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A YANG Data Model for BGP Communities
draft-ietf-grow-yang-bgp-communities-07

Document Type Active Internet-Draft (grow WG)
Author Martin Pels
Last updated 2025-10-15
Replaces draft-pels-grow-yang-bgp-communities
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draft-ietf-grow-yang-bgp-communities-07
Network Working Group                                            M. Pels
Internet-Draft                                                  RIPE NCC
Intended status: Standards Track                         15 October 2025
Expires: 18 April 2026

                 A YANG Data Model for BGP Communities
                draft-ietf-grow-yang-bgp-communities-07

Abstract

   This document defines a YANG data model for the structured
   specification of BGP communities.  The model provides operators with
   a way to publish their locally defined BGP communities in a
   standardized format.

   Two YANG modules are defined in this document.  The first is designed
   for stand-alone usage.  The second is used to augment the "ietf-bgp"
   YANG module[I-D.ietf-idr-bgp-model] with BGP community annotations.

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 18 April 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Tree view . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Base Module . . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Augmentation Module . . . . . . . . . . . . . . . . . . . . .  16
   7.  Operational guidelines  . . . . . . . . . . . . . . . . . . .  19
     7.1.  Publishing guidelines . . . . . . . . . . . . . . . . . .  19
     7.2.  Parsing guidelines  . . . . . . . . . . . . . . . . . . .  19
   8.  IANA considerations . . . . . . . . . . . . . . . . . . . . .  20
     8.1.  YANG Namespace Registration . . . . . . . . . . . . . . .  20
     8.2.  YANG Module Registration  . . . . . . . . . . . . . . . .  20
     8.3.  YANG SID Allocation . . . . . . . . . . . . . . . . . . .  20
   9.  Implementation status . . . . . . . . . . . . . . . . . . . .  20
     9.1.  Publishing implementations  . . . . . . . . . . . . . . .  21
     9.2.  Parser implementations  . . . . . . . . . . . . . . . . .  21
   10. Security considerations . . . . . . . . . . . . . . . . . . .  22
     10.1.  Publishing considerations  . . . . . . . . . . . . . . .  22
     10.2.  Parsing considerations . . . . . . . . . . . . . . . . .  23
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  23
   12. Informative References  . . . . . . . . . . . . . . . . . . .  24
   Appendix A.  JSON Examples  . . . . . . . . . . . . . . . . . . .  26
     A.1.  RFC8195 Selective NO_EXPORT definition  . . . . . . . . .  26
     A.2.  RFC4384 Data Collection definition  . . . . . . . . . . .  28
   Appendix B.  Acknowledgements . . . . . . . . . . . . . . . . . .  29
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  29

1.  Introduction

   ISPs use BGP communities to add information to their prefix
   announcements or to let customers influence routing behaviour inside
   the network of the ISP.  Each ISP defines for itself which BGP
   communities to support and how the structure of these communities
   should be interpreted.  This document provides a YANG[RFC7950] module
   for describing the structure and meaning of BGP communities[RFC1997],
   Extended BGP communities[RFC4360] and Large BGP communities[RFC8092].
   ISPs can use this standardized format to publish their community

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   definitions.  Section 3 elaborates on further advantages of using
   such a standardized format.

   Section 4 and Section 5 describe the base module.  Section 6
   describes a module which augments the "ietf-bgp" YANG
   module[I-D.ietf-idr-bgp-model] with BGP community annotations.

2.  Terminology

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

   The meaning of the symbols in tree diagrams are defined in [RFC8340].

3.  Rationale

   ISPs may define various BGP communities that have local significance
   within their network.  These communities could be used to add
   miscellaneous information to a prefix announcement.  For example, a
   community "64501:1:528" may signify that the AS with ASN 64501 is
   originating a prefix from a point of presence in The Netherlands (ISO
   3166-1 code 528).  Communities could be used to allow customers of an
   ISP to control the routing behavior of their prefixes inside the ISP.
   For example, a community "64501:4:64498" attached to a prefix
   advertised to AS64501 by a customer may be interpreted by AS64501 to
   mean that this prefix must not be propagated to AS64498.

