



6MAN                                                            F. Zhang
Internet-Draft                                                    Y. Zhu
Intended status: Standards Track                           China Telecom
Expires: 31 August 2026                                            B. Wu
                                                                  Huawei
                                                                   J. Hu
                                                           China Telecom
                                                        27 February 2026


              YANG Data Model for IPv6 Neighbor Discovery
            draft-ietf-6man-ipv6-neighbor-discovery-yang-03

Abstract

   This document defines a YANG data model to configure and manage IPv6
   Neighbor Discovery (ND) and related functions, including IPv6 address
   resolution, redirect function, proxy Neighbor Advertisement, Neighbor
   Unreachability Detection (NUD), Duplicate Address Detection (DAD),
   and Enhanced Duplicate Address Detection.

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 31 August 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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



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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Design of the Data Model  . . . . . . . . . . . . . . . . . .   4
     2.1.  IPv6 Address Resolution and Redirect Function . . . . . .   4
     2.2.  Proxy Neighbor Advertisement  . . . . . . . . . . . . . .   5
     2.3.  Neighbor Unreachability Detection . . . . . . . . . . . .   5
     2.4.  Duplicate Address Detection . . . . . . . . . . . . . . .   5
     2.5.  IPv6 Neighbor Discovery Data Model  . . . . . . . . . . .   6
   3.  IPv6 Neighbor Discovery YANG Module . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  14
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  14
   8.  Informative References  . . . . . . . . . . . . . . . . . . .  16
   Appendix A.  Data Model Examples  . . . . . . . . . . . . . . . .  16
     A.1.  Configured Static IPv6 Neighbor Cache Entry . . . . . . .  16
     A.2.  Configuration of Proxy Neighbor Advertisement, NUD, and
           DAD . . . . . . . . . . . . . . . . . . . . . . . . . . .  17
   Appendix B.  Coverage of IPv6 ND Functions in YANG Modules  . . .  18
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Introduction

   This document defines a YANG data model "ietf-ipv6-nd" to configure
   and manage IPv6 Neighbor Discovery (ND) and related functions,
   including IPv6 address resolution [RFC4861], redirect function
   [RFC4861], proxy Neighbor Advertisement [RFC4861], Neighbor
   Unreachability Detection (NUD) [RFC4861], Duplicate Address Detection
   (DAD) [RFC4862], and Enhanced Duplicate Address Detection [RFC7527].

   Basic neighbor management functionality is supported by the "ietf-ip"
   YANG data model [RFC8344], and there is already a draft
   [I-D.ietf-intarea-arp-yang-model] extending the basic ARP YANG
   functionality to cover optional ARP features and related statistics,
   which applies only to IPv4.  Thus, an extension for IPv6 is required
   to maintain the Neighbor Cache entries.

   [RFC4861] specifies the Neighbor Discovery protocol for IPv6, and
   [RFC4862] specifies related functions.  This document covers IPv6
   address resolution [RFC4861], redirect function [RFC4861], proxy



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   Neighbor Advertisement [RFC4861], NUD [RFC4861], DAD [RFC4862], and
   Enhanced DAD [RFC7527].  Other function, such as Router and Prefix
   Discovery [RFC4861] are covered by submodule "ietf-ipv6-router-
   advertisements" in [RFC8349], and static neighbor cache entries and
   Stateless Address Autoconfiguration [RFC4862] are covered by module
   "ietf-ip" in [RFC8344].

   The model is based on YANG 1.1 as defined in [RFC7950] and conforms
   to Network Management Datastore Architecture (NMDA) as defined in
   [RFC8342].

