Internet DRAFT - draft-xu-grow-bmp-route-policy-attr-trace

draft-xu-grow-bmp-route-policy-attr-trace







Network Working Group                                              F. Xu
Internet-Draft                                                   Tencent
Intended status: Standards Track                                 T. Graf
Expires: January 28, 2021                                       Swisscom
                                                                   Y. Gu
                                                               S. Zhuang
                                                                   Z. Li
                                                                  Huawei
                                                           July 27, 2020


             BGP Route Policy and Attribute Trace Using BMP
              draft-xu-grow-bmp-route-policy-attr-trace-05

Abstract

   The generation of BGP adj-rib-in, local-rib or adj-rib-out comes from
   BGP route exchange and route policy processing.  BGP Monitoring
   Protocol (BMP) provides the monitoring of BGP adj-rib-in [RFC7854],
   BGP local-rib [I-D.ietf-grow-bmp-local-rib] and BGP adj-rib-out
   [I-D.ietf-grow-bmp-adj-rib-out].  By monitoring these BGP RIB's the
   full state of the network is visible, but how route-policies affect
   the route propagation or changes BGP attributes is still not.  This
   document describes a method of using BMP to record the trace data on
   how BGP routes are (not) changed under the process of route policies.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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 January 28, 2021.



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Copyright Notice

   Copyright (c) 2020 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 extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  BGP Route Policy and Attribute Trace Overview . . . . . .   3
     1.2.  Use cases . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Extension of BMP for Route Policy and Attribute Trace . . . .   4
     2.1.  Common Header . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Per Peer Header . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Route Policy and Attribute Trace Message  . . . . . . . .   4
       2.3.1.  VRF/Table TLV . . . . . . . . . . . . . . . . . . . .   7
       2.3.2.  Policy TLV  . . . . . . . . . . . . . . . . . . . . .   8
       2.3.3.  Pre Policy Attribute TLV  . . . . . . . . . . . . . .  12
       2.3.4.  Post Policy Attribute TLV . . . . . . . . . . . . . .  12
       2.3.5.  String TLV  . . . . . . . . . . . . . . . . . . . . .  13
   3.  Implementation Considerations . . . . . . . . . . . . . . . .  13
   4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  13
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   The typical processing procedure after receiving a BGP Update Message
   at a routing device is as follows: 1.  Adding the pre-policy routes
   into the pre-policy adj-rib-in (if any); 2.  Filtering the pre-policy
   routes through inbound route policies; 3.  Selecting the BGP best
   routes from the post-policy routes; 4.  Adding the selected routes
   into the BGP local-rib; 5-a.  Adding the BGP best routes from local-
   rib to the core routing table manager for selection; 5-b.  Filtering
   the routes from BGP local-rib through outbound route policies w.r.t.
   per peer or peer groups; 6.  Sending the BGP adj-rib-out to the
   target peer or peer groups.  Details may vary by vendors.  The BGP



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   Monitoring Protocol (BMP) can be utilized to monitor BGP routes in
   forms of adj-rib-in, local-rib and adj-rib-out.  However, the
   complete procedure from inbound to outbound policy processing,
   including other policies, e.g., route redistribution, route selection
   and so on, is currently unobserved.  For example, there are 10 policy
   items (or nodes) configured under one outbound route policy per a
   specific peer.  By collecting the local-rib and adj-rib-out through
   BMP, the operator finds that the outbound policy didn't work as
   expected.  However, it's hard to distinguish which one of the 10
   policy items/nodes is responsible for the failure.

1.1.  BGP Route Policy and Attribute Trace Overview

   This document describes a method that records and reports how each
   policy item/node processes the routes (e.g., changes the route
   attribute).  Each policy item/node processing is called an event
   thereafter in this document.  Compared with conventional BGP rib
   entry, which consists of prefix/mask, route attributes, e.g., next
   hop, MED, local preference, AS path, and so on, the event record
   discussed in this document includes extra information, such as event
   index, timestamp, policy information, and so on.  For example, if a
   route is processed by 5 policy items/nodes, there can be 5 event
   records for the same prefix/mask.  Each event is numbered in order of
   time (e.g., the time of policy execution).  The policy information
   includes the policy name and item/node ID/name so that the server/
   controller can map to the exact policy either directly from the
   device or from the configurations collected at the server side.

   This document defines a new BMP message type to carry the recorded
   policy and route data.  More detailed message format is defined in
   Section 2.  The message is called the BMP Route Policy and Attribute
   Trace Message thereafter in this document.

