         "RFC 7911: Advertisement of Multiple Paths in BGP.";
     }

     feature bfd {
       description
         "Support for BFD detection of BGP neighbor reachability.";
       reference
         "RFC 5880: Bidirectional Forward Detection (BFD),
          RFC 5881: Bidirectional Forward Detection for IPv4 and IPv6
                    (Single Hop),
          RFC 5883: Bidirectional Forwarding Detection (BFD) for
                    Multihop Paths.";
     }




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     feature clear-neighbors {
       description
         "Clearing of BGP neighbors is supported.";
     }

     feature clear-routes {
       description
         "Clearing of BGP routes is supported.";
     }

     feature clear-statistics {
       description
         "Clearing of BGP statistics is supported.";
     }

     feature damping {
       description
         "Weighted route dampening is supported.";
     }

     feature graceful-restart {
       description
         "Graceful restart as defined in RFC 4724 is supported.";
     }

     feature route-refresh {
       description
         "Support for the BGP Route Refresh capability.";
       reference
         "RFC 2918: Route Refresh Capability for BGP-4.";
     }

     feature ttl-security {
       description
         "BGP Time To Live (TTL) security check support.";
       reference
         "RFC 5082: The Generalized TTL Security Mechanism (GTSM).";
     }

     /*
      * Identities.
      */

     /* BGP Origin Attribute Types. */

     typedef bgp-origin-attr-type {
       type enumeration {
         enum igp {



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           description
             "Origin of the NLRI is internal";
         }
         enum egp {
           description
             "Origin of the NLRI is EGP";
         }
         enum incomplete {
           description
             "Origin of the NLRI is neither IGP or EGP";
         }
       }
       description
         "Type definition for standard BGP origin attribute";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Sec 4.3.";
     }

     /* BGP AS_PATH Segment Type Identities. */

     identity as-path-segment-type {
       description
         "Base AS Path Segment Type. In [BGP-4], the path segment type
          is a 1-octet field with the following values defined.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.3.";
     }

     identity as-set {
       base as-path-segment-type;
       description
         "Unordered set of autonomous systems that a route in the UPDATE
          message has traversed.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.3.";
     }

     identity as-sequence {
       base as-path-segment-type;
       description
         "Ordered set of autonomous systems that a route in the UPDATE
          message has traversed.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 4.3.";
     }

     identity as-confed-sequence {
       base as-path-segment-type;



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       description
         "Ordered set of Member Autonomous Systems in the local
          confederation that the UPDATE message has traversed.";
       reference
         "RFC 5065: Autonomous System Configuration for BGP.";
     }

     identity as-confed-set {
       base as-path-segment-type;
       description
         "Unordered set of Member Autonomous Systems in the local
          confederation that the UPDATE message has traversed.";
       reference
         "RFC 5065: Autonomous System Configuration for BGP.";
     }

     /* BGP Peer-Types */

     typedef peer-type {
       type enumeration {
         enum internal {
           description
             "Internal (IBGP) peer";
         }
         enum external {
           description
             "External (EBGP) peer";
         }
         enum confederation-internal {
           description
             "Confederation Internal (IBGP) peer.";
         }
         enum confederation-external {
           description
             "Confederation External (EBGP) peer.";
         }
       }
       description
         "Labels a peer or peer group as explicitly internal,
          external, or the related confederation type.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Sec 1.1.
          RFC 5065: Autonomous System Configuration for BGP.";
     }

     /* BGP Capability Identities. */

     identity bgp-capability {



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       description
         "Base identity for a BGP capability";
     }

     identity mp-bgp {
       base bgp-capability;
       description
         "Multi-protocol extensions to BGP";
       reference
         "RFC 4760: Multiprotocol Extentions for BGP-4.";
     }

     identity route-refresh {
       base bgp-capability;
       description
         "The BGP route-refresh functionality";
       reference
         "RFC 2918: Route Refresh Capability for BGP-4.";
     }

     identity asn32 {
       base bgp-capability;
       description
         "4-byte (32-bit) AS number functionality";
       reference
         "RFC6793: BGP Support for Four-Octet Autonomous System (AS)
                   Number Space.";
     }

     identity graceful-restart {
       if-feature "graceful-restart";
       base bgp-capability;
       description
         "Graceful restart functionality";
       reference
         "RFC 4724: Graceful Restart Mechanism for BGP.";
     }

     identity add-paths {
       if-feature "add-paths";
       base bgp-capability;
       description
         "Advertisement of multiple paths for the same address prefix
          without the new paths implicitly replacing any previous
          ones.";
       reference
         "RFC 7911: Advertisement of Multiple Paths in BGP.";
     }



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     /* BGP AFI-SAFI Type Identities. */

     identity afi-safi-type {
       description
         "Base identity type for AFI,SAFI tuples for BGP-4";
       reference
         "RFC4760: Multiprotocol Extentions for BGP-4.";
     }

     identity ipv4-unicast {
       base afi-safi-type;
       description
         "IPv4 unicast (AFI,SAFI = 1,1)";
       reference
         "RFC4760: Multiprotocol Extentions for BGP-4.";
     }

     identity ipv4-labeled-unicast {
       base afi-safi-type;
       description
         "Labeled IPv4 unicast (AFI,SAFI = 1,4)";
       reference
         "RFC 8277: Using BGP to Bind MPLS Labels to Address Prefixes.";
     }

     identity ipv6-unicast {
       base afi-safi-type;
       description
         "IPv6 unicast (AFI,SAFI = 2,1)";
       reference
         "RFC4760: Multiprotocol Extentions for BGP-4.";
     }

     identity ipv6-labeled-unicast {
       base afi-safi-type;
       description
         "Labeled IPv6 unicast (AFI,SAFI = 2,4)";
       reference
         "RFC 8277: Using BGP to Bind MPLS Labels to Address Prefixes.";
     }

     identity l3vpn-ipv4-unicast {
       base afi-safi-type;
       description
         "Unicast IPv4 MPLS L3VPN (AFI,SAFI = 1,128)";
       reference
         "RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs).";
     }



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     identity l3vpn-ipv4-multicast {
       base afi-safi-type;
       description
         "Multicast IPv4 MPLS L3VPN (AFI,SAFI = 1,129)";
       reference
         "RFC 6514: BGP Encodings and Procedures for Multicast in
          MPLS/BGP IP VPNs.";
     }

     identity l3vpn-ipv6-unicast {
       base afi-safi-type;
       description
         "Unicast IPv6 MPLS L3VPN (AFI,SAFI = 2,128)";
       reference
         "RFC 4659: BGP-MPLS IP Virtual Private Network (VPN) Extension
          for IPv6 VPN.";
     }

     identity l3vpn-ipv6-multicast {
       base afi-safi-type;
       description
         "Multicast IPv6 MPLS L3VPN (AFI,SAFI = 2,129)";
       reference
         "RFC 6514: BGP Encodings and Procedures for Multicast in
          MPLS/BGP IP VPNs.";
     }

     identity l2vpn-evpn {
       base afi-safi-type;
       description
         "BGP MPLS Based Ethernet VPN (AFI,SAFI = 25,70)";
       reference
         "RFC 7432: BGP MPLS-Based Ethernet VPN.";
     }

     identity l2vpn-vpls {
       base afi-safi-type;
       description
         "BGP-signalled VPLS (AFI,SAFI = 25,65)";
       reference
         "RFC 4761: Virtual Private LAN Service (VPLS) Using BGP for
          Auto-Discovery and Signaling.";
     }

     /* BGP Remove Private AS Identities. */

     identity remove-private-as-option {
       description



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         "Base identity for options for removing private autonomous
          system numbers from the AS_PATH attribute";
     }

     identity private-as-remove-all {
       base remove-private-as-option;
       description
         "Strip all private autonomous system numbers from the AS_PATH.
          This action is performed regardless of the other content of
          the AS_PATH attribute, and for all instances of private AS
          numbers within that attribute.";
     }

     identity private-as-replace-all {
       base remove-private-as-option;
       description
         "Replace all instances of private autonomous system numbers in
          the AS_PATH with the local BGP speaker's autonomous system
          number. This action is performed regardless of the other
          content of the AS_PATH attribute, and for all instances of
          private AS number within that attribute.";
     }

     /*
      * Typedefs.
      */

     typedef bgp-session-direction {
       type enumeration {
         enum inbound {
           description
             "Refers to all NLRI received from the BGP peer";
         }
         enum oubound {
           description
             "Refers to all NLRI advertised to the BGP peer";
         }
       }
       description
         "Type to describe the direction of NLRI transmission";
     }

     /* BGP Route Reflector Types. */

     typedef rr-cluster-id-type {
       type union {
         type uint32;
         type yang:dotted-quad;



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       }
       description
         "Union type for route reflector cluster ids:
          option 1: 4-byte number
          option 2: IP address";
       reference
         "RFC 4456: BGP Route Reflection.";
     }

     /* BGP Graceful Restart Types. */

     typedef graceful-restart-time-type {
       type uint16 {
         range "0..4096";
       }
       units "seconds";
       description
         "This is the estimated time (in seconds) it will take for the
          BGP session to be re-established after a restart.  This can be
          used to speed up routing convergence by its peer in case that
          the BGP speaker does not come back after a restart.";
       reference
          "RFC 4724: Graceful Restart Mechanism for BGP, Section 3.";
     }

     typedef graceful-restart-flags {
       type bits {
         bit restart {
           position 0;
           description
             "The most significant bit is defined as the Restart
              State (R) bit, which can be used to avoid possible
              deadlock caused by waiting for the End-of-RIB marker
              when multiple BGP speakers peering with each other
              restart.  When set (value 1), this bit indicates
              that the BGP speaker has restarted, and its peer
              MUST NOT wait for the End-of-RIB marker from the
              speaker before advertising routing information to
              the speaker.";
           reference
             "RFC 4724: Graceful Restart Mechanism for BGP,
              Section 3.";
         }
         bit notification {
           position 1;
           description
             "The second most significant bit is defined in [RFC 8538]
              as the Graceful Notification ('N') bit.  It is used to



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              indicate Graceful Restart support for BGP NOTIFICATION
              messages.  A BGP speaker indicates support for the
              procedures in this document by advertising a Graceful
              Restart Capability with its 'N' bit set (value 1).";
           reference
             "RFC 8538: Notification Message Support for BGP Graceful
              Restart, Section 2.";
         }
       }
       description
         "Restart Flags bits as defined for BGP Graceful Restart and its
          extensions.";
       reference
         "RFC 4724: Graceful Restart Mechanism for BGP,
          RFC 8538: Notification Message Support for BGP Graceful
          Restart.";
     }

     typedef graceful-restart-flags-for-afi {
       type bits {
         bit forwarding-preserved {
           position 0;
           description
             "The most significant bit is defined as the
              Forwarding State (F) bit, which can be used to
              indicate whether the forwarding state for routes
              that were advertised with the given AFI and SAFI
              has indeed been preserved during the previous BGP
              restart.  When set (value 1), the bit indicates
              that the forwarding state has been preserved.";
            reference
              "RFC 4724: Graceful Restart Mechanism for BGP,
               Section 3.";
         }
       }
       description
         "Flags for Address Family bits as defined for BGP Graceful
          Restart and its extensions.";
       reference
         "RFC 4724: Graceful Restart Mechanism for BGP.";
     }

     /* BGP Remove Private AS Types. */

     typedef remove-private-as-option {
       type identityref {
         base remove-private-as-option;
       }



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       description
         "Set of options for configuring how private AS path numbers
          are removed from advertisements";
     }

   }
   <CODE ENDS>

7.4.  BGP community types module

   <CODE BEGINS> file "iana-bgp-community-types@2023-07-05.yang"
   module iana-bgp-community-types {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:iana-bgp-community-types";
     prefix bct;

     import ietf-inet-types {
       prefix inet;
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Types.";
     }

     // meta

     organization
       "IANA";
     contact
       "Internet Assigned Numbers Authority

        Postal: ICANN
                12025 Waterfront Drive, Suite 300
                Los Angeles, CA 90094-2536
                United States of America
        Tel:    +1 310 301 5800
        <mailto:iana@iana.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This module contains data definitions for BGP Communities in
        their various forms.  It can be imported by modules that make
        use of BGP attributes.



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        This YANG module is maintained by IANA and reflects the
        'BGP Identities for Community' and 'BGP definitions for
        Community type' registries.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP-4).";
     }

     /*
      * Features.
      */

     feature send-communities {
       description
         "Enable the propagation of communities.";
     }

     /*
      * Identities.
      */

     /* BGP Well-Known Standard (RFC 1997) Community Identities. */

     identity bgp-well-known-std-community {
       description



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         "Base identity for reserved communities within the standard
          community space defined by RFC 1997. These communities must
          fall within the range 0xFFFF0000 to 0xFFFFFFFF";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     identity no-export {
       base bgp-well-known-std-community;
       description
         "Do not export NLRI received carrying this community outside
          the bounds of this autonomous system, or this confederation
          (if the local autonomous system is a confederation member AS).
           This community has a value of 0xFFFFFF01.";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     identity no-advertise {
       base bgp-well-known-std-community;
       description
         "All NLRI received carrying this community must not be
          advertised to other BGP peers. This community has a value of
          0xFFFFFF02.";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     identity no-export-subconfed {
       base bgp-well-known-std-community;
       description
         "All NLRI received carrying this community must not be
          advertised to external BGP peers - including over
          confederation sub-AS boundaries. This community has a value of
          0xFFFFFF03.";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     identity no-peer {
       base bgp-well-known-std-community;
       description
         "An autonomous system receiving NLRI tagged with this community
          is advised not to re-advertise the NLRI to external bilateral
          peer autonomous systems. An AS may also filter received NLRI
          from bilateral peer sessions when they are tagged with this
          community value. This community has a value of 0xFFFFFF04.";
       reference



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         "RFC 3765: NOPEER Community for BGP.";
     }

     /* BGP Community Send Identities. */

     identity send-community-feature {
       description
         "Base identity to identify send-community feature.";
     }

     identity standard {
       base send-community-feature;
       description
         "Send standard communities.";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     identity extended {
       base send-community-feature;
       description
         "Send extended communities.";
       reference
         "RFC 4360: BGP Extended Communities Attribute.";
     }

     identity large {
       base send-community-feature;
       description
         "Send large communities.";
       reference
         "RFC 8092: BGP Large Communities Attribute.";
     }

     /*
      * Typedefs.
      */

     /* BGP Community Types. */

     typedef bgp-community-regexp-type {
       type string;
       description
         "Type definition for communities specified as regular
          expression patterns.

          A compliant implementation of this type MUST accept a POSIX.2
          Extended Regular Expression excluding the following features:



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          - character class expressions (Section 9.3.5)
          - collating symbols (Section 9.3.5)
          - equivalence classes (Section 9.3.5)
          - back-reference expressions (Section 9.3.6)

          Implementations MAY accept additional forms of regular
          expressions as long as the minimally compliant form documented
          above is accepted.";
       reference
         "IEEE Std 1003.1-2017: The Open Group Base Specifications Issue
          7, 2018 edition.";
     }

     typedef bgp-std-community-type {
       type union {
         type uint32;
         type string {
           pattern '([0-9]|[1-9][0-9]{1,3}|[1-5][0-9]{4}|'
                 + '6[0-5][0-9]{3}|66[0-4][0-9]{2}|'
                 + '665[0-2][0-9]|6653[0-5]):'
                 + '([0-9]|[1-9][0-9]{1,3}|[1-5][0-9]{4}|'
                 + '6[0-5][0-9]{3}|66[0-4][0-9]{2}|'
                 + '665[0-2][0-9]|6653[0-5])';
         }
       }
       description
         "Type definition for standard community attributes.";
       reference
         "RFC 1997: BGP Communities Attribute.";
     }

     typedef bgp-well-known-community-type {
       type identityref {
         base bgp-well-known-std-community;
       }
       description
         "Type definition for well-known IETF community attribute
          values.";
       reference
         "IANA Border Gateway Protocol (BGP) Well Known Communities";
     }

     /* BGP Large Community Types. */

     typedef bgp-large-community-type {
       type string {
         // 4-octets global:4-octets local part-1:4-octets local part-2.
         pattern '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'



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               + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9]):'
               + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
               + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9]):'
               + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
               + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9])';
       }
       description
         "Type definition for a large BGP community";
       reference
         "RFC 8092: BGP Large Communities Attribute.";
     }

     /* IPv6 BGP Exteneded Community Types. */

     typedef bgp-ipv6-ext-community-type {
       type union {
         type string {
           pattern 'ipv6-route\-target:'
                + '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
                + '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
                + '(((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.){3}'
                + '(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])))'
                + ':'
                + '(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|'
                + '6[0-4][0-9]{3}|'
                + '[1-5][0-9]{4}|[1-9][0-9]{0,3}|0)';
            pattern 'ipv6-route\-target:'
                + '((([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
                + '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?))'
                + ':'
                + '(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|'
                + '6[0-4][0-9]{3}|'
                + '[1-5][0-9]{4}|[1-9][0-9]{0,3}|0)';
           /*
            * description
            *   "Type 0x00, Sub-Type 0x02: IPv6 Route-Target
            *    ipv6-route-target:(IPv6 address):(local-admin)
            *    16 octets global administrator and 2 octets local
            *    administrator.
            *
            *    Note: The patterns above are excerpted from RFC 8294.";
            * reference
            *   "RFC 5701: IPv6 Address Specific BGP Extended Community
            *    Attribute, Section 3.";
            */
         }

         type string {



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           pattern 'ipv6-route\-origin:'
                + '((:|[0-9a-fA-F]{0,4}):)([0-9a-fA-F]{0,4}:){0,5}'
                + '((([0-9a-fA-F]{0,4}:)?(:|[0-9a-fA-F]{0,4}))|'
                + '(((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.){3}'
                + '(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])))'
                + ':'
                + '(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|'
                + '6[0-4][0-9]{3}|'
                + '[1-5][0-9]{4}|[1-9][0-9]{0,3}|0)';
            pattern 'ipv6-route\-origin:'
                + '((([^:]+:){6}(([^:]+:[^:]+)|(.*\..*)))|'
                + '((([^:]+:)*[^:]+)?::(([^:]+:)*[^:]+)?))'
                + ':'
                + '(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|'
                + '6[0-4][0-9]{3}|'
                + '[1-5][0-9]{4}|[1-9][0-9]{0,3}|0)';
           /*
            * description
            *   "Type 0x00, Sub-Type 0x03: IPv6 Route-Origin
            *    ipv6-route-origin:(IPv6 address):(local-admin)
            *    16 octets global administrator and 2 octets local
            *    administrator.
            *
            *    Note: The patterns above are excerpted from RFC 8294.";
            * reference
            *   "RFC 5701: IPv6 Address Specific BGP Extended Community
            *    Attribute, Section 3.";
            */
         }

         type string {
           // raw with 20 octets
           pattern 'ipv6-raw:'
                + '([0-9A-Fa-f][0-9A-Fa-f]:){19}'
                + '[0-9A-Fa-f][0-9A-Fa-f]';
         }
       }
       description
         "Type definition for IPv6 extended community attributes.
          It includes a way to specify a 'raw' string that
          is followed by 20 bytes of octet string to support
          new and experimental type definitions.";
       reference
         "RFC 5701: IPv6 Address Specific BGP Extended Community
          Attribute, Section 3.";
     }

     /* BGP Extended Community Types. */



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     typedef bgp-ext-community-type {
       type union {
         type string {
           pattern 'route\-target:(6[0-5][0-5][0-3][0-5]|'
                 + '[1-5][0-9]{4}|[1-9][0-9]{1,4}|[0-9]):'
                 + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
                 + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9])';
           /*
            * description
            *   "Type 0x00, Sub-Type 0x02: Route-Target
            *    route-target:(ASN):(local-admin)
            *    2 octets global administrator and 4 octets local
            *    administrator.";
            * reference
            *   "RFC 4360: BGP Extended Communities Attribute,
            *    Section 4.";
            */
         }

         type string {
           pattern 'route\-target:'
                 + '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'
                 + '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|'
                 + '2[0-4][0-9]|25[0-5]):'
                 + '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'
                 + '[1-9][0-9]{1,4}|[0-9])';
           /*
            * description
            *   "Type 0x01, Sub-Type 0x02: Route-Target
            *    route-target:(IPv4):(local-admin)
            *    4 octets IP address global administrator and 2 octets
            *    local administrator.";
            * reference
            *   "RFC 4360: BGP Extended Communities Attribute,
            *    Section 4.";
            */
         }

         type string {
           pattern 'route\-target:'
                 + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
                 + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9])'
                 + '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'
                 + '[1-9][0-9]{1,4}|[0-9])';
           /*
            * description
            *   "Type 0x02, Sub-Type 0x02: Route-Target
            *    route-target:(ASN):(local-admin)