1.1.  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 following terms are defined in [RFC8342]:

   *  configuration

   *  system state

   *  operational state

   The following terms are defined in [RFC7950]:

   *  augment

   *  container

   *  data model

   *  data node

   *  leaf

   *  list

   *  module

   *  schema tree

   The following terms are defined in [RFC4861]:

   *  Neighbor Discovery



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   *  Neighbor Advertisement

   *  proxy Neighbor Advertisement

   *  Neighbor Unreachability Detection

   The following term is defined in [RFC4862]:

   *  Duplicate Address Detection

   *  Stateless Address Autoconfiguration

   The following term is defined in [RFC7527]:

   *  Enhanced Duplicate Address Detection

1.2.  Tree Diagrams

   Tree diagrams used in this document follow the notation defined in
   [RFC8340].

2.  Design of the Data Model

   The YANG data model for IPv6 ND defines global configurations and
   augments the "ietf-ip" [RFC8344] to provide per-interface
   configuration.  It configures and manages IPv6 address resolution and
   redirect functions based on the IPv6 ND protocol, as well as other
   related functions, including proxy Neighbor Advertisement, NUD, DAD,
   and Enhanced DAD.

   Note that the features related to ICMP Router and Prefix Discovery
   are outside the scope of this module, since they have already been
   defined in the submodule "ietf-ipv6-router-advertisements" [RFC8349].
   Static neighbor cache entries and stateless address autoconfiguration
   [RFC4862] are also out of the scope, as they are covered by "ietf-
   ip"[RFC8344].

2.1.  IPv6 Address Resolution and Redirect Function

   The data model augments the "/if:interfaces/if:interface/ip:ipv6"
   path defined in the "ietf-ip" module [RFC8344] for IPv6 ND protocol
   [RFC4861].

   The "ns-interval" leaf defines the interval of retransmitting
   Neighbor Solicitation messages when a node tries to learn the link-
   layer address of another node.





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   For the management of Neighbor Cache entries, the "stale-timeout"
   leaves define the timeout for STALE entries, while the "age" leaf
   augments the "/if:interfaces/if:interface/ip:ipv6/ip:neighbor" path
   to indicate the elapsed time since the Neighbor Cache entry was last
   confirmed reachable.

   The "statistics" container defines a collection of interface-related
   statistics on IPv6 ND messages.

   The "redirect" leaf enables the sending of Redirect messages.

2.2.  Proxy Neighbor Advertisement

   The "proxy-na" leaf augmenting "ietf-ip" [RFC8344] defines the
   configurations of proxy Neighbor Advertisements [RFC4861], which
   indicate that a router is willing to accept packets not explicitly
   addressed to itself.  After receiving a Neighbor Solicitation message
   whose destination address is not its own IPv6 address, a proxy router
   replies to the source with a Neighbor Advertisement message carrying
   its own link-layer address and the IPv6 address of the original
   destination.

2.3.  Neighbor Unreachability Detection

   The "reachable-time" leaf defines the time to confirm a neighbor's
   reachability for NUD.  A neighbor's state changes from REACHABLE to
   STALE when there is no other reachability confirmation from the
   neighbor within the "reachable-time".

   The "ns-interval" leaf also indicates the interval for retransmitting
   Neighbor Solicitation messages used by NUD.

2.4.  Duplicate Address Detection

   The "dup-addr-detect-transmits" leaf, which indicates the number of
   consecutive Neighbor Solicitation messages sent while performing
   Duplicate Address Detection (DAD) [RFC4862], has already been defined
   in "ietf-ip" [RFC8344].  The value of "dup-addr-detect-transmits" can
   be set to 0 to disable DAD.

   The "ns-interval" leaf also indicates the interval for retransmitting
   Neighbor Solicitation messages during DAD.

   The "enhanced-dad" container augmenting "ietf-ip" [RFC8344] defines
   the configurations for enhanced DAD [RFC7527], which is used to
   automatically detect the looped-back IPv6 ND messages used in DAD.





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   The "auto-resolve" leaf enables automated action when a duplicate is
   detected.  When enabled, a trusted router may log a system management
   message, drop the received ND message, and block the untrusted IPv6
   host nodes from which the duplicate NS (DAD) or NA message was
   received.

