



Softwire Working Group                                      M. Boucadair
Internet-Draft                                                    Orange
Intended status: Standards Track                               I. Farrer
Expires: December 15, 2019                           Deutsche Telekom AG
                                                                R. Asati
                                                     Cisco Systems, Inc.
                                                           June 13, 2019


                   Tunnel Interface Types YANG Module
                    draft-ietf-softwire-iftunnel-07

Abstract

   This document specifies the initial version of a YANG module
   containing a collection of IANA maintained YANG identities, used as
   interface types for tunnel interfaces.  The module reflects the
   "tunnelType" registry maintained by IANA.  The latest revision of
   this YANG module can be obtained from the IANA web site.

   Tunnel type values are not directly added to the Tunnel Interface
   Types YANG module; they must instead be added to the "tunnelType"
   IANA registry.  Once a new tunnel type registration is made by IANA
   for a new tunneling scheme or even an existing one that is not
   already listed in the current registry (e.g., LISP, NSH), IANA will
   update the Tunnel Interface Types YANG module accordingly.

   Some of the IETF-defined tunneling techniques are not listed in the
   current IANA registry.  It is not the intent of this document to
   update the existing IANA registry with a comprehensive list of tunnel
   technologies.  Registrants must follow the IETF registration
   procedure for interface types whenever a new tunnel type is needed.

Editorial Note (To be removed by RFC Editor)

   Please update these statements in the document with the RFC number to
   be assigned to this document:

   o  "This version of this YANG module is part of RFC XXXX;"

   o  "RFC XXXX: Tunnel Interface Types YANG Module";

   o  "reference: RFC XXXX"

   o  "...must be updated as defined in RFCXXXX."

   Please update the "revision" date of the YANG modules.




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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 December 15, 2019.

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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  IANA Tunnel Type YANG Module  . . . . . . . . . . . . . . . .   3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     4.1.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   8
     4.2.  Updates to the IANA tunnelType Table  . . . . . . . . . .   9
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Example Usage  . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16





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1.  Introduction

   This document specifies the initial version of the iana-tunnel-type
   YANG module containing a collection of IANA maintained YANG
   identities identifying tunnel interface types.  The module reflects
   IANA's registry maintained at [TUNNELTYPE-IANA-REGISTRY].  The latest
   revision of this module can be obtained from the IANA web site.

   Tunnel-specific extensions may be added to the Interface module
   [RFC8343] as a function of the tunnel type.  An example of this is
   provided in Appendix A.  It is not the intention of this document to
   define tunnel-specific extensions for every tunnel encapsulation
   technology; those are discussed in dedicated documents such as
   [I-D.ietf-softwire-yang].  Likewise, it is out of the scope of this
   document to update the existing IANA registry
   [TUNNELTYPE-IANA-REGISTRY] with a comprehensive list of tunnel
   technologies.  Guidelines and registration procedures for interface
   types and sub-types are discussed in [I-D.thaler-iftype-reg].

   This document uses the common YANG types defined in [RFC6991] and
   adopts the Network Management Datastore Architecture (NMDA
   [RFC8342]).

   The terminology for describing YANG modules is defined in [RFC7950].
   The meanings of the symbols used in the tree diagram are defined in
   [RFC8340].

2.  IANA Tunnel Type YANG Module

   The iana-tunnel-type module imports the 'iana-if-type' module defined
   in [RFC7224].

   The initial version of the module includes tunnel types defined in
   [RFC4087], [RFC7856], [RFC7870], and [RFC6346].

   <CODE BEGINS> file "iana-tunnel-type@2019-04-04.yang"

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

     import iana-if-type  {
       prefix ift;
       reference
         "RFC 7224: IANA Interface Type YANG Module";
     }




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     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>";

     description
       "This module contains a collection of YANG identities defined
       by IANA and used as interface types for tunnel interfaces.

       Copyright (c) 2019 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 Simplified BSD License
       set forth in Section 4.c of the IETF Trust's Legal Provisions
       Relating to IETF Documents
       (http://trustee.ietf.org/license-info).