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            *    4 octets global administrator and 2 octets local
            *    administrator.";
            * reference
            *   "RFC 5668: 4-Octet AS Specific BGP Extended Community,
            *    Section 4.";
            */
         }

         type string {
           pattern 'route\-origin:(6[0-5][0-5][0-3][0-5]|'
                 + '[1-5][0-9]{4}|[1-9][0-9]{1,4}|[0-9]):'
                 + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
                 + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9])';
           /*
            * description
            *   "Type 0x01, Sub-Type 0x03: Route-Origin
            *    route-target:(ASN):(local-admin)
            *    2 octets global administrator and 4 octets local
            *    administrator.";
            * reference
            *   "RFC 4360: BGP Extended Communities Attribute,
            *    Section 5.";
            */
         }

         type string {
           pattern 'route\-origin:'
                 + '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'
                 + '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|'
                 + '2[0-4][0-9]|25[0-5]):'
                 + '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'
                 + '[1-9][0-9]{1,4}|[0-9])';
           /*
            * description
            *   "Type 0x01, Sub-Type 0x03: Route-Target
            *    route-target:(IPv4):(local-admin)
            *    4 octets IP address global administrator and 2 octets
            *    local administrator.";
            * reference
            *   "RFC 4360: BGP Extended Communities Attribute,
            *    Section 5.";
            */
         }

         type string {
           pattern 'route\-origin:'
                 + '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|'
                 + '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[0-9])'



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                 + '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'
                 + '[1-9][0-9]{1,4}|[0-9])';
           /*
            * description
            *   "Type 0x02, Sub-Type 0x03: Route-Origin
            *    route-origin:(ASN):(local-admin)
            *    4 octets global administrator and 2 octets local
            *    administrator.";
            * reference
            *   "RFC 5668: 4-Octet AS Specific BGP Extended Community,
            *    Section 4.";
            */
         }

         type string {
           // raw with 8 octets
           pattern 'raw:'
                + '([0-9A-Fa-f][0-9A-Fa-f]:){7}'
                + '[0-9A-Fa-f][0-9A-Fa-f]';
         }
       }
       description
         "Type definition for extended community attributes.
          It includes a way to specify a 'raw' string that
          is followed by 8 bytes of octet string to support
          new and experimental type definitions.";
       reference
         "RFC 4360: BGP Extended Communities Attribute.";
     }
   }
   <CODE ENDS>

7.5.  BGP policy module

   <CODE BEGINS> file "ietf-bgp-policy@2023-07-05.yang"
   module ietf-bgp-policy {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-policy";
     prefix bp;

     // import some basic types

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-routing-policy {



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       prefix rt-pol;
       reference
         "RFC 9067: A YANG Data Model for Routing Policy";
     }
     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import iana-bgp-community-types {
       prefix bct;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This module contains data definitions for BGP routing policy.
        It augments the base routing-policy module with BGP-specific
        options for conditions and actions.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as



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        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     /*
      * typedef statements
      */

     typedef bgp-set-community-option-type {
       type enumeration {
         enum add {
           description
             "Add the specified communities to the existing
              community attribute.";
         }
         enum remove {
           description
             "Remove the specified communities from the
              existing community attribute.";
         }
         enum replace {
           description
             "Replace the existing community attribute with
              the specified communities. If an empty set is
              specified, this removes the community attribute
              from the route.";
         }
       }
       description
         "Type definition for options when setting the community
          attribute in a policy action.";
     }

     typedef bgp-next-hop-type {
       type union {
         type inet:ip-address-no-zone;
         type enumeration {
           enum self {
             description
               "Special designation for local router's own
                address, i.e., next-hop-self.";
           }



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         }
       }
       description
         "Type definition for specifying next-hop in policy actions.";
     }

     typedef bgp-set-med-type {
       type union {
         type string {
           pattern '[+-]([0-9]{1,8}|[0-3][0-9]{1,9}|4[0-1][0-9]{1,8}|'
                 + '428[0-9]{1,7}|429[0-3][0-9]{1,6}|42948[0-9]{1,5}|'
                 + '42949[0-5][0-9]{1,4}|429496[0-6][0-9]{1,3}|'
                 + '4294971[0-9]{1,2}|42949728[0-9]|42949729[0-5])';
         }
         type enumeration {
           enum igp {
             description
               "Set the MED value to the IGP cost toward the
                next hop for the route.";
           }
           enum med-plus-igp {
             description
               "Before comparing MED values for path selection, adds to
                the MED the cost of the IGP route to the BGP next-hop
                destination.

                This option replaces the MED value for the router,
                but does not affect the IGP metric comparison. As a
                result, when multiple routes have the same value
                after the MED-plus-IPG comparison, and route selection
                continues, the IGP route metric is also compared, even
                though it was added to the MED value and compared
                earlier in the selection process.

                Useful when the downstream AS requires the complete
                cost of a certain route that is received across
                multiple ASs.";
           }
         }
         type uint32;
       }
       description
         "Type definition for specifying how the BGP MED can
          be set in BGP policy actions. The three choices are to set
          the MED directly, increment/decrement using +/- notation,
          and setting it to the IGP cost (predefined value).";
     }




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     grouping equality-operator {
       description
         "Grouping used for common equality operations in BGP policy.";
       choice operation {
         case eq {
           leaf eq {
             type empty;
             description
               "Check to see if the value is equal.";
           }
         }

         case lt-or-eq {
           leaf lt-or-eq {
             type empty;
             description
               "Check to see if the value is less than or equal.";
           }
         }

         case gt-or-eq {
           leaf gt-or-eq {
             type empty;
             description
               "Check to see if the value is greater than or
                equal.";
           }
         }
         description
           "Choice of operations on the value";
       }
     }

     // Identities

     // augment statements

     augment "/rt-pol:routing-policy/rt-pol:defined-sets" {
       description
         "Adds BGP defined sets container to routing policy model.";
       container bgp-defined-sets {
         description
           "BGP-related set definitions for policy match conditions.";
         container as-path-sets {
           description
             "Enclosing container for list of define AS path sets.";
           list as-path-set {
             key "name";



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             description
               "List of defined AS path sets.";
             leaf name {
               type string;
               description
                 "Name of the AS path set -- this is used to reference
                  the set in match conditions.";
             }
             leaf-list member {
               type string;
               description
                 "AS path regular expression using BGP YANG AS_PATH
                  regular expression syntax.  If any of the regular
                  expressions in the lists are matched, the as-path-set
                  is considered matched.";
               reference
                 "RFC XXXX: YANG Model for Border Gateway Protocol
                  (BGP-4), Appendix F.3.";
             }
           }
         }

         container community-sets {
           description
             "Enclosing container for list of defined BGP community
              sets.";
           list community-set {
             key "name";
             description
               "List of defined BGP community sets.";
             leaf name {
               type string;
               description
                 "Name / label of the community set -- this is used to
                  reference the set in match conditions.";
             }
             leaf-list member {
               type union {
                 type bct:bgp-well-known-community-type;
                 type bct:bgp-std-community-type;
                 type bct:bgp-community-regexp-type;
               }
               description
                 "Members of the community set";
             }
           }
         }




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         container ext-community-sets {
           description
             "Enclosing container for list of extended BGP community
              sets";
           list ext-community-set {
             key "name";
             description
               "List of defined extended BGP community sets";
             leaf name {
               type string;
               description
                 "Name / label of the extended community set -- this is
                  used to reference the set in match conditions";
             }
             leaf-list member {
               type union {
                 type bct:bgp-ext-community-type;
                 type bct:bgp-community-regexp-type;
               }
               description
                 "Members of the extended community set.";
             }
           }
         }

         container ipv6-ext-community-sets {
           description
             "Enclosing container for list of extended IPv6 BGP
              community sets";
           list ipv6-ext-community-set {
             key "name";
             description
               "List of defined IPv6 extended BGP community sets";
             leaf name {
               type string;
               description
                 "Name / label of the IPv6 extended community set --
                  this is used to reference the set in match
                  conditions";
             }
             leaf-list member {
               type union {
                 type bct:bgp-ipv6-ext-community-type;
                 type bct:bgp-community-regexp-type;
               }
               description
                 "Members of the IPv6 extended community set.";
             }



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           }
         }

         container large-community-sets {
           description
             "Enclosing container for list of large BGP community
              sets";
           list large-community-set {
             key "name";
             description
               "List of defined large BGP community sets";
             leaf name {
               type string;
               description
                 "Name / label of the large community set -- this is
                  used to reference the set in match conditions";
             }
             leaf-list member {
               type union {
                 type bct:bgp-large-community-type;
                 type bct:bgp-community-regexp-type;
               }
               description
                 "Members of the large community set.";
             }
           }
         }

         container next-hop-sets {
           description
             "Definition of a list of IPv4 or IPv6 next-hops which can
              be matched in a routing policy.";

           list next-hop-set {
             key "name";
             description
               "List of defined next-hop sets for use in policies.";

             leaf name {
               type string;
               description
                 "Name of the next-hop set.";
             }
             leaf-list next-hop {
               type bgp-next-hop-type;
               description
                 "List of IP addresses in the next-hop set.";
             }



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           }
         }
       }
     }

     augment "/rt-pol:routing-policy/rt-pol:policy-definitions/" +
             "rt-pol:policy-definition/rt-pol:statements/" +
             "rt-pol:statement/rt-pol:conditions" {
       description
         "BGP policy conditions added to routing policy module.";

       container bgp-conditions {
         description
           "Top-level container for BGP specific policy conditions.";

         container local-pref {
           description
             "Value and comparison operations for conditions based on
              the value of the BGP LOCAL_PREF.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.5.";

           leaf value {
             type uint32;
             description
               "BGP LOCAL_PREF value for comparison to the entry in the
                BGP route.";
           }

           uses equality-operator;
         }

         container med {
           description
             "Value and comparison operations for conditions based on
              the value of the BGP MULTI_EXIT_DISC (MED)";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.4.";

           leaf value {
             type uint32;
             description
               "BGP MED value for comparison to the entry in the BGP
                route.";
           }




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           uses equality-operator;
         }

         leaf origin-eq {
           type bt:bgp-origin-attr-type;
           description
             "Condition to check if the route origin is equal to the
              specified value.";
         }

         container match-afi-safi {
           description
             "Match an address family according to the logic defined in
              the match-set-options leaf.";
           leaf-list afi-safi-in {
             type identityref {
               base bt:afi-safi-type;
             }
             description
               "List of address families which the NLRI may be within.";
           }
           uses rt-pol:match-set-options-restricted-group;
         }

         container match-neighbor {
           description
             "Match a neighbor according to the logic defined in the
              match-set-options leaf.";

           leaf-list neighbor-eq {
             type inet:ip-address;
             description
               "List of neighbor addresses to check for in the ingress
                direction.";
           }
           uses rt-pol:match-set-options-restricted-group;
         }

         leaf route-type {
           type enumeration {
             enum internal {
               description
                 "route type is internal.";
             }
             enum external {
               description
                 "route type is external.";
             }



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           }
           description
             "Condition to check the route type in the route update.";
         }

         container community-count {
           description
             "Value and comparison operations for conditions based on
              the number of communities in the route update.";

           leaf community-count {
             type uint32;
             description
               "Value for the number of communities in the route
                update.";
           }

           uses equality-operator;
         }

         container as-path-length {
           description
             "Value and comparison operations for conditions based on
              the length of the AS path in the route update.

              The as-path-length SHALL be calculated and SHALL follow
              RFC 4271 rules.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";

           leaf as-path-length {
             type uint32;
             description
               "Value of the AS path length in the route update.";
           }

           uses equality-operator;
         }

         container match-community-set {
           description
             "Top-level container for match conditions on communities.
              Match a referenced community-set according to the logic
              defined in the match-set-options leaf.";
           leaf community-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/community-sets/"



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                  + "community-set/name";
             }
             description
               "References a defined community set.";
           }
           uses rt-pol:match-set-options-group;
         }

         container match-ext-community-set {
           description
             "Match a referenced extended community-set according to the
              logic defined in the match-set-options leaf.";
           leaf ext-community-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/ext-community-sets/"
                  + "ext-community-set/name";
             }
             description
               "References a defined extended community set.";
           }
           leaf ext-community-match-kind {
             type enumeration {
               enum ext-community {
                 description
                   "Perform the match against the ext-community RIB
                    attribute.";
               }
               enum ext-community-raw {
                 description
                   "Perform the match against the ext-community-raw RIB
                    attribute.";
               }
             }
             default ext-community;
             description
               "Extended communities may be matched by the ext-community
                RIB attribute, or the ext-community-raw RIB attribute.
                This leaf selects which leaf to perform the match
                operation against.";
           }
           uses rt-pol:match-set-options-group;
         }

         container match-ipv6-ext-community-set {
           description
             "Match a referenced IPv6 extended community-set according
              to the logic defined in the match-set-options leaf.";



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           leaf ipv6-ext-community-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/ipv6-ext-community-sets/"
                  + "ipv6-ext-community-set/name";
             }
             description
               "References a defined IPv6 extended community set.";
           }
           leaf ipv6-ext-community-match-kind {
             type enumeration {
               enum ipv6-ext-community {
                 description
                   "Perform the match against the IPv6 ext-community RIB
                    attribute.";
               }
               enum ipv6-ext-community-raw {
                 description
                   "Perform the match against the IPv6 ext-community-raw
                    RIB attribute.";
               }
             }
             default ipv6-ext-community;
             description
               "IPv6 Extended communities may be matched by the
                ipv6-ext-community RIB attribute, or the
                ipv6-ext-community-raw RIB attribute.  This leaf selects
                which leaf to perform the match operation against.";
           }
           uses rt-pol:match-set-options-group;
         }

         container match-large-community-set {
           description
             "Match a referenced large community-set according to the
              logic defined in the match-set-options leaf.";
           leaf large-community-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/large-community-sets/"
                  + "large-community-set/name";
             }
             description
               "References a defined large community set.";
           }
           uses rt-pol:match-set-options-group;
         }




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         container match-as-path-set {
           description
             "Match a referenced as-path set according to the logic
              defined in the match-set-options leaf.";
           leaf as-path-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/as-path-sets/"
                  + "as-path-set/name";
             }
             description
               "References a defined AS path set";
           }
           uses rt-pol:match-set-options-group;
         }

         container match-next-hop-set {
           description
             "Match a referenced next-hop set according to the logic
              defined in the match-set-options leaf.";
           leaf next-hop-set {
             type leafref {
               path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                  + "bgp-defined-sets/next-hop-sets/"
                  + "next-hop-set/name";
             }
             description
               "Reference a defined next-hop set.";
           }
           uses rt-pol:match-set-options-restricted-group;
         }
       }
     }

     augment "/rt-pol:routing-policy/rt-pol:policy-definitions/" +
             "rt-pol:policy-definition/rt-pol:statements/" +
             "rt-pol:statement/rt-pol:actions" {
       description
         "BGP policy actions added to routing policy module.";
       container bgp-actions {
         description
           "Top-level container for BGP-specific actions";
         leaf set-route-origin {
           type bt:bgp-origin-attr-type;
           description
             "Set the origin attribute to the specified value";
         }
         leaf set-local-pref {



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           type uint32;
           description
             "Set the local pref attribute on the route.";
         }
         leaf set-next-hop {
           type bgp-next-hop-type;
           description
             "Set the next-hop attribute in the route.";
         }
         leaf set-med {
           type bgp-set-med-type;
           description
             "Set the med metric attribute in the route.";
         }

         container set-as-path-prepend {
           description
             "Action to prepend local AS number to the AS-path a
              specified number of times";

           leaf repeat-n {
             type uint8 {
               range "1..max";
             }
             description
               "Number of times to prepend the AS number to the AS
                path. The value should be between 1 and the maximum
                supported by the implementation.";
           }
           leaf-list asn {
             type inet:as-number;
             description
               "AS number to prepend to the AS path.";
           }
         }

         container set-community {
           description
             "Action to set the community attributes of the route, along
              with options to modify how the community is modified.
              Communities may be set using an inline list OR
              reference to an existing defined set (not both).";

           leaf options {
             type bgp-set-community-option-type;
             description
               "Options for modifying the community attribute with
                the specified values.  These options apply to both



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                methods of setting the community attribute.";
           }

           choice method {
             description
               "Indicates the method used to specify the extended
                communities for the set-community action";
             case inline {
               leaf-list communities {
                 type union {
                   type bct:bgp-well-known-community-type;
                   type bct:bgp-std-community-type;
                 }
                 description
                   "Set the community values for the update inline with
                    a list.";
               }
             }

             case reference {
               leaf community-set-ref {
                 type leafref {
                   path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                      + "bgp-defined-sets/"
                      + "community-sets/community-set/name";
                 }
                 description
                   "References a defined community set by name";
               }
             }
           }
         }

         container set-ext-community {
           description
             "Action to set the extended community attributes of the
              route, along with options to modify how the community is
              modified. Extended communities may be set using an inline
              list OR a reference to an existing defined set (but not
              both).";

           leaf options {
             type bgp-set-community-option-type;
             description
               "Options for modifying the community attribute with
                the specified values.  These options apply to both
                methods of setting the community attribute.";
           }



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           choice method {
             description
               "Indicates the method used to specify the extended
                communities for the set-ext-community action";
             case inline {
               leaf-list communities {
                 type bct:bgp-ext-community-type;
                 description
                   "Set the extended community values for the update
                    inline with a list.";
               }
             }
             case reference {
               leaf ext-community-set-ref {
                 type leafref {
                   path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                      + "bgp-defined-sets/ext-community-sets/"
                      + "ext-community-set/name";
                 }
                 description
                   "References a defined extended community set by
                    name.";
               }
             }
           }
         }

         container set-ipv6-ext-community {
           description
             "Action to set the IPv6 extended community attributes of
              the route, along with options to modify how the community
              is modified. IPv6 extended communities may be set using an
              inline list OR a reference to an existing defined set (but
              not both).";

           leaf options {
             type bgp-set-community-option-type;
             description
               "Options for modifying the community attribute with
                the specified values.  These options apply to both
                methods of setting the community attribute.";
           }

           choice method {
             description
               "Indicates the method used to specify the IPv6 extended
                communities for the set-ipv6-ext-community action";
             case inline {



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               leaf-list communities {
                 type bct:bgp-ipv6-ext-community-type;
                 description
                   "Set the IPv6 extended community values for the
                    update inline with a list.";
               }
             }
             case reference {
               leaf ipv6-ext-community-set-ref {
                 type leafref {
                   path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                      + "bgp-defined-sets/ipv6-ext-community-sets/"
                      + "ipv6-ext-community-set/name";
                 }
                 description
                   "References a defined IPv6 extended community set by
                    name.";
               }
             }
           }
         }

         container set-large-community {
           description
             "Action to set the large community attributes of the
              route, along with options to modify how the community is
              modified. Large communities may be set using an inline
              list OR a reference to an existing defined set (but not
              both).";

           leaf options {
             type bgp-set-community-option-type;
             description
               "Options for modifying the community attribute with
                the specified values. These options apply to both
                methods of setting the community attribute.";
           }

           choice method {
             description
               "Indicates the method used to specify the large
                communities for the set-large-community action";
             case inline {
               leaf-list communities {
                 type bct:bgp-large-community-type;
                 description
                   "Set the large community values for the update
                    inline with a list.";



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               }
             }
             case reference {
               leaf large-community-set-ref {
                 type leafref {
                   path "/rt-pol:routing-policy/rt-pol:defined-sets/"
                      + "bgp-defined-sets/large-community-sets/"
                      + "large-community-set/name";
                 }
                 description
                   "References a defined extended community set by
                    name.";
               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

7.6.  RIB modules and submodules

7.6.1.  BGP RIB types module

   <CODE BEGINS> file "iana-bgp-rib-types@2023-07-05.yang"
   module iana-bgp-rib-types {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:iana-bgp-rib-types";
     prefix brt;

     organization
       "IANA";
     contact
       "Internet Assigned Numbers Authority

        Postal: ICANN
                12025 Waterfront Drive, Suite 300
                Los Angeles, CA 90094-2536
                United States of America
        Tel:    +1 310 301 5800
        <mailto:iana@iana.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";




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     description
       "Defines identity and type definitions associated with
        the BGP RIB modules.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     identity ineligible-route-reason {
       description
         "Base identity for reason code for routes that are rejected as
          ineligible. Some derived entities are based on BMP v3.";
       reference
         "RFC 7854: BGP Monitoring Protocol.";
     }

     identity ineligible-cluster-loop {
       base ineligible-route-reason;
       description
         "Route was ineligible due to CLUSTER_LIST loop";
     }

     identity ineligible-as-loop {
       base ineligible-route-reason;
       description



