



6MAN                                                            F. Zhang
Internet-Draft                                                    Y. Zhu
Intended status: Standards Track                           China Telecom
Expires: 13 November 2026                                          B. Wu
                                                                  Huawei
                                                                   J. Hu
                                                           China Telecom
                                                             12 May 2026


              YANG Data Model for IPv6 Neighbor Discovery
            draft-ietf-6man-ipv6-neighbor-discovery-yang-05

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 13 November 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.  Neighbor Unreachability Detection . . . . . . . . . . . .   5
     2.3.  Proxy Neighbor Advertisement  . . . . . . . . . . . . . .   5
     2.4.  Duplicate Address Detection . . . . . . . . . . . . . . .   5
     2.5.  IPv6 Neighbor Discovery Data Model  . . . . . . . . . . .   5
   3.  IPv6 Neighbor Discovery YANG Module . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  13
   8.  Informative References  . . . . . . . . . . . . . . . . . . .  15
   Appendix A.  Data Model Examples  . . . . . . . . . . . . . . . .  16
     A.1.  Configuration of Static IPv6 Neighbor Cache Entry . . . .  16
     A.2.  Configuration of Proxy Neighbor Advertisement, Redirect,
           NUD, and DAD  . . . . . . . . . . . . . . . . . . . . . .  17
   Appendix B.  Coverage of IPv6 ND Functions in YANG Modules  . . .  19
   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 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

   *  Neighbor Advertisement

   *  proxy Neighbor Advertisement

   *  Neighbor Unreachability Detection



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   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 augments the "ietf-ip" [RFC8344] to
   provide per-interface configuration and management of 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.

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

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







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2.2.  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.

2.3.  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.

2.4.  Duplicate Address Detection

   The "dup-addr-detect-transmits" leaf, as defined in "ietf-ip"
   [RFC8344], indicates the number of consecutive Neighbor Solicitation
   messages sent while performing Duplicate Address Detection (DAD)
   [RFC4862].  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.

   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.





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   module: ietf-ipv6-nd

     augment /if:interfaces/if:interface/ip:ipv6:
       +--rw nd
          +--rw reachable-time?   uint32
          +--rw ns-interval?      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].

   <CODE BEGINS> file "ietf-ipv6-nd@2026-04-20.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



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         "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
        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.";
     reference
       "RFC4861: Neighbor Discovery for IP version 6 (IPv6)



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        RFC4862: IPv6 Stateless Address Autoconfiguration
        RFC7527: Enhanced Duplicate Address Detection";

     revision 2026-04-20 {
       description
         "Initial version.";
       reference
         "RFC XXXX: YANG Data Model for IPv6 Neighbor Discovery";
     }

     /* Data nodes */

     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 {
             range "1..3600000";
           }
           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 redirect {
           type boolean;
           default "false";
           description



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             "Controls whether sending of ICMP Redirect messages
              on the interface is enabled or disabled.
               true -  Sending of ICMP Redirect messages is enabled,
               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



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             "RFC7527: Enhanced Duplicate Address Detection";
         }
         container statistics {
           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 {



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             type yang:counter64;
             description
               "The number of sent Router Advertisement packets.";
           }
           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>

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

   This section is modeled after the template described in Section 3.7.1
   of [RFC9907].

   The "ietf-ipv6-nd" YANG module defines a data model that is designed
   to be accessed via YANG-based management protocols, such as the
   Network Configuration Protocol (NETCONF) [RFC6241] and RESTCONF
   [RFC8040].  These YANG-based management protocols (1) have to use a
   secure transport layer (e.g., Secure Shell (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 a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., "config true", which is the
   default).  All writable data nodes are likely to be sensitive or
   vulnerable in some network environments.  Write operations (e.g.,
   edit-config) and delete operations to these data nodes without proper
   protection or authentication can have a negative effect on network
   operations.  The following subtrees and data nodes have particular
   sensitivities/vulnerabilities:

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd: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/v6nd:nd/v6nd:ns-interval

   This leaf is used to set the interval of retransmitting Neighbor
   Solicitations, which could allow DoS attacks.

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:redirect






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   This leaf is used to enable the sending of Redirect messages on an
   interface, which could allow traffic to be misdirected, potentially
   resulting in traffic hijacking, man-in-the-middle attacks, or DoS
   attacks.

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:proxy-na

   This leaf is used to enable proxy Neighbor Advertisement on an
   interface, which could allow spoofing traffic to be injected.

   Some of the readable data nodes in this YANG 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.  Specifically, the following
   subtrees and data nodes have particular sensitivities/
   vulnerabilities:

   * /if:interfaces/if:interface/ip:ipv6/ip:neighbor/v6nd:age

   Unauthorized access to this node may disclose information about IPv6
   neighbor reachability and activity patterns on the network.