2.5.  IPv6 Neighbor Discovery Data Model

   This document defines the YANG module "ietf-ipv6-nd", which has the
   following structure.

   module: ietf-ipv6-nd
     +--rw nd
        +--rw stale-timeout?   uint32

     augment /if:interfaces/if:interface/ip:ipv6:
       +--rw nd
          +--rw reachable-time?   uint32
          +--rw ns-interval?      uint32
          +--rw stale-timeout?    uint32
          +--rw redirect?         boolean
          +--rw proxy-na?         boolean
          +--rw enhanced-dad
          |  +--rw enable?         boolean
          |  +--rw auto-resolve?   boolean
          +--ro statistics
             +--ro in-ns-pkts?          yang:counter64
             +--ro in-na-pkts?          yang:counter64
             +--ro in-rs-pkts?          yang:counter64
             +--ro in-ra-pkts?          yang:counter64
             +--ro in-redirect-pkts?    yang:counter64
             +--ro out-ns-pkts?         yang:counter64
             +--ro out-na-pkts?         yang:counter64
             +--ro out-rs-pkts?         yang:counter64
             +--ro out-ra-pkts?         yang:counter64
             +--ro out-redirect-pkts?   yang:counter64
     augment /if:interfaces/if:interface/ip:ipv6/ip:neighbor:
       +--ro age?   uint32

3.  IPv6 Neighbor Discovery YANG Module

   This section presents the YANG module of IPv6 Neighbor Discovery
   defined in this document.

   This module imports modules from Common YANG Data Types [RFC6991], A
   YANG Data Model for Interface Management [RFC8343], and A YANG Data
   Model for IP Management [RFC8344].




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<CODE BEGINS> file "ietf-ipv6-nd@2026-02-27.yang"
module ietf-ipv6-nd {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ipv6-nd";
  prefix v6nd;

  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A Yang Data Model for Interface Management";
  }
  import ietf-ip {
    prefix ip;
    reference
      "RFC 8344: A Yang Data Model for IP Management";
  }

  organization
    "IETF IPv6 Maintenance Working Group (6man)";
  contact
    "WG Web:  <https://datatracker.ietf.org/wg/6man/>
     WG List: <mailto:6man@ietf.org>

     Author:  Fan Zhang
              <zhangf52@chinatelecom.cn>
     Author:  Yongqing Zhu
              <zhuyq8@chinatelecom.cn>
     Author:  Bo Wu
              <lana.wubo@huawei.com>
     Author:  Jiayuan Hu
              <hujy5@chinatelecom.cn>";
  description
    "This YANG module defines a YANG data model to configure and manage
     IPv6 Neighbor Discovery (ND) and related functions, including
     IPv6 address resolution, redirect, proxy Neighbor
     Advertisement, Neighbor Unreachability Detection (NUD), Duplicate
     Address Detection (DAD), and Enhanced DAD.

     The model is based on YANG 1.1 as defined in RFC 7950 and
     conforms to Network Management Datastore Architecture (NMDA)
     as defined in RFC 8342.

     Copyright (c) 2026 IETF Trust and the persons identified as



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     authors of the code.  All rights reserved.

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

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

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.";
  reference
    "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
     RFC4862: IPv6 Stateless Address Autoconfiguration
     RFC7527: Enhanced Duplicate Address Detection";

  revision 2026-02-27 {
    description
      "Initial version";
    reference
      "RFC XXXX: YANG Data Model for IPv6 Neighbor Discovery";
  }

  /* Data nodes */

  container nd {
    description
      "Global parameters for IPv6 ND.";
    leaf stale-timeout {
      type uint32;
      units "seconds";
      description
        "The global timeout for Neighbor Cache entry in the STALE
         state. This value applies to all interfaces unless overridden
         by a per-interface setting.";
      reference
        "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                  Section 5.3";
    }
  }