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         "Route was ineligible due to AS_PATH loop";
     }

     identity ineligible-originator {
       base ineligible-route-reason;
       description
         "Route was ineligible due to ORIGINATOR_ID. For example, update
          has local router as originator";
     }

     identity ineligible-confed {
       base ineligible-route-reason;
       description
         "Route was ineligible due to a loop in the AS_CONFED_SEQUENCE
          or AS_CONFED_SET attributes";
     }

     identity bgp-not-selected-bestpath {
       description
         "Base identity for indicating reason a route was was not
          selected by BGP route selection algorithm";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section 9.1.";
     }

     identity local-pref-lower {
       base bgp-not-selected-bestpath;
       description
         "Route has a lower localpref attribute than current best path";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.";
     }

     identity as-path-longer {
       base bgp-not-selected-bestpath;
       description
         "Route has a longer AS path attribute than current best path";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (a).";
     }

     identity origin-type-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher origin type, i.e., IGP origin is preferred
          over EGP or incomplete";



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       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (b).";
     }

     identity med-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher MED, or metric, attribute than the current
          best path";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (c).";
     }

     identity prefer-external {
       base bgp-not-selected-bestpath;
       description
         "Route source is via IBGP, rather than EGP.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (d).";
     }

     identity nexthop-cost-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher interior cost to the next hop.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (e).";
     }

     identity higher-router-id {
       base bgp-not-selected-bestpath;
       description
         "Route was sent by a peer with a higher BGP Identifier value.";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
          Section 9.1.2.2 (f).";
     }

     identity higher-peer-address {
       base bgp-not-selected-bestpath;
       description
         "Route was sent by a peer with a higher IP address";
       reference
         "RFC 4271: A Border Gateway Protocol 4 (BGP-4),



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          Section 9.1.2.2 (g).";
     }

     identity bgp-not-selected-policy {
       description
         "Base identity for reason code for routes that are rejected
          due to policy";
     }

     identity rejected-import-policy {
       base bgp-not-selected-policy;
       description
         "Route was rejected after applying import policies.";
     }
   }
   <CODE ENDS>

7.6.2.  BGP RIB submodule

   <CODE BEGINS> file "ietf-bgp-rib@2023-07-05.yang"
   submodule ietf-bgp-rib {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     /*
      * Import and Include
      */

     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Types.";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Types.";
     }
     include ietf-bgp-rib-tables;

     // groupings of attributes in three categories:



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     //  - shared across multiple routes
     //  - common to Loc-RIB and Adj-RIB, but not shared across routes
     //  - specific to Loc-RIB or Adj-RIB
     // groupings of annotations for each route or table
     include ietf-bgp-rib-attributes;

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper dot net).";

     description
       "Defines a submodule for representing BGP Routing Information
        Base (RIB) contents.  The submodule supports 5 logical RIBs per
        address family:

        loc-rib: This is the main BGP routing table for the local
        routing instance, containing best-path selections for each
        prefix.  The key for the loc-rib will correspond either to a
        route in the adj-rib-in-post table, described below, or a route
        redistributed from another protocol.

        adj-rib-in-pre: This is a per-neighbor table containing the BGP
        routes received from the neighbor before any local input policy
        rules has been applied.  This can be considered the 'raw' routes
        from a given neighbor.

        adj-rib-in-post: This table is a per-neighbor table containing
        the routes received from the neighbor that are eligible for
        best-path selection after local input policy rules have been
        applied. The 'best-path' leaf is attached to the route selected
        by the BGP Decision Process (RFC 4271, Section 9.1).  Such
        routes may be present in the loc-rib table, described above,
        when local configuration determines that the BGP best-path will
        be used for that destination.

        adj-rib-in-post: This is a per-neighbor table containing the
        routes received from the neighbor that are eligible for
        best-path selection after local input policy rules have been
        applied.

        adj-rib-out-pre: This is a per-neighbor table containing routes



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        eligible for sending (advertising) to the neighbor before output
        policy rules have been applied.

        adj-rib-out-post: This is a per-neighbor table containing routes
        eligible for sending (advertising) to the neighbor after output
        policy rules have been applied.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping attr-set-attributes {
       description
         "A grouping for all BGP Path Attribute set parameters.";

       container attributes {
         description
           "A container for attribute set parameters.";

         leaf origin {
           type bt:bgp-origin-attr-type;
           description
             "BGP attribute defining the origin of the path
              information.";
           reference



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             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.1.";
         }
         container as-path {
           description
             "Enclosing container for the list of AS path segments.

              In the Adj-RIB-In or Adj-RIB-Out, this list should show
              the received or sent AS_PATH, respectively.  For
              example, if the local router is not 4-byte capable, this
              value should consist of 2-octet ASNs or the AS_TRANS
              (AS 23456) values received or sent in BGP updates.

              In the Loc-RIB, this list should reflect the effective
              AS path for the route, e.g., a 4-octet value if the
              local router is 4-octet capable.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
              RFC 6793: BGP Support for Four-octet AS Number Space
              RFC 5065: Autonomous System Confederations for BGP.";
           list segment {
             config false;
             uses bgp-as-path-segment;
             description
               "List of AS PATH segments";
           }
         }
         leaf next-hop {
           type inet:ip-address;
           description
             "BGP next hop attribute defining the IP address of the
              router that should be used as the next hop to the
              destination.  Used when the BGP routes' nexthop for that
              AFI/SAFI can be represented as an IPv4/IPv6 address.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.3.";
         }
         leaf link-local-next-hop {
           type inet:ipv6-address;
           description
             "When both a global and a link-local next-hop are sent
              when following RFC 2545 procedures, this leaf contains
              the link-local next-hop.";
           reference
             "RFC 2545: Use of BGP-4 Multiprotocol Extensions for IPv6
              Inter-Domain Routing.";
         }



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         leaf med {
           type uint32;
           description
             "BGP multi-exit discriminator attribute used in the BGP
              route selection process.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.4.";
         }
         leaf local-pref {
           type uint32;
           description
             "BGP local preference attribute sent to internal peers to
              indicate the degree of preference for externally learned
              routes.  The route with the highest local preference
              value is preferred.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.5.";
         }
         container as4-path {
           description
             "This is the path encoded with 4-octet
              AS numbers in the optional transitive AS4_PATH attribute.
              This value is populated with the received or sent
              attribute in Adj-RIB-In or Adj-RIB-Out, respectively.
              It should not be populated in Loc-RIB since the Loc-RIB
              is expected to store the effective AS-Path in the
              as-path leaf regardless of being 4-octet or 2-octet.";
           reference
             "RFC 6793: BGP Support for Four-octet AS Number Space";
           list segment {
             config false;
             uses bgp-as-path-segment;
             description
               "List of AS PATH segments";
           }
         }
         container aggregator {
           config false;
           description
             "BGP attribute indicating the prefix has been
              aggregated by the specified AS and router.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.7,
              RFC 6793: BGP Support for Four-octet AS Number Space.";
           leaf as {



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             type inet:as-number;
             description
               "AS number of the autonomous system that performed the
                aggregation.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
                4.3, Path Attributes (g).";
           }
           leaf identifier {
             type yang:dotted-quad;
             description
               "BGP Identifier of the router that performed the
                aggregation.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
                4.3, Path Attributes (g).";
           }
         }
         container aggregator4 {
           config false;
           description
             "BGP attribute indicating the prefix has been
              aggregated by the specified AS and router.
              This value is populated with the received or sent
              attribute in Adj-RIB-In or Adj-RIB-Out, respectively.
              It should not be populated in Loc-RIB since the Loc-RIB
              is expected to store the effective AGGREGATOR in the
              aggregator/as leaf regardless of being 4-octet or
              2-octet.";
           reference
             "RFC 6793: BGP Support for Four-octet AS Number Space.";
           leaf as4 {
             type inet:as-number;
             description
               "AS number of the autonomous system that performed the
                aggregation (4-octet representation).  This value is
                populated if an upstream router is not 4-octet capable.
                Its semantics are similar to the AS4_PATH optional
                transitive attribute";
             reference
               "RFC 6793: BGP Support for Four-octet AS Number Space,
                Section 3,
                RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
                4.3, Path Attributes (g).";
           }
           leaf identifier {
             type yang:dotted-quad;
             description



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               "BGP Identifier of the router that performed the
                aggregation.";
             reference
               "RFC 6793: BGP Support for Four-octet AS Number Space,
                Section 3,
                RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
                4.3, Path Attributes (g).";
           }
         }
         leaf atomic-aggregate {
           type boolean;
           description
             "BGP attribute indicating that the prefix is an atomic
              aggregate; i.e., the peer selected is a less specific
              route without selecting a more specific route that is
              subsumed by it.";
           reference
             "RFC 4271: A Border Gateway Protocol 4 (BGP-4), Section
              5.1.6.";
         }
         leaf originator-id {
           type yang:dotted-quad;
           description
             "BGP attribute that provides the id as an IPv4 address
              of the originator of the announcement.";
           reference
             "RFC 4456: BGP Route Reflection: An Alternative to Full
              Mesh Internal BGP (IBGP).";
         }
         leaf-list cluster-list {
           type yang:dotted-quad;
           description
             "Represents the reflection path that the route has
              passed.";
           reference
             "RFC 4456: BGP Route Reflection: An Alternative to Full
              Mesh Internal BGP (IBGP).";
         }
         leaf aigp-metric {
           type uint64;
           description
             "BGP path attribute representing the accumulated IGP
              metric for the path";
           reference
             "RFC 7311: The Accumulated IGP Metric Attribute for BGP.";
         }
       }
     }



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     grouping attr-sets {
       description
         "A grouping for all sets of path attributes.";

       container attr-sets {
         description
           "Enclosing container for the list of path attribute sets";

         list attr-set {
           key "index";
           description
             "List of path attributes that may be in use by multiple
              routes in the table";
           leaf index {
             type uint64;
             description
               "System generated index for each attribute set.  The
                index is used to reference an attribute set from a
                specific path.  Multiple paths may reference the same
                attribute set.";
           }
           uses attr-set-attributes;
         }
       }
     }

     grouping rib {
       description
         "Grouping for rib.";

       container rib {
         config false;
         uses attr-sets;
         container communities {
           description
             "Enclosing container for the list of community attribute
              sets.";
           list community {
             key "index";
             config false;
             description
               "List of path attributes that may be in use by multiple
                routes in the table.";
             leaf index {
               type uint64;
               description
                 "System generated index for each attribute set.  The
                  index is used to reference an attribute set from a



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                  specific path.  Multiple paths may reference the same
                  attribute set.";
             }
             uses bgp-community-attr-state;
           }
         }
         container ext-communities {
           description
             "Enclosing container for the list of extended community
              attribute sets.";
           list ext-community {
             key "index";
             config false;
             description
               "List of path attributes that may be in use by multiple
                routes in the table.";
             leaf index {
               type uint64;
               description
                 "System generated index for each attribute set.  The
                  index is used to reference an attribute set from a
                  specific path.  Multiple paths may reference the same
                  attribute set.";
             }
             uses ext-community-attributes;
           }
         }
         container ipv6-ext-communities {
           description
             "Enclosing container for the list of IPv6 extended
              community attribute sets.";
           list ipv6-ext-community {
             key "index";
             config false;
             description
               "List of path attributes that may be in use by multiple
                routes in the table.";
             leaf index {
               type uint64;
               description
                 "System generated index for each attribute set.  The
                  index is used to reference an attribute set from a
                  specific path.  Multiple paths may reference the same
                  attribute set.";
             }
             uses ipv6-ext-community-attributes;
           }
         }



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         container large-communities {
           description
             "Enclosing container for the list of large community
              attribute sets.";
           list large-community {
             key "index";
             config false;
             description
               "List of path attributes that may be in use by multiple
                routes in the table.";
             leaf index {
               type uint64;
               description
                 "System generated index for each attribute set. The
                  index is used to reference an attribute set from a
                  specific path.  Multiple paths may reference the same
                  attribute set.";
             }
             uses large-community-attributes;
           }
         }

         container afi-safis {
           config false;
           description
             "Enclosing container for address family list.";
           list afi-safi {
             key "name";
             description
               "List of afi-safi types.";
             leaf name {
               type identityref {
                 base bt:afi-safi-type;
               }
               description
                 "AFI,SAFI name.";
             }
             container ipv4-unicast {
               when "../name = 'bt:ipv4-unicast'" {
                 description
                   "Include this container for IPv4 unicast RIB.";
               }
               description
                 "Routing tables for IPv4 unicast -- active when the
                  afi-safi name is ipv4-unicast.";

               container loc-rib {
                 config false;



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                 description
                   "Container for the IPv4 Unicast BGP Loc-RIB data.";
                 container routes {
                   description
                     "Enclosing container for list of routes in the
                      routing table.";
                   list route {
                     key "prefix origin path-id";
                     description
                       "List of routes in the table, keyed by the route
                        prefix, the route origin, and path-id. The route
                        origin can be either the neighbor address from
                        which the route was learned, or the source
                        protocol that injected the route. The path-id
                        distinguishes routes for the same prefix
                        received from a neighbor (e.g., if add-paths is
                        enabled).";
                     leaf prefix {
                       type inet:ipv4-prefix;
                       description
                         "The IPv4 prefix corresponding to the route.";
                     }
                     uses bgp-loc-rib-common-keys;
                     uses bgp-loc-rib-common-attr-refs;
                     uses bgp-common-route-annotations-state;
                     uses bgp-unknown-attr-top;
                     uses rib-ext-route-annotations;
                   }
                 }
               }

               container neighbors {
                 config false;
                 description
                   "Enclosing container for neighbor list.";
                 list neighbor {
                   key "neighbor-address";
                   description
                     "List of neighbors (peers) of the local BGP
                      speaker.";
                   leaf neighbor-address {
                     type inet:ip-address;
                     description
                       "IP address of the BGP neighbor or peer.";
                   }
                   container adj-rib-in-pre {
                     description
                       "Per-neighbor table containing the BGP routes



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                        received from the neighbor before any local
                        input policy rules or filters have been applied.
                        This can be considered the 'raw' routes from
                        the neighbor.";
                     uses ipv4-adj-rib-common;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-in state for the containing
                          neighbor. Subsequently, implementations might
                          issue a 'route refresh' if 'route refresh' has
                          been negotiated, or reset the session. ";
                     }
                   }
                   container adj-rib-in-post {
                     description
                       "Per-neighbor table containing the paths received
                        from the neighbor that are eligible for
                        best-path selection after local input policy
                        rules have been applied.";
                     uses ipv4-adj-rib-in-post;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-in state for the containing
                          neighbor. Subsequently, implementations might
                          issue a 'route refresh' if 'route refresh' has
                          been negotiated, or reset the session. ";
                     }
                   }
                   container adj-rib-out-pre {
                     description
                       "Per-neighbor table containing paths eligible for
                        sending (advertising) to the neighbor before
                        output policy rules have been applied.";
                     uses ipv4-adj-rib-common;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-out state for the
                          containing neighbor. Subsequently, neighbors
                          will announce BGP updates to resynchronize
                          these routes.";
                     }
                   }
                   container adj-rib-out-post {
                     description
                       "Per-neighbor table containing paths eligible for
                        sending (advertising) to the neighbor after
                        output policy rules have been applied.";
                     uses ipv4-adj-rib-common;



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                     uses clear-routes {
                       description
                         "Clears the adj-rib-out state for the
                          containing neighbor. Subsequently, neighbors
                          will announce BGP updates to resynchronize
                          these routes.";
                     }
                   }
                 }
               }
             }

             container ipv6-unicast {
               when "../name = 'bt:ipv6-unicast'" {
                 description
                   "Include this container for IPv6 unicast RIB.";
               }
               description
                 "Routing tables for IPv6 unicast -- active when the
                  afi-safi name is ipv6-unicast.";

               container loc-rib {
                 config false;
                 description
                   "Container for the IPv6 BGP Loc-RIB data.";
                 container routes {
                   description
                     "Enclosing container for list of routes in the
                      routing table.";
                   list route {
                     key "prefix origin path-id";
                     description
                       "List of routes in the table, keyed by the route
                        prefix, the route origin, and path-id. The route
                        origin can be either the neighbor address from
                        which the route was learned, or the source
                        protocol that injected the route. The path-id
                        distinguishes routes for the same prefix
                        received from a neighbor (e.g., if add-paths is
                        enabled).";
                     leaf prefix {
                       type inet:ipv6-prefix;
                       description
                         "The IPv6 prefix corresponding to the route.";
                     }
                     uses bgp-loc-rib-common-keys;
                     uses bgp-loc-rib-common-attr-refs;
                     uses bgp-common-route-annotations-state;



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                     uses bgp-unknown-attr-top;
                     uses rib-ext-route-annotations;
                   }
                 }
               }

               container neighbors {
                 config false;
                 description
                   "Enclosing container for neighbor list.";
                 list neighbor {
                   key "neighbor-address";
                   description
                     "List of neighbors (peers) of the local BGP
                      speaker.";
                   leaf neighbor-address {
                     type inet:ip-address;
                     description
                       "IP address of the BGP neighbor or peer.";
                   }
                   container adj-rib-in-pre {
                     description
                       "Per-neighbor table containing the BGP routes
                        received from the neighbor before any local
                        input policy rules or filters have been applied.
                        This can be considered the 'raw' routes from
                        the neighbor.";
                     uses ipv6-adj-rib-common;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-in state for the containing
                          neighbor. Subsequently, implementations might
                          issue a 'route refresh' if 'route refresh' has
                          been negotiated, or reset the session. ";
                     }
                   }
                   container adj-rib-in-post {
                     description
                       "Per-neighbor table containing the paths received
                        from the neighbor that are eligible for
                        best-path selection after local input policy
                        rules have been applied.";
                     uses ipv6-adj-rib-in-post;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-in state for the containing
                          neighbor. Subsequently, implementations might
                          issue a 'route refresh' if 'route refresh' has



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                          been negotiated, or reset the session. ";
                     }
                   }
                   container adj-rib-out-pre {
                     description
                       "Per-neighbor table containing paths eligible for
                        sending (advertising) to the neighbor before
                        output policy rules have been applied.";
                     uses ipv6-adj-rib-common;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-out state for the
                          containing neighbor. Subsequently, neighbors
                          will announce BGP updates to resynchronize
                          these routes.";
                     }
                   }
                   container adj-rib-out-post {
                     description
                       "Per-neighbor table containing paths eligible for
                        sending (advertising) to the neighbor after
                        output policy rules have been applied.";
                     uses ipv6-adj-rib-common;
                     uses clear-routes {
                       description
                         "Clears the adj-rib-out state for the
                          containing neighbor. Subsequently, neighbors
                          will announce BGP updates to resynchronize
                          these routes.";
                     }
                   }
                 }
               }
             }
           }
         }
         description
           "Top level container for BGP RIB.";
       }
     }
   }
   <CODE ENDS>

7.6.3.  BGP RIB attributes submodule







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   <CODE BEGINS> file "ietf-bgp-rib-attributes@2023-07-05.yang"
   submodule ietf-bgp-rib-attributes {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     // import some basic types

     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import iana-bgp-community-types {
       prefix bct;
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }

     // meta

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com),
                 Jeffrey Haas (jhaas at juniper.net).";

     description
       "This submodule contains common data definitions for BGP
        attributes for use in BGP RIB tables.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set



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        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping bgp-as-path-segment {
       description
         "Data for representing BGP AS-PATH segment";

       leaf type {
         type identityref {
           base bt:as-path-segment-type;
         }
         description
           "The type of AS-PATH segment";
       }
       leaf-list member {
         type inet:as-number;
         description
           "List of the AS numbers in the AS-PATH segment";
       }
     }

     grouping bgp-unknown-attr-top {
       description
         "Unknown path attributes that are not expected to be shared
          across route entries, common to LOC-RIB and Adj-RIB";
       container unknown-attributes {
         description
           "Unknown path attributes that were received in the UPDATE
            message which contained the prefix.";




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         list unknown-attribute {
           key "attr-type";
           description
             "This list contains received attributes that are
              unrecognized or unsupported by the local router. The list
              may be empty.";

           leaf optional {
             type boolean;
             description
               "Defines whether the attribute is optional (if
                set to true) or well-known (if set to false).
                Set in the high-order bit of the BGP attribute
                flags octet.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf transitive {
             type boolean;
             description
               "Defines whether an optional attribute is transitive
                (if set to true) or non-transitive (if set to false).
                For well-known attributes, the transitive flag must be
                set to true. Set in the second high-order bit of the BGP
                attribute flags octet.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf partial {
             type boolean;
             description
               "Defines whether the information contained in the
                optional transitive attribute is partial (if set to
                true) or complete (if set to false). For well-known
                attributes and for optional non-transitive attributes,
                the partial flag must be set to false. Set in the third
                high-order bit of the BGP attribute flags octet.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf extended {
             type boolean;
             description
               "Defines whether the attribute length is one octet
                (if set to false) or two octets (if set to true). Set in