   For both use cases it is necessary for the ISP to communicate the
   meaning of their locally defined communities to others.  Currently
   this is typically done by publishing a list of communities on a web
   page, or as a remark inside an "autnum" object in the Internet
   Routing Registry.  This makes it cumbersome to determine whether and
   where an ISP publishes community information.  The lack of a well-
   defined structure makes it hard to create a standardized publishing
   mechanism, and to develop tools for automatically parsing community
   information and eventually triggering configuration actions.

   The purpose of the YANG model defined in this document is to provide
   a standardized format for publishing community definitions.  These
   definitions help applications to interpret the structure and purpose
   of BGP communities.  For example, looking glasses may use the
   published definitions to parse communities seen in BGP announcements
   and display their meaning.  Another potential use case is in
   generating routing policy configurations based on community
   definitions published by an upstream ASN.  This could be achieved

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   automatically using external tooling to generate router
   configurations, or inside a router's command-line interface by
   importing the definitions and providing the CLI-user with available
   choices for manual configuration.

   This document only describes a data model for the publishing format
   of community definitions.  The publishing location and publishing
   mechanism used are outside the scope of this specification.  The data
   model does not make any assumption about the protocol used to
   publish/retrieve formatted data following the model.

4.  Tree view

   The following tree diagram provides an overview of the "ietf-bgp-
   communities" data model.

   module: ietf-bgp-communities
     +--ro bgp-communities
        +--ro serial?                 uint32
        +--ro autonomous-system-id?   inet:as-number
        +--ro uri?                    inet:uri
        +--ro description?            string
        +--ro contact-url?            inet:uri
        +--ro contact* [email-address]
        |  +--ro email-address          inet:email-address
        |  +--ro name?                  string
        |  +--ro role?                  string
        |  +--ro organization?          string
        |  +--ro organizational-unit?   string
        +--ro regular* [name]
        |  +--ro name            community-name
        |  +--ro category?       community-category
        |  +--ro description?    community-description
        |  +--ro global-admin    two-octet-as-number
        |  +--ro local-admin
        |     +--ro format?   local-admin-format
        |     +--ro field* [name]
        |        +--ro name           field-name
        |        +--ro length?        uint8
        |        +--ro pattern        field-pattern
        |        +--ro description?   field-description
        +--ro extended* [name]
        |  +--ro name           community-name
        |  +--ro category?      community-category
        |  +--ro description?   community-description
        |  +--ro type           uint8
        |  +--ro subtype        uint8
        |  +--ro (global-admin)

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        |  |  +--:(asn)
        |  |  |  +--ro asn?     two-octet-as-number
        |  |  +--:(asn4)
        |  |     +--ro asn4?    inet:as-number
        |  +--ro local-admin
        |     +--ro format?   local-admin-format
        |     +--ro field* [name]
        |        +--ro name           field-name
        |        +--ro length?        uint8
        |        +--ro pattern        field-pattern
        |        +--ro description?   field-description
        +--ro large* [name]
           +--ro name                 community-name
           +--ro category?            community-category
           +--ro description?         community-description
           +--ro global-admin         inet:as-number
           +--ro local-data-part-1
           |  +--ro format?   local-admin-format
           |  +--ro field* [name]
           |     +--ro name           field-name
           |     +--ro length?        uint8
           |     +--ro pattern        field-pattern
           |     +--ro description?   field-description
           +--ro local-data-part-2
              +--ro format?   local-admin-format
              +--ro field* [name]
                 +--ro name           field-name
                 +--ro length?        uint8
                 +--ro pattern        field-pattern
                 +--ro description?   field-description

5.  Base Module

   This section contains the base YANG module for BGP community
   definitions.

   Several elements in this module use data types from
   [I-D.ietf-netmod-rfc6991-bis].  These data types are represented with
   the prefix "inet".

   <CODE BEGINS> file "ietf-bgp-communities@2025-08-26.yang"

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

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     import ietf-inet-types {
       prefix inet;
       reference
         "draft-ietf-netmod-rfc6991-bis-18: Common YANG Data Types";
     }

     organization
       "IETF GROW Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/grow/>
        WG List:  <mailto:grow@ietf.org>

        Author:   Martin Pels
          <mailto:mpels@ripe.net>";
     description
       "This module describes a structure for BGP Communities

        Copyright (c) 2025 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

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

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

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

     // RFC-EDITOR: please update YYYY with this RFC ID

     revision 2025-08-26 {
       description
         "Initial revision.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     typedef two-octet-as-number {
       type uint16;

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       description
         "This type represents autonomous system numbers, which
          identify an Autonomous System (AS).

