Internet DRAFT - draft-scharf-tcpm-yang-tcp

draft-scharf-tcpm-yang-tcp







TCPM                                                           M. Scharf
Internet-Draft                                      Hochschule Esslingen
Intended status: Standards Track                               V. Murgai
Expires: May 7, 2020                                   Cisco Systems Inc
                                                         M. Jethanandani
                                                                  VMware
                                                       November 04, 2019


    YANG Model for Transmission Control Protocol (TCP) Configuration
                     draft-scharf-tcpm-yang-tcp-03

Abstract

   This document specifies a YANG model for TCP on devices that are
   configured by network management protocols.  The YANG model defines
   groupings for fundamental parameters that can be modified in many TCP
   implementations.  The model includes definitions from YANG Groupings
   for TCP Client and TCP Servers (I-D.ietf-netconf-tcp-client-server).
   The model is NMDA (RFC 8342) compliant.

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 May 7, 2020.

Copyright Notice

   Copyright (c) 2019 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



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   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
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Model Overview  . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Modeling Scope  . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Basic TCP Configuration Parameters  . . . . . . . . . . .   5
     3.3.  Model Design  . . . . . . . . . . . . . . . . . . . . . .   7
     3.4.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   8
     3.5.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   8
   4.  TCP Configuration YANG Model  . . . . . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
     5.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  14
     5.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  15
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  17
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  18
   Appendix B.  Changes compared to previous versions  . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19

1.  Introduction

   The Transmission Control Protocol (TCP) [RFC0793] is used by many
   applications in the Internet, including control and management
   protocols.  Therefore, TCP is implemented on network elements that
   can be configured via network management protocols such as NETCONF
   [RFC6241] or RESTCONF [RFC8040].  This document specifies a YANG
   [RFC7950] 1.1 model for configuring TCP on network elements that
   support YANG data models, and is Network Management Datastore
   Architecture (NMDA) [RFC8342] compliant.  This document includes
   definitions from YANG Groupings for TCP Clients and TCP Servers
   [I-D.ietf-netconf-tcp-client-server].  The model focuses on
   fundamental and standard TCP functions that are widely implemented.
   The model can be augmented to address more advanced or
   implementation-specific TCP features.

   Many protocol stacks on internet hosts use other methods to configure
   TCP, such as operating system configuration or policies.  Many TCP/IP
   stacks cannot be configured by network management protocols such as
   NETCONF [RFC6241] or RESTCONF [RFC8040] and they do not use YANG data
   models.  Yet, such TCP implementations often also have means to



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   configure the parameters listed in this document.  All parameters
   defined in this document are optional.

   This specification is orthogonal to Management Information Base (MIB)
   for the Transmission Control Protocol (TCP) [RFC4022].  The TCP
   Extended Statistics MIB [RFC4898] is also available, and there are
   MIBs for UDP Management Information Base for the User Datagram
   Protocol (UDP) [RFC4113] and Stream Control Transmission Protocol
   (SCTP) Management Information Base (MIB) [RFC3873].  It is possible
   to translate a MIB into a YANG model, for instance using Translation
   of Structure of Management Information Version 2 (SMIv2) MIB Modules
   to YANG Modules [RFC6643].  However, this approach is not used in
   this document, as such a translated model would not be up-to-date.

   There are also other related YANG models.  Examples are:

   o  Application protocol models may include TCP parameters, for
      example in case of BGP YANG Model for Service Provider Networks
      [I-D.ietf-idr-bgp-model].

   o  TCP header attributes are modeled in other models, such as YANG
      Data Model for Network Access Control Lists (ACLs) [RFC8519] and
      Distributed Denial-of-Service Open Thread Signaling (DOTS) Data
      Channel Specification [I-D.ietf-dots-data-channel].

   o  TCP-related configuration of a NAT (e.g., NAT44, NAT64,
      Destination NAT, ...) is defined in A YANG Module for Network
      Address Translation (NAT) and Network Prefix Translation (NPT)
      [RFC8512] and A YANG Data Model for Dual-Stack Lite (DS-Lite)
      [RFC8513].

2.  Requirements Language

   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.