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  augment "/if:interfaces/if:interface/ip:ipv6" {
    description
      "Augments interface configuration and state data with
       parameters of IPv6 ND.";
    container nd {
      description
        "Parameters of IPv6 ND.";
      leaf reachable-time {
        type uint32;
        units "milliseconds";
        default "30000";
        description
          "The time to confirm a neighbor's reachability for NUD.";
        reference
          "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                    Section 6.3.2 - BaseReachableTime";
      }
      leaf ns-interval {
        type uint32 {
          range "1..max";
        }
        units "milliseconds";
        default "1000";
        description
          "The interval of retransmitting Neighbor Solicitations to a
           neighbor for address resolution, NUD, or DAD.";
        reference
          "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                    Section 6.3.2";
      }
      leaf stale-timeout {
        type uint32;
        units "seconds";
        description
          "The timeout for Neighbor Cache entry in the STALE state on
           the interface. If configured, this value overrides the global
           stale-timeout.";
        reference
          "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                    Section 5.3";
      }
      leaf redirect {
        type boolean;
        default "false";
        description
          "Controls whether sending of ICMP Redirect messages
           on the interface is enabled or disabled.
            true -  Sending of ICMP Redirect messages is enabled,



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            false - Sending of ICMP Redirect messages is disabled.";
        reference
          "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                    Section 8";
      }
      leaf proxy-na {
        type boolean;
        default "false";
        description
          "Controls whether proxies for one or more other nodes by
           sending proxy Neighbor Advertisement.
            true -  Proxy NA is enabled,
            false - Proxy NA is disabled.";
        reference
          "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                    Section 7.2.8";
      }
      container enhanced-dad {
        description
          "Parameters of Enhanced DAD algorithm.";
        leaf enable {
          type boolean;
          default "false";
          description
            "Controls whether Enhanced DAD algorithm is enabled or
             disabled.";
          reference
            "RFC7527: Enhanced Duplicate Address Detection
                      Section 4";
        }
        leaf auto-resolve {
          when "../enable = 'true'";
          type boolean;
          default "false";
          description
            "Controls whether the automated action is taken when
             detecting duplicates. A trusted router can log a system
             management message, drop the received ND message, and
             block the untrusted IPv6 host nodes from which the
             duplicate NS(DAD) or NA message was received.";
          reference
            "RFC7527: Enhanced Duplicate Address Detection
                      Section 5";
        }
        reference
          "RFC7527: Enhanced Duplicate Address Detection";
      }
      container statistics {



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        config false;
        description
          "A collection of interface-related statistics about IPv6
           ND messages.";
        leaf in-ns-pkts {
          type yang:counter64;
          description
            "The number of received Neighbor Solicitation packets.";
        }
        leaf in-na-pkts {
          type yang:counter64;
          description
            "The number of received Neighbor Advertisement packets.";
        }
        leaf in-rs-pkts {
          type yang:counter64;
          description
            "The number of received Router Solicitation packets.";
        }
        leaf in-ra-pkts {
          type yang:counter64;
          description
            "The number of received Router Advertisement packets.";
        }
        leaf in-redirect-pkts {
          type yang:counter64;
          description
            "The number of received Redirect packets.";
        }
        leaf out-ns-pkts {
          type yang:counter64;
          description
            "The number of sent Neighbor Solicitation packets.";
        }
        leaf out-na-pkts {
          type yang:counter64;
          description
            "The number of sent Neighbor Advertisement packets.";
        }
        leaf out-rs-pkts {
          type yang:counter64;
          description
            "The number of sent Router Solicitation packets.";
        }
        leaf out-ra-pkts {
          type yang:counter64;
          description
            "The number of sent Router Advertisement packets.";



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        }
        leaf out-redirect-pkts {
          type yang:counter64;
          description
            "The number of sent Redirect packets.";
        }
      }
    }
  }

  augment "/if:interfaces/if:interface/ip:ipv6/ip:neighbor" {
    description
      "Augments IPv6 neighbor list with parameters of IPv6 address
       resolution based on IPv6 ND.";
    leaf age {
      when "../ip:origin = 'dynamic'";
      type uint32;
      units "seconds";
      config false;
      description
        "The time that has passed since receipt of the last
         reachability confirmation for the neighbor. Ignored when the
         neighbor entry is static.";
      reference
        "RFC4861: Neighbor Discovery for IP version 6 (IPv6)
                  Section 7.3.3";
    }
  }
}

<CODE ENDS>

                               Figure 1

4.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in [RFC3688], the following registration is
   requested to be made:

       URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd
       Registrant Contact: The IESG.
       XML: N/A, the requested URI is an XML namespace.