          Autonomous system numbers were originally limited to 16
          bits.  BGP extensions have enlarged the autonomous system
          number space to 32 bits.  The two-octet-as-number type uses
          an uint16 base type for use cases where the enlarged number
          space is not supported.";
       reference
         "RFC 1930: Guidelines for creation, selection, and
          registration of an Autonomous System (AS)";
     }

     typedef community-name {
       type string {
         length "1..255";
         pattern '[^\s]+';
       }
       description
         "This type restricts values for the name of a BGP community.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     typedef community-category {
       type enumeration {
         enum informational {
           value 0;
           description
             "Informational community";
         }
         enum action {
           value 1;
           description
             "Action community";
         }
       }
       description
         "This type restricts values for the category of a BGP
          community.";
       reference
         "RFC 8195: Use of BGP Large Communities";
     }

     typedef community-description {
       type string {

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         length "1..65535";
       }
       description
         "This type restricts values for the description of a BGP
          community.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     typedef local-admin-format {
       type enumeration {
         enum decimal {
           value 0;
           description
             "Decimal number string";
         }
         enum binary {
           value 1;
           description
             "Bit string";
         }
       }
       description
         "This type defines the format options for a BGP community
          Local Administrator/Local Data field encoding";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     typedef field-name {
       type string {
         length "1..255";
         pattern '[^\s]+';
       }
       description
         "This type restricts values for the name leaf of a BGP
          community Local Administrator/Local Data field.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     typedef field-pattern {
       type string {
         length "1..4095";
         pattern '[-0-9.,*?^$+|(){}\[\]]+';

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       }
       description
         "This type restricts values for the pattern leaf of a BGP
          community Local Administrator/Local Data field.  Patterns
          are described as POSIX Extended Regular Expressions";
       reference
         "IEEE 1003.2-1992: Information Technology - Portable
          Operating System Interface (POSIX) - Part 2: Shell and
          Utilities (Vol. 1)";
     }

     typedef field-description {
       type string {
         length "1..65535";
         pattern '(\*)|([^*]+)';
       }
       description
         "This type restricts values for the description leaf of a BGP
          community Local Administrator/Local Data field.  The string
          containing a single asterisk '*' indicates that the value of
          the field should be used as description.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     grouping local-admin-fields {
       description
         "A group of subfields inside the Local Administrator/Local
          Data section of a BGP Community";
       list field {
         key "name";
         ordered-by user;
         description
           "Ordered list of fields with their meanings";
         leaf name {
           type field-name;
           description
             "The name of the field";
         }
         leaf length {
           type uint8;
           description
             "Length of the field.  If local-admin-format is 'decimal',
              this is a number of digits.  In case local-admin-format is
              'binary', it is a number of bits.

              Parsers use the field length to determine how many

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              decimals or bits from the Local Administrator part of the
              community are used by this field.  If this leaf is not
              defined, the length is assumed to be the maximum allowed
              length of the entire field list.  In this case the field
              list MUST NOT contain more than one element.";
         }
         leaf pattern {
           type field-pattern;
           mandatory true;
           description
             "Used by parsers to match on the content of the field.
              This could be a single value or a regular expression
              pattern matching multiple values.";
         }
         leaf description {
           type field-description;
           description
             "A text description of the field pattern.  This description
              can be used to provide meaning to specific values for a
              field.";
         }
       }
     }

     grouping maintainer-contact {
       description
         "A maintainer contact entry";
       leaf email-address {
         type inet:email-address;
         description
           "Maintainer contact e-mail address";
       }
       leaf name {
         type string {
           length "1..255";
         }
         description
           "Maintainer contact name";
       }
       leaf role {
         type string {
           length "1..255";
         }
         description
           "Maintainer contact role";
       }
       leaf organization {
         type string {