3.  Model Overview

3.1.  Modeling Scope

   TCP is implemented on many different system architectures.  As a
   result, there are may different and often implementation-specific
   ways to configure parameters of the TCP protocol engine.  In
   addition, in many TCP/IP stacks configuration exists for different
   scopes:



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   o  Global configuration: Many TCP implementations have configuration
      parameters that affect all TCP connections.  Typical examples
      include enabling or disabling optional protocol features.

   o  Interface configuration: It can be useful to use different TCP
      parameters on different interfaces, e.g., different device ports
      or IP interfaces.  In that case, TCP parameters can be part of the
      interface configuration.  Typical examples are the Maximum Segment
      Size (MSS) or configuration related to hardware offloading.

   o  Connection parameters: Many implementations have means to
      influence the behavior of each TCP connection, e.g., on the
      programming interface used by applications.  A typical example are
      socket options in the socket API, such as disabling the Nagle
      algorithm by TCP_NODELAY.  If an application uses such an
      interface, it is possible that the configuration of the
      application or application protocol includes TCP-related
      parameters.  An example is the BGP YANG Model for Service Provider
      Networks [I-D.ietf-idr-bgp-model].

   o  Policies: Setting of TCP parameters can also be part of system
      policies, templates, or profiles.  An example would be the
      preferences defined in the TAPS interface An Abstract Application
      Layer Interface to Transport Services [I-D.ietf-taps-interface].

   There is no ground truth for setting certain TCP parameters, and
   traditionally different implementation have used different modeling
   approaches.  For instance, one implementation may define a given
   configuration parameter globally, while another one uses per-
   interface settings, and both approaches work well for the
   corresponding use cases.  Also, different systems may use different
   default values.

   The YANG model defined in this document includes definitions from the
   YANG Groupings for TCP Clients and TCP Servers
   [I-D.ietf-netconf-tcp-client-server].  Similar to the base model,
   this specification defines YANG groupings.  This allows reuse of
   these groupings in different YANG data models.  It is intended that
   these groupings will be used either standalone or for TCP-based
   protocols as part of a stack of protocol-specific configuration
   models.

   In addition to configuration of the TCP protocol engine, a TCP
   implementation typically also offers access to operational state and
   statistics.  This includes amongst others:






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   o  Statistics: Counters for the number of active/passive opens, sent
      and received segments, errors, and possibly other detailed
      debugging information

   o  TCP connection table: Access to status information for all TCP
      connections

   o  TCP listener table: Tnformation about all TCP listening endpoints

   Similar to the TCP MIB [RFC4022], this document also specifies a TCP
   connection table.

   TODO: A future version of this document may include statistics
   equivalent to the TCP MIB [RFC4022]:

   o  active-opens

   o  passive-opens

   o  attempt-fails

   o  establish-resets

   o  currently-established

   o  in-segments

   o  out-segments

   o  retransmitted-segments

   o  in-errors

   o  out-resets

3.2.  Basic TCP Configuration Parameters

   There are a number of basic system parameters that are configurable
   on many TCP implementations, even if not all TCP implementations may
   indeed have exactly all these settings.  Also, the syntax, semantics
   and scope (e.g., global or interface-specific) can be different in
   different system architectures.

   The following list of fundamental parameters considers both TCP
   implementations on hosts and on routers:

   o  Keepalives (see also [I-D.ietf-netconf-tcp-client-server])




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      *  Idle-time (in seconds): integer

      *  Probe-interval (in seconds): integer

      *  Max-probes: integer

   o  Maximum MSS (in byte): integer

   o  FIN timeout (in seconds): integer

   o  SACK (disable/enable): boolean

   o  Timestamps (disable/enable): boolean

   o  Path MTU Discovery (disable/enable): boolean

   o  ECN

      *  Enabling (disable/passive/active): enumeration

   TCP-AO is increasingly supported on routers and also requires
   configuration.

   Some other parameters are also common but not ubiquitously supported,
   or modeled in very different ways:

   o  Delayed ACK timeout (in ms)

   o  Initial RTO value (in ms)

   o  Maximum number of retransmissions

   o  Window scaling

   o  Maximum number of connections

   TCP can be implemented in different ways and design choices by the
   protocol engine often affect configuration options.  In a number of
   areas there are major differences between different software
   architectures.  As a result, there are not many commonalities in the
   corresponding configuration parameters:

   o  Window size: TCP stacks can either store window state variables
      (such as the congestion window) in segments or in bytes.

   o  Buffer sizes: The memory management depends on the operating
      system.  As the size of buffers can vary over several orders of




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      magnitude, very different implementations exist.  This typically
      influences TCP flow control.

   o  Timers: Timer implementation is another area in which TCP stacks
      may differ.

   o  Congestion control algorithms: Many congestion control algorithms
      have configuration parameters, but except for fundamental
      properties they often tie into the specific implementation.

   This document only models fundamental system parameters that are
   configurable on many TCP implementations, and for which the
   configuration is reasonably similar.

3.3.  Model Design

   [[Editor's node: This section requires further work.]]