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                the fourth high-order bit of the BGP attribute flags
                octet.";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf attr-type {
             type uint8;
             description
               "1-octet value encoding the attribute type code";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf attr-len {
             type uint16;
             description
               "One or two octet attribute length field indicating the
                length of the attribute data in octets.  If the Extended
                Length attribute flag is set, the length field is 2
                octets, otherwise it is 1 octet";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }

           leaf attr-value {
             type binary {
               length "0..65535";
             }
             description
               "Raw attribute value, not including the attribute
                flags, type, or length.  The maximum length
                of the attribute value data is 2^16-1 per the max value
                of the attr-len field (2 octets).";
             reference
               "RFC 4271: A Border Gateway Protocol 4 (BGP-4).";
           }
         }
       }
     }

     grouping bgp-adj-rib-attr-state {
       description
         "Path attributes that are not expected to be shared across
          route entries, specific to Adj-RIB";
       leaf path-id {
         type uint32;
         description



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           "When the BGP speaker supports advertisement of multiple
            paths for a prefix, the path identifier is used to
            uniquely identify a route based on the combination of the
            prefix and path id.  In the Adj-RIB-In, the path-id value is
            the value received in the update message.   In the Loc-RIB,
            if used, it should represent a locally generated path-id
            value for the corresponding route.  In Adj-RIB-Out, it
            should be the value sent to a neighbor when add-paths is
            used, i.e., the capability has been negotiated.";
         reference
           "RFC 7911: Advertisement of Multiple Paths in BGP.";
       }
     }

     grouping bgp-community-attr-state {
       description
         "Common definition of BGP community attributes";
       leaf-list community {
         type union {
           type bct:bgp-well-known-community-type;
           type bct:bgp-std-community-type;
         }
         description
           "List of standard or well-known BGP community
            attributes.";
       }
     }

     grouping ext-community-attributes {
       description
         "A grouping for all extended community parameters.";

       leaf-list ext-community {
         type bct:bgp-ext-community-type;
         description
           "List of BGP extended community attributes. The received
            extended community may be an explicitly modeled
            type or unknown, represented by an 8-octet value
            formatted according to RFC 4360.";
         reference
           "RFC 4360: BGP Extended Communities Attribute.";
       }

       leaf-list ext-community-raw {
         type string {
           // raw with 8 octets
           pattern 'raw:([0-9A-F][0-9A-F]:){7}[0-9A-F][0-9A-F]';
         }



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         description
           "ext-community type in raw format only.";
       }
     }

     grouping ipv6-ext-community-attributes {
       description
         "A grouping for all IPv6 extended community parameters.";

       leaf-list ipv6-ext-community {
         type bct:bgp-ipv6-ext-community-type;
         description
           "List of BGP IPv6 extended community attributes. The received
            IPv6 extended community may be an explicitly modeled
            type or unknown, represented by an 20-octet value
            formatted according to RFC 5701.";
         reference
           "RFC 5701: IPv6 Address Specific BGP Extended Community
            Attribute, Section 3.";
       }

       leaf-list ipv6-ext-community-raw {
         type string {
           // raw with 20 octets
           pattern 'ipv6-raw:'
                + '([0-9A-Fa-f][0-9A-Fa-f]:){19}'
                + '[0-9A-Fa-f][0-9A-Fa-f]';
         }
         description
           "IPv6 ext-community type in raw format only.";
       }
     }

     grouping large-community-attributes {
       description
         "A grouping for all large community parameters.";

       leaf-list large-community {
         type bct:bgp-large-community-type;
         description
           "List of BGP large community attributes.";
         reference
           "RFC 8092: BGP Large Communities Attribute.";
       }
     }
   }
   <CODE ENDS>




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7.6.4.  BGP RIB tables submodule

   <CODE BEGINS> file "ietf-bgp-rib-tables@2023-07-05.yang"
   submodule ietf-bgp-rib-tables {
     yang-version 1.1;
     belongs-to ietf-bgp {
       prefix bgp;
     }

     // import some basic types

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types.";
     }
     import ietf-routing {
       prefix rt;
       reference
         "RFC 8022: A YANG Data Model for Routing Management.";
     }
     import iana-bgp-types {
       prefix bt;
       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP-4).";
     }
     import iana-bgp-rib-types {
       prefix brt;
       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP-4).";
     }
     include ietf-bgp-rib-attributes;

     organization
       "IETF IDR Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com,
                 Jeffrey Haas (jhaas at juniper.net).";



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     description
       "This submodule contains structural data definitions for
        BGP routing tables.

        Copyright (c) 2023 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject to
        the license terms contained in, the Revised BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
        for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     revision 2023-07-05 {
       description
         "Initial Version";
       reference
         "RFC XXXX: YANG Model for Border Gateway Protocol (BGP-4).";
     }

     grouping bgp-common-route-annotations-state {
       description
         "Data definitions for flags and other information attached
          to routes in both LOC-RIB and Adj-RIB";
       leaf last-modified {
         type yang:timeticks;
         description
           "Timestamp when this path was last modified.

            The value is the timestamp in seconds relative to
            the Unix Epoch (Jan 1, 1970 00:00:00 UTC).";
       }
       leaf eligible-route {
         type boolean;
         description
           "Indicates that the route is eligible for selection for the
            best route in the Loc-Rib in BGP's Decision Process.";



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         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
            Section 9.1.";
       }
       leaf ineligible-reason {
         type identityref {
           base brt:ineligible-route-reason;
         }
         description
           "If the route is ineligible for selection for the best route
            in the Loc-Rib in BGP's Decision process, this indicates the
            reason.";
         reference
           "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
            Section 9.1.";
       }
     }

     grouping bgp-adj-rib-in-post-route-annotations-state {
       description
         "Data definitions for information attached to routes in the
          Adj-RIB-In post-policy table";
       leaf best-path {
         type boolean;
         default "false";
         description
           "Current path was selected as the best path. Best path
            should indicate that the route is present in BGP Loc-RIB.";
       }
     }

     grouping rib-ext-route-annotations {
       description
         "Extended annotations for routes in the routing tables";
       leaf reject-reason {
         type union {
           type identityref {
             base brt:bgp-not-selected-bestpath;
           }
           type identityref {
             base brt:bgp-not-selected-policy;
           }
         }
         description
           "Indicates the reason the route is not used, either due to
            policy filtering or bestpath selection";
       }
     }



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     grouping bgp-adj-rib-common-attr-refs {
       description
         "Definitions of common references to attribute sets for
          multiple AFI-SAFIs for Adj-RIB tables.";
       leaf attr-index {
         type leafref {
           path "../../../../../../../../../attr-sets/"
              + "attr-set/index";
         }
         description
           "Reference to the common attribute group for the
            route.";
       }
       leaf community-index {
         type leafref {
           path "../../../../../../../../../communities/community/"
              + "index";
         }
         description
           "Reference to the community attribute for the route.";
       }
       leaf ext-community-index {
         type leafref {
           path "../../../../../../../../../ext-communities/"
              + "ext-community/index";
         }
         description
           "Reference to the extended community attribute for the
            route.";
       }
       leaf large-community-index {
         type leafref {
           path "../../../../../../../../../large-communities/"
              + "large-community/index";
         }
         description
           "Reference to the large community attribute for the
            route.";
       }
     }

     grouping bgp-loc-rib-common-attr-refs {
       description
         "Definitions of common references to attribute sets for
          multiple AFI-SAFIs for Loc-RIB tables.";
       leaf attr-index {
         type leafref {
           path "../../../../../../../attr-sets/attr-set/"



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              + "index";
         }
         description
           "Reference to the common attribute group for the
            route.";
       }
       leaf community-index {
         type leafref {
           path "../../../../../../../communities/community/"
              + "index";
         }
         description
           "Reference to the community attribute for the route.";
       }
       leaf ext-community-index {
         type leafref {
           path "../../../../../../../ext-communities/"
              + "ext-community/index";
         }
         description
           "Reference to the extended community attribute for the
            route.";
       }
       leaf large-community-index {
         type leafref {
           path "../../../../../../../large-communities/"
              + "large-community/index";
         }
         description
           "Reference to the large community attribute for the
            route.";
       }
     }

     grouping bgp-loc-rib-common-keys {
       description
         "Common references used in keys for IPv4 and IPv6
          Loc-RIB entries.";
       leaf origin {
         type union {
           type inet:ip-address;
           type identityref {
             base rt:routing-protocol;
           }
         }
         description
           "Indicates the origin of the route.  If the route is learned
            from a neighbor, this value is the neighbor address.  If



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            the route was injected or redistributed from another
            protocol, the origin indicates the source protocol for the
            route.";
       }
       leaf path-id {
         type uint32;
         description
           "If the route is learned from a neighbor, the path-id
            corresponds to the path-id for the route in the
            corresponding adj-rib-in-post table.  If the route is
            injected from another protocol, or the neighbor does not
            support BGP add-paths, the path-id should be set
            to zero, also the default value.

            However, YANG does not allow default values to be set
            for parameters that form the key, so a default value
            cannot be set here.";
       }
     }

     grouping clear-routes {
       description
         "Action to clear BGP routes.";
       container clear-routes {
         if-feature "bt:clear-routes";
         action clear {
           input {
             leaf clear-at {
               type yang:date-and-time;
               description
                 "The time, in the future when the clear operation will
                  be initiated.";
             }
           }
           output {
             leaf clear-finished-at {
               type yang:date-and-time;
               description
                 "The time when the clear operation finished.";
             }
           }
         }
         description
           "Action commands to clear routes governed by a if-feature.";
       }
     }

     grouping ipv4-adj-rib-common {



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       description
         "Common structural grouping for each IPv4 Adj-RIB table.";
       container routes {
         config false;
         description
           "Enclosing container for list of routes in the routing
            table.";
         list route {
           key "prefix path-id";
           description
             "List of routes in the table, keyed by a combination of
              the route prefix and path-id to distinguish multiple
              routes received from a neighbor for the same prefix;
              e.g., when BGP add-paths is enabled.";
           leaf prefix {
             type inet:ipv4-prefix;
             description
               "Prefix for the route.";
           }
           uses bgp-adj-rib-attr-state;
           uses bgp-adj-rib-common-attr-refs;
           uses bgp-common-route-annotations-state;
           uses bgp-unknown-attr-top;
           uses rib-ext-route-annotations;
         }
       }
     }

     grouping ipv4-adj-rib-in-post {
       description
         "Common structural grouping for the IPv4 Adj-RIB-In
          post-policy table.";
       container routes {
         config false;
         description
           "Enclosing container for list of routes in the routing
            table.";
         list route {
           key "prefix path-id";
           description
             "List of routes in the table, keyed by a combination of
              the route prefix and path-id to distinguish multiple
              routes received from a neighbor for the same prefix;
              e.g., when BGP add-paths is enabled.";
           leaf prefix {
             type inet:ipv4-prefix;
             description
               "Prefix for the route.";



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           }
           uses bgp-adj-rib-attr-state;
           uses bgp-adj-rib-common-attr-refs;
           uses bgp-common-route-annotations-state;
           uses bgp-adj-rib-in-post-route-annotations-state;
           uses bgp-unknown-attr-top;
           uses rib-ext-route-annotations;
         }
       }
     }

     grouping ipv6-adj-rib-common {
       description
         "Common structural grouping for each IPv6 Adj-RIB table.";
       container routes {
         config false;
         description
           "Enclosing container for list of routes in the routing
            table.";
         list route {
           key "prefix path-id";
           description
             "List of routes in the table.";
           leaf prefix {
             type inet:ipv6-prefix;
             description
               "Prefix for the route.";
           }
           uses bgp-adj-rib-attr-state;
           uses bgp-adj-rib-common-attr-refs;
           uses bgp-common-route-annotations-state;
           uses bgp-unknown-attr-top;
           uses rib-ext-route-annotations;
         }
       }
     }

     grouping ipv6-adj-rib-in-post {
       description
         "Common structural grouping for the IPv6 Adj-RIB-In
          post-policy table.";
       container routes {
         config false;
         description
           "Enclosing container for list of routes in the routing
            table.";
         list route {
           key "prefix path-id";



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           description
             "List of routes in the table.";
           leaf prefix {
             type inet:ipv6-prefix;
             description
               "Prefix for the route.";
           }
           uses bgp-adj-rib-attr-state;
           uses bgp-adj-rib-common-attr-refs;
           uses bgp-common-route-annotations-state;
           uses bgp-adj-rib-in-post-route-annotations-state;
           uses bgp-unknown-attr-top;
           uses rib-ext-route-annotations;
         }
       }
     }
   }
   <CODE ENDS>

8.  Contributors

   Previous versions of this document saw contributions from Anees
   Shaikh, Rob Shakir, Kevin D'Souza, Alexander Clemm, Aleksandr
   Zhadkin, and Xufeng Liu.

9.  Acknowledgements

   The authors are grateful for valuable contributions to this document
   and the associated models from: Ebben Aires, Pavan Beeram, Chris
   Chase, Ed Crabbe, Luyuan Fang, Bill Fenner, Akshay Gattani, Josh
   George, Vijay Gill, Matt John, Dhanendra Jain, Acee Lindem, Ina
   Minei, Carl Moberg, Ashok Narayanan, Einar Nilsen-Nygaard, Adam
   Simpson, Puneet Sood, Jason Sterne, Jeff Tantsura, Jim Uttaro, and
   Gunter Vandevelde.

   Credit is also due to authors of the OpenConfig, whose model was
   relied upon to come up with this model.

   Special thanks to Robert Wilton who helped convert the YANG models to
   a NMDA compatible model, to Yingzhen Qu who contributed to the policy
   part of the module, and to Derek Yeung in helping out with Extended
   Communities support in the model.

10.  References

10.1.  Normative references





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   [RFC1997]  Chandra, R., Traina, P., and T. Li, "BGP Communities
              Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
              <https://www.rfc-editor.org/info/rfc1997>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2439]  Villamizar, C., Chandra, R., and R. Govindan, "BGP Route
              Flap Damping", RFC 2439, DOI 10.17487/RFC2439, November
              1998, <https://www.rfc-editor.org/info/rfc2439>.

   [RFC2918]  Chen, E., "Route Refresh Capability for BGP-4", RFC 2918,
              DOI 10.17487/RFC2918, September 2000,
              <https://www.rfc-editor.org/info/rfc2918>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <https://www.rfc-editor.org/info/rfc4360>.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <https://www.rfc-editor.org/info/rfc4364>.

   [RFC4456]  Bates, T., Chen, E., and R. Chandra, "BGP Route
              Reflection: An Alternative to Full Mesh Internal BGP
              (IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
              <https://www.rfc-editor.org/info/rfc4456>.

   [RFC4659]  De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
              "BGP-MPLS IP Virtual Private Network (VPN) Extension for
              IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006,
              <https://www.rfc-editor.org/info/rfc4659>.

   [RFC4724]  Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y.
              Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724,
              DOI 10.17487/RFC4724, January 2007,
              <https://www.rfc-editor.org/info/rfc4724>.



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   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <https://www.rfc-editor.org/info/rfc4760>.

   [RFC4761]  Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
              LAN Service (VPLS) Using BGP for Auto-Discovery and
              Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007,
              <https://www.rfc-editor.org/info/rfc4761>.

   [RFC5065]  Traina, P., McPherson, D., and J. Scudder, "Autonomous
              System Confederations for BGP", RFC 5065,
              DOI 10.17487/RFC5065, August 2007,
              <https://www.rfc-editor.org/info/rfc5065>.

   [RFC5701]  Rekhter, Y., "IPv6 Address Specific BGP Extended Community
              Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009,
              <https://www.rfc-editor.org/info/rfc5701>.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
              <https://www.rfc-editor.org/info/rfc5880>.

   [RFC5881]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
              DOI 10.17487/RFC5881, June 2010,
              <https://www.rfc-editor.org/info/rfc5881>.

   [RFC5883]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
              June 2010, <https://www.rfc-editor.org/info/rfc5883>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.






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   [RFC6514]  Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
              Encodings and Procedures for Multicast in MPLS/BGP IP
              VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
              <https://www.rfc-editor.org/info/rfc6514>.

   [RFC6793]  Vohra, Q. and E. Chen, "BGP Support for Four-Octet
              Autonomous System (AS) Number Space", RFC 6793,
              DOI 10.17487/RFC6793, December 2012,
              <https://www.rfc-editor.org/info/rfc6793>.

   [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", RFC 6811,
              DOI 10.17487/RFC6811, January 2013,
              <https://www.rfc-editor.org/info/rfc6811>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7607]  Kumari, W., Bush, R., Schiller, H., and K. Patel,
              "Codification of AS 0 Processing", RFC 7607,
              DOI 10.17487/RFC7607, August 2015,
              <https://www.rfc-editor.org/info/rfc7607>.

   [RFC7911]  Walton, D., Retana, A., Chen, E., and J. Scudder,
              "Advertisement of Multiple Paths in BGP", RFC 7911,
              DOI 10.17487/RFC7911, July 2016,
              <https://www.rfc-editor.org/info/rfc7911>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8092]  Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas,
              I., and N. Hilliard, "BGP Large Communities Attribute",
              RFC 8092, DOI 10.17487/RFC8092, February 2017,
              <https://www.rfc-editor.org/info/rfc8092>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.






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   [RFC8177]  Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J.
              Zhang, "YANG Data Model for Key Chains", RFC 8177,
              DOI 10.17487/RFC8177, June 2017,
              <https://www.rfc-editor.org/info/rfc8177>.

   [RFC8277]  Rosen, E., "Using BGP to Bind MPLS Labels to Address
              Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
              <https://www.rfc-editor.org/info/rfc8277>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8349]  Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
              Routing Management (NMDA Version)", RFC 8349,
              DOI 10.17487/RFC8349, March 2018,
              <https://www.rfc-editor.org/info/rfc8349>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8528]  Bjorklund, M. and L. Lhotka, "YANG Schema Mount",
              RFC 8528, DOI 10.17487/RFC8528, March 2019,
              <https://www.rfc-editor.org/info/rfc8528>.

   [RFC8529]  Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
              Liu, "YANG Data Model for Network Instances", RFC 8529,
              DOI 10.17487/RFC8529, March 2019,
              <https://www.rfc-editor.org/info/rfc8529>.

   [RFC9067]  Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data
              Model for Routing Policy", RFC 9067, DOI 10.17487/RFC9067,
              October 2021, <https://www.rfc-editor.org/info/rfc9067>.

   [RFC9293]  Eddy, W., Ed., "Transmission Control Protocol (TCP)",
              STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
              <https://www.rfc-editor.org/info/rfc9293>.

   [RFC9314]  Jethanandani, M., Ed., Rahman, R., Ed., Zheng, L., Ed.,
              Pallagatti, S., and G. Mirsky, "YANG Data Model for
              Bidirectional Forwarding Detection (BFD)", RFC 9314,
              DOI 10.17487/RFC9314, September 2022,
              <https://www.rfc-editor.org/info/rfc9314>.






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   [I-D.ietf-tcpm-yang-tcp]
              Scharf, M., Jethanandani, M., and V. Murgai, "A YANG Model
              for Transmission Control Protocol (TCP) Configuration and
              State", Work in Progress, Internet-Draft, draft-ietf-tcpm-
              yang-tcp-09, 11 September 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tcpm-
              yang-tcp-09>.

10.2.  Informative references

   [RFC2385]  Heffernan, A., "Protection of BGP Sessions via the TCP MD5
              Signature Option", RFC 2385, DOI 10.17487/RFC2385, August
              1998, <https://www.rfc-editor.org/info/rfc2385>.

   [RFC2622]  Alaettinoglu, C., Villamizar, C., Gerich, E., Kessens, D.,
              Meyer, D., Bates, T., Karrenberg, D., and M. Terpstra,
              "Routing Policy Specification Language (RPSL)", RFC 2622,
              DOI 10.17487/RFC2622, June 1999,
              <https://www.rfc-editor.org/info/rfc2622>.

   [RFC3765]  Huston, G., "NOPEER Community for Border Gateway Protocol
              (BGP) Route Scope Control", RFC 3765,
              DOI 10.17487/RFC3765, April 2004,
              <https://www.rfc-editor.org/info/rfc3765>.

   [RFC4451]  McPherson, D. and V. Gill, "BGP MULTI_EXIT_DISC (MED)
              Considerations", RFC 4451, DOI 10.17487/RFC4451, March
              2006, <https://www.rfc-editor.org/info/rfc4451>.

   [RFC5082]  Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C.
              Pignataro, "The Generalized TTL Security Mechanism
              (GTSM)", RFC 5082, DOI 10.17487/RFC5082, October 2007,
              <https://www.rfc-editor.org/info/rfc5082>.

   [RFC5398]  Huston, G., "Autonomous System (AS) Number Reservation for
              Documentation Use", RFC 5398, DOI 10.17487/RFC5398,
              December 2008, <https://www.rfc-editor.org/info/rfc5398>.