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           length "1..255";
         }
         description
           "Maintainer contact organization";
       }
       leaf organizational-unit {
         type string {
           length "1..255";
         }
         description
           "Maintainer contact organizational unit";
       }
     }

     grouping regular-community {
       description
         "A Regular BGP community definition";
       leaf name {
         type community-name;
         description
           "Community name";
       }
       leaf category {
         type community-category;
         description
           "Category of the community";
       }
       leaf description {
         type community-description;
         description
           "Description for the community";
       }
       leaf global-admin {
         type two-octet-as-number;
         mandatory true;
         description
           "Global Administrator field";
       }
       container local-admin {
         description
           "Local Administrator Field";
         leaf format {
           type local-admin-format;
           default "decimal";
           description
             "Format used for parsing Local Administrator subfields";
         }
         uses local-admin-fields;

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       }
       reference
         "RFC 1997: BGP Communities Attribute";
     }

     grouping extended-community {
       description
         "An Extended BGP community definition";
       leaf name {
         type community-name;
         description
           "Community name";
       }
       leaf category {
         type community-category;
         description
           "Category of the community";
       }
       leaf description {
         type community-description;
         description
           "Description for the community";
       }
       leaf type {
         type uint8 {
           range "0|2|64|66";
         }
         mandatory true;
         description
           "High-order Type of the community.  Supported values are 0
            (0x00) for Transitive Two-Octet AS-Specific Extended
            Communities, 2 (0x02) for Transitive Four-Octet
            AS-Specific Extended Communities, 64 (0x40) for
            Non-Transitive Two-Octet AS-Specific Extended Communities
            and 66 (0x42) for Non-Transitive Four-Octet AS-Specific
            Extended Communities.";
       }
       leaf subtype {
         type uint8;
         mandatory true;
         description
           "Low-order Sub-Type of the community";
       }
       choice global-admin {
         mandatory true;
         description
           "Global Administrator Field";
         case asn {

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           leaf asn {
             type two-octet-as-number;
             must "../type = 0 or ../type = 64" {
               error-message
                 "../type must match Two-Octet AS-Specific Community";
             }
             description
               "Two-Octet AS";
           }
         }
         case asn4 {
           leaf asn4 {
             type inet:as-number;
             must "../type = 2 or ../type = 66" {
               error-message
                 "../type must match Four-Octet AS-Specific Community";
             }
             description
               "Four-Octet AS";
           }
         }
       }
       container local-admin {
         description
           "Local Administrator Field";
         leaf format {
           type local-admin-format;
           default "decimal";
           description
             "Format used for parsing Local Administrator subfields";
         }
         uses local-admin-fields;
       }
       reference
         "RFC 4360: BGP Extended Communities Attribute";
     }

     grouping large-community {
       description
         "A Large BGP community definition";
       leaf name {
         type community-name;
         description
           "Community name";
       }
       leaf category {
         type community-category;
         description

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           "Category of the community";
       }
       leaf description {
         type community-description;
         description
           "Description for the community";
       }
       leaf global-admin {
         type inet:as-number;
         mandatory true;
         description
           "Global Administrator field";
       }
       container local-data-part-1 {
         description
           "Local Data Part 1 Field";
         leaf format {
           type local-admin-format;
           default "decimal";
           description
             "Format used for parsing Local Data Part 1 subfields";
         }
         uses local-admin-fields;
       }
       container local-data-part-2 {
         description
           "Local Data Part 2 Field";
         leaf format {
           type local-admin-format;
           default "decimal";
           description
             "Format used for parsing Local Data Part 2 subfields";
         }
         uses local-admin-fields;
       }
       reference
         "RFC 8092: BGP Large Communities Attribute";
     }

     container bgp-communities {
       config false;
       description
         "A community set";
       leaf serial {
         type uint32;
         must ". > 0" {
           error-message "serial must not be 0";
         }