   This document extends the YANG model "ietf-tcp-common" defined in
   [I-D.ietf-netconf-tcp-client-server].  The intention is to define
   YANG groupings for TCP parameters so that they can be used in
   different YANG models.

   As an example for the configuration of SACK, a YANG model could
   import the YANG model "ietf-tcp-common" as well as the model defined
   in this document as follows:

   module example-tcp {
     namespace "http://example.com/tcp";
     prefix tcp;

     import ietf-tcp {
       prefix tcp;
     }

     import ietf-tcp-common {
       prefix tcpcmn;
     }

     container example-tcp-config {
       description "Example TCP stack configuration";

       uses tcpcmn:tcp-common-grouping;
       uses tcp:tcp-sack-grouping;
     }
   }





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3.4.  Tree Diagram

   This section provides a abridged tree diagram for the YANG module
   defined in this document.  Annotations used in the diagram are
   defined in YANG Tree Diagrams [RFC8340].

   module: ietf-tcp
     +--rw tcp!
        +--rw connections
              ...

3.5.  Example Usage

   [[Editor's note: This section is TBD.]]

4.  TCP Configuration YANG Model

   Editor's note: How to use ietf-tcp-common as basis?  For instance, is
   the tcp-system-grouping therein needed?

   <CODE BEGINS> file "ietf-tcp@2019-11-04.yang"

   module ietf-tcp {
     yang-version "1.1";
     namespace "urn:ietf:params:xml:ns:yang:ietf-tcp";
     prefix "tcp";

     import ietf-tcp-client {
       prefix "tcpc";
     }
     import ietf-tcp-server {
       prefix "tcps";
     }
     import ietf-tcp-common {
       prefix "tcpcmn";
     }
     import ietf-inet-types {
       prefix "inet";
     }

     organization
       "IETF TCPM Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/tcpm>
        WG List:  <tcpm@ietf.org>

        Authors: Michael Scharf (michael.scharf at hs-esslingen dot de)



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                 Vishal Murgai (vmurgai at cisco dot com)
                 Mahesh Jethanandani (mjethanandani at gmail dot com)";

     description
       "This module focuses on fundamental and standard TCP functions
        that widely implemented. The model can be augmented to address
        more advanced or implementation specific TCP features.";

     revision "2019-11-04" {
       description
         "Initial Version";
       reference
         "RFC XXX, TCP Configuration.";
     }

     // Features
     feature server {
       description
         "TCP Server configuration supported.";
     }

     feature client {
       description
         "TCP Client configuration supported.";
     }

     // TCP-AO Groupings

     grouping mkt {
       leaf options {
         type binary;
         description
           "This flag indicates whether TCP options other than TCP-AO
            are included in the MAC calculation. When options are
            included, the content of all options, in the order present,
            is included in the MAC, with TCP-AO's MAC field zeroed out.
            When the options are not included, all options other than
            TCP-AO are excluded from all MAC calculations (skipped over,
            not zeroed).

            Note that TCP-AO, with its MAC field zeroed out, is always
            included in the MAC calculation, regardless of the setting
            of this flag; this protects the indication of the MAC length
            as well as the key ID fields (KeyID, RNextKeyID). The option
            flag applies to TCP options in both directions
            (incoming and outgoing segments).";
         reference
           "RFC 5925: The TCP Authentication Option.";



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       }

       leaf key-id {
         type uint8;
         description
           "TBD";
       }

       leaf rnext-key-id {
         type uint8;
         description
           "TBD";
       }
       description
         "A Master Key Tuple (MKT) describes TCP-AO properties to be
          associated with one or more connections.";
     }

     grouping ao {
       leaf enable {
         type boolean;
         default "false";
         description
           "Enable support of TCP-Authentication Option (TCP-AO).";
       }

       leaf current-key {
         type binary;
         description
           "The Master Key Tuple (MKT) currently used to authenticate
            outgoing segments, whose SendID is inserted in outgoing
            segments as KeyID. Incoming segments are authenticated
            using the MKT corresponding to the segment and its TCP-AO
            KeyID as matched against the MKT TCP connection identifier
            and the MKT RecvID. There is only one current-key at any
            given time on a particular connection.

            Every TCP connection in a non-IDLE state MUST have at most
            one current_key specified.";
         reference
           "RFC 5925: The TCP Authentication Option.";
       }

       leaf rnext-key {
         type binary;
         description
           "The MKT currently preferred for incoming (received)
            segments, whose RecvID is inserted in outgoing segments as



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            RNextKeyID.