1.2.  Use cases

   There are cases that a new policy is configured incorrectly, e.g.,
   setting an incorrect community value, or policy placed in incorrect
   order among other policies.  These may result in incorrect route
   attribute modification, best route selection mistake, or route
   distribution mistake.  With the correlated record of policy and
   route, the server/controller is able to identify the unexpected route
   change and its responsible policy.  Considering the fact that the BGP
   route policy impacts not only the route processing within the
   individual device but also the route distribution to its peers, the
   route trace data of a single device is always analyzed in correlation
   with such data collected from its peer devices.





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   Apart from the policy validation application, the route trace data
   can also be analyzed to discover the route propagation path within
   the network.  With the route's inbound and outbound event records
   collect from each related device, the server is able to find the
   propagation path hop by hop.  The identified path is helpful for
   operators to better understand its network, and thus benefiting both
   network troubleshooting and network planning.

2.  Extension of BMP for Route Policy and Attribute Trace

2.1.  Common Header

   This document defines a new BMP message type to carry the Route
   Policy and Attribute Trace data.

   o  Type = TBD: Route Policy and Attribute Trace Message

   The new defined message type is indicated in the Message Type field
   of the BMP common header.

2.2.  Per Peer Header

   The Route Policy and Attribute Trace Message is not per peer based,
   thus it does not require the Per Peer Header.

2.3.  Route Policy and Attribute Trace Message

   The Route Policy and Attribute Trace Message format is defined as
   follows:






















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     +---------------------------------------------------------------+
     |V|                          Reserved                           |
     +---------------------------------------------------------------+
     |                        Route Distinguisher                    |
     +---------------------------------------------------------------+
     |                          Prefix length                        |
     +---------------------------------------------------------------+
     |                              Prefix                           |
     +---------------------------------------------------------------+
     |                           Route Origin                        |
     +---------------------------------------------------------------+
     |                          Event count                          |
     +---------------------------------------------------------------+
     |                       Total event length                      |
     +---------------------------------------------------------------+
     |                            1st Event                          |
     +---------------------------------------------------------------+
     |                            2nd Event                          |
     +---------------------------------------------------------------+
     ~                                                               ~
     +                            ......                             +
     ~                                                               ~
     +---------------------------------------------------------------+
     |                           Last Event                          |
     +---------------------------------------------------------------+

       Figure 1: Route Policy and Attribute Trace Message format

   o  Flags (1 Byte): The V flag indicates that the Peer address is an
      IPv6 address.  For IPv4 peers, this is set to 0.

   o  Route Distinguisher (8 Bytes): indicates the route distinguisher
      (RD) related to the route.

   o  Prefix Length (1 Byte): indicates the length of the prefix.

   o  Prefix (16 Bytes): indicates the monitored prefix, with mask
      defined by Prefix Length field.  It is 4 bytes long if an IPv4
      address is carried in this field (with the 12 most significant
      bytes zero-filled) and 16 bytes long if an IPv6 address is carried
      in this field.

   o  Route Origin (4 Bytes): indicates the BGP router ID where this
      route is learned from.  If the route is locally generated, this
      field is zero filled.

   o  Event Count (1 Byte): indicates the total number of policy
      processing event recorded in this message.



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   o  Total event length (2 Byte): indicates the total length of the
      following fields including all events, where the total number is
      indicated by the Event Count field.

   o  1 ~ Last event: indicates each event, stacked one by one in order
      of time.  The event format is further defined as follows.

   +---------------------------------------------------------------+
   |                       Single event length                     |
   +---------------------------------------------------------------+
   |                           Event index                         |
   +---------------------------------------------------------------+
   |                       Timestamp(seconds)                      |
   +---------------------------------------------------------------+
   |                       Timestamp(microseconds)                 |
   +---------------------------------------------------------------+
   |                        Path Identifier                        |
   +---------------------------------------------------------------+
   |                              AFI                              |
   +---------------------------------------------------------------+
   |                              SAFI                             |
   +---------------------------------------------------------------+
   |                          VRF/Table TLV                        |
   +---------------------------------------------------------------+
   |                            Policy TLV                         |
   +---------------------------------------------------------------+
   |                     Pre Policy Attribute TLV                  |
   +---------------------------------------------------------------+
   |                     Post Policy Attribute TLV                 |
   +---------------------------------------------------------------+
   |                            String TLV                         |
   +---------------------------------------------------------------+

                        Figure 2: Event format

   o  Single event length (2 Byte): indicates the total length of a
      single policy process event, including the following fields that
      belong to this event.

   o  Event index (1 Byte): indicates the sequence number of this event,
      staring from 1 and increases by 1 for each event recorded in
      order.

   o  Timestamp (8 Bytes): indicates the time when the policy of this
      event starts execution, expressed in seconds and microseconds
      since midnight (zero hour), January 1, 1970 (UTC).