       This version of this YANG module is part of RFC XXXX; see
       the RFC itself for full legal notices.";

     revision 2019-04-04 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: Tunnel Interface Types YANG Module";
     }
     identity other {
       base ift:tunnel;
       description
         "None of the following values.";
       reference
        "RFC 4087: IP Tunnel MIB";
     }
     identity direct {
       base ift:tunnel;
       description
         "No intermediate header.";
       reference
         "RFC 2003: IP Encapsulation within IP



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          RFC 4213: Basic Transition Mechanisms for IPv6 Hosts
                    and Routers";
      }
      identity gre {
        base ift:tunnel;
        description
          "GRE encapsulation.";
        reference
         "RFC 1701: Generic Routing Encapsulation (GRE)
          RFC 1702: Generic Routing Encapsulation over IPv4 networks
          RFC 7676: IPv6 Support for Generic Routing Encapsulation
                    (GRE)";
     }
     identity minimal {
       base ift:tunnel;
       description
         "Minimal encapsulation.";
       reference
         "RFC 2004: Minimal Encapsulation within IP";
     }
     identity l2tp {
       base ift:tunnel;
       description
         "L2TP encapsulation.";
      reference
        "RFC 2661: Layer Two Tunneling Protocol (L2TP)";
     }
     identity pptp {
       base ift:tunnel;
       description
         "PPTP encapsulation.";
       reference
         "RFC 2637: Point-to-Point Tunneling Protocol (PPTP)";
     }
     identity l2f {
       base ift:tunnel;
       description
         "L2F encapsulation.";
       reference
         "RFC 2341: Cisco Layer Two Forwarding (Protocol) (L2F)";
     }
     identity udp {
       base ift:tunnel;
       description
         "UDP encapsulation.";
       reference
         "Section 3.1.11 of RFC 8085";
     }



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     identity atmp {
       base ift:tunnel;
       description
        "ATMP encapsulation.";
       reference
         "RFC 2107: Ascend Tunnel Management Protocol - ATMP";
     }
     identity msdp {
       base ift:tunnel;
       description
         "MSDP encapsulation.";
       reference
         "RFC 3618: Multicast Source Discovery Protocol (MSDP)";
     }
     identity sixtofour {
       base ift:tunnel;
       description
         "6to4 encapsulation.";
       reference
         "RFC 3056: Connection of IPv6 Domains via IPv4 Clouds";
     }
     identity sixoverfour {
       base ift:tunnel;
       description
         "6over4 encapsulation.";
       reference
         "RFC 2529: Transmission of IPv6 over IPv4 Domains without
                    Explicit Tunnels";
     }
     identity isatap {
       base ift:tunnel;
       description
         "ISATAP encapsulation.";
       reference
         "RFC 5214:  Intra-Site Automatic Tunnel Addressing Protocol
                    (ISATAP)";
     }
     identity teredo {
       base ift:tunnel;
       description
         "Teredo encapsulation.";
       reference
         "RFC 4380: Teredo- Tunneling IPv6 over UDP through
                    Network Address Translations (NATs)";
     }
     identity iphttps {
       base ift:tunnel;
       description



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         "IP over HTTPS (IP-HTTPS) Tunneling Protocol.";
       reference
         "Microsoft Corporation, IP over HTTPS (IP-HTTPS) Tunneling
          Protocol Specification,
          https://msdn.microsoft.com/en-us/library/dd358571.aspx";
     }
     identity softwiremesh {
       base ift:tunnel;
       description
         "softwire mesh tunnel.";
       reference
         "RFC 5565: Softwire Mesh Framework";
     }
     identity dslite {
       base ift:tunnel;
       description
         "DS-Lite tunnel.";
       reference
         "RFC 6333: Dual-Stack Lite Broadband Deployments Following
                    IPv4 Exhaustion";
     }
     identity aplusp {
       base ift:tunnel;
       description
         "A+P encapsulation.";
       reference
         "RFC 6346: The Address plus Port (A+P) Approach to the IPv4
                    Address Shortage";
     }
   }
   <CODE ENDS>

3.  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.





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   The module defined in this document defines YANG identities for the
   iana-tunnel-types registry.  These identities are intended to be
   referenced by other YANG modules, and by themselves do not expose any
   nodes which are writable, contain read-only state, or RPCs.  As such,
   there are no additional security issues to be considered relating to
   the module defined in this document.

4.  IANA Considerations

4.1.  YANG Module

   This document requests IANA to register the following URI in the "ns"
   subregistry within the "IETF XML Registry" [RFC3688]:

            URI: urn:ietf:params:xml:ns:yang:iana-tunnel-type
            Registrant Contact: IANA.
            XML: N/A; the requested URI is an XML namespace.