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         description
           "Version number of the community set.  This value wraps and
            should be compared using sequence space arithmetic.
            Publishing implementations are free to decide how to
            generate this value.  One example method is to use the
            YYYYMMDDnn syntax as commonly used inside the DNS.";
         reference
           "RFC 1912: Common DNS Operational and Configuration Errors";
       }
       leaf autonomous-system-id {
         type inet:as-number;
         description
           "Autonomous System authoritative for the community set";
       }
       leaf uri {
         type inet:uri;
         description
           "Publication point for the community set";
       }
       leaf description {
         type string {
           length "1..65535";
         }
         description
           "A description for the community set";
       }
       leaf contact-url {
         type inet:uri;
         description
           "A reference to a webpage with maintainer contact
            information";
       }
       list contact {
         key "email-address";
         description
           "A list of contacts for the community set maintainer(s)";
         uses maintainer-contact;
       }
       list regular {
         must
           "(./global-admin = ../autonomous-system-id) or
            (./global-admin >= 64512 and ./global-admin <= 65534)" {
             error-message
               "global-admin must be private ASN or match
                autonomous-system-id";
         }
         key "name";
         ordered-by user;

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         description
           "A list of objects describing RFC 1997 BGP Communities";
         uses regular-community;
       }
       list extended {
         must
           "(./asn = ../autonomous-system-id) or
            (./asn4 = ../autonomous-system-id) or
            (./asn >= 64512 and ./asn <= 65534) or
            (./asn4 >= 4200000000 and ./asn4 <= 4294967294)" {
           error-message
             "global-admin must be private ASN or match
              autonomous-system-id";
         }
         key "name";
         ordered-by user;
         description
           "A list of objects describing RFC 4360 Extended BGP
            Communities.  Two-Octet and Four-Octet AS Specific
            communities are supported by this model.";
         uses extended-community;
       }
       list large {
         must
           "(./global-admin = ../autonomous-system-id) or
            (./global-admin >= 64512 and ./global-admin <= 65534) or
            (./global-admin >= 4200000000 and
             ./global-admin <= 4294967294)" {
           error-message
             "global-admin must be private ASN or match
              autonomous-system-id";
         }
         key "name";
         ordered-by user;
         description
           "A list of objects describing RFC 8092 Large BGP
            Communities";
         uses large-community;
       }
     }
   }
   <CODE ENDS>

6.  Augmentation Module

   This section contains a YANG module defining augmentations for the
   "ietf-bgp" YANG module.  It can be used to annotate BGP communities
   in a BGP RIB.

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   <CODE BEGINS> file "ietf-bgp-communities-annotate@2025-08-26.yang"

   module ietf-bgp-communities-annotate {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-bgp-communities-annotate";
     prefix bgp-comm-an;

     import ietf-bgp-communities {
       prefix bgp-comm;
       reference
         "draft-ietf-grow-yang-bgp-communities-07: A YANG Data
          Model for BGP Communities";
     }
     import ietf-routing {
       prefix rt;
       reference
         "RFC 8349: A YANG Data Model for Routing Management
          (NMDA Version).";
     }
     import ietf-bgp {
       prefix bgp;
       reference
         "draft-ietf-idr-bgp-model-18: YANG Model for Border
          Gateway Protocol (BGP-4)";
     }

     organization
       "IETF GROW Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/grow/>
        WG List:  <mailto:grow@ietf.org>

        Author:   Martin Pels
          <mailto:mpels@ripe.net>";
     description
       "This module augments the ietf-bgp module with support for
        community annotations.

        Copyright (c) 2025 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

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

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

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

     // RFC-EDITOR: please update YYYY with this RFC ID

     revision 2025-08-26 {
       description
         "Initial revision.";
       reference
         "RFC YYYY: A YANG Data Model for BGP Communities
          RFC-EDITOR: please update YYYY with this RFC ID";
     }

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/bgp:bgp/bgp:rib/"
           + "bgp:communities/bgp:community" {
       description
         "Augments a Regular BGP community from the
          ietf-bgp module with an optional annotation.";
       container annotation {
         presence "true";
         description
           "The presence of this container indicates
            that a community definition is available";
         uses bgp-comm:regular-community;
       }
     }

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/bgp:bgp/bgp:rib/"
           + "bgp:ext-communities/bgp:ext-community" {
       description
         "Augments an Extended BGP community from the
          ietf-bgp module with an optional annotation.";
       container annotation {
         presence "true";
         description
           "The presence of this container indicates
            that a community definition is available";
         uses bgp-comm:extended-community;
       }
     }

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     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/bgp:bgp/bgp:rib/"
           + "bgp:large-communities/bgp:large-community" {
       description
         "Augments a Large BGP community from the
          ietf-bgp module with an optional annotation.";
       container annotation {
         presence "true";
         description
           "The presence of this container indicates
            that a community definition is available";
         uses bgp-comm:large-community;
       }
     }
   }
   <CODE ENDS>

7.  Operational guidelines

7.1.  Publishing guidelines

   Operators SHOULD only publish BGP community definitions for networks
   they control.  This may include communities where the Global
   Administrator field contains a private ASN, if this community has a
   local meaning inside the network of the publisher.