   [RFC5925]  Touch, J., Mankin, A., and R. Bonica, "The TCP
              Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
              June 2010, <https://www.rfc-editor.org/info/rfc5925>.

   [RFC6151]  Turner, S. and L. Chen, "Updated Security Considerations
              for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
              RFC 6151, DOI 10.17487/RFC6151, March 2011,
              <https://www.rfc-editor.org/info/rfc6151>.





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   [RFC7454]  Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
              and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
              February 2015, <https://www.rfc-editor.org/info/rfc7454>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [I-D.ietf-idr-deprecate-as-set-confed-set]
              Kumari, W. A., Sriram, K., Hannachi, L., and J. Haas,
              "Deprecation of AS_SET and AS_CONFED_SET in BGP", Work in
              Progress, Internet-Draft, draft-ietf-idr-deprecate-as-set-
              confed-set-10, 16 January 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              deprecate-as-set-confed-set-10>.

Appendix A.  Examples

   This section tries to show some examples in how the model can be
   used.

A.1.  Creating BGP Instance

   This example shows how to enable BGP for a IPv4 unicast address
   family.

























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   [note: '\' line wrapping for formatting only]

   <?xml version="1.0" encoding="UTF-8"?>
   <routing
       xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
     <control-plane-protocols>
       <control-plane-protocol>
         <type
             xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</\
   type>
         <name>BGP</name>
         <bgp
             xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
           <global>
             <as>64496</as>
             <afi-safis>
               <afi-safi>
                 <name
                     xmlns:bt=
                     "urn:ietf:params:xml:ns:yang:iana-bgp-types">bt:ip\
   v4-unicast</name>
               </afi-safi>
             </afi-safis>
           </global>
         </bgp>
       </control-plane-protocol>
     </control-plane-protocols>
   </routing>

A.2.  Neighbor Address Family Configuration

   This example shows how to configure a BGP neighbor, where the remote
   address is 192.0.2.1, the remote AS number is 64497, and the address
   family of the neighbor is IPv4 unicast.  The neighbor is configured
   for route flap prevention and it set up for standard and large
   communities.  In addition, BFD is configured at a neighbor level with
   a local multiplier of 2, a desired minimum transmit interval, and a
   required minimum receive interval of 3.3 ms.

   [note: '\' line wrapping for formatting only]

   <!--
       This example shows a neighbor configuration with damping.
   -->

   <?xml version="1.0" encoding="UTF-8"?>
   <routing
       xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"



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       xmlns:bt="urn:ietf:params:xml:ns:yang:iana-bgp-types"
       xmlns:bct="urn:ietf:params:xml:ns:yang:iana-bgp-community-types"\
   >
     <control-plane-protocols>
       <control-plane-protocol>
         <type
             xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</\
   type>
         <name>name:BGP</name>
         <bgp
             xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
           <global>
             <as>64496</as>
             <afi-safis>
               <afi-safi>
                 <name>bt:ipv4-unicast</name>
               </afi-safi>
             </afi-safis>
           </global>
           <neighbors>
             <neighbor>
               <remote-address>192.0.2.1</remote-address>
               <peer-as>64497</peer-as>
               <route-flap-damping>
                 <enable>true</enable>
                 <suppress-above>4.0</suppress-above>
                 <reuse-above>3.0</reuse-above>
                 <max-flap>15.0</max-flap>
                 <reach-decay>100</reach-decay>
                 <unreach-decay>500</unreach-decay>
                 <keep-history>1000</keep-history>
               </route-flap-damping>
               <send-community>bct:standard</send-community>
               <send-community>bct:large</send-community>
               <description>"Peer Router B"</description>
               <afi-safis>
                 <afi-safi>
                   <name>bt:ipv4-unicast</name>
                 </afi-safi>
               </afi-safis>
               <transport>
                 <tcp-mss>1400</tcp-mss>
                 <mtu-discovery>true</mtu-discovery>
                 <bfd>
                   <enabled>true</enabled>
                   <local-multiplier>2</local-multiplier>
                   <desired-min-tx-interval>3300</desired-min-tx-interv\
   al>



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                   <required-min-rx-interval>3300</required-min-rx-inte\
   rval>
                 </bfd>
               </transport>
             </neighbor>
           </neighbors>
         </bgp>
       </control-plane-protocol>
     </control-plane-protocols>
   </routing>

A.3.  IPv6 Neighbor Configuration

   This example shows how to configure a BGP peer, where the remote peer
   has a IPv6 address, uses TCP-AO to secure the session with the peer,
   and uses non-default timers for hold-time and keepalive.

   [note: '\' line wrapping for formatting only]

   <?xml version="1.0" encoding="UTF-8"?>
   <key-chains
       xmlns="urn:ietf:params:xml:ns:yang:ietf-key-chain">
     <key-chain>
       <name>bgp-key-chain</name>
       <description>"An example of TCP-AO configuration for BGP"</descr\
   iption>
       <key>
         <key-id>55</key-id>
         <lifetime>
           <send-lifetime>
             <start-date-time>2017-01-01T00:00:00Z</start-date-time>
             <end-date-time>2017-02-01T00:00:00Z</end-date-time>
           </send-lifetime>
           <accept-lifetime>
             <start-date-time>2016-12-31T23:59:55Z</start-date-time>
             <end-date-time>2017-02-01T00:00:05Z</end-date-time>
           </accept-lifetime>
         </lifetime>
         <crypto-algorithm>aes-cmac-prf-128</crypto-algorithm>
         <key-string>
           <keystring>testvector</keystring>
         </key-string>
         <authentication
             xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp">
           <keychain>bgp-key-chain</keychain>
           <ao>
             <send-id>65</send-id>
             <recv-id>87</recv-id>



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           </ao>
         </authentication>
       </key>
       <key>
         <key-id>56</key-id>
         <lifetime>
           <send-lifetime>
             <start-date-time>2017-01-01T00:00:00Z</start-date-time>
             <end-date-time>2017-02-01T00:00:00Z</end-date-time>
           </send-lifetime>
           <accept-lifetime>
             <start-date-time>2016-12-31T23:59:55Z</start-date-time>
             <end-date-time>2017-02-01T00:00:05Z</end-date-time>
           </accept-lifetime>
         </lifetime>
         <crypto-algorithm>aes-cmac-prf-128</crypto-algorithm>
         <key-string>
           <keystring>testvector</keystring>
         </key-string>
         <authentication
             xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp">
           <keychain>bgp-key-chain</keychain>
           <ao>
             <send-id>65</send-id>
             <recv-id>87</recv-id>
           </ao>
         </authentication>
       </key>
     </key-chain>
   </key-chains>

   <routing
       xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
     <control-plane-protocols>
       <control-plane-protocol>
         <type
             xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</\
   type>
         <name>name:BGP</name>
         <bgp
             xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
           <global>
             <as>64496</as>
             <afi-safis>
               <afi-safi>
                 <name
                     xmlns:bt=
                     "urn:ietf:params:xml:ns:yang:iana-bgp-types">bt:ip\



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   v6-unicast</name>
               </afi-safi>
             </afi-safis>
           </global>
           <neighbors>
             <neighbor>
               <remote-address>2001:db8::</remote-address>
               <enabled>true</enabled>
               <transport>
                 <secure-session>
                   <enabled>true</enabled>
                   <options>
                     <ao-keychain>bgp-key-chain</ao-keychain>
                   </options>
                 </secure-session>
               </transport>
               <peer-as>64497</peer-as>
               <description>"Peer Router B"</description>
               <timers>
                 <hold-time>120</hold-time>
                 <keepalive>70</keepalive>
               </timers>
               <afi-safis>
                 <afi-safi>
                   <name
                       xmlns:bt=
                       "urn:ietf:params:xml:ns:yang:iana-bgp-types">bt:\
   ipv6-unicast</name>
                 </afi-safi>
               </afi-safis>
             </neighbor>
           </neighbors>
         </bgp>
       </control-plane-protocol>
     </control-plane-protocols>
   </routing>

A.4.  VRF Configuration

   This example shows how BGP can be configured for two VRFs, red and
   blue.  In this case, the two network instances share a common AS, and
   distinguish between the instances using the router id.









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   [note: '\' line wrapping for formatting only]

   <?xml version="1.0" encoding="UTF-8"?>
   <network-instances
       xmlns="urn:ietf:params:xml:ns:yang:ietf-network-instance">
     <network-instance>
       <name>vrf-red</name>
       <vrf-root>
         <routing
             xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
           <router-id>192.0.2.1</router-id>
           <control-plane-protocols>
             <control-plane-protocol>
               <type
                   xmlns:bgp=
                   "urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</type\
   >
               <name>BGP</name>
               <bgp
                   xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
                 <global>
                   <as>64496</as>
                   <afi-safis>
                     <afi-safi>
                       <name
                           xmlns:bt=
                           "urn:ietf:params:xml:ns:yang:iana-bgp-types"\
   >bt:ipv4-unicast</name>
                     </afi-safi>
                   </afi-safis>
                 </global>
               </bgp>
             </control-plane-protocol>
           </control-plane-protocols>
         </routing>
       </vrf-root>
     </network-instance>
     <network-instance>
       <name>vrf-blue</name>
       <vrf-root>
         <routing
             xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
           <router-id>192.0.2.2</router-id>
           <control-plane-protocols>
             <control-plane-protocol>
               <type
                   xmlns:bgp=
                   "urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</type\



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   >
               <name>BGP</name>
               <bgp
                   xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
                 <global>
                   <as>64496</as>
                   <afi-safis>
                     <afi-safi>
                       <name
                           xmlns:bt=
                           "urn:ietf:params:xml:ns:yang:iana-bgp-types"\
   >bt:ipv4-unicast</name>
                     </afi-safi>
                   </afi-safis>
                 </global>
               </bgp>
             </control-plane-protocol>
           </control-plane-protocols>
         </routing>
       </vrf-root>
     </network-instance>
   </network-instances>

A.5.  BGP Policy - Match Prefix and Set Community

   Routing policy using community value involves configuring rules to
   match community values in the inbound or outbound direction.  In this
   example, which is heavily borrowed from the example on the Cisco
   community page, we look at "match community exact" match, which
   happens only when BGP updates have the same community values as
   specified in the community list.

   The topology in this example consists of three routers, R1, R2, and
   R3, configured with AS value of 1, 2 and 3 respectively.  R1
   advertises 5 prefixes to R2 and R3, as shown below.

   *  1.1.1.1/32 and 2.2.2.2/32 with community 11:11

   *  3.3.3.3/32 and 4.4.4.4/32 with community 11:11 and 22:22

   *  5.5.5.5/32 with community 33.33










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   Route Policy TO_R2 defines the policy that R1 uses in route updates
   towards R2.  It consists of three statements, statement 10 that has a
   exact match rule for the prefix list L0andL1, and a set-community
   action of add for 11:11.  The second statement, statement 20,
   consists of an exact match rule for prefix list L2andL3, with a set
   community action of remove for 11:11 22:22.  The final statement,
   statement 30, consists of an exact match rule for prefix list L4,
   with a set community action of replace for 33:33.

   [note: '\' line wrapping for formatting only]

   <?xml version="1.0" encoding="UTF-8"?>
   <routing-policy
       xmlns="urn:ietf:params:xml:ns:yang:ietf-routing-policy">
     <defined-sets>
       <prefix-sets>
         <prefix-set>
           <name>L0andL1</name>
           <mode>ipv4</mode>
           <prefixes>
             <prefix-list>
               <ip-prefix>1.1.1.1/32</ip-prefix>
               <mask-length-lower>32</mask-length-lower>
               <mask-length-upper>32</mask-length-upper>
             </prefix-list>
             <prefix-list>
               <ip-prefix>2.2.2.2/32</ip-prefix>
               <mask-length-lower>32</mask-length-lower>
               <mask-length-upper>32</mask-length-upper>
             </prefix-list>
           </prefixes>
         </prefix-set>
         <prefix-set>
           <name>L2andL3</name>
           <mode>ipv4</mode>
           <prefixes>
             <prefix-list>
               <ip-prefix>3.3.3.3/32</ip-prefix>
               <mask-length-lower>32</mask-length-lower>
               <mask-length-upper>32</mask-length-upper>
             </prefix-list>
             <prefix-list>
               <ip-prefix>4.4.4.4/32</ip-prefix>
               <mask-length-lower>32</mask-length-lower>
               <mask-length-upper>32</mask-length-upper>
             </prefix-list>
           </prefixes>
         </prefix-set>



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         <prefix-set>
           <name>L4</name>
           <mode>ipv4</mode>
           <prefixes>
             <prefix-list>
               <ip-prefix>5.5.5.5/32</ip-prefix>
               <mask-length-lower>32</mask-length-lower>
               <mask-length-upper>32</mask-length-upper>
             </prefix-list>
           </prefixes>
         </prefix-set>
       </prefix-sets>
     </defined-sets>
     <policy-definitions>
       <policy-definition>
         <name>TO_R2</name>
         <statements>
           <statement>
             <name>10</name>
             <conditions>
               <match-prefix-set>
                 <prefix-set>L0andL1</prefix-set>
               </match-prefix-set>
             </conditions>
             <actions>
               <bgp-actions
                   xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp-policy">\

                 <set-community>
                   <options>add</options>
                   <communities>11:11</communities>
                 </set-community>
               </bgp-actions>
             </actions>
           </statement>
           <statement>
             <name>20</name>
             <conditions>
               <match-prefix-set>
                 <prefix-set>L2andL3</prefix-set>
               </match-prefix-set>
             </conditions>
             <actions>
               <bgp-actions
                   xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp-policy">\

                 <set-community>
                   <options>remove</options>



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                   <communities>11:11</communities>
                   <communities>22:22</communities>
                 </set-community>
               </bgp-actions>
             </actions>
           </statement>
           <statement>
             <name>30</name>
             <conditions>
               <match-prefix-set>
                 <prefix-set>L4</prefix-set>
               </match-prefix-set>
             </conditions>
             <actions>
               <bgp-actions
                   xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp-policy">\

                 <set-community>
                   <options>replace</options>
                   <communities>33:33</communities>
                 </set-community>
               </bgp-actions>
             </actions>
           </statement>
         </statements>
       </policy-definition>
     </policy-definitions>
   </routing-policy>

   <routing
       xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"
       xmlns:bt="urn:ietf:params:xml:ns:yang:iana-bgp-types"
       xmlns:bct="urn:ietf:params:xml:ns:yang:iana-bgp-community-types"\
   >
     <control-plane-protocols>
       <control-plane-protocol>
         <type
             xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp</\
   type>
         <name>BGP</name>
         <bgp
             xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
           <global>
             <as>1</as>
             <afi-safis>
               <afi-safi>
                 <name>bt:ipv4-unicast</name>
               </afi-safi>



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             </afi-safis>
           </global>
           <neighbors>
             <neighbor>
               <remote-address>10.1.1.2</remote-address>
               <peer-as>2</peer-as>
               <afi-safis>
                 <afi-safi>
                   <name>bt:ipv4-unicast</name>
                 </afi-safi>
               </afi-safis>
               <send-community>bct:standard</send-community>
               <apply-policy>
                 <export-policy>TO_R2</export-policy>
                 <default-export-policy>accept-route</default-export-po\
   licy>
               </apply-policy>
             </neighbor>
           </neighbors>
         </bgp>
       </control-plane-protocol>
     </control-plane-protocols>
   </routing>

A.6.  BGP Policy - Match Next-hop and Set Community

   In this example, a "next-hop-set" is configured using option "invert"
   from "matct-set-options" to match next-hop not equal to "192.0.2.2"
   and then set community to 55:55.






















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   [note: '\' line wrapping for formatting only]

   <?xml version='1.0' encoding='UTF-8'?>
     <routing-policy xmlns="urn:ietf:params:xml:ns:yang:ietf-routing-po\
   licy">
       <defined-sets>
         <bgp-defined-sets xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp-\
   policy">
           <next-hop-sets>
             <next-hop-set>
               <name>nexthop_not2</name>
               <next-hop>192.0.2.2</next-hop>
             </next-hop-set>
           </next-hop-sets>
         </bgp-defined-sets>
       </defined-sets>
       <policy-definitions>
         <policy-definition>
           <name>nexthop_not2_community</name>
           <statements>
             <statement>
               <name>100</name>
               <conditions>
                 <bgp-conditions xmlns="urn:ietf:params:xml:ns:yang:iet\
   f-bgp-policy">
                   <match-next-hop-set>
                     <next-hop-set>nexthop_not2</next-hop-set>
                     <match-set-options>invert</match-set-options>
                   </match-next-hop-set>
                 </bgp-conditions>
               </conditions>
               <actions>
                 <bgp-actions xmlns="urn:ietf:params:xml:ns:yang:ietf-b\
   gp-policy">
                   <set-community>
                     <options>add</options>
                     <communities>55:55</communities>                  \

                   </set-community>
                 </bgp-actions>
               </actions>
             </statement>
           </statements>
         </policy-definition>
       </policy-definitions>
     </routing-policy>





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Appendix B.  How to add a new AFI and Augment a Module

   This section explains how a new AFI can be defined in a new module
   and how that module can then be augmented.  Assume that the new AFI
   being defined is called 'foo' which extends the base identity of
   'afi-safi-type', and the augmentation is to add a new container for
   'foo' under two different XPaths.  The example shows how the base
   identity can be extended to add this new AFI, and then use the
   augmented containers be used to add 'foo' specific information.

   module example-newafi-bgp {
     yang-version 1.1;
     namespace "http://example.com/ns/example-newafi-bgp";
     prefix example-newafi-bgp;

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types.";
     }

     import ietf-routing {
       prefix rt;
       reference
         "RFC 8349, A YANG Data Model for Routing Management
          (NMDA Version)";
     }

     import ietf-bgp {
       prefix "bgp";
       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP).";
     }

     import iana-bgp-types {
       prefix "bt";
     }

     organization
       "Newafi model group.";

     contact
       "abc@newafi.com";
     description
       "This YANG module defines and uses new AFI.";

     revision 2023-07-05 {
       description



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         "Creating new AFI and using in this model";

       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP).";
     }

     identity foo {
       base bt:afi-safi-type;
       description
         "New AFI type foo.";
     }

     augment "/rt:routing/rt:control-plane-protocols/" +
             "rt:control-plane-protocol/bgp:bgp/bgp:global/" +
             "bgp:afi-safis/bgp:afi-safi" {
       when "derived-from-or-self(bgp:name, 'foo')" {
         description
           "This augmentation is valid for a AFI/SAFI instance
            of 'foo'";
       }
       container foo {
         description
           "Container to add 'foo' specific AFI/SAFI information.
            First add the common stuff.";
         uses bgp:mp-all-afi-safi-common;
       }
     }

     augment "/rt:routing/rt:control-plane-protocols/" +
             "rt:control-plane-protocol/bgp:bgp/" +
             "bgp:rib/bgp:afi-safis/bgp:afi-safi" {
       when "derived-from-or-self(bgp:name, 'foo')" {
         description
           "This augmentation is valid for a AFI/SAFI instance
            of 'foo'";
       }

       container foo {
         description
           "Container to add 'foo' rib specific information.
            First add the common stuff.";
         container loc-rib {
           config false;
           description
             "Container for the 'foo' BGP LOC-RIB data.";
           container routes {
             description
               "Enclosing container for list of routes in the routing



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                table.";
             list route {
               key "prefix origin path-id";
               description
                 "List of routes in the table, keyed by the route
                  prefix, the route origin, and path-id.  The route
                  origin can be either the neighbor address from which
                  the route was learned, or the source protocol that
                  injected the route.  The path-id distinguishes routes
                  for the same prefix received from a neighbor (e.g.,
                  if add-paths is enabled).";
               leaf prefix {
                 type inet:ip-address;
                 description
                   "The 'foo' prefix corresponding to the route.";
               }
               uses bgp:bgp-loc-rib-common-keys;
               uses bgp:bgp-loc-rib-common-attr-refs;
               uses bgp:bgp-common-route-annotations-state;
               uses bgp:bgp-unknown-attr-top;
               uses bgp:rib-ext-route-annotations;
             }
             uses bgp:clear-routes;
           }
         }

         container neighbors {
           config false;
           description
             "Enclosing container for neighbor list.";
           list neighbor {
             key "neighbor-address";
             description
               "List of neighbors (peers) of the local BGP speaker.";
             leaf neighbor-address {
               type inet:ip-address;
               description
                 "IP address of the BGP neighbor or peer.";
             }
             container adj-rib-in-pre {
               description
                 "Per-neighbor table containing the NLRI updates
                received from the neighbor before any local input
                policy rules or filters have been applied.  This can
                be considered the 'raw' updates from the neighbor.";
               uses bgp:ipv4-adj-rib-common;
             }
             container adj-rib-in-post {



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               description
                 "Per-neighbor table containing the paths received from
                the neighbor that are eligible for best-path selection
                after local input policy rules have been applied.";
               uses bgp:ipv4-adj-rib-in-post;
             }
             container adj-rib-out-pre {
               description
                 "Per-neighbor table containing paths eligible for
                sending (advertising) to the neighbor before output
                policy rules have been applied.";
               uses bgp:ipv4-adj-rib-common;
             }
             container adj-rib-out-post {
               description
                 "Per-neighbor table containing paths eligible for
                sending (advertising) to the neighbor after output
                policy rules have been applied.";
               uses bgp:ipv4-adj-rib-common;
             }
           }
         }
       }
     }
   }

Appendix C.  How to deviate a module

   This example shows how the BGP can be deviated to indicate two nodes
   that the particular implementation is choosing not to support.





