   This document requests IANA to register the following following YANG
   module in the "YANG Module Names" subregistry [RFC7950] within the
   "YANG Parameters" registry.

            Name: iana-tunnel-type
            Namespace: urn:ietf:params:xml:ns:yang:iana-tunnel-type
            Prefix: iana-tunnel-type
            Reference: RFC XXXX

   This document defines the initial version of the IANA-maintained
   iana-tunnel-type YANG module.  IANA is requested to add this note:

      Tunnel type values must not be directly added to the iana-tunnel-
      type YANG module.  They must instead be respectively added to the
      "tunnelType" sub-registry (under the "ifType definitions"
      registry).

   When a tunnel type is added to the "tunnelType" sub-registry, a new
   "identity" statement must be added to the iana-tunnel-type YANG
   module.  The name of the "identity" is the lower-case of the
   corresponding enumeration in the IANAifType-MIB (i.e.,
   IANAtunnelType).  The "identity" statement should have the following
   sub-statements defined:

   "base":        Contains 'ift:tunnel'.

   "description": Replicates the description from the registry.

   "reference":   Replicates the reference from the registry and add the
                  title of the document.



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   Unassigned or reserved values are not present in the module.

   When the iana-tunnel-type YANG module is updated, a new "revision"
   statement must be added in front of the existing revision statements.

   IANA is requested to add this note to "tunnelType" sub-registry:

      When this registry is modified, the YANG module iana-tunnel-type
      must be updated as defined in RFCXXXX.

4.2.  Updates to the IANA tunnelType Table

   This document requests IANA to update the following entries available
   at https://www.iana.org/assignments/smi-numbers/smi-
   numbers.xhtml#smi-numbers-6:

   OLD:

   Decimal Name         Description            References
   2       direct       no intermediate header [RFC4087]
   3       gre          GRE encapsulation      [RFC4087]
   4       minimal      Minimal encapsulation  [RFC4087]
   5       l2tp         L2TP encapsulation     [RFC4087]
   6       pptp         PPTP encapsulation     [RFC4087]
   7       l2f          L2F encapsulation      [RFC4087]
   8       udp          UDP encapsulation      [RFC4087]
   9       atmp         ATMP encapsulation     [RFC4087]
   10      msdp         MSDP encapsulation     [RFC4087]
   11      sixToFour    6to4 encapsulation     [RFC4087]
   12      sixOverFour  6over4 encapsulation   [RFC4087]
   13      isatap       ISATAP encapsulation   [RFC4087]
   14      teredo       Teredo encapsulation   [RFC4087]
   16      softwireMesh softwire mesh tunnel   [RFC7856]
   17      dsLite       DS-Lite tunnel         [RFC7870]

















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   NEW:

   Decimal Name         Description            References
   2       direct       no intermediate header [RFC2003]
                                               [RFC4213]
   3       gre          GRE encapsulation      [RFC1701]
                                               [RFC1702]
                                               [RFC7676]
   4       minimal      Minimal encapsulation  [RFC2004]
   5       l2tp         L2TP encapsulation     [RFC2661]
   6       pptp         PPTP encapsulation     [RFC2637]
   7       l2f          L2F encapsulation      [RFC2341]
   8       udp          UDP encapsulation      [RFC8085]
   9       atmp         ATMP encapsulation     [RFC2107]
   10      msdp         MSDP encapsulation     [RFC3618]
   11      sixToFour    6to4 encapsulation     [RFC3056]
   12      sixOverFour  6over4 encapsulation   [RFC2529]
   13      isatap       ISATAP encapsulation   [RFC5214]
   14      teredo       Teredo encapsulation   [RFC4380]
   16      softwireMesh softwire mesh tunnel   [RFC5565]
   17      dsLite       DS-Lite tunnel         [RFC6333]

5.  Acknowledgements

   Special thanks to Tom Petch and Martin Bjorklund for the detailed
   review and suggestions.

   Thanks to Andy Bierman for the Yangdoctors review.

   Thanks to Dale Worley, David Black, and Yaron Sheffer for the review.

6.  References

6.1.  Normative References

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

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

   [RFC7224]  Bjorklund, M., "IANA Interface Type YANG Module",
              RFC 7224, DOI 10.17487/RFC7224, May 2014,
              <https://www.rfc-editor.org/info/rfc7224>.

   [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>.

   [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>.