   When publishing community definitions with overlapping field
   patterns, these definitions MUST be ordered from most to least
   preferred.  This ensures parsers can perform deterministic matching
   (see Section 7.2).  For example, a definition for a single community
   "64500:123" needs to be specified before a definition that matches a
   covering range of communities "64500:*".

7.2.  Parsing guidelines

   A published BGP community definition can be used by parsers to
   display information about a received community.  If a received
   community matches multiple published community definitions, the first
   matching definition in the published order takes precedence.

   Parsers that use published community definitions from multiple
   operators SHOULD NOT attempt to match received communities where the
   Global Administrator field contains a private ASN, unless they have
   some method to determine which published definition is the
   authoritative one.

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   By default, communities are compared using the decimal representation
   of the fields.  If "format" for a Local Administrator or Local Data
   Part is set to "binary", the fields in the received community are
   converted to strings of zeros and ones before comparison.

   See Section 10.2 for security considerations when parsing community
   definitions.

8.  IANA considerations

8.1.  YANG Namespace Registration

   This document registers the following XML namespace URN in the "IETF
   XML Registry", following the format defined in [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-communities
   Registrant Contact: The IESG.
   XML: N/A, the requested URI is an XML namespace.

8.2.  YANG Module Registration

   This document registers the following YANG module in the "YANG Module
   Names" registry [RFC6020]:

   Name: ietf-bgp-communities
   Maintained by IANA? N
   Namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-communities
   Prefix: bgp-comm
   Reference: RFC YYYY
   RFC-EDITOR: please update YYYY with this RFC ID

8.3.  YANG SID Allocation

   This document registers the following entry in the "IETF YANG SID"
   registry [RFC9595]:

   SID range entry point: TBD
   SID range size: 100
   YANG module name: ietf-bgp-communities
   Reference: RFC YYYY
   RFC-EDITOR: please update YYYY with this RFC ID

9.  Implementation status

   RFC-EDITOR: Please remove this section and the accompanying
   reference(s) before publication.

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   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in [RFC7942].
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   According to [RFC7942], "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.
   It is up to the individual working groups to use this information as
   they see fit".

9.1.  Publishing implementations

   The following networks are known to publish BGP community definitions
   according to this specification.

   +========+============================================+============+
   | ASN    | Publication URI                            | YANG model |
   |        |                                            | revision   |
   +========+============================================+============+
   | 197000 | as197000.json                              | 2025-08-26 |
   |        | (https://web.admindns.ripe.net/draft-ietf- |            |
   |        | grow-yang-bgp-communities/as197000.json)   |            |
   +--------+--------------------------------------------+------------+
   | 25152  | as25152.json                               | 2025-08-26 |
   |        | (https://web.admindns.ripe.net/draft-ietf- |            |
   |        | grow-yang-bgp-communities/as25152.json)    |            |
   +--------+--------------------------------------------+------------+

                   Table 1: Publishing implementations

9.2.  Parser implementations

   The following known parser implementations exist.

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      +===============================================+============+
      | Name                                          | YANG model |
      |                                               | revision   |
      +===============================================+============+
      | NLNOG Looking Glass                           | 2025-07-04 |
      | (https://github.com/NLNOG/lg.ring.nlnog.net/) |            |
      +-----------------------------------------------+------------+

                     Table 2: Parser implementations

10.  Security considerations

10.1.  Publishing considerations

   This section is modeled after the template described in Section 3.7
   of [I-D.ietf-netmod-rfc8407bis].

   The "ietf-bgp-communities" YANG module defines a data model that is
   designed to be accessed via YANG-based management protocols, such as
   NETCONF [RFC6241] and RESTCONF [RFC8040].  These YANG-based
   management protocols (1) have to use a secure transport layer (e.g.,
   SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use
   mutual authentication.

   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.