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   module example-newco-bgp {
     yang-version 1.1;
     namespace "http://example.com/ns/example-newco-bgp";
     prefix example-newco-bgp;

     import ietf-bgp {
       prefix "bgp";
     }

     organization
       "Newco model group.";

     contact
       "abc@newco.com";
     description
       "This YANG module deviates IETF BGP YANG module.";

     revision 2023-07-05 {
       description
         "Creating NewCo deviations to ietf-bgp model";

       reference
         "RFC XXXX: YANG module for Border Gateway Protocol (BGP).";
     }

     deviation "/bgp:bgp/bgp:global/bgp:graceful-restart/" +
               "bgp:restart-time" {
       deviate not-supported;
     }

     deviation "/bgp:bgp/bgp:global/bgp:graceful-restart/" +
               "bgp:stale-route-time" {
       deviate not-supported;
     }
   }

Appendix D.  Complete configuration tree diagram

   Here is a complete tree diagram for the configuration and operational
   part of the model.

   module: ietf-bgp

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw bgp
          +--rw global!
          |  +--rw as                         inet:as-number



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          |  +--rw identifier?                yang:dotted-quad
          |  +--rw distance
          |  |  +--rw external?   uint8
          |  |  +--rw internal?   uint8
          |  +--rw confederation
          |  |  +--rw enabled?      boolean
          |  |  +--rw identifier?   inet:as-number
          |  |  +--rw member-as*    inet:as-number
          |  +--rw graceful-restart {bt:graceful-restart}?
          |  |  +--rw enabled?             boolean
          |  |  +--rw restart-time?        bt:graceful-restart-time-type
          |  |  +--rw stale-routes-time?   uint32
          |  |  +--rw helper-only?         boolean
          |  +--rw use-multiple-paths
          |  |  +--rw enabled?   boolean
          |  |  +--rw ebgp
          |  |  |  +--rw allow-multiple-as?   boolean
          |  |  |  +--rw maximum-paths?       uint32
          |  |  +--rw ibgp
          |  |     +--rw maximum-paths?   uint32
          |  +--rw route-selection-options
          |  |  +--rw always-compare-med?           boolean
          |  |  +--rw ignore-as-path-length?        boolean
          |  |  +--rw external-compare-router-id?   boolean
          |  |  +--rw advertise-inactive-routes?    boolean
          |  |  +--rw enable-aigp?                  boolean
          |  |  +--rw ignore-next-hop-igp-metric?   boolean
          |  |  +--rw enable-med?                   boolean
          |  |  +--rw med-plus-igp
          |  |     +--rw enabled?          boolean
          |  |     +--rw igp-multiplier?   uint16
          |  |     +--rw med-multiplier?   uint16
          |  +--rw afi-safis
          |  |  +--rw afi-safi* [name]
          |  |     +--rw name                       identityref
          |  |     +--rw enabled?                   boolean
          |  |     +--ro statistics
          |  |     |  +--ro total-paths?      yang:gauge32
          |  |     |  +--ro total-prefixes?   yang:gauge32
          |  |     +--rw graceful-restart {bt:graceful-restart}?
          |  |     |  +--rw enabled?   boolean
          |  |     +--rw route-selection-options
          |  |     |  +--rw always-compare-med?           boolean
          |  |     |  +--rw ignore-as-path-length?        boolean
          |  |     |  +--rw external-compare-router-id?   boolean
          |  |     |  +--rw advertise-inactive-routes?    boolean
          |  |     |  +--rw enable-aigp?                  boolean
          |  |     |  +--rw ignore-next-hop-igp-metric?   boolean



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          |  |     |  +--rw enable-med?                   boolean
          |  |     |  +--rw med-plus-igp
          |  |     |     +--rw enabled?          boolean
          |  |     |     +--rw igp-multiplier?   uint16
          |  |     |     +--rw med-multiplier?   uint16
          |  |     +--rw add-paths {bt:add-paths}?
          |  |     |  +--rw receive?                  boolean
          |  |     |  +--rw (send)?
          |  |     |  |  +--:(max)
          |  |     |  |  |  +--rw max?                uint8
          |  |     |  |  +--:(all)
          |  |     |  |     +--rw all?                empty
          |  |     |  +--rw eligible-prefix-policy?   leafref
          |  |     +--rw use-multiple-paths
          |  |     |  +--rw enabled?   boolean
          |  |     |  +--rw ebgp
          |  |     |  |  +--rw allow-multiple-as?   boolean
          |  |     |  |  +--rw maximum-paths?       uint32
          |  |     |  +--rw ibgp
          |  |     |     +--rw maximum-paths?   uint32
          |  |     +--rw apply-policy
          |  |     |  +--rw import-policy*           leafref
          |  |     |  +--rw default-import-policy?   default-policy-type
          |  |     |  +--rw export-policy*           leafref
          |  |     |  +--rw default-export-policy?   default-policy-type
          |  |     +--rw ipv4-unicast
          |  |     |  +--rw prefix-limit
          |  |     |  |  +--rw max-prefixes?            uint32
          |  |     |  |  +--rw warning-threshold-pct?
          |  |     |  |  |       rt-types:percentage
          |  |     |  |  +--rw teardown?                boolean
          |  |     |  |  +--rw idle-time?               union
          |  |     |  |  +--ro prefix-limit-exceeded?   boolean
          |  |     |  +--rw send-default-route?   boolean
          |  |     +--rw ipv6-unicast
          |  |     |  +--rw prefix-limit
          |  |     |  |  +--rw max-prefixes?            uint32
          |  |     |  |  +--rw warning-threshold-pct?
          |  |     |  |  |       rt-types:percentage
          |  |     |  |  +--rw teardown?                boolean
          |  |     |  |  +--rw idle-time?               union
          |  |     |  |  +--ro prefix-limit-exceeded?   boolean
          |  |     |  +--rw send-default-route?   boolean
          |  |     +--rw ipv4-labeled-unicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage



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          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw ipv6-labeled-unicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage
          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l3vpn-ipv4-unicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage
          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l3vpn-ipv6-unicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage
          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l3vpn-ipv4-multicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage
          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l3vpn-ipv6-multicast
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage
          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l2vpn-vpls
          |  |     |  +--rw prefix-limit
          |  |     |     +--rw max-prefixes?            uint32
          |  |     |     +--rw warning-threshold-pct?
          |  |     |     |       rt-types:percentage



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          |  |     |     +--rw teardown?                boolean
          |  |     |     +--rw idle-time?               union
          |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |     +--rw l2vpn-evpn
          |  |        +--rw prefix-limit
          |  |           +--rw max-prefixes?            uint32
          |  |           +--rw warning-threshold-pct?
          |  |           |       rt-types:percentage
          |  |           +--rw teardown?                boolean
          |  |           +--rw idle-time?               union
          |  |           +--ro prefix-limit-exceeded?   boolean
          |  +--rw apply-policy
          |  |  +--rw import-policy*           leafref
          |  |  +--rw default-import-policy?   default-policy-type
          |  |  +--rw export-policy*           leafref
          |  |  +--rw default-export-policy?   default-policy-type
          |  +--ro statistics
          |     +--ro total-paths?      yang:gauge32
          |     +--ro total-prefixes?   yang:gauge32
          +--rw neighbors
          |  +--rw neighbor* [remote-address]
          |  |  +--rw remote-address            inet:ip-address
          |  |  +--rw peer-group?
          |  |  |       -> ../../../peer-groups/peer-group/name
          |  |  +--ro local-address?            inet:ip-address
          |  |  +--ro local-port?               inet:port-number
          |  |  +--ro remote-port?              inet:port-number
          |  |  +--ro peer-type?                bt:peer-type
          |  |  +--ro identifier?               yang:dotted-quad
          |  |  +--ro dynamically-configured?   empty
          |  |  +--rw enabled?                  boolean
          |  |  +--rw peer-as?                  inet:as-number
          |  |  +--rw local-as?                 inet:as-number
          |  |  +--rw remove-private-as?
          |  |  |       bt:remove-private-as-option
          |  |  +--rw route-flap-damping {bt:damping}?
          |  |  |  +--rw enable?           boolean
          |  |  |  +--rw suppress-above?   decimal64
          |  |  |  +--rw reuse-above?      decimal64
          |  |  |  +--rw max-flap?         decimal64
          |  |  |  +--rw reach-decay?      uint32
          |  |  |  +--rw unreach-decay?    uint32
          |  |  |  +--rw keep-history?     uint32
          |  |  +--rw send-community*           identityref
          |  |  |       {bct:send-communities}?
          |  |  +--rw description?              string
          |  |  +--rw timers
          |  |  |  +--rw connect-retry-interval?             uint16



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          |  |  |  +--rw hold-time?                          uint16
          |  |  |  +--ro negotiated-hold-time?               uint16
          |  |  |  +--rw keepalive?                          uint16
          |  |  |  +--rw min-as-origination-interval?        uint16
          |  |  |  +--rw min-route-advertisement-interval?   uint16
          |  |  +--rw transport
          |  |  |  +--rw local-address?    union
          |  |  |  +--rw tcp-mss?          tcp:mss
          |  |  |  +--rw mtu-discovery?    boolean
          |  |  |  +--rw ebgp-multihop
          |  |  |  |  +--rw enabled?        boolean
          |  |  |  |  +--rw multihop-ttl?   uint8
          |  |  |  +--rw passive-mode?     boolean
          |  |  |  +--rw ttl-security?     uint8 {bt:ttl-security}?
          |  |  |  +--rw secure-session
          |  |  |  |  +--rw enabled?   boolean
          |  |  |  |  +--rw options
          |  |  |  |     +--rw (option)?
          |  |  |  |        +--:(ao)
          |  |  |  |        |  +--rw ao-keychain?
          |  |  |  |        |          key-chain:key-chain-ref
          |  |  |  |        +--:(md5)
          |  |  |  |        |  +--rw md5-keychain?
          |  |  |  |        |          key-chain:key-chain-ref
          |  |  |  |        +--:(ipsec)
          |  |  |  |           +--rw sa?             string
          |  |  |  +--rw bfd {bt:bfd}?
          |  |  |     +--rw enabled?                          boolean
          |  |  |     +--rw local-multiplier?                 multiplier
          |  |  |     |       {client-base-cfg-parms}?
          |  |  |     +--rw (interval-config-type)?
          |  |  |             {client-base-cfg-parms}?
          |  |  |        +--:(tx-rx-intervals)
          |  |  |        |  +--rw desired-min-tx-interval?    uint32
          |  |  |        |  +--rw required-min-rx-interval?   uint32
          |  |  |        +--:(single-interval)
          |  |  |                 {single-minimum-interval}?
          |  |  |           +--rw min-interval?               uint32
          |  |  +--rw treat-as-withdraw?        boolean
          |  |  +--rw logging-options
          |  |  |  +--rw log-neighbor-state-changes?   boolean
          |  |  +--rw route-reflector
          |  |  |  +--rw cluster-id?   bt:rr-cluster-id-type
          |  |  |  +--rw client?       boolean
          |  |  +--rw as-path-options
          |  |  |  +--rw allow-own-as?             uint8
          |  |  |  +--rw replace-peer-as?          boolean
          |  |  |  +--rw disable-peer-as-filter?   boolean



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          |  |  +--rw add-paths {bt:add-paths}?
          |  |  |  +--rw receive?                  boolean
          |  |  |  +--rw (send)?
          |  |  |  |  +--:(max)
          |  |  |  |  |  +--rw max?                uint8
          |  |  |  |  +--:(all)
          |  |  |  |     +--rw all?                empty
          |  |  |  +--rw eligible-prefix-policy?   leafref
          |  |  +--rw use-multiple-paths
          |  |  |  +--rw enabled?   boolean
          |  |  |  +--rw ebgp
          |  |  |     +--rw allow-multiple-as?   boolean
          |  |  +--rw apply-policy
          |  |  |  +--rw import-policy*           leafref
          |  |  |  +--rw default-import-policy?   default-policy-type
          |  |  |  +--rw export-policy*           leafref
          |  |  |  +--rw default-export-policy?   default-policy-type
          |  |  +--rw graceful-restart {bt:graceful-restart}?
          |  |  |  +--rw enabled?             boolean
          |  |  |  +--rw restart-time?
          |  |  |  |       bt:graceful-restart-time-type
          |  |  |  +--rw stale-routes-time?   uint32
          |  |  |  +--rw helper-only?         boolean
          |  |  |  +--ro peer-restart-time?   uint16
          |  |  |  +--ro peer-restarting?     boolean
          |  |  |  +--ro local-restarting?    boolean
          |  |  |  +--ro mode?                enumeration
          |  |  +--rw prefix-limit
          |  |  |  +--rw max-prefixes?            uint32
          |  |  |  +--rw warning-threshold-pct?   rt-types:percentage
          |  |  |  +--rw teardown?                boolean
          |  |  |  +--rw idle-time?               union
          |  |  |  +--ro prefix-limit-exceeded?   boolean
          |  |  +--rw afi-safis
          |  |  |  +--rw afi-safi* [name]
          |  |  |     +--rw name                    identityref
          |  |  |     +--rw enabled?                boolean
          |  |  |     +--ro active?                 boolean
          |  |  |     +--ro prefixes
          |  |  |     |  +--ro received?    yang:zero-based-counter32
          |  |  |     |  +--ro sent?        yang:zero-based-counter32
          |  |  |     |  +--ro installed?   yang:gauge32
          |  |  |     +--rw graceful-restart {bt:graceful-restart}?
          |  |  |     |  +--rw enabled?
          |  |  |     |  |       boolean
          |  |  |     |  +--ro received?
          |  |  |     |  |       boolean
          |  |  |     |  +--ro advertised?



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          |  |  |     |  |       boolean
          |  |  |     |  +--ro local-forwarding-state-preserved?
          |  |  |     |  |       boolean
          |  |  |     |  +--ro forwarding-state-preserved?
          |  |  |     |  |       boolean
          |  |  |     |  +--ro end-of-rib-received?
          |  |  |     |          boolean
          |  |  |     +--rw apply-policy
          |  |  |     |  +--rw import-policy*           leafref
          |  |  |     |  +--rw default-import-policy?
          |  |  |     |  |       default-policy-type
          |  |  |     |  +--rw export-policy*           leafref
          |  |  |     |  +--rw default-export-policy?
          |  |  |     |          default-policy-type
          |  |  |     +--rw ipv4-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |  |  +--rw max-prefixes?            uint32
          |  |  |     |  |  +--rw warning-threshold-pct?
          |  |  |     |  |  |       rt-types:percentage
          |  |  |     |  |  +--rw teardown?                boolean
          |  |  |     |  |  +--rw idle-time?               union
          |  |  |     |  |  +--ro prefix-limit-exceeded?   boolean
          |  |  |     |  +--rw send-default-route?   boolean
          |  |  |     +--rw ipv6-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |  |  +--rw max-prefixes?            uint32
          |  |  |     |  |  +--rw warning-threshold-pct?
          |  |  |     |  |  |       rt-types:percentage
          |  |  |     |  |  +--rw teardown?                boolean
          |  |  |     |  |  +--rw idle-time?               union
          |  |  |     |  |  +--ro prefix-limit-exceeded?   boolean
          |  |  |     |  +--rw send-default-route?   boolean
          |  |  |     +--rw ipv4-labeled-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw ipv6-labeled-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean



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          |  |  |     +--rw l3vpn-ipv4-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw l3vpn-ipv6-unicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw l3vpn-ipv4-multicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw l3vpn-ipv6-multicast
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw l2vpn-vpls
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean
          |  |  |     +--rw l2vpn-evpn
          |  |  |     |  +--rw prefix-limit
          |  |  |     |     +--rw max-prefixes?            uint32
          |  |  |     |     +--rw warning-threshold-pct?
          |  |  |     |     |       rt-types:percentage
          |  |  |     |     +--rw teardown?                boolean
          |  |  |     |     +--rw idle-time?               union
          |  |  |     |     +--ro prefix-limit-exceeded?   boolean



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          |  |  |     +--rw use-multiple-paths
          |  |  |        +--rw enabled?   boolean
          |  |  |        +--rw ebgp
          |  |  |           +--rw allow-multiple-as?   boolean
          |  |  +--rw session-state?            enumeration
          |  |  +--ro last-established?         yang:date-and-time
          |  |  +--ro capabilities
          |  |  |  +--ro advertised-capabilities* [code index]
          |  |  |  |  +--ro code     uint8
          |  |  |  |  +--ro index    uint8
          |  |  |  |  +--ro name?    identityref
          |  |  |  |  +--ro value
          |  |  |  |     +--ro mpbgp
          |  |  |  |     |  +--ro afi?    iana-rt-types:address-family
          |  |  |  |     |  +--ro safi?   iana-rt-types:bgp-safi
          |  |  |  |     |  +--ro name?   identityref
          |  |  |  |     +--ro graceful-restart
          |  |  |  |     |  +--ro flags?
          |  |  |  |     |  |       bt:graceful-restart-flags
          |  |  |  |     |  +--ro unknown-flags?   bits
          |  |  |  |     |  +--ro restart-time?
          |  |  |  |     |  |       bt:graceful-restart-time-type
          |  |  |  |     |  +--ro afi-safis* []
          |  |  |  |     |     +--ro afi?
          |  |  |  |     |     |       iana-rt-types:address-family
          |  |  |  |     |     +--ro safi?
          |  |  |  |     |     |       iana-rt-types:bgp-safi
          |  |  |  |     |     +--ro afi-safi-flags?
          |  |  |  |     |     |       bt:graceful-restart-flags-for-afi
          |  |  |  |     |     +--ro afi-safi-unknown-flags?   bits
          |  |  |  |     +--ro asn32
          |  |  |  |     |  +--ro as?   inet:as-number
          |  |  |  |     +--ro add-paths
          |  |  |  |        +--ro afi-safis* []
          |  |  |  |           +--ro afi?
          |  |  |  |           |       iana-rt-types:address-family
          |  |  |  |           +--ro safi?   iana-rt-types:bgp-safi
          |  |  |  |           +--ro mode?   enumeration
          |  |  |  +--ro received-capabilities* [code index]
          |  |  |  |  +--ro code     uint8
          |  |  |  |  +--ro index    uint8
          |  |  |  |  +--ro name?    identityref
          |  |  |  |  +--ro value
          |  |  |  |     +--ro mpbgp
          |  |  |  |     |  +--ro afi?    iana-rt-types:address-family
          |  |  |  |     |  +--ro safi?   iana-rt-types:bgp-safi
          |  |  |  |     |  +--ro name?   identityref
          |  |  |  |     +--ro graceful-restart



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          |  |  |  |     |  +--ro flags?
          |  |  |  |     |  |       bt:graceful-restart-flags
          |  |  |  |     |  +--ro unknown-flags?   bits
          |  |  |  |     |  +--ro restart-time?
          |  |  |  |     |  |       bt:graceful-restart-time-type
          |  |  |  |     |  +--ro afi-safis* []
          |  |  |  |     |     +--ro afi?
          |  |  |  |     |     |       iana-rt-types:address-family
          |  |  |  |     |     +--ro safi?
          |  |  |  |     |     |       iana-rt-types:bgp-safi
          |  |  |  |     |     +--ro afi-safi-flags?
          |  |  |  |     |     |       bt:graceful-restart-flags-for-afi
          |  |  |  |     |     +--ro afi-safi-unknown-flags?   bits
          |  |  |  |     +--ro asn32
          |  |  |  |     |  +--ro as?   inet:as-number
          |  |  |  |     +--ro add-paths
          |  |  |  |        +--ro afi-safis* []
          |  |  |  |           +--ro afi?
          |  |  |  |           |       iana-rt-types:address-family
          |  |  |  |           +--ro safi?   iana-rt-types:bgp-safi
          |  |  |  |           +--ro mode?   enumeration
          |  |  |  +--ro negotiated-capabilities*   identityref
          |  |  +--ro errors
          |  |  |  +--ro received
          |  |  |  |  +--ro last-notification?
          |  |  |  |  |       yang:date-and-time
          |  |  |  |  +--ro last-error?
          |  |  |  |  |       identityref
          |  |  |  |  +--ro last-error-code?                   uint8
          |  |  |  |  +--ro last-error-subcode?                uint8
          |  |  |  |  +--ro last-encapsulated-error?
          |  |  |  |  |       identityref
          |  |  |  |  +--ro last-encapsulated-error-code?      uint8
          |  |  |  |  +--ro last-encapsulated-error-subcode?   uint8
          |  |  |  |  +--ro last-error-data?                   binary
          |  |  |  +--ro sent
          |  |  |     +--ro last-notification?
          |  |  |     |       yang:date-and-time
          |  |  |     +--ro last-error?
          |  |  |     |       identityref
          |  |  |     +--ro last-error-code?                   uint8
          |  |  |     +--ro last-error-subcode?                uint8
          |  |  |     +--ro last-encapsulated-error?
          |  |  |     |       identityref
          |  |  |     +--ro last-encapsulated-error-code?      uint8
          |  |  |     +--ro last-encapsulated-error-subcode?   uint8
          |  |  |     +--ro last-error-data?                   binary
          |  |  +--ro statistics



