6MAN F. Zhang Internet-Draft Y. Zhu Intended status: Standards Track China Telecom Expires: 5 March 2027 B. Wu Huawei J. Hu China Telecom 1 September 2026 YANG Data Model for IPv6 Neighbor Discovery draft-ietf-6man-ipv6-neighbor-discovery-yang-08 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 5 March 2027. 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 5 March 2027 [Page 1] Internet-Draft ND YANG model September 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. 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 . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 5. Security Considerations . . . . . . . . . . . . . . . . . . . 16 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.1. Normative References . . . . . . . . . . . . . . . . . . 17 7.2. Informative References . . . . . . . . . . . . . . . . . 18 Appendix A. Example Proxy Neighbor Advertisement, Redirect, NUD, and DAD Configuration . . . . . . . . . . . . . . . . . . 20 Appendix B. Coverage of IPv6 ND Functions in YANG Modules . . . 22 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 1. Introduction This document defines a YANG [RFC7950] 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 IPv6 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 Neighbor Advertisement [RFC4861], NUD [RFC4861], DAD [RFC4862], and Zhang, et al. Expires 5 March 2027 [Page 2] Internet-Draft ND YANG model September 2026 Enhanced DAD [RFC7527]. Other functions, 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]. Neighbor Discovery Optimization for 6LoWPANs [RFC6775] and other related extensions, such as those specified in [RFC8505], [RFC8928], and [RFC9010], are out of scope of this document. 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 Zhang, et al. Expires 5 March 2027 [Page 3] Internet-Draft ND YANG model September 2026 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 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 "retrans-timer" 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 per-interface operational statistics for each type of IPv6 ND messages. Zhang, et al. Expires 5 March 2027 [Page 4] Internet-Draft ND YANG model September 2026 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 "retrans-timer" 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 "retrans-timer" 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. Zhang, et al. Expires 5 March 2027 [Page 5] Internet-Draft ND YANG model September 2026 module: ietf-ipv6-nd augment /if:interfaces/if:interface/ip:ipv6: +--rw nd +--rw reachable-time? uint32 +--rw retrans-timer? uint32 +--rw redirect? boolean +--rw proxy-na? boolean +--rw enhanced-dad | +--rw enable? boolean | +--rw auto-resolve? boolean +--ro statistics +--ro ns-stats | +--ro in-pkts? yang:counter64 | +--ro out-pkts? yang:counter64 | +--ro drop-pkts? yang:counter64 | +--ro in-unicast-pkts? yang:counter64 | +--ro in-multicast-pkts? yang:counter64 | +--ro out-unicast-pkts? yang:counter64 | +--ro out-multicast-pkts? yang:counter64 | +--ro drop-bad-code-pkts? yang:counter64 | +--ro drop-bad-hoplimit-pkts? yang:counter64 | +--ro drop-bad-len-pkts? yang:counter64 | +--ro drop-bad-option-pkts? yang:counter64 | +--ro drop-checksum-err-pkts? yang:counter64 | +--ro drop-fragmented-pkts? yang:counter64 | +--ro out-nud-pkts? yang:counter64 +--ro na-stats | +--ro in-pkts? yang:counter64 | +--ro out-pkts? yang:counter64 | +--ro drop-pkts? yang:counter64 | +--ro in-unicast-pkts? yang:counter64 | +--ro in-multicast-pkts? yang:counter64 | +--ro out-unicast-pkts? yang:counter64 | +--ro out-multicast-pkts? yang:counter64 | +--ro drop-bad-code-pkts? yang:counter64 | +--ro drop-bad-hoplimit-pkts? yang:counter64 | +--ro drop-bad-len-pkts? yang:counter64 | +--ro drop-bad-option-pkts? yang:counter64 | +--ro drop-checksum-err-pkts? yang:counter64 | +--ro drop-fragmented-pkts? yang:counter64 | +--ro in-solicited-pkts? yang:counter64 | +--ro in-unsolicited-pkts? yang:counter64 | +--ro in-override-pkts? yang:counter64 | +--ro in-nonoverride-pkts? yang:counter64 | +--ro out-solicited-pkts? yang:counter64 | +--ro out-unsolicited-pkts? yang:counter64 | +--ro out-override-pkts? yang:counter64 Zhang, et al. Expires 5 March 2027 [Page 6] Internet-Draft ND YANG model September 2026 | +--ro out-nonoverride-pkts? yang:counter64 +--ro rs-stats | +--ro in-pkts? yang:counter64 | +--ro out-pkts? yang:counter64 | +--ro drop-pkts? yang:counter64 | +--ro in-unicast-pkts? yang:counter64 | +--ro in-multicast-pkts? yang:counter64 | +--ro out-unicast-pkts? yang:counter64 | +--ro out-multicast-pkts? yang:counter64 | +--ro drop-bad-code-pkts? yang:counter64 | +--ro drop-bad-hoplimit-pkts? yang:counter64 | +--ro drop-bad-len-pkts? yang:counter64 | +--ro drop-bad-option-pkts? yang:counter64 | +--ro drop-checksum-err-pkts? yang:counter64 | +--ro drop-fragmented-pkts? yang:counter64 +--ro ra-stats | +--ro in-pkts? yang:counter64 | +--ro out-pkts? yang:counter64 | +--ro drop-pkts? yang:counter64 | +--ro in-unicast-pkts? yang:counter64 | +--ro in-multicast-pkts? yang:counter64 | +--ro out-unicast-pkts? yang:counter64 | +--ro out-multicast-pkts? yang:counter64 | +--ro drop-bad-code-pkts? yang:counter64 | +--ro drop-bad-hoplimit-pkts? yang:counter64 | +--ro drop-bad-len-pkts? yang:counter64 | +--ro drop-bad-option-pkts? yang:counter64 | +--ro drop-checksum-err-pkts? yang:counter64 | +--ro drop-fragmented-pkts? yang:counter64 +--ro redirect-stats +--ro in-pkts? yang:counter64 +--ro out-pkts? yang:counter64 +--ro drop-pkts? yang:counter64 +--ro drop-bad-code-pkts? yang:counter64 +--ro drop-bad-hoplimit-pkts? yang:counter64 +--ro drop-bad-len-pkts? yang:counter64 +--ro drop-bad-option-pkts? yang:counter64 +--ro drop-checksum-err-pkts? yang:counter64 +--ro drop-fragmented-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. Zhang, et al. Expires 5 March 2027 [Page 7] Internet-Draft ND YANG model September 2026 This module imports modules from Common YANG Data Types [RFC9911], A YANG Data Model for Interface Management [RFC8343], and A YANG Data Model for IP Management [RFC8344]. 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 9911: 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 6MAN (IPv6 Maintenance) Working Group"; contact "WG Web: WG List: 6MAN 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. Zhang, et al. Expires 5 March 2027 [Page 8] Internet-Draft ND YANG model September 2026 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). All revisions of IETF and IANA published modules can be found at the YANG Parameters registry group (https://www.iana.org/assignments/yang-parameters). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; // RFC Ed: replace '2026-04-20' with the module publication date // the format is (YYYY-MM-DD) // replace XXXX with actual RFC number and remove // this note revision 2026-04-20 { description "Initial version."; reference "RFC XXXX: YANG Data Model for IPv6 Neighbor Discovery"; } /* Groupings */ grouping nd-basic-statistics { description "Grouping for basic statistics for IPv6 ND messages."; leaf in-pkts { type yang:counter64; description "The total number of packets received."; } leaf out-pkts { type yang:counter64; description "The total number of packets transmitted."; } leaf drop-pkts { type yang:counter64; Zhang, et al. Expires 5 March 2027 [Page 9] Internet-Draft ND YANG model September 2026 description "The total number of packets discarded."; } } grouping nd-unicast-multicast-statistics { description "Grouping for statistics for IPv6 ND messages categorized by unicast and multicast."; leaf in-unicast-pkts { type yang:counter64; description "The total number of packets received with the destination address as a unicast address."; } leaf in-multicast-pkts { type yang:counter64; description "The total number of packets received with the destination address as a multicast address."; } leaf out-unicast-pkts { type yang:counter64; description "The total number of packets transmitted with the destination address as a unicast address."; } leaf out-multicast-pkts { type yang:counter64; description "The total number of packets transmitted with the destination address as a multicast address."; } } grouping nd-drop-statistics { description "Grouping for statistics for IPv6 ND messages discarded by reason."; leaf drop-bad-code-pkts { type yang:counter64; description "The total number of packets discarded due to invalid code."; } leaf drop-bad-hoplimit-pkts { type yang:counter64; description "The total number of packets discarded due to invalid hop Zhang, et al. Expires 5 March 2027 [Page 10] Internet-Draft ND YANG model September 2026 limits."; } leaf drop-bad-len-pkts { type yang:counter64; description "The total number of packets discarded due to invalid length."; } leaf drop-bad-option-pkts { type yang:counter64; description "The total number of packets discarded due to invalid option."; } leaf drop-checksum-err-pkts { type yang:counter64; description "The total number of packets discarded due to checksum errors."; } leaf drop-fragmented-pkts { type yang:counter64; description "The total number of packets discarded due to fragmentation."; } } /* 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 retrans-timer { type uint32 { range "1..max"; Zhang, et al. Expires 5 March 2027 [Page 11] Internet-Draft ND YANG model September 2026 } 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 - RetransTimer"; } 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, 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 { Zhang, et al. Expires 5 March 2027 [Page 12] Internet-Draft ND YANG model September 2026 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 { config false; description "A collection of interface-related statistics about IPv6 ND messages."; container ns-stats { description "Statistics for Neighbor Solicitation packets."; uses nd-basic-statistics; uses nd-unicast-multicast-statistics; uses nd-drop-statistics; leaf out-nud-pkts { type yang:counter64; description "The total number of NS packets transmitted for NUD."; } } container na-stats { description "Statistics for Neighbor Advertisement packets."; uses nd-basic-statistics; uses nd-unicast-multicast-statistics; uses nd-drop-statistics; leaf in-solicited-pkts { type yang:counter64; description "The total number of solicited NA packets received."; } leaf in-unsolicited-pkts { type yang:counter64; description "The total number of unsolicited NA packets received."; Zhang, et al. Expires 5 March 2027 [Page 13] Internet-Draft ND YANG model September 2026 } leaf in-override-pkts { type yang:counter64; description "The total number of override NA packets received."; } leaf in-nonoverride-pkts { type yang:counter64; description "The total number of non-override NA packets received."; } leaf out-solicited-pkts { type yang:counter64; description "The total number of solicited NA packets transmitted."; } leaf out-unsolicited-pkts { type yang:counter64; description "The total number of unsolicited NA packets transmitted."; } leaf out-override-pkts { type yang:counter64; description "The total number of override NA packets transmitted."; } leaf out-nonoverride-pkts { type yang:counter64; description "The total number of non-override NA packets transmitted."; } } container rs-stats { description "Statistics for Router Solicitation packets."; uses nd-basic-statistics; uses nd-unicast-multicast-statistics; uses nd-drop-statistics; } container ra-stats { description "Statistics for Router Advertisement packets."; uses nd-basic-statistics; uses nd-unicast-multicast-statistics; uses nd-drop-statistics; } container redirect-stats { Zhang, et al. Expires 5 March 2027 [Page 14] Internet-Draft ND YANG model September 2026 description "Statistics for Redirect packets."; uses nd-basic-statistics; uses nd-drop-statistics; } } } } 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"; } } } 4. IANA Considerations IANA is requested to register the following URI in the "ns" registry within the "IETF XML Registry" group [RFC3688]: URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd Registrant Contact: The IESG XML: N/A; the requested URI is an XML namespace. IANA is requested to register the following YANG module in the "YANG Module Names" registry [RFC6020] within the "YANG Parameters" registry group. Name: ietf-ipv6-nd Maintained by IANA? N Namespace: urn:ietf:params:xml:ns:yang:ietf-ipv6-nd Prefix: v6nd Reference: RFC XXXX Zhang, et al. Expires 5 March 2027 [Page 15] Internet-Draft ND YANG model September 2026 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 [RFC9846], 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:retrans-timer 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 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 Zhang, et al. Expires 5 March 2027 [Page 16] Internet-Draft ND YANG model September 2026 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. References 7.1. Normative References [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, . Zhang, et al. Expires 5 March 2027 [Page 17] Internet-Draft ND YANG model September 2026 [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, . [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, . [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, . [RFC9911] Schönwälder, J., Ed., "Common YANG Data Types", RFC 9911, DOI 10.17487/RFC9911, December 2025, . 