   There are no data nodes defined in this YANG module that are
   writable/creatable/deletable.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  Specifically,
   the following subtrees and data nodes have particular sensitivities/
   vulnerabilities:

   *  bgp-communities/contact/email-address

   *  bgp-communities/contact/name

   Disclosing this information may be misused, e.g., for tracking and
   data correlation.  Publishers MUST NOT populate these elements with
   Personally Identifiable Information (PII).  For example, these
   elements may be set with information that refers to generic contact
   information, not pointing to specific individuals.

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10.2.  Parsing considerations

   The YANG module described in this document may be used to specify BGP
   community definitions in different serialization formats, such as
   XML, JSON or CBOR.  Applications that parse these community
   definitions SHOULD reject objects that do not conform to the YANG
   model.  Furthermore, parsers SHOULD check that the sum of the
   specified Local Administrator or Local Data Part field lengths in
   each community definition does not exceed the local part size of the
   specified community type.  For example, a Regular BGP community
   definition with format "decimal" containing a field of length 4 and a
   field of length 2 would be illegal, as the Local Administrator field
   has a maximum length of 65535 (5 digits).

   The "bgp-communities/contact-url" element may contain a link to an
   untrusted webpage.  Parsers MAY opt to render the URL as plain text
   rather than a clickable link, to prevent inadvertent exposure of
   information by users of the rendered output.

   Several elements with the "string" data type may be used to display
   information in a web page or application.  Parsers should take care
   that the appropriate escaping is performed to protect against cross-
   site scripting attacks.

11.  Normative References

   [I-D.ietf-idr-bgp-model]
              Jethanandani, M., Patel, K., Hares, S., and J. Haas, "YANG
              Model for Border Gateway Protocol (BGP-4)", Work in
              Progress, Internet-Draft, draft-ietf-idr-bgp-model-18, 21
              October 2024, <https://datatracker.ietf.org/doc/html/
              draft-ietf-idr-bgp-model-18>.

   [I-D.ietf-netmod-rfc6991-bis]
              Schönwälder, J., "Common YANG Data Types", Work in
              Progress, Internet-Draft, draft-ietf-netmod-rfc6991-bis-
              18, 23 June 2025, <https://datatracker.ietf.org/doc/html/
              draft-ietf-netmod-rfc6991-bis-18>.

   [RFC1930]  Hawkinson, J. and T. Bates, "Guidelines for creation,
              selection, and registration of an Autonomous System (AS)",
              BCP 6, RFC 1930, DOI 10.17487/RFC1930, March 1996,
              <https://www.rfc-editor.org/info/rfc1930>.

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

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

   [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>.

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

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8349]  Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
              Routing Management (NMDA Version)", RFC 8349,
              DOI 10.17487/RFC8349, March 2018,
              <https://www.rfc-editor.org/info/rfc8349>.

   [RFC9595]  Veillette, M., Ed., Pelov, A., Ed., Petrov, I., Ed.,
              Bormann, C., and M. Richardson, "YANG Schema Item
              iDentifier (YANG SID)", RFC 9595, DOI 10.17487/RFC9595,
              July 2024, <https://www.rfc-editor.org/info/rfc9595>.

12.  Informative References

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-28, 5 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-28>.

   [IEEE.1003-2.1992]
              Institute of Electrical and Electronics Engineers,
              "Information Technology - Portable Operating System
              Interface (POSIX) - Part 2: Shell and Utilities (Vol. 1)",
              IEEE Standard 1003.2, IEEE 1003.2-1992, IEEE ieee-1003-2,
              1992.

   [RFC1912]  Barr, D., "Common DNS Operational and Configuration
              Errors", RFC 1912, DOI 10.17487/RFC1912, February 1996,
              <https://www.rfc-editor.org/info/rfc1912>.

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   [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>.

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

   [RFC4252]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
              January 2006, <https://www.rfc-editor.org/info/rfc4252>.

   [RFC4384]  Meyer, D., "BGP Communities for Data Collection", BCP 114,
              RFC 4384, DOI 10.17487/RFC4384, February 2006,
              <https://www.rfc-editor.org/info/rfc4384>.

   [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>.

   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,
              <https://www.rfc-editor.org/info/rfc7942>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [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>.