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          |  |     +--ro established-transitions?
          |  |     |       yang:zero-based-counter32
          |  |     +--ro messages
          |  |     |  +--ro total-received?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro total-sent?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro updates-received?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro updates-sent?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro erroneous-updates-withdrawn?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro erroneous-updates-attribute-discarded?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro in-update-elapsed-time?
          |  |     |  |       yang:gauge32
          |  |     |  +--ro notifications-received?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro notifications-sent?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro route-refreshes-received?
          |  |     |  |       yang:zero-based-counter32
          |  |     |  +--ro route-refreshes-sent?
          |  |     |          yang:zero-based-counter32
          |  |     +--ro queues
          |  |     |  +--ro input?    yang:gauge32
          |  |     |  +--ro output?   yang:gauge32
          |  |     +---x clear {bt:clear-statistics}?
          |  |        +---w input
          |  |        |  +---w clear-at?   yang:date-and-time
          |  |        +--ro output
          |  |           +--ro clear-finished-at?   yang:date-and-time
          |  +---n established
          |  |  +-- remote-address?   -> ../../neighbor/remote-address
          |  +---n backward-transition
          |  |  +-- remote-addr?
          |  |  |       -> ../../neighbor/remote-address
          |  |  +-- notification-received
          |  |  |  +-- last-notification?
          |  |  |  |       yang:date-and-time
          |  |  |  +-- last-error?                        identityref
          |  |  |  +-- last-error-code?                   uint8
          |  |  |  +-- last-error-subcode?                uint8
          |  |  |  +-- last-encapsulated-error?           identityref
          |  |  |  +-- last-encapsulated-error-code?      uint8
          |  |  |  +-- last-encapsulated-error-subcode?   uint8
          |  |  +-- notification-sent



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          |  |     +-- last-notification?
          |  |     |       yang:date-and-time
          |  |     +-- last-error?                        identityref
          |  |     +-- last-error-code?                   uint8
          |  |     +-- last-error-subcode?                uint8
          |  |     +-- last-encapsulated-error?           identityref
          |  |     +-- last-encapsulated-error-code?      uint8
          |  |     +-- last-encapsulated-error-subcode?   uint8
          |  +---x clear {bt:clear-neighbors}?
          |     +---w input
          |     |  +---w (operation)?
          |     |  |  +--:(operation-admin)
          |     |  |  |  +---w admin?          empty
          |     |  |  +--:(operation-hard)
          |     |  |  |  +---w hard?           empty
          |     |  |  +--:(operation-soft)
          |     |  |  |  +---w soft?           empty
          |     |  |  +--:(operation-soft-inbound)
          |     |  |     +---w soft-inbound?   empty {bt:route-refresh}?
          |     |  +---w clear-at?             yang:date-and-time
          |     +--ro output
          |        +--ro clear-finished-at?   yang:date-and-time
          +--rw peer-groups
          |  +--rw peer-group* [name]
          |     +--rw name                  string
          |     +--rw peer-as?              inet:as-number
          |     +--rw local-as?             inet:as-number
          |     +--rw remove-private-as?    bt:remove-private-as-option
          |     +--rw route-flap-damping {bt:damping}?
          |     |  +--rw enable?           boolean
          |     |  +--rw suppress-above?   decimal64
          |     |  +--rw reuse-above?      decimal64
          |     |  +--rw max-flap?         decimal64
          |     |  +--rw reach-decay?      uint32
          |     |  +--rw unreach-decay?    uint32
          |     |  +--rw keep-history?     uint32
          |     +--rw send-community*       identityref
          |     |       {bct:send-communities}?
          |     +--rw description?          string
          |     +--rw timers
          |     |  +--rw connect-retry-interval?             uint16
          |     |  +--rw hold-time?                          uint16
          |     |  +--ro negotiated-hold-time?               uint16
          |     |  +--rw keepalive?                          uint16
          |     |  +--rw min-as-origination-interval?        uint16
          |     |  +--rw min-route-advertisement-interval?   uint16
          |     +--rw transport
          |     |  +--rw local-address?    union



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          |     |  +--rw tcp-mss?          tcp:mss
          |     |  +--rw mtu-discovery?    boolean
          |     |  +--rw ebgp-multihop
          |     |  |  +--rw enabled?        boolean
          |     |  |  +--rw multihop-ttl?   uint8
          |     |  +--rw passive-mode?     boolean
          |     |  +--rw ttl-security?     uint8 {bt:ttl-security}?
          |     |  +--rw secure-session
          |     |  |  +--rw enabled?   boolean
          |     |  |  +--rw options
          |     |  |     +--rw (option)?
          |     |  |        +--:(ao)
          |     |  |        |  +--rw ao-keychain?
          |     |  |        |          key-chain:key-chain-ref
          |     |  |        +--:(md5)
          |     |  |        |  +--rw md5-keychain?
          |     |  |        |          key-chain:key-chain-ref
          |     |  |        +--:(ipsec)
          |     |  |           +--rw sa?             string
          |     |  +--rw bfd {bt:bfd}?
          |     |     +--rw enabled?                          boolean
          |     |     +--rw local-multiplier?                 multiplier
          |     |     |       {client-base-cfg-parms}?
          |     |     +--rw (interval-config-type)?
          |     |             {client-base-cfg-parms}?
          |     |        +--:(tx-rx-intervals)
          |     |        |  +--rw desired-min-tx-interval?    uint32
          |     |        |  +--rw required-min-rx-interval?   uint32
          |     |        +--:(single-interval)
          |     |                 {single-minimum-interval}?
          |     |           +--rw min-interval?               uint32
          |     +--rw treat-as-withdraw?    boolean
          |     +--rw logging-options
          |     |  +--rw log-neighbor-state-changes?   boolean
          |     +--rw route-reflector
          |     |  +--rw cluster-id?   bt:rr-cluster-id-type
          |     |  +--rw client?       boolean
          |     +--rw as-path-options
          |     |  +--rw allow-own-as?             uint8
          |     |  +--rw replace-peer-as?          boolean
          |     |  +--rw disable-peer-as-filter?   boolean
          |     +--rw add-paths {bt:add-paths}?
          |     |  +--rw receive?                  boolean
          |     |  +--rw (send)?
          |     |  |  +--:(max)
          |     |  |  |  +--rw max?                uint8
          |     |  |  +--:(all)
          |     |  |     +--rw all?                empty



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          |     |  +--rw eligible-prefix-policy?   leafref
          |     +--rw use-multiple-paths
          |     |  +--rw enabled?   boolean
          |     |  +--rw ebgp
          |     |     +--rw allow-multiple-as?   boolean
          |     +--rw apply-policy
          |     |  +--rw import-policy*           leafref
          |     |  +--rw default-import-policy?   default-policy-type
          |     |  +--rw export-policy*           leafref
          |     |  +--rw default-export-policy?   default-policy-type
          |     +--rw dynamic-peers
          |     |  +--rw dynamic-peer-list* [prefix]
          |     |     +--rw prefix    inet:ip-prefix
          |     +--rw graceful-restart {bt:graceful-restart}?
          |     |  +--rw enabled?             boolean
          |     |  +--rw restart-time?
          |     |  |       bt:graceful-restart-time-type
          |     |  +--rw stale-routes-time?   uint32
          |     |  +--rw helper-only?         boolean
          |     +--rw prefix-limit
          |     |  +--rw max-prefixes?            uint32
          |     |  +--rw warning-threshold-pct?   rt-types:percentage
          |     |  +--rw teardown?                boolean
          |     |  +--rw idle-time?               union
          |     +--rw afi-safis
          |        +--rw afi-safi* [name]
          |           +--rw name                    identityref
          |           +--rw enabled?                boolean
          |           +--rw graceful-restart {bt:graceful-restart}?
          |           |  +--rw enabled?   boolean
          |           +--rw add-paths {bt:add-paths}?
          |           |  +--rw receive?                  boolean
          |           |  +--rw (send)?
          |           |  |  +--:(max)
          |           |  |  |  +--rw max?                uint8
          |           |  |  +--:(all)
          |           |  |     +--rw all?                empty
          |           |  +--rw eligible-prefix-policy?   leafref
          |           +--rw use-multiple-paths
          |           |  +--rw enabled?   boolean
          |           |  +--rw ebgp
          |           |     +--rw allow-multiple-as?   boolean
          |           +--rw apply-policy
          |           |  +--rw import-policy*           leafref
          |           |  +--rw default-import-policy?
          |           |  |       default-policy-type
          |           |  +--rw export-policy*           leafref
          |           |  +--rw default-export-policy?



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          |           |          default-policy-type
          |           +--rw ipv4-unicast
          |           |  +--rw prefix-limit
          |           |  |  +--rw max-prefixes?            uint32
          |           |  |  +--rw warning-threshold-pct?
          |           |  |  |       rt-types:percentage
          |           |  |  +--rw teardown?                boolean
          |           |  |  +--rw idle-time?               union
          |           |  |  +--ro prefix-limit-exceeded?   boolean
          |           |  +--rw send-default-route?   boolean
          |           +--rw ipv6-unicast
          |           |  +--rw prefix-limit
          |           |  |  +--rw max-prefixes?            uint32
          |           |  |  +--rw warning-threshold-pct?
          |           |  |  |       rt-types:percentage
          |           |  |  +--rw teardown?                boolean
          |           |  |  +--rw idle-time?               union
          |           |  |  +--ro prefix-limit-exceeded?   boolean
          |           |  +--rw send-default-route?   boolean
          |           +--rw ipv4-labeled-unicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw ipv6-labeled-unicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l3vpn-ipv4-unicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l3vpn-ipv6-unicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage



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          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l3vpn-ipv4-multicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l3vpn-ipv6-multicast
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l2vpn-vpls
          |           |  +--rw prefix-limit
          |           |     +--rw max-prefixes?            uint32
          |           |     +--rw warning-threshold-pct?
          |           |     |       rt-types:percentage
          |           |     +--rw teardown?                boolean
          |           |     +--rw idle-time?               union
          |           |     +--ro prefix-limit-exceeded?   boolean
          |           +--rw l2vpn-evpn
          |              +--rw prefix-limit
          |                 +--rw max-prefixes?            uint32
          |                 +--rw warning-threshold-pct?
          |                 |       rt-types:percentage
          |                 +--rw teardown?                boolean
          |                 +--rw idle-time?               union
          |                 +--ro prefix-limit-exceeded?   boolean
          +--ro rib
             +--ro attr-sets
             |  +--ro attr-set* [index]
             |     +--ro index         uint64
             |     +--ro attributes
             |        +--ro origin?
             |        |       bt:bgp-origin-attr-type
             |        +--ro as-path
             |        |  +--ro segment* []
             |        |     +--ro type?     identityref
             |        |     +--ro member*   inet:as-number
             |        +--ro next-hop?              inet:ip-address
             |        +--ro link-local-next-hop?   inet:ipv6-address



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             |        +--ro med?                   uint32
             |        +--ro local-pref?            uint32
             |        +--ro as4-path
             |        |  +--ro segment* []
             |        |     +--ro type?     identityref
             |        |     +--ro member*   inet:as-number
             |        +--ro aggregator
             |        |  +--ro as?           inet:as-number
             |        |  +--ro identifier?   yang:dotted-quad
             |        +--ro aggregator4
             |        |  +--ro as4?          inet:as-number
             |        |  +--ro identifier?   yang:dotted-quad
             |        +--ro atomic-aggregate?      boolean
             |        +--ro originator-id?         yang:dotted-quad
             |        +--ro cluster-list*          yang:dotted-quad
             |        +--ro aigp-metric?           uint64
             +--ro communities
             |  +--ro community* [index]
             |     +--ro index        uint64
             |     +--ro community*   union
             +--ro ext-communities
             |  +--ro ext-community* [index]
             |     +--ro index                uint64
             |     +--ro ext-community*       bct:bgp-ext-community-type
             |     +--ro ext-community-raw*   string
             +--ro ipv6-ext-communities
             |  +--ro ipv6-ext-community* [index]
             |     +--ro index                     uint64
             |     +--ro ipv6-ext-community*
             |     |       bct:bgp-ipv6-ext-community-type
             |     +--ro ipv6-ext-community-raw*   string
             +--ro large-communities
             |  +--ro large-community* [index]
             |     +--ro index              uint64
             |     +--ro large-community*   bct:bgp-large-community-type
             +--ro afi-safis
                +--ro afi-safi* [name]
                   +--ro name            identityref
                   +--ro ipv4-unicast
                   |  +--ro loc-rib
                   |  |  +--ro routes
                   |  |     +--ro route* [prefix origin path-id]
                   |  |        +--ro prefix
                   |  |        |       inet:ipv4-prefix
                   |  |        +--ro origin                   union
                   |  |        +--ro path-id                  uint32
                   |  |        +--ro attr-index?              leafref
                   |  |        +--ro community-index?         leafref



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                   |  |        +--ro ext-community-index?     leafref
                   |  |        +--ro large-community-index?   leafref
                   |  |        +--ro last-modified?
                   |  |        |       yang:timeticks
                   |  |        +--ro eligible-route?          boolean
                   |  |        +--ro ineligible-reason?
                   |  |        |       identityref
                   |  |        +--ro unknown-attributes
                   |  |        |  +--ro unknown-attribute* [attr-type]
                   |  |        |     +--ro optional?     boolean
                   |  |        |     +--ro transitive?   boolean
                   |  |        |     +--ro partial?      boolean
                   |  |        |     +--ro extended?     boolean
                   |  |        |     +--ro attr-type     uint8
                   |  |        |     +--ro attr-len?     uint16
                   |  |        |     +--ro attr-value?   binary
                   |  |        +--ro reject-reason?           union
                   |  +--ro neighbors
                   |     +--ro neighbor* [neighbor-address]
                   |        +--ro neighbor-address    inet:ip-address
                   |        +--ro adj-rib-in-pre
                   |        |  +--ro routes
                   |        |  |  +--ro route* [prefix path-id]
                   |        |  |     +--ro prefix
                   |        |  |     |       inet:ipv4-prefix
                   |        |  |     +--ro path-id
                   |        |  |     |       uint32
                   |        |  |     +--ro attr-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro ext-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro large-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro last-modified?
                   |        |  |     |       yang:timeticks
                   |        |  |     +--ro eligible-route?
                   |        |  |     |       boolean
                   |        |  |     +--ro ineligible-reason?
                   |        |  |     |       identityref
                   |        |  |     +--ro unknown-attributes
                   |        |  |     |  +--ro unknown-attribute*
                   |        |  |     |          [attr-type]
                   |        |  |     |     +--ro optional?     boolean
                   |        |  |     |     +--ro transitive?   boolean
                   |        |  |     |     +--ro partial?      boolean
                   |        |  |     |     +--ro extended?     boolean



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                   |        |  |     |     +--ro attr-type     uint8
                   |        |  |     |     +--ro attr-len?     uint16
                   |        |  |     |     +--ro attr-value?   binary
                   |        |  |     +--ro reject-reason?
                   |        |  |             union
                   |        |  +--ro clear-routes {bt:clear-routes}?
                   |        |     +---x clear
                   |        |        +---w input
                   |        |        |  +---w clear-at?
                   |        |        |          yang:date-and-time
                   |        |        +--ro output
                   |        |           +--ro clear-finished-at?
                   |        |                   yang:date-and-time
                   |        +--ro adj-rib-in-post
                   |        |  +--ro routes
                   |        |  |  +--ro route* [prefix path-id]
                   |        |  |     +--ro prefix
                   |        |  |     |       inet:ipv4-prefix
                   |        |  |     +--ro path-id
                   |        |  |     |       uint32
                   |        |  |     +--ro attr-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro ext-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro large-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro last-modified?
                   |        |  |     |       yang:timeticks
                   |        |  |     +--ro eligible-route?
                   |        |  |     |       boolean
                   |        |  |     +--ro ineligible-reason?
                   |        |  |     |       identityref
                   |        |  |     +--ro best-path?
                   |        |  |     |       boolean
                   |        |  |     +--ro unknown-attributes
                   |        |  |     |  +--ro unknown-attribute*
                   |        |  |     |          [attr-type]
                   |        |  |     |     +--ro optional?     boolean
                   |        |  |     |     +--ro transitive?   boolean
                   |        |  |     |     +--ro partial?      boolean
                   |        |  |     |     +--ro extended?     boolean
                   |        |  |     |     +--ro attr-type     uint8
                   |        |  |     |     +--ro attr-len?     uint16
                   |        |  |     |     +--ro attr-value?   binary
                   |        |  |     +--ro reject-reason?
                   |        |  |             union



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                   |        |  +--ro clear-routes {bt:clear-routes}?
                   |        |     +---x clear
                   |        |        +---w input
                   |        |        |  +---w clear-at?
                   |        |        |          yang:date-and-time
                   |        |        +--ro output
                   |        |           +--ro clear-finished-at?
                   |        |                   yang:date-and-time
                   |        +--ro adj-rib-out-pre
                   |        |  +--ro routes
                   |        |  |  +--ro route* [prefix path-id]
                   |        |  |     +--ro prefix
                   |        |  |     |       inet:ipv4-prefix
                   |        |  |     +--ro path-id
                   |        |  |     |       uint32
                   |        |  |     +--ro attr-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro ext-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro large-community-index?
                   |        |  |     |       leafref
                   |        |  |     +--ro last-modified?
                   |        |  |     |       yang:timeticks
                   |        |  |     +--ro eligible-route?
                   |        |  |     |       boolean
                   |        |  |     +--ro ineligible-reason?
                   |        |  |     |       identityref
                   |        |  |     +--ro unknown-attributes
                   |        |  |     |  +--ro unknown-attribute*
                   |        |  |     |          [attr-type]
                   |        |  |     |     +--ro optional?     boolean
                   |        |  |     |     +--ro transitive?   boolean
                   |        |  |     |     +--ro partial?      boolean
                   |        |  |     |     +--ro extended?     boolean
                   |        |  |     |     +--ro attr-type     uint8
                   |        |  |     |     +--ro attr-len?     uint16
                   |        |  |     |     +--ro attr-value?   binary
                   |        |  |     +--ro reject-reason?
                   |        |  |             union
                   |        |  +--ro clear-routes {bt:clear-routes}?
                   |        |     +---x clear
                   |        |        +---w input
                   |        |        |  +---w clear-at?
                   |        |        |          yang:date-and-time
                   |        |        +--ro output
                   |        |           +--ro clear-finished-at?



