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 Zhang, et al. Expires 31 August 2026 [Page 1] Internet-Draft ND YANG model February 2026 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 Zhang, et al. Expires 31 August 2026 [Page 2] Internet-Draft ND YANG model February 2026 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 Zhang, et al. Expires 31 August 2026 [Page 3] Internet-Draft ND YANG model February 2026 * 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. Zhang, et al. Expires 31 August 2026 [Page 4] Internet-Draft ND YANG model February 2026 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. Zhang, et al. Expires 31 August 2026 [Page 5] Internet-Draft ND YANG model February 2026 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]. Zhang, et al. Expires 31 August 2026 [Page 6] Internet-Draft ND YANG model February 2026 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: WG List: Author: Fan Zhang Author: Yongqing Zhu Author: Bo Wu Author: Jiayuan Hu "; 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 Zhang, et al. Expires 31 August 2026 [Page 7] Internet-Draft ND YANG model February 2026 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"; } } Zhang, et al. Expires 31 August 2026 [Page 8] Internet-Draft ND YANG model February 2026 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, Zhang, et al. Expires 31 August 2026 [Page 9] Internet-Draft ND YANG model February 2026 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 { Zhang, et al. Expires 31 August 2026 [Page 10] Internet-Draft ND YANG model February 2026 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."; Zhang, et al. Expires 31 August 2026 [Page 11] Internet-Draft ND YANG model February 2026 } 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"; } } } 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]. Zhang, et al. Expires 31 August 2026 [Page 12] Internet-Draft ND YANG model February 2026 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. Zhang, et al. Expires 31 August 2026 [Page 13] Internet-Draft ND YANG model February 2026 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, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [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, . [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, September 2007, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [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, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . Zhang, et al. Expires 31 August 2026 [Page 14] Internet-Draft ND YANG model February 2026 [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [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, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [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, . [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, . [RFC8344] Bjorklund, M., "A YANG Data Model for IP Management", RFC 8344, DOI 10.17487/RFC8344, March 2018, . [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, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . Zhang, et al. Expires 31 August 2026 [Page 15] Internet-Draft ND YANG model February 2026 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, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [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, . [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, . 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]. Zhang, et al. Expires 31 August 2026 [Page 16] Internet-Draft ND YANG model February 2026 eth0 ianaift:ethernetCsmacd 2001:db8::2 00:00:5E:00:53:AB 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]. Zhang, et al. Expires 31 August 2026 [Page 17] Internet-Draft ND YANG model February 2026 eth0 ianaift:ethernetCsmacd 1 30000 1000 1200 true 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 | Zhang, et al. Expires 31 August 2026 [Page 18] Internet-Draft ND YANG model February 2026 | | |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 | Zhang, et al. Expires 31 August 2026 [Page 19] Internet-Draft ND YANG model February 2026 +------+----------------------+---------------+------------------------------------------------+ |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 | +------+----------------------+---------------+------------------------------------------------+ Zhang, et al. Expires 31 August 2026 [Page 20] Internet-Draft ND YANG model February 2026 |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 Zhang, et al. Expires 31 August 2026 [Page 21]