            Each TCP connection in a non-IDLE state MUST have at most
            one rnext_key specified.";
         reference
           "RFC 5925: The TCP Authentication Option.";
       }

       leaf-list sne {
         type uint32;
         min-elements 1;
         max-elements 2;
         description
           "A pair of Sequence Number Extensions (SNEs). SNEs are used
            to prevent replay attacks. Each SNE is initialized to zero
            upon connection establishment.";
         reference
           "RFC 5925: The TCP Authentication Option.";
       }

       leaf-list mkt {
         type binary;
         min-elements 1;
         description
           "One or more MKTs. These are the MKTs that match this
            connection's socket pair.";
         reference
           "RFC 5925: The TCP Authentication Option.";
       }
       description
         "Authentication Option (AO) for TCP.";
       reference
         "RFC 5925: The TCP Authentication Option.";
     }

     // TCP general configuration groupings

     grouping tcp-mss-grouping {
       description "Maximum Segment Size (MSS) parameters";

       leaf tcp-mss {
         type uint16;
         description
           "Sets the max segment size for TCP connections.";
       }
     } // grouping tcp-mss-grouping

     grouping tcp-mtu-grouping {



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       description "Maximum Transfer Unit (MTU) discovery parameters";

       leaf tcp-mtu-discovery {
         type boolean;
         default false;
         description
           "Turns path mtu discovery for TCP connections on (true) or
            off (false)";
       }
     } // grouping tcp-mtu-grouping

     grouping tcp-sack-grouping {
       description "Selective Acknowledgements (SACK) parameters";

       leaf sack-enable {
         type boolean;

         description
           "Enable support of Selective Acknowledgements (SACK)";
       }
     } // grouping tcp-sack-grouping

     grouping tcp-timestamps-grouping {
       description "Timestamp parameters";

       leaf timestamps-enable {
         type boolean;

         description
           "Enable support of timestamps";
       }
     } // grouping tcp-timestamps-grouping

     grouping tcp-fin-timeout-grouping {
       description "TIME WAIT timeout parameters";

       leaf fin-timeout {
         type uint16;
         units "seconds";
         description
           "When a connection is closed actively, it must linger in
            TIME-WAIT state for a time 2xMSL (Maximum Segment Lifetime).
            This parameter sets the TIME-WAIT timeout duration in
            seconds.";
       }
     } // grouping tcp-fin-timeout-grouping

     grouping tcp-ecn-grouping {



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       description "Explicit Congestion Notification (ECN) parameters";

       leaf ecn-enable {
         type enumeration {
           enum disable;
           enum passive;
           enum active;
         }
         description
           "Enabling of ECN.";
       }
     } // grouping tcp-ecn-grouping


     // augment statements

     container tcp {
       presence "The container for TCP configuration.";

       description
         "TCP container.";

       container connections {
         list connection {
           key "local-address remote-address local-port remote-port";

           leaf local-address {
             type inet:ip-address;
             description
               "Local address that forms the connection identifier.";
           }

           leaf remote-address {
             type inet:ip-address;
             description
               "Remote address that forms the connection identifier.";
           }

           leaf local-port {
             type inet:port-number;
             description
               "Local TCP port that forms the connection identifier.";
           }

           leaf remote-port {
             type inet:port-number;
             description
               "Remote TCP port that forms the connection identifier.";



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           }

           container common {
             uses tcpcmn:tcp-common-grouping;
             uses ao;
             description
               "Common definitions of TCP configuration. This includes
                parameters such as keepalives and idle time, that can
                be part of either the client or server.";
           }

           container server {
             if-feature server;
             uses tcps:tcp-server-grouping;
             description
               "Definitions of TCP server configuration.";
           }

           container client {
             if-feature client;
             uses tcpc:tcp-client-grouping;
             description
               "Definitions of TCP client configuration.";
           }
           description
             "Connection related parameters.";
         }
         description
           "A container of all TCP connections.";
       }
     }
   }




   <CODE ENDS>

5.  IANA Considerations

5.1.  The IETF XML Registry

   This document registers two URIs in the "ns" subregistry of the IETF
   XML Registry [RFC3688].  Following the format in IETF XML Registry
   [RFC3688], the following registrations are requested:






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      URI: urn:ietf:params:xml:ns:yang:ietf-tcp
      Registrant Contact: The TCPM WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

5.2.  The YANG Module Names Registry

   This document registers a YANG modules in the YANG Module Names
   registry YANG - A Data Modeling Language [RFC6020].  Following the
   format in YANG - A Data Modeling Language [RFC6020], the following
   registrations are requested:

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

6.  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 Network Configuration 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.

7.  References

7.1.  Normative References

   [I-D.ietf-netconf-tcp-client-server]
              Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients
              and TCP Servers", draft-ietf-netconf-tcp-client-server-03
              (work in progress), October 2019.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <https://www.rfc-editor.org/info/rfc793>.