   [TUNNELTYPE-IANA-REGISTRY]
              Internet Assigned Numbers Authority, "ifType definitions:
              tunnelType", <https://www.iana.org/assignments/smi-
              numbers/smi-numbers.xhtml#smi-numbers-6>.

6.2.  Informative References

   [I-D.ietf-softwire-yang]
              Farrer, I. and M. Boucadair, "YANG Modules for IPv4-in-
              IPv6 Address plus Port (A+P) Softwires", draft-ietf-
              softwire-yang-16 (work in progress), January 2019.

   [I-D.thaler-iftype-reg]
              Thaler, D. and D. Romascanu, "Guidelines and Registration
              Procedures for Interface Types", draft-thaler-iftype-
              reg-02 (work in progress), March 2019.





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   [RFC1701]  Hanks, S., Li, T., Farinacci, D., and P. Traina, "Generic
              Routing Encapsulation (GRE)", RFC 1701,
              DOI 10.17487/RFC1701, October 1994,
              <https://www.rfc-editor.org/info/rfc1701>.

   [RFC1702]  Hanks, S., Li, T., Farinacci, D., and P. Traina, "Generic
              Routing Encapsulation over IPv4 networks", RFC 1702,
              DOI 10.17487/RFC1702, October 1994,
              <https://www.rfc-editor.org/info/rfc1702>.

   [RFC2003]  Perkins, C., "IP Encapsulation within IP", RFC 2003,
              DOI 10.17487/RFC2003, October 1996,
              <https://www.rfc-editor.org/info/rfc2003>.

   [RFC2004]  Perkins, C., "Minimal Encapsulation within IP", RFC 2004,
              DOI 10.17487/RFC2004, October 1996,
              <https://www.rfc-editor.org/info/rfc2004>.

   [RFC2107]  Hamzeh, K., "Ascend Tunnel Management Protocol - ATMP",
              RFC 2107, DOI 10.17487/RFC2107, February 1997,
              <https://www.rfc-editor.org/info/rfc2107>.

   [RFC2341]  Valencia, A., Littlewood, M., and T. Kolar, "Cisco Layer
              Two Forwarding (Protocol) "L2F"", RFC 2341,
              DOI 10.17487/RFC2341, May 1998,
              <https://www.rfc-editor.org/info/rfc2341>.

   [RFC2529]  Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4
              Domains without Explicit Tunnels", RFC 2529,
              DOI 10.17487/RFC2529, March 1999,
              <https://www.rfc-editor.org/info/rfc2529>.

   [RFC2637]  Hamzeh, K., Pall, G., Verthein, W., Taarud, J., Little,
              W., and G. Zorn, "Point-to-Point Tunneling Protocol
              (PPTP)", RFC 2637, DOI 10.17487/RFC2637, July 1999,
              <https://www.rfc-editor.org/info/rfc2637>.

   [RFC2661]  Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn,
              G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"",
              RFC 2661, DOI 10.17487/RFC2661, August 1999,
              <https://www.rfc-editor.org/info/rfc2661>.

   [RFC3056]  Carpenter, B. and K. Moore, "Connection of IPv6 Domains
              via IPv4 Clouds", RFC 3056, DOI 10.17487/RFC3056, February
              2001, <https://www.rfc-editor.org/info/rfc3056>.






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   [RFC3618]  Fenner, B., Ed. and D. Meyer, Ed., "Multicast Source
              Discovery Protocol (MSDP)", RFC 3618,
              DOI 10.17487/RFC3618, October 2003,
              <https://www.rfc-editor.org/info/rfc3618>.

   [RFC4087]  Thaler, D., "IP Tunnel MIB", RFC 4087,
              DOI 10.17487/RFC4087, June 2005,
              <https://www.rfc-editor.org/info/rfc4087>.

   [RFC4213]  Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
              for IPv6 Hosts and Routers", RFC 4213,
              DOI 10.17487/RFC4213, October 2005,
              <https://www.rfc-editor.org/info/rfc4213>.

   [RFC4380]  Huitema, C., "Teredo: Tunneling IPv6 over UDP through
              Network Address Translations (NATs)", RFC 4380,
              DOI 10.17487/RFC4380, February 2006,
              <https://www.rfc-editor.org/info/rfc4380>.

   [RFC5214]  Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
              Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214,
              DOI 10.17487/RFC5214, March 2008,
              <https://www.rfc-editor.org/info/rfc5214>.

   [RFC5565]  Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh
              Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009,
              <https://www.rfc-editor.org/info/rfc5565>.