7.2. Informative References Zhang, et al. Expires 5 March 2027 [Page 18] Internet-Draft ND YANG model September 2026 [RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006, . [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, . [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, DOI 10.17487/RFC6775, November 2012, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C. Perkins, "Registration Extensions for IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Neighbor Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018, . [RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik, "Address-Protected Neighbor Discovery for Low-Power and Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November 2020, . [RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves, "Temporary Address Extensions for Stateless Address Autoconfiguration in IPv6", RFC 8981, DOI 10.17487/RFC8981, February 2021, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . Zhang, et al. Expires 5 March 2027 [Page 19] Internet-Draft ND YANG model September 2026 [RFC9010] Thubert, P., Ed. and M. Richardson, "Routing for RPL (Routing Protocol for Low-Power and Lossy Networks) Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021, . [RFC9846] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 9846, DOI 10.17487/RFC9846, July 2026, . [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, . [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, . Appendix A. Example Proxy Neighbor Advertisement, Redirect, NUD, and DAD Configuration This example illustrates the configuration of enabling proxy Neighbor Advertisement, Redirect, NUD, DAD, and enhanced DAD on interface eth0 with setting the "dup-addr-detect-transmits" leaf as 2, the "reachable-time" leaf as 40000 milliseconds, and the "retrans-timer" leaf as 2000 milliseconds, using the ietf-interfaces module [RFC8343], the ietf-ip module [RFC8344], and the IPv6 ND module. Zhang, et al. Expires 5 March 2027 [Page 20] Internet-Draft ND YANG model September 2026 eth0 ianaift:ethernetCsmacd 2 40000 2000 true true true true 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": 2, "ietf-ipv6-nd:nd": { "reachable-time": 40000, "retrans-timer": 2000, "redirect": true, "proxy-na": true, "enhanced-dad": { "enable": true, "auto-resolve": true } } } } ] } } Zhang, et al. Expires 5 March 2027 [Page 21] Internet-Draft ND YANG model September 2026 Appendix B. Coverage of IPv6 ND Functions in YANG Modules This appendix summarizes 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 3.4 of [RFC8981]. +=========+======================+==============+=================+ |RFC |Function/Parameter |Covered by |Path | |(Section)| | | | +=========+======================+==============+=================+ |4861 |Neighbor Cache |ietf-ip |/if:interfaces | |s5.1 | | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:neighbor | +---------+----------------------+--------------+-----------------+ |4862 |Prefix List |ietf-ipv6- |/if:interfaces | |s5.1 |(AdvPrefixList) |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:prefix-list| +---------+----------------------+--------------+-----------------+ |4861 |IsRouter |ietf-ip |/if:interfaces | |s6.2.1 | | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:forwarding | +---------+----------------------+--------------+-----------------+ |4861 |AdvSendAdvertisements |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:ipv6-router| | | | |-advertisements | +---------+----------------------+--------------+-----------------+ |4861 |MaxRtrAdvInterval |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:max-rtr | | | | |-adv-interval | +---------+----------------------+--------------+-----------------+ |4861 |MinRtrAdvInterval |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | Zhang, et al. Expires 5 March 2027 [Page 22] Internet-Draft ND YANG model September 2026 | | | |/v6ur:min-rtr | | | | |-adv-interval | +---------+----------------------+--------------+-----------------+ |4861 |AdvManagedFlag |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6/ | | | | |v6ur:managed-flag| +---------+----------------------+--------------+-----------------+ |4861 |AdvOtherConfigFlag |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:