   This document registers a YANG module in the YANG Module Names
   registry [RFC6020].





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       name: ietf-ipv6-nd
       namespace: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd
       prefix: v6nd
       reference: RFC XXXX

5.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040] . The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The NETCONF Access Control Model (NACM) [RFC8341] provides the means
   to restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

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

   *  /if:interfaces/if:interface/ip:ipv6/ipv6-nd:nd/ipv6-nd:proxy-na -
      This leaf is used to enable proxy Neighbor Advertisement on an
      interface, which could allow spoofing traffic to be injected.

   *  /if:interfaces/if:interface/ip:ipv6/ipv6-nd:nd/ipv6-nd:reachable-
      time - This leaf is used to consider a neighbor reachable since
      the last confirmation of reachability, which could be set to big
      values to prolong the effect of spoofing Neighbor Cache entries or
      small values to cause unnecessary frequent NUDs.

   *  /if:interfaces/if:interface/ip:ipv6/ipv6-nd:nd/ipv6-nd:ns-interval
      - This leaf is used to set the interval of retransmitting Neighbor
      Solicitations, which could allow DoS attacks.

   *  /ipv6-nd:nd/ipv6-nd:stale-timeout and
      /if:interfaces/if:interface/ip:ipv6/ipv6-nd:nd/ipv6-nd:stale-
      timeout - These leaves are used to set the timeout for Neighbor
      Cache entry in the STALE state, which could allow the consumption
      of cache.




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   Some of the readable data nodes in the ietf-ipv6-nd module may be
   considered sensitive or vulnerable in some network environments.  It
   is thus important to control read access (e.g., via get, get-config,
   or notification) to these data nodes.

6.  Acknowledgments

   The authors would like to thank Bin Han, Acee Lindem, Jen Linkova,
   Éric Vyncke, and many others for their helpful comments and
   suggestions.

   Thanks to Ebben Aries for the review and comments.

7.  Normative References

   [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>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <https://www.rfc-editor.org/info/rfc4862>.

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

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

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




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

   [RFC7527]  Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E.,
              and W. George, "Enhanced Duplicate Address Detection",
              RFC 7527, DOI 10.17487/RFC7527, April 2015,
              <https://www.rfc-editor.org/info/rfc7527>.

   [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>.

   [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>.

   [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>.

   [RFC8344]  Bjorklund, M., "A YANG Data Model for IP Management",
              RFC 8344, DOI 10.17487/RFC8344, March 2018,
              <https://www.rfc-editor.org/info/rfc8344>.

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

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.




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8.  Informative References

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
              <https://www.rfc-editor.org/info/rfc4941>.

   [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>.

   [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>.

   [I-D.ietf-intarea-arp-yang-model]
              Zheng, F., Wu, B., Wilton, R., Zhang, F., Zhu, Y., and X.
              Ding, "A YANG Data Model for ARP", Work in Progress,
              Internet-Draft, draft-ietf-intarea-arp-yang-model-00, 16
              October 2025, <https://datatracker.ietf.org/doc/html/
              draft-ietf-intarea-arp-yang-model-00>.

Appendix A.  Data Model Examples

A.1.  Configured Static IPv6 Neighbor Cache Entry

   This example illustrates the manual configuration for a Neighbor
   Cache entry of interface eth0 for peer 2001:db8::2 with link-layer
   address 00:00:5E:00:53:AB statically.

   Note: '\' line wrapping per [RFC8792].



