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   o  Path Identifier (4 Bytes): used to distinguish multiple BGP paths
      for the same prefix.  If there's no path ID, this field is zero
      filled.

   o  AFI (2 Bytes)/SAFI (1 Byte): indicates the AFI/SAFI of the route.

   o  VRF/Table TLV (Variable): indicates the VRFinformation of the
      route.  The format of the VRF/Table TLV is further defined in
      Figure 3.  The VRF/Table ID TLV is optional.  At most one VRF/
      Table TLV can be included in each Route Policy and Attribute Trace
      Message.

   o  Policy TLV (Variable): indicates the ID of the route policy of
      this event, which is user specific or vendor specific, which can
      be used for mapping to the actual policy content.  The policy
      content data retrieval is out of the scope of this document.  The
      format of the Policy ID TLV is further defined in Figure 4.  The
      Policy ID TLV is optional.  At most one Policy TLV can be included
      in each Route Policy and Attribute Trace Message.

   o  Pre Policy Attribute TLV (Variable): include the BGP route
      attributes before the policy is executed.  The format of the Pre-
      policy Attribute TLV is further defined in Figure 4.  The Pre-
      policy Attribute TLV is optional.  At most one Pre Policy
      Attribute TLV can be included in each Route Policy and Attribute
      Trace Message.

   o  Post Policy Attribute TLV (Variable): include the BGP route
      attributes after the policy is executed.  The format of the Post-
      policy Attribute TLV is further defined in Figure 5.  The Post-
      policy Attribute TLV is optional.  At most one Post Policy
      Attribute TLV can be included in each Route Policy and Attribute
      Trace Message.

   o  String TLV (Variable): leaves for future extension.  The String
      TLV is optional.  One or more String TLVs can be included in each
      Route Policy and Attribute Trace Message.

2.3.1.  VRF/Table TLV












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     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-------------------------------+-------------------------------+
     |          Type = TBD1          |            Length             |
     +-------------------------------+-------------------------------+
     |                         VRF/Table ID                          |
     +---------------------------------------------------------------+
     ~                         VRF/Table Name                        ~
     |                                                               |
     +---------------------------------------------------------------+

                        Figure 3: VRF/Table TLV

   o  Type = TBD1 (2 Byte): VRF/Table TLV.

   o  Length (2 Byte): indicates the total length of the VRF/Table ID
      field and the VRF/Table Name field.

   o  VRF/Table ID (4 Bytes): indicates the VRF or table ID of this
      route.

   o  VRF/Table name (Variable): indicates the VRF or table name of this
      route in the format of ASCII string.  The string size MUST be
      within the range of 1 to 255 bytes.

2.3.2.  Policy TLV

























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     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-------------------------------+-------------------------------+
     |          Type = TBD2          |            Length             |
     +---------------+-------------------------------+---------------+
     |M|P|D|  Res.   |  Policy Count | Policy Class. |
     +---------------+---------------+---------------+---------------+
     ~                          Peer Address                         ~
     +                                                               +
     +---------------------------------------------------------------+
     |                          Peer Router ID                       |
     +---------------------------------------------------------------+
     |                            Peer AS                            |
     +---------------------------------------------------------------+
     ~                                                               ~
     +                           1st Policy          +---------------+
     |                                               |C|R|   Res.    |
     +---------------------------------------------------------------+
     ~                                .                              ~
     +                                .                              +
     ~                                .                              ~
     +---------------------------------------------------------------+
     ~                                                               ~
     +                           Last Policy         +---------------+
     |                                               |C|R|   Res.    |
     +---------------------------------------------------------------+

                        Figure 4: Policy TLV

   o  Type = TBD2 (2 Byte): Policy TLV.

   o  Length (2 Byte): indicates the length of the Policy Value field
      that follows it.  The Policy value field includes the reserved
      Flag Byte, Policy Count field, Policy Classification field, Peer
      Router ID field, Peer AS field, and each Policy field.

   o  Flag Byte (1 Byte): the M bit (the left most bit) indicates if the
      route in this event is matched (once or multiple times) or not by
      any policies. "0" means no match and "1" means else wise.  When
      the M bit is set to "0", the Post Policy Attribute TLV SHALL not
      be included in the Message.  The P bit (the second left bit)
      indicates if the matched result is Permit or Deny. "0" means Deny,
      and "1" means Permit.  When the M bit is set to "0", any value of
      the P bit SHOULD be ignored.  When the P bit is set to "0", the
      Post Policy Attribute TLV SHALL not be included in the Message.
      The D bit (the third left bit) indicates if there exists any
      difference between the pre-policy attributes and the post policy
      attributes. "0" means no difference, and "1" means difference