   [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>.



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

   [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>.

   [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>.

   [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>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [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>.

   [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>.

   [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>.




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7.2.  Informative References

   [I-D.ietf-dots-data-channel]
              Boucadair, M. and R. K, "Distributed Denial-of-Service
              Open Threat Signaling (DOTS) Data Channel Specification",
              draft-ietf-dots-data-channel-31 (work in progress), July
              2019.

   [I-D.ietf-idr-bgp-model]
              Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
              YANG Model for Service Provider Networks", draft-ietf-idr-
              bgp-model-07 (work in progress), October 2019.

   [I-D.ietf-taps-interface]
              Trammell, B., Welzl, M., Enghardt, T., Fairhurst, G.,
              Kuehlewind, M., Perkins, C., Tiesel, P., Wood, C., and T.
              Pauly, "An Abstract Application Layer Interface to
              Transport Services", draft-ietf-taps-interface-04 (work in
              progress), July 2019.

   [RFC3873]  Pastor, J. and M. Belinchon, "Stream Control Transmission
              Protocol (SCTP) Management Information Base (MIB)",
              RFC 3873, DOI 10.17487/RFC3873, September 2004,
              <https://www.rfc-editor.org/info/rfc3873>.

   [RFC4022]  Raghunarayan, R., Ed., "Management Information Base for
              the Transmission Control Protocol (TCP)", RFC 4022,
              DOI 10.17487/RFC4022, March 2005,
              <https://www.rfc-editor.org/info/rfc4022>.

   [RFC4113]  Fenner, B. and J. Flick, "Management Information Base for
              the User Datagram Protocol (UDP)", RFC 4113,
              DOI 10.17487/RFC4113, June 2005,
              <https://www.rfc-editor.org/info/rfc4113>.

   [RFC4898]  Mathis, M., Heffner, J., and R. Raghunarayan, "TCP
              Extended Statistics MIB", RFC 4898, DOI 10.17487/RFC4898,
              May 2007, <https://www.rfc-editor.org/info/rfc4898>.

   [RFC6643]  Schoenwaelder, J., "Translation of Structure of Management
              Information Version 2 (SMIv2) MIB Modules to YANG
              Modules", RFC 6643, DOI 10.17487/RFC6643, July 2012,
              <https://www.rfc-editor.org/info/rfc6643>.








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   [RFC8512]  Boucadair, M., Ed., Sivakumar, S., Jacquenet, C.,
              Vinapamula, S., and Q. Wu, "A YANG Module for Network
              Address Translation (NAT) and Network Prefix Translation
              (NPT)", RFC 8512, DOI 10.17487/RFC8512, January 2019,
              <https://www.rfc-editor.org/info/rfc8512>.

   [RFC8513]  Boucadair, M., Jacquenet, C., and S. Sivakumar, "A YANG
              Data Model for Dual-Stack Lite (DS-Lite)", RFC 8513,
              DOI 10.17487/RFC8513, January 2019,
              <https://www.rfc-editor.org/info/rfc8513>.

   [RFC8519]  Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
              "YANG Data Model for Network Access Control Lists (ACLs)",
              RFC 8519, DOI 10.17487/RFC8519, March 2019,
              <https://www.rfc-editor.org/info/rfc8519>.

Appendix A.  Acknowledgements

   Michael Scharf was supported by the StandICT.eu project, which is
   funded by the European Commission under the Horizon 2020 Programme.

   The following persons have contributed to this document by reviews:
   Mohamed Boucadair

Appendix B.  Changes compared to previous versions

   Changes compared to draft-scharf-tcpm-yang-tcp-02

   o  Initial proposal of a YANG model including base configuration
      parameters, TCP-AO configuration, and a connection list

   o  Editorial bugfixes and outdated references reported by Mohamed
      Boucadair

   o  Additional co-author Mahesh Jethanandani

   Changes compared to draft-scharf-tcpm-yang-tcp-01

   o  Alignment with [I-D.ietf-netconf-tcp-client-server]

   o  Removing backward-compatibility to the TCP MIB

   o  Additional co-author Vishal Murgai

   Changes compared to draft-scharf-tcpm-yang-tcp-00

   o  Editorial improvements




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Authors' Addresses

   Michael Scharf
   Hochschule Esslingen - University of Applied Sciences
   Flandernstr. 101
   Esslingen  73732
   Germany

   Email: michael.scharf@hs-esslingen.de


   Vishal Murgai
   Cisco Systems Inc

   Email: vmurgai@cisco.com


   Mahesh Jethanandani
   VMware

   Email: mjethanandani@gmail.com






























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