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   <?xml version="1.0" encoding="utf-8"?>
   <interfaces \
     xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces" \
     xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
     <interface>
     <name>eth0</name>
     <type>ianaift:ethernetCsmacd</type>
     <!-- other parameters from ietf-interfaces omitted -->

     <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
       <!-- ipv6 address configuration parameters omitted -->
       <neighbor>
       <ip>2001:db8::2</ip>
       <link-layer-address>00:00:5E:00:53:AB</link-layer-address>
       </neighbor>
     </ipv6>
     </interface>
   </interfaces>

                                  Figure 2

A.2.  Configuration of Proxy Neighbor Advertisement, NUD, and DAD

   This example illustrates the configuration of enabling proxy Neighbor
   Advertisement, NUD, and DAD with setting the "dup-addr-detect-
   transmits" leaf as 1, the "reachable-time" leaf as 30000
   milliseconds, and the "ns-interval" leaf as 1000 milliseconds.

   Note: '\' line wrapping per [RFC8792].






















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   <?xml version="1.0" encoding="utf-8"?>
   <interfaces \
     xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces" \
     xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
     <interface>
     <name>eth0</name>
     <type>ianaift:ethernetCsmacd</type>
     <!-- other parameters from ietf-interfaces omitted -->

       <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
         <dup-addr-detect-transmits>1</dup-addr-detect-transmits>
         <!-- ipv6 address configuration parameters omitted -->

         <nd xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv6-nd">
           <reachable-time>30000</reachable-time>
           <ns-interval>1000</ns-interval>
           <stale-timeout>1200</stale-timeout>
           <proxy-na>true</proxy-na>
         </nd>
       </ipv6>
     </interface>
   </interfaces>

                                  Figure 3

Appendix B.  Coverage of IPv6 ND Functions in YANG Modules

   This appendix analyzes the functional elements related to the IPv6 ND
   protocol and identifies whether they are covered by existing IETF
   YANG modules or defined in this document.

   The table below maps the relevant RFCs, functions or parameters, the
   corresponding YANG modules, and their specific data paths.  The
   functions are defined in [RFC4861] (Neighbor Discovery for IP version
   6 (IPv6)), [RFC4862] (IPv6 Stateless Address Autoconfiguration), and
   other RFC extending IPv6 ND functions.  The parameters are defined in
   Section 6.2.1 and 6.3.2 of [RFC4861], Section 5.1 of [RFC4862], and
   Section 3.3 of [RFC4941].

   +======+======================+===============+================================================+
   |RFC   |Function/Parameter    |Covered by     |Path                                            |
   |(Sec) |                      |               |                                                |
   +======+======================+===============+================================================+
   |4861  |Neighbor Cache        |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:neighbor |
   |s5.1  |                      |               |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4862  |Prefix List           |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |s5.1  |(AdvPrefixList)       |router-        |list                                            |



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   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |IsRouter              |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/            |
   |s6.2.1|                      |               |ip:forwarding                                   |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvSendAdvertisements |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:ipv6-  |
   |s6.2.1|                      |router-        |router-advertisements                           |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |MaxRtrAdvInterval     |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:max-   |
   |s6.2.1|                      |router-        |rtr-adv-interval                                |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |MinRtrAdvInterval     |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:min-   |
   |s6.2.1|                      |router-        |rtr-adv-interval                                |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvManagedFlag        |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/            |
   |s6.2.1|                      |router-        |v6ur:managed-flag                               |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvOtherConfigFlag    |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:other- |
   |s6.2.1|                      |router-        |config-flag                                     |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvLinkMTU            |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:link-  |
   |s6.2.1|                      |router-        |mtu                                             |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvReachableTime (for |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/            |
   |s6.2.1|RA)                   |router-        |v6ur:reachable-time                             |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvRetransTimer       |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/            |
   |s6.2.1|                      |router-        |v6ur:retrans-timer                              |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvCurHopLimit        |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:cur-   |
   |s6.2.1|                      |router-        |hop-limit                                       |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvDefaultLifetime    |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/            |
   |s6.2.1|                      |router-        |v6ur:default-lifetime                           |
   |      |                      |advertisements |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvPrefixList         |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |s6.2.1|/AdvValidLifetime     |router-        |list/v6ur:prefix/v6ur:control-adv-              |
   |      |                      |advertisements |prefixes/v6ur:advertise/v6ur:valid-lifetime     |