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      exists.  When the D bit is set to "0", the Post Policy Attribute
      TLV SHALL not be included in the Message.

   o  Policy Count (1 Byte): indicates the number of policies carried in
      this event.

   o  Policy Classification (1 Byte): indicates the category of the
      policy.  Currently 8 policy categories are defined: "00000000"
      indicates the Inbound policy; "00000001" indicates the Outbound
      policy; "00000010" indicating the Multi-protocol Redistribute
      policy (including routes import from other protocols, like ISIS/
      OSPF and static routes), "00000011" indicates the Cross-VRF
      Redistribute policy (route import between VRF and global table and
      between VRFs); "00000100" indicates VRF Import policy (e.g., an
      IPv4 route within a VRF transformed from a VPNv4 route),
      "00000101" indicates VRF Export policy (e.g., a VPNv4 route
      transformed from an IPv4 route within an VRF); "00000110"
      indicates the Network policy (BGP network installment and
      advertisement), "00000111" indicates the Aggregation policy;
      "00001000" indicating the Route Withdraw (triggered by BGP Update
      or local actions, e.g., route aggregation).  Specifications
      regarding each category can be included in the String TLV.  For
      the route update, i.e., route creation and withdrawal, that is not
      processed by any route policy, the Policy Category field is set
      per the route update point.  In addition, the Policy ID field in
      the Policy ID TLV SHOULD be set to 0.

   o

   +---------------------------------------+
   |   Value  |Policy Classification       |
   +---------------------------------------+
   | 00000000 | Inbound policy             |
   | 00000001 | Outbound policy            |
   | 00000010 | Multi-protocol Redistribute|
   | 00000011 | Cross-VRF Redistribute     |
   | 00000100 | VRF import                 |
     00000101 | VRF export                 |
   | 00000110 | Network                    |
   | 00000111 | Aggregation                |
   | 00001000 | Route Withdraw             |
   +----------+----------------------------+

     Table 1: Policy Classification

   o  Peer Address: The remote IP address associated with the TCP
      session over which the encapsulated PDU was received.  It is 4
      bytes long if an IPv4 address is carried in this field (with the



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      12 most significant bytes zero-filled) and 16 bytes long if an
      IPv6 address is carried in this field.

   o  Peer Router ID (4 Bytes): indicates the BGP Router ID where this
      policy is configured under.  This field is used in combination
      with the Policy Classification field.  If the Policy
      Classification field is set to "00000000", meaning Inbound policy,
      then this field is set to the BGP router ID where the route is
      received from; if the Policy Classification field is set to
      "00000001", meaning Outbound policy, then this field is set to the
      BGP router ID where the route is distributed to; If the Policy
      Direction field is set to any other values, then this field is set
      to all zeros.

   o  Peer AS (4 Bytes): indicates the AS number of the BGP Peer that
      defined the Peer ID field.

   o  1st ~ Last Policy (Variable): indicates the Policy name and the
      Item ID of each policy match.

   o  Flag Byte (1 Byte): the C bit (left most bit) indicates if the
      next subsequent policy has chaining relationship to the current
      policy. "1" means it's chaining relationship and "0" means else
      wise.  For the flag byte following the Last Policy field, the C
      bit SHALL be set to "0".  The R bit (second left bit) indicates if
      the next subsequent policy has recursion to the current policy.
      "1" means it's recursion and "0" means else wise.  For the flag
      byte following the Last Policy field, the R bit SHALL be set to
      "0".

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-------------------------------+-------------------------------+
     |       Policy Name Length      |      Policy Item ID Length    |
     +-------------------------------+-------------------------------+
     ~                           Policy Name                         ~
     +                                                               +
     +---------------------------------------------------------------+
     ~                         Policy Item ID                        ~
     +                                                               +
     +---------------------------------------------------------------+

                     Figure 5: Policy field format

   The Policy field consists of the Policy Name (Variable) and the
   Policy Item ID (Variable).  The Policy Name and Policy Item ID fields
   are in the format of ASCII string.  The length of Policy Name is
   indicated by the Policy Name Length (2 Bytes) field.  The length of



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   Policy Item ID is indicated by the Policy Item ID Length (2 Bytes)
   field.