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:redirect

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:proxy-na

   * /if:interfaces/if:interface/ip:ipv6/v6nd:nd/v6nd:enhanced-dad

   Unauthorized access to these nodes may disclose device behavior and
   security-related configuration of IPv6 Neighbor Discovery functions.

6.  Acknowledgments

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

   Thanks to Ebben Aries for the review and comments.

7.  Normative References

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







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   [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>.

   [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>.

   [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>.






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   [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>.

8.  Informative References

   [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>.

   [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>.

   [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>.

   [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>.

   [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>.

   [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>.

   [RFC9907]  Bierman, A., Boucadair, M., Ed., and Q. Wu, "Guidelines
              for Authors and Reviewers of Documents Containing YANG
              Data Models", BCP 216, RFC 9907, DOI 10.17487/RFC9907,
              March 2026, <https://www.rfc-editor.org/info/rfc9907>.









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   [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 Extensions", Work in
              Progress, Internet-Draft, draft-ietf-intarea-arp-yang-
              model-01, 13 April 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-intarea-
              arp-yang-model-01>.

Appendix A.  Data Model Examples

A.1.  Configuration of 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, using the ietf-interfaces
   module [RFC8343] and the ietf-ip module [RFC8344].

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

   The following is the same example using JSON format.


















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   {
     "ietf-interfaces:interfaces": {
       "interface": [
         {
           "name": "eth0",
           "type": "iana-if-type:ethernetCsmacd",
           "ietf-ip:ipv6": {
             "neighbor": [
               {
                 "ip": "2001:db8::2",
                 "link-layer-address": "00:00:5E:00:53:AB"
               }
             ]
           }
         }
       ]
     }
   }

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

   This example illustrates the configuration of enabling proxy Neighbor
   Advertisement, Redirect, NUD, DAD, and enhanced 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,
   using the ietf-interfaces module [RFC8343], the ietf-ip module
   [RFC8344], and the IPv6 ND module.























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   <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>
       <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
         <dup-addr-detect-transmits>1</dup-addr-detect-transmits>
         <nd xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv6-nd">
           <reachable-time>30000</reachable-time>
           <ns-interval>1000</ns-interval>
           <redirect>true</redirect>
           <proxy-na>true</proxy-na>
           <enhanced-dad>
             <enable>true</enable>
             <auto-resolve>true</auto-resolve>
           </enhanced-dad>
         </nd>
       </ipv6>
     </interface>
   </interfaces>

   The following is the same example using JSON format.

   {
     "ietf-interfaces:interfaces": {
       "interface": [
         {
           "name": "eth0",
           "type": "iana-if-type:ethernetCsmacd",
           "ietf-ip:ipv6": {
             "dup-addr-detect-transmits": 1,
             "ietf-ipv6-nd:nd": {
               "reachable-time": 30000,
               "ns-interval": 1000,
               "redirect": true,
               "proxy-na": true,
               "enhanced-dad": {
                 "enable": true,
                 "auto-resolve": true
               }
             }
           }
         }
       ]
     }
   }





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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
   [RFC7527] (Enhanced Duplicate Address Detection).  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                                            |
   |(Section)|                      |               |                                                |
   +=========+======================+===============+================================================+
   |4861 s5.1|Neighbor Cache        |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:neighbor |
   +---------+----------------------+---------------+------------------------------------------------+
   |4862 s5.1|Prefix List           |ietf-ipv6-     |/if:interfaces/if:interface/ip:ipv6/v6ur:prefix-|
   |         |(AdvPrefixList)       |router-        |list                                            |
   |         |                      |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-  |



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   |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     |
   +---------+----------------------+---------------+------------------------------------------------+
   |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     |Proxy Neighbor        |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |s7.2.8   |Advertisements        |               |v6nd:proxy-na                                   |



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   +---------+----------------------+---------------+------------------------------------------------+
   |4861 s8  |Redirect              |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |         |                      |               |v6nd:redirect                                   |
   +---------+----------------------+---------------+------------------------------------------------+
   |4862 s5.1|DupAddrDetectTransmits|ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:dup-addr-|
   |         |                      |               |detect-transmits                                |
   +---------+----------------------+---------------+------------------------------------------------+
   |4862 s5.5|Creation of Global    |ietf-ip        |/if:interfaces/if:interface/ip:ipv6/ip:autoconf/|
   |         |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                 |
   +---------+----------------------+---------------+------------------------------------------------+
   |7527 s4  |Enhanced Duplicate    |ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |         |Address Detection     |               |v6nd:enhanced-dad                               |
   +---------+----------------------+---------------+------------------------------------------------+
   |7527 s5  |Automated Resolving of|ietf-ipv6-nd   |/if:interfaces/if:interface/ip:ipv6/v6nd:nd/    |
   |         |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








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   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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