   [RFC8195]  Snijders, J., Heasley, J., and M. Schmidt, "Use of BGP
              Large Communities", RFC 8195, DOI 10.17487/RFC8195, June
              2017, <https://www.rfc-editor.org/info/rfc8195>.

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   [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>.

   [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>.

   [RFC8792]  Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
              "Handling Long Lines in Content of Internet-Drafts and
              RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
              <https://www.rfc-editor.org/info/rfc8792>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/info/rfc9000>.

Appendix A.  JSON Examples

   This section shows example use cases for the YANG module defined in
   this document, using JSON encoding (see [RFC7951]).  The examples
   contain long lines that may be folded, as described in [RFC8792].

A.1.  RFC8195 Selective NO_EXPORT definition

   A JSON definition for the example Large BGP community described in
   [RFC8195], Section 4.1.1 looks as follows.

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   =============== NOTE: '\' line wrapping per RFC 8792 ================

   {
     "ietf-bgp-communities:bgp-communities": {
       "autonomous-system-id": 64497,
       "serial": 2023080101,
       "uri": "http://example.net/peering/communities",
       "description": "BGP Community example for ASN-Based Selective \
   NO_EXPORT",
       "contact": [
         {
           "email-address": "noc@example.net",
           "name": "Example.net contact",
           "role": "Administrative contact",
           "organization": "Example.net",
           "organizational-unit": "NOC"
         }
       ],
       "large": [
         {
           "name": "RFC8195-NOEXPORT-ASN",
           "category": "action",
           "description": "Do not export route to ASN",
           "global-admin": 64497,
           "local-data-part-1": {
             "field": [
               {
                 "name": "Function",
                 "pattern": "4",
                 "description": "ASN-No-Export"
               }
             ]
           },
           "local-data-part-2": {
             "field": [
               {
                 "name": "ASN",
                 "pattern": ".*",
                 "description": "*"
               }
             ]
           }
         }
       ]
     }
   }

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A.2.  RFC4384 Data Collection definition

   A JSON definition for the example Regular and Extended BGP
   communities described in [RFC4384], Section 4 looks as follows.

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   {
     "ietf-bgp-communities:bgp-communities": {
       "autonomous-system-id": 10876,
       "serial": 2023080101,
       "uri": "http://example.net/peering/communities",
       "description": "BGP Community example for Data Collection",
       "contact-url": "https://example.net/contact",
       "regular": [
         {
           "name": "RFC4384-REGULAR-ORIGIN-OC/FJ",
           "description": "A national route over a terrestrial link \
   from the Fiji Islands",
           "global-admin": 10876,
           "local-admin": {
             "format": "binary",
             "field": [
               {
                 "name": "Region",
                 "length": 5,
                 "pattern": "00010",
                 "description": "OC"
               },
               {
                 "name": "Satellite",
                 "length": 1,
                 "pattern": "0",
                 "description": "*"
               },
               {
                 "name": "Country",
                 "length": 10,
                 "pattern": "0011110010",
                 "description": "FJ"
               }
             ]
           }
         }
       ],
       "extended": [
         {
           "name": "RFC4384-EXTENDED-ORIGIN-OC/FJ",

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           "description": "A national route over a terrestrial link \
   from the Fiji Islands",
           "type": 0,
           "subtype": 8,
           "asn": 10876,
           "local-admin": {
             "format": "binary",
             "field": [
               {
                 "name": "Reserved",
                 "length": 16,
                 "pattern": "0000000000000000"
               },
               {
                 "name": "Region",
                 "length": 5,
                 "pattern": "00010",
                 "description": "OC"
               },
               {
                 "name": "Satellite",
                 "length": 1,
                 "pattern": "0",
                 "description": "*"
               },
               {
                 "name": "Country",
                 "length": 10,
                 "pattern": "0011110010",
                 "description": "FJ"
               }
             ]
           }
         }
       ]
     }
   }

Appendix B.  Acknowledgements

   The author would like to thank Jeffrey Haas, Luuk Hendriks, Jasper
   den Hertog, Teun Vink, Tom Petch, Dale Carder, Mohamed Boucadair and
   Ladislav Lhotka for contributing ideas and feedback to this document.

Author's Address

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   Martin Pels
   RIPE NCC
   Netherlands
   Email: mpels@ripe.net

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