2.3.3.  Pre Policy Attribute TLV

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-------------------------------+-------------------------------+
   |          Type = TBD3          |            Length             |
   +-------------------------------+-------------------------------+
   ~                  Pre Policy Attribute sub TLVs                ~
   +                                                               +
   +---------------------------------------------------------------+

                   Figure 6: Pre Policy Attribute TLV

   o  Type = TBD3 (2 Byte): Pre Policy Attribute TLV.

   o  Pre Policy Attribute length (2 Byte): indicates the total length
      of the following Pre Policy Attribute sub TLVs.

   o  Pre Policy Attribute sub TLVs (Variable): include the BGP route
      attributes before the policy is executed.

2.3.4.  Post Policy Attribute TLV

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-------------------------------+-------------------------------+
   |          Type = TBD4          |            Length             |
   +-------------------------------+-------------------------------+
   ~                 Post Policy Attribute sub TLVs                ~
   +                                                               +
   +---------------------------------------------------------------+

                   Figure 7: Post Policy Attribute TLV

   o  Type = TBD4 (2 Byte): Post Policy Attribute TLV.

   o  Post Policy Attribute length (2 Byte): indicates the total length
      of the following Post Policy Attribute sub TLVs.

   o  Post Policy Attribute sub TLVs (Variable): include the BGP route
      attributes after the policy is executed.







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2.3.5.  String TLV

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-------------------------------+-------------------------------+
   |          Type = TBD5          |            Length             |
   +-------------------------------+-------------------------------+
   ~                             Value                             ~
   +                                                               +
   +---------------------------------------------------------------+

                       Figure 8: String TLV

   o  Type = TBD5 (2 Byte): String TLV.

   o  Length (2 Byte): indicates the length of the following value
      field.

   o  Value (Variable): the textual expression of user-specific
      information in ASCII format.

   An example of using the String TLV is expressing the route policy
   xpath information instead of using the Policy TLV.

3.  Implementation Considerations

   Considering the data amount of monitoring the route and policy trace
   of all routes from all BMP clients, users MAY trigger the monitoring
   at any user-specific time.  Users MAY configure locally at the BMP
   client to monitor only user-specific routes or all the routes.  In
   addition, users MAY configure locally at the BMP client whether to
   report the TLVs that are optional according to their own
   requirements, i.e., the Pre Policy Attribute TLV, Post Policy
   Attribute TLV, Policy ID TLV, and String TLV.

   Successive recored events from one device MAY be encapsulated in one
   Route Policy and Attribute Trace Message or multiple Route Policy and
   Attribute Trace Messages per the user configuration.

4.  Acknowledgments

   TBD.

5.  IANA Considerations

   This document defines the following new BMP Message type
   (Section 2.1).




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   o  Type = TBD: Route Policy and Attribute Trace Message.

   This document defines the following new TLV types for the Route
   Policy and Attribute Trace Message (Section 2.3).

   o  Type = TBD1 (2 Byte): VRF/Table TLV.

   o  Type = TBD2 (2 Byte): Policy TLV.

   o  Type = TBD3 (2 Byte): Pre Policy Attribute TLV.

   o  Type = TBD4 (2 Byte): Post Policy Attribute TLV.

   o  Type = TBD5 (2 Byte): String TLV.

6.  Security Considerations

   TBD.

7.  Normative References

   [I-D.ietf-grow-bmp-adj-rib-out]
              Evens, T., Bayraktar, S., Lucente, P., Mi, K., and S.
              Zhuang, "Support for Adj-RIB-Out in BGP Monitoring
              Protocol (BMP)", draft-ietf-grow-bmp-adj-rib-out-07 (work
              in progress), August 2019.

   [I-D.ietf-grow-bmp-local-rib]
              Evens, T., Bayraktar, S., Bhardwaj, M., and P. Lucente,
              "Support for Local RIB in BGP Monitoring Protocol (BMP)",
              draft-ietf-grow-bmp-local-rib-07 (work in progress), May
              2020.

   [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>.

   [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>.

   [RFC5492]  Scudder, J. and R. Chandra, "Capabilities Advertisement
              with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
              2009, <https://www.rfc-editor.org/info/rfc5492>.





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   [RFC7854]  Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP
              Monitoring Protocol (BMP)", RFC 7854,
              DOI 10.17487/RFC7854, June 2016,
              <https://www.rfc-editor.org/info/rfc7854>.

Authors' Addresses

   Feng Xu
   Tencent
   Guangzhou
   China

   Email: oliverxu@tencent.com


   Thomas Graf
   Swisscom
   Binzring 17
   Zuerich  8045
   Switzerland

   Email: thomas.graf@swisscom.com


   Yunan Gu
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: guyunan@huawei.com


   Shunwan Zhuang
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: zhuangshunwan@huawei.com











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Internet-Draft        Route Policy-Attribute Trace             July 2020


   Zhenbin Li
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: lizhenbin@huawei.com












































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