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   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvPrefixList         |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |s6.2.1|/AdvOnLinkFlag        |router-        |list/v6ur:prefix/v6ur:control-adv-              |
   |      |                      |advertisements |prefixes/v6ur:advertise/v6ur:on-link-flag       |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvPrefixList/        |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |s6.2.1|AdvPreferredLifetime  |router-        |list/v6ur:prefix/v6ur:control-adv-              |
   |      |                      |advertisements |prefixes/v6ur:advertise/v6ur:preferred-lifetime |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |AdvPrefixList/        |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |s6.2.1|AdvAutonomousFlag     |router-        |list/v6ur:prefix/v6ur:control-adv-              |
   |      |                      |advertisements |prefixes/v6ur:advertise/v6ur:autonomous-flag    |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |BaseReachableTime     |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s6.3.2|                      |               |v6nd:reachable-time                             |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |RetransTimer(for NS)  |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s6.3.2|                      |               |v6nd:ns-interval                                |
   |/4862 |                      |               |                                                |
   |s5.1  |                      |               |                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |CurHopLimit(for Node) |(reuse         |                                                |
   |s6.3.2|                      |AdvCurHopLimit)|                                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |Timeout for stale     |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s5.3  |information           |               |v6nd:stale-timeout                              |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |Proxy Neighbor        |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s7.2.8|Advertisements        |               |v6nd:proxy-na                                   |
   +------+----------------------+---------------+------------------------------------------------+
   |4861  |Redirect              |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s8    |                      |               |v6nd:redirect                                   |
   +------+----------------------+---------------+------------------------------------------------+
   |4862  |DupAddrDetectTransmits|ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:dup-addr-|
   |s5.1  |                      |               |detect-transmits                                |
   +------+----------------------+---------------+------------------------------------------------+
   |4862  |Creation of Global    |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:autoconf/|
   |s5.5  |Addresses             |               |ip:create-global-addresses                      |
   +------+----------------------+---------------+------------------------------------------------+
   |4941  |Creation of Temporary |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:autoconf/|
   |      |Addresses             |               |ip:create-temporary-addresses                   |
   +------+----------------------+---------------+------------------------------------------------+
   |4941  |TEMP_VALID_LIFETIME   |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:autoconf/|
   |      |                      |               |ip:temporary-valid-lifetime                     |
   +------+----------------------+---------------+------------------------------------------------+
   |4941  |TEMP_PREFERRED_       |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:autoconf/|
   |      |LIFETIME              |               |ip:temporary-preferred-lifetime                 |
   +------+----------------------+---------------+------------------------------------------------+



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   |7527  |Enhanced Duplicate    |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s4    |Address Detection     |               |v6nd:enhanced-dad                               |
   +------+----------------------+---------------+------------------------------------------------+
   |7527  |Automated Resolving of|ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s5    |Duplicates            |               |v6nd:auto-resolve                               |
   +------+----------------------+---------------+------------------------------------------------+

           Table 1: Coverage of IPv6 ND Functions in YANG Modules

Contributors

   Bin Han
   Huawei
   China
   Email: hanbin3@huawei.com


Authors' Addresses

   Fan Zhang
   China Telecom
   Guangzhou
   China
   Email: zhangf52@chinatelecom.cn


   Yongqing Zhu
   China Telecom
   Guangzhou
   China
   Email: zhuyq8@chinatelecom.cn


   Bo Wu
   Huawei
   China
   Email: lana.wubo@huawei.com


   Jiayuan Hu
   China Telecom
   Guangzhou
   China
   Email: hujy5@chinatelecom.cn







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