   [RFC6333]  Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
              Stack Lite Broadband Deployments Following IPv4
              Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011,
              <https://www.rfc-editor.org/info/rfc6333>.

   [RFC6346]  Bush, R., Ed., "The Address plus Port (A+P) Approach to
              the IPv4 Address Shortage", RFC 6346,
              DOI 10.17487/RFC6346, August 2011,
              <https://www.rfc-editor.org/info/rfc6346>.

   [RFC7676]  Pignataro, C., Bonica, R., and S. Krishnan, "IPv6 Support
              for Generic Routing Encapsulation (GRE)", RFC 7676,
              DOI 10.17487/RFC7676, October 2015,
              <https://www.rfc-editor.org/info/rfc7676>.

   [RFC7856]  Cui, Y., Dong, J., Wu, P., Xu, M., and A. Yla-Jaaski,
              "Softwire Mesh Management Information Base (MIB)",
              RFC 7856, DOI 10.17487/RFC7856, May 2016,
              <https://www.rfc-editor.org/info/rfc7856>.




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   [RFC7870]  Fu, Y., Jiang, S., Dong, J., and Y. Chen, "Dual-Stack Lite
              (DS-Lite) Management Information Base (MIB) for Address
              Family Transition Routers (AFTRs)", RFC 7870,
              DOI 10.17487/RFC7870, June 2016,
              <https://www.rfc-editor.org/info/rfc7870>.

   [RFC8085]  Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
              Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
              March 2017, <https://www.rfc-editor.org/info/rfc8085>.

   [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>.

   [RFC8343]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
              <https://www.rfc-editor.org/info/rfc8343>.

Appendix A.  Example Usage

   The following example illustrates how the Interface YANG module can
   be augmented with tunnel-specific parameters.  In this example, the
   module is augmented with a 'remote-endpoint' for the tunnel.  A tree
   structure is provided below:

   module: example-iftunnel-extension
     augment /if:interfaces/if:interface:
       +--rw remote-endpoint?   inet:ipv6-address

   The 'example-iftunnel-extension' module imports the modules defined
   in [RFC6991] and [RFC8343] in addition to the "iana-tunnel-type"
   module defined in this document.

   module example-iftunnel-extension {
     yang-version 1.1;

     namespace "urn:ietf:params:xml:ns:yang:example-iftunnel-extension";
     prefix example;

     import ietf-inet-types {
       prefix inet;
       reference
         "Section 4 of RFC 6991";
     }

     import ietf-interfaces {
       prefix if;
       reference



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         "RFC 8343: A YANG Data Model for Interface Management";
     }

     import iana-tunnel-type  {
       prefix iana-tunnel-type;
       reference
         "RFC XXXX:  A Tunnel Extension to the Interface Management
                     YANG Module";
     }

     organization "IETF Softwire Working Group";

     contact

       "WG Web:   <https://datatracker.ietf.org/wg/softwire/>
        WG List:  <mailto:softwire@ietf.org>

        Author:  Mohamed Boucadair
                 <mailto:mohamed.boucadair@orange.com>";

      description
         "This is an example YANG module to extend the Interface YANG
          module with tunnel-specific parameters.

         Copyright (c) 2019 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 Simplified BSD License
         set forth in Section 4.c of the IETF Trust's Legal Provisions
         Relating to IETF Documents
         (http://trustee.ietf.org/license-info).

         This version of this YANG module is part of RFC XXXX; see
         the RFC itself for full legal notices.";

     revision 2019-04-04 {
       description
         "Initial revision.";
       reference
         "RFC XXXX:  Tunnel Interface Types YANG Module";
     }

     augment "/if:interfaces/if:interface" {
       when "derived-from(if:type, 'iana-tunnel-type:gre')";
       description
         "Augments Interface module with specific tunnel parameters.";



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       leaf remote-endpoint {
         type inet:ipv6-address;
         description
           "IPv6 address of the remote GRE endpoint.";
       }
     }
   }

Authors' Addresses

   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com


   Ian Farrer
   Deutsche Telekom AG
   CTO-ATI,Landgrabenweg 151
   Bonn, NRW  53227
   Germany

   Email: ian.farrer@telekom.de


   Rajiv Asati
   Cisco Systems, Inc.
   7025 Kit Creek Rd.
   RTP, NC  27709
   USA

   Email: Rajiva@cisco.com

















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