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                   |        |                   yang:date-and-time
                   |        +--ro adj-rib-out-post
                   |           +--ro routes
                   |           |  +--ro route* [prefix path-id]
                   |           |     +--ro prefix
                   |           |     |       inet:ipv4-prefix
                   |           |     +--ro path-id
                   |           |     |       uint32
                   |           |     +--ro attr-index?
                   |           |     |       leafref
                   |           |     +--ro community-index?
                   |           |     |       leafref
                   |           |     +--ro ext-community-index?
                   |           |     |       leafref
                   |           |     +--ro large-community-index?
                   |           |     |       leafref
                   |           |     +--ro last-modified?
                   |           |     |       yang:timeticks
                   |           |     +--ro eligible-route?
                   |           |     |       boolean
                   |           |     +--ro ineligible-reason?
                   |           |     |       identityref
                   |           |     +--ro unknown-attributes
                   |           |     |  +--ro unknown-attribute*
                   |           |     |          [attr-type]
                   |           |     |     +--ro optional?     boolean
                   |           |     |     +--ro transitive?   boolean
                   |           |     |     +--ro partial?      boolean
                   |           |     |     +--ro extended?     boolean
                   |           |     |     +--ro attr-type     uint8
                   |           |     |     +--ro attr-len?     uint16
                   |           |     |     +--ro attr-value?   binary
                   |           |     +--ro reject-reason?
                   |           |             union
                   |           +--ro clear-routes {bt:clear-routes}?
                   |              +---x clear
                   |                 +---w input
                   |                 |  +---w clear-at?
                   |                 |          yang:date-and-time
                   |                 +--ro output
                   |                    +--ro clear-finished-at?
                   |                            yang:date-and-time
                   +--ro ipv6-unicast
                      +--ro loc-rib
                      |  +--ro routes
                      |     +--ro route* [prefix origin path-id]
                      |        +--ro prefix
                      |        |       inet:ipv6-prefix



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                      |        +--ro origin                   union
                      |        +--ro path-id                  uint32
                      |        +--ro attr-index?              leafref
                      |        +--ro community-index?         leafref
                      |        +--ro ext-community-index?     leafref
                      |        +--ro large-community-index?   leafref
                      |        +--ro last-modified?
                      |        |       yang:timeticks
                      |        +--ro eligible-route?          boolean
                      |        +--ro ineligible-reason?
                      |        |       identityref
                      |        +--ro unknown-attributes
                      |        |  +--ro unknown-attribute* [attr-type]
                      |        |     +--ro optional?     boolean
                      |        |     +--ro transitive?   boolean
                      |        |     +--ro partial?      boolean
                      |        |     +--ro extended?     boolean
                      |        |     +--ro attr-type     uint8
                      |        |     +--ro attr-len?     uint16
                      |        |     +--ro attr-value?   binary
                      |        +--ro reject-reason?           union
                      +--ro neighbors
                         +--ro neighbor* [neighbor-address]
                            +--ro neighbor-address    inet:ip-address
                            +--ro adj-rib-in-pre
                            |  +--ro routes
                            |  |  +--ro route* [prefix path-id]
                            |  |     +--ro prefix
                            |  |     |       inet:ipv6-prefix
                            |  |     +--ro path-id
                            |  |     |       uint32
                            |  |     +--ro attr-index?
                            |  |     |       leafref
                            |  |     +--ro community-index?
                            |  |     |       leafref
                            |  |     +--ro ext-community-index?
                            |  |     |       leafref
                            |  |     +--ro large-community-index?
                            |  |     |       leafref
                            |  |     +--ro last-modified?
                            |  |     |       yang:timeticks
                            |  |     +--ro eligible-route?
                            |  |     |       boolean
                            |  |     +--ro ineligible-reason?
                            |  |     |       identityref
                            |  |     +--ro unknown-attributes
                            |  |     |  +--ro unknown-attribute*
                            |  |     |          [attr-type]



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                            |  |     |     +--ro optional?     boolean
                            |  |     |     +--ro transitive?   boolean
                            |  |     |     +--ro partial?      boolean
                            |  |     |     +--ro extended?     boolean
                            |  |     |     +--ro attr-type     uint8
                            |  |     |     +--ro attr-len?     uint16
                            |  |     |     +--ro attr-value?   binary
                            |  |     +--ro reject-reason?
                            |  |             union
                            |  +--ro clear-routes {bt:clear-routes}?
                            |     +---x clear
                            |        +---w input
                            |        |  +---w clear-at?
                            |        |          yang:date-and-time
                            |        +--ro output
                            |           +--ro clear-finished-at?
                            |                   yang:date-and-time
                            +--ro adj-rib-in-post
                            |  +--ro routes
                            |  |  +--ro route* [prefix path-id]
                            |  |     +--ro prefix
                            |  |     |       inet:ipv6-prefix
                            |  |     +--ro path-id
                            |  |     |       uint32
                            |  |     +--ro attr-index?
                            |  |     |       leafref
                            |  |     +--ro community-index?
                            |  |     |       leafref
                            |  |     +--ro ext-community-index?
                            |  |     |       leafref
                            |  |     +--ro large-community-index?
                            |  |     |       leafref
                            |  |     +--ro last-modified?
                            |  |     |       yang:timeticks
                            |  |     +--ro eligible-route?
                            |  |     |       boolean
                            |  |     +--ro ineligible-reason?
                            |  |     |       identityref
                            |  |     +--ro best-path?
                            |  |     |       boolean
                            |  |     +--ro unknown-attributes
                            |  |     |  +--ro unknown-attribute*
                            |  |     |          [attr-type]
                            |  |     |     +--ro optional?     boolean
                            |  |     |     +--ro transitive?   boolean
                            |  |     |     +--ro partial?      boolean
                            |  |     |     +--ro extended?     boolean
                            |  |     |     +--ro attr-type     uint8



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                            |  |     |     +--ro attr-len?     uint16
                            |  |     |     +--ro attr-value?   binary
                            |  |     +--ro reject-reason?
                            |  |             union
                            |  +--ro clear-routes {bt:clear-routes}?
                            |     +---x clear
                            |        +---w input
                            |        |  +---w clear-at?
                            |        |          yang:date-and-time
                            |        +--ro output
                            |           +--ro clear-finished-at?
                            |                   yang:date-and-time
                            +--ro adj-rib-out-pre
                            |  +--ro routes
                            |  |  +--ro route* [prefix path-id]
                            |  |     +--ro prefix
                            |  |     |       inet:ipv6-prefix
                            |  |     +--ro path-id
                            |  |     |       uint32
                            |  |     +--ro attr-index?
                            |  |     |       leafref
                            |  |     +--ro community-index?
                            |  |     |       leafref
                            |  |     +--ro ext-community-index?
                            |  |     |       leafref
                            |  |     +--ro large-community-index?
                            |  |     |       leafref
                            |  |     +--ro last-modified?
                            |  |     |       yang:timeticks
                            |  |     +--ro eligible-route?
                            |  |     |       boolean
                            |  |     +--ro ineligible-reason?
                            |  |     |       identityref
                            |  |     +--ro unknown-attributes
                            |  |     |  +--ro unknown-attribute*
                            |  |     |          [attr-type]
                            |  |     |     +--ro optional?     boolean
                            |  |     |     +--ro transitive?   boolean
                            |  |     |     +--ro partial?      boolean
                            |  |     |     +--ro extended?     boolean
                            |  |     |     +--ro attr-type     uint8
                            |  |     |     +--ro attr-len?     uint16
                            |  |     |     +--ro attr-value?   binary
                            |  |     +--ro reject-reason?
                            |  |             union
                            |  +--ro clear-routes {bt:clear-routes}?
                            |     +---x clear
                            |        +---w input



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                            |        |  +---w clear-at?
                            |        |          yang:date-and-time
                            |        +--ro output
                            |           +--ro clear-finished-at?
                            |                   yang:date-and-time
                            +--ro adj-rib-out-post
                               +--ro routes
                               |  +--ro route* [prefix path-id]
                               |     +--ro prefix
                               |     |       inet:ipv6-prefix
                               |     +--ro path-id
                               |     |       uint32
                               |     +--ro attr-index?
                               |     |       leafref
                               |     +--ro community-index?
                               |     |       leafref
                               |     +--ro ext-community-index?
                               |     |       leafref
                               |     +--ro large-community-index?
                               |     |       leafref
                               |     +--ro last-modified?
                               |     |       yang:timeticks
                               |     +--ro eligible-route?
                               |     |       boolean
                               |     +--ro ineligible-reason?
                               |     |       identityref
                               |     +--ro unknown-attributes
                               |     |  +--ro unknown-attribute*
                               |     |          [attr-type]
                               |     |     +--ro optional?     boolean
                               |     |     +--ro transitive?   boolean
                               |     |     +--ro partial?      boolean
                               |     |     +--ro extended?     boolean
                               |     |     +--ro attr-type     uint8
                               |     |     +--ro attr-len?     uint16
                               |     |     +--ro attr-value?   binary
                               |     +--ro reject-reason?
                               |             union
                               +--ro clear-routes {bt:clear-routes}?
                                  +---x clear
                                     +---w input
                                     |  +---w clear-at?
                                     |          yang:date-and-time
                                     +--ro output
                                        +--ro clear-finished-at?
                                                yang:date-and-time





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Appendix E.  Complete policy tree diagram

   Here is a complete tree diagram for the policy portion of the model.

   module: ietf-bgp-policy

     augment /rt-pol:routing-policy/rt-pol:defined-sets:
       +--rw bgp-defined-sets
          +--rw as-path-sets
          |  +--rw as-path-set* [name]
          |     +--rw name      string
          |     +--rw member*   string
          +--rw community-sets
          |  +--rw community-set* [name]
          |     +--rw name      string
          |     +--rw member*   union
          +--rw ext-community-sets
          |  +--rw ext-community-set* [name]
          |     +--rw name      string
          |     +--rw member*   union
          +--rw ipv6-ext-community-sets
          |  +--rw ipv6-ext-community-set* [name]
          |     +--rw name      string
          |     +--rw member*   union
          +--rw large-community-sets
          |  +--rw large-community-set* [name]
          |     +--rw name      string
          |     +--rw member*   union
          +--rw next-hop-sets
             +--rw next-hop-set* [name]
                +--rw name        string
                +--rw next-hop*   bgp-next-hop-type
     augment /rt-pol:routing-policy/rt-pol:policy-definitions
               /rt-pol:policy-definition/rt-pol:statements
               /rt-pol:statement/rt-pol:conditions:
       +--rw bgp-conditions
          +--rw local-pref
          |  +--rw value?            uint32
          |  +--rw (operation)?
          |     +--:(eq)
          |     |  +--rw eq?         empty
          |     +--:(lt-or-eq)
          |     |  +--rw lt-or-eq?   empty
          |     +--:(gt-or-eq)
          |        +--rw gt-or-eq?   empty
          +--rw med
          |  +--rw value?            uint32
          |  +--rw (operation)?



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          |     +--:(eq)
          |     |  +--rw eq?         empty
          |     +--:(lt-or-eq)
          |     |  +--rw lt-or-eq?   empty
          |     +--:(gt-or-eq)
          |        +--rw gt-or-eq?   empty
          +--rw origin-eq?                      bt:bgp-origin-attr-type
          +--rw match-afi-safi
          |  +--rw afi-safi-in*         identityref
          |  +--rw match-set-options?   match-set-options-type
          +--rw match-neighbor
          |  +--rw neighbor-eq*         inet:ip-address
          |  +--rw match-set-options?   match-set-options-type
          +--rw route-type?                     enumeration
          +--rw community-count
          |  +--rw community-count?   uint32
          |  +--rw (operation)?
          |     +--:(eq)
          |     |  +--rw eq?          empty
          |     +--:(lt-or-eq)
          |     |  +--rw lt-or-eq?    empty
          |     +--:(gt-or-eq)
          |        +--rw gt-or-eq?    empty
          +--rw as-path-length
          |  +--rw as-path-length?   uint32
          |  +--rw (operation)?
          |     +--:(eq)
          |     |  +--rw eq?         empty
          |     +--:(lt-or-eq)
          |     |  +--rw lt-or-eq?   empty
          |     +--:(gt-or-eq)
          |        +--rw gt-or-eq?   empty
          +--rw match-community-set
          |  +--rw community-set?       leafref
          |  +--rw match-set-options?   match-set-options-type
          +--rw match-ext-community-set
          |  +--rw ext-community-set?          leafref
          |  +--rw ext-community-match-kind?   enumeration
          |  +--rw match-set-options?          match-set-options-type
          +--rw match-ipv6-ext-community-set
          |  +--rw ipv6-ext-community-set?          leafref
          |  +--rw ipv6-ext-community-match-kind?   enumeration
          |  +--rw match-set-options?
          |          match-set-options-type
          +--rw match-large-community-set
          |  +--rw large-community-set?   leafref
          |  +--rw match-set-options?     match-set-options-type
          +--rw match-as-path-set



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          |  +--rw as-path-set?         leafref
          |  +--rw match-set-options?   match-set-options-type
          +--rw match-next-hop-set
             +--rw next-hop-set?        leafref
             +--rw match-set-options?   match-set-options-type
     augment /rt-pol:routing-policy/rt-pol:policy-definitions
               /rt-pol:policy-definition/rt-pol:statements
               /rt-pol:statement/rt-pol:actions:
       +--rw bgp-actions
          +--rw set-route-origin?         bt:bgp-origin-attr-type
          +--rw set-local-pref?           uint32
          +--rw set-next-hop?             bgp-next-hop-type
          +--rw set-med?                  bgp-set-med-type
          +--rw set-as-path-prepend
          |  +--rw repeat-n?   uint8
          |  +--rw asn*        inet:as-number
          +--rw set-community
          |  +--rw options?
          |  |       bgp-set-community-option-type
          |  +--rw (method)?
          |     +--:(inline)
          |     |  +--rw communities*         union
          |     +--:(reference)
          |        +--rw community-set-ref?   leafref
          +--rw set-ext-community
          |  +--rw options?
          |  |       bgp-set-community-option-type
          |  +--rw (method)?
          |     +--:(inline)
          |     |  +--rw communities*
          |     |          bct:bgp-ext-community-type
          |     +--:(reference)
          |        +--rw ext-community-set-ref?   leafref
          +--rw set-ipv6-ext-community
          |  +--rw options?
          |  |       bgp-set-community-option-type
          |  +--rw (method)?
          |     +--:(inline)
          |     |  +--rw communities*
          |     |          bct:bgp-ipv6-ext-community-type
          |     +--:(reference)
          |        +--rw ipv6-ext-community-set-ref?   leafref
          +--rw set-large-community
             +--rw options?
             |       bgp-set-community-option-type
             +--rw (method)?
                +--:(inline)
                |  +--rw communities*



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                |          bct:bgp-large-community-type
                +--:(reference)
                   +--rw large-community-set-ref?   leafref

Appendix F.  BGP YANG Model AS_PATH Regular Expressions

F.1.  AS_PATH Regular Expressions in Implementations

   Implementations of BGP have different ways of rendering the received
   BGP AS_PATH in their interfaces.  Deployed implementations generally
   render the AS_PATHs consistently from left to right where the left-
   most AS number matches the neighbor AS; most recently prepended AS,
   per Section 5.1.2 of [RFC4271].  Deployed implementations also use
   different characters to match the associated AS_PATH segment types.
   Those segment types are AS_SEQUENCE, AS_SET, AS_CONFED_SEQUENCE,
   AS_CONFED_SET.  Implementations also have no fully standardized way
   to render white-space between AS numbers in combination with possible
   characters denoting the AS_PATH segment types.

   This YANG model standardizes no particular rendering format for an
   AS_PATH.  This permits the model to be generally applicable for
   implementations of BGP and does not conflict with deployed formatting
   choices.

   AS_PATH regular expressions are a common tool used in BGP policy.
   Such regular expressions match on components of the AS_PATH.  In
   deployed implementations of BGP, there are two common high-level
   forms of AS_PATH matching:

   *  Character based tokens.  In this form, AS numbers are treated as a
      string of characters.  Regular expressions are evaluated vs. the
      characters in the string.  E.g. "64503+" will match "64503",
      "645033", etc.

   *  Integer based tokens.  In this form, AS numbers are treated as
      tokens.  Regular expressions are evaluated vs. the full integers.
      E.g.  "64503+" will match "64503", "64503 64503".

F.2.  Why not use standard POSIX regular expressions?

   *  It would be necessary to standardize the format of the AS_PATH in
      this module.  See above for reasons this was not chosen.

   *  Consistently dealing with separator token in the configured
      AS_PATH regular expression can be error-prone.  Operators
      interacting with BGP data using "grep" are familiar with this
      challenge.




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   *  POSIX character-based regular expressions readily map to
      implementations that match on character based tokens, but do not
      easily map to integer based token implementation.  Integer based
      token matches can be expressed in implementations that do
      character based tokens.

   *  Additionally, YANG by default doesn't use POSIX for its regular
      expressions.

F.3.  BGP YANG AS_PATH Regular Expressions

   To address the points above, the BGP YANG AS_PATH regular expressions
   are a subset of, and are inspired by, the prior work in Section 5.4
   of RPSL [RFC2622].

   ASN
      ASN is an 4-byte AS Number, from 1..4294967295.  0 is not a valid
      AS Number and is not permitted to be advertised in BGP AS_PATHs
      per [RFC7607].

   . 
      matches any single AS number in the AS_PATH.

   [...]
      is an AS number set.  It matches AS_PATHs with AS numbers listed
      between the brackets.  The AS numbers in the set are separated by
      white-space characters.  If a '-' is used between two AS numbers
      in this set, all AS numbers in the range between the two AS
      numbers are included in the set.

   [^...]
      is a complemented AS number set.  It matches an AS_PATH which is
      not matched by the numbers in the set.

   ^ 
      Matches the empty string at the beginning of an AS_PATH.

   $ 
      Matches the empty string at the end of an AS_PATH.

   Unary postfix operators * + ?  {m} {m,n} {m,}
      For a regular expression A, A* matches zero or more occurrences of
      A; A+ matches one or more occurrences of A; A?  matches zero or
      one occurrence of A; A{m} matches m occurrence of A; A{m,n}
      matches m to n occurrence of A; A{m,} matches m or more occurrence
      of A.  For example, [AS1 AS2]{2} matches AS1 AS1, AS1 AS2, AS2
      AS1, and AS2 AS2.




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   Binary catenation operator
      This is an implicit operator and exists between two regular
      expressions A and B when no other explicit operator is specified.
      The resulting expression A B matches an AS-path if A matches some
      prefix of the AS-path and B matches the rest of the AS-path.

   Binary alternative (or) operator |
      For a regular expressions A and B, A | B matches any AS-path that
      is matched by A or B.

   (...)
      Parenthesis can be used to override the default order of
      evaluation.

   Whitespace in a BGP YANG AS_PATH regular expression is only used to
   separate tokens within the regular expression.  It is otherwise
   without meaning and may be included or omitted for visual clarity.

F.4.  Matching AS_PATH Segment Types in AS_PATH Regular Expressions

   There are no deployed implementations of BGP AS_PATH regular
   expression matches that permit matching of AS_PATH segment types.
   Known implementations simply ignore the segment types for their
   internal representation strings used by that implementation's regular
   expression.  While this would seem to be problematic, and may create
   difficulties in some specific scenarios, the following reasons have
   mitigated this consideration over the years:

   *  AS_SET or AS_CONFED_SET in the AS_PATH not only introduces
      additional character tokens for delimiting the segment, but mean
      that the contents of that position within the AS_PATH may vary.
      In general, implementations of AS_SETs will sort the contents of
      the AS_SET, but this is only a recommendation and not a protocol
      requirement.  AS_SETs are being deprecated for implementation and
      deployment in BGP due to the issues that they raise in BGP
      security features.  See
      [I-D.ietf-idr-deprecate-as-set-confed-set].

   *  BGP Confederation are the always the left-most ASes in the
      AS_PATH.  As a result, matching on confederation ASes may be done
      using the '^' anchor character against the locally-configured
      Confederation member ASes.  These are typically either publicly
      registered AS numbers under the control of a single entity, or
      private AS numbers that are scrubbed as part of route filtering
      purposes at the provider's network edge.






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F.5.  BGP YANG AS_PATH Regular Expressions ABNF

   TBD...

F.6.  Example BGP YANG AS_PATH Regular Expressions

   64496
      Matches the AS_PATH that contains at least one instance of 64496,
      regardless of its position.

   ^64496$
      Matches the AS_PATH that is exactly one AS long, and that AS is
      64496.

   ^64496
      Matches the AS_PATH where the left-most (neighbor) AS is 64496.

   64496$
      Matches the AS_PATH where the right-most (origin) AS is 64496.

   [64496 64500]
      Matches the AS_PATH where at least one of the ASes is either 64496
      or 64500.

   [^64496 64500]
      Matches the AS_PATH where neither 64496 nor 64500 are present in
      the AS_PATH.

   [64496-64511]
      Matches the AS_PATH where at least one AS number is in the range
      64496..64511, inclusive.  This matches the documentation AS
      numbers in [RFC5398].

   64496 64500
      Matches the AS_PATH where 64496 is present and immediately
      followed by 64500.

   64496 | 64500
      Matches the AS_PATH where 64496 or 64500 occur in the AS_PATH.

   ^ 64496 .{2} ( 64500 | [64505-64511] )
      Matches the AS_PATH where the left-most (neighbor) AS is 64496, is
      followed immediately by any two ASes and either 64500 or an AS in
      the range 64505..64511.

Authors' Addresses





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   Mahesh Jethanandani
   Kloud Services
   Email: mjethanandani@gmail.com


   Keyur Patel
   Arrcus
   CA
   United States of America
   Email: keyur@arrcus.com


   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI 48176
   United States of America
   Email: shares@ndzh.com


   Jeffrey Haas
   Juniper Networks
   Email: jhaas@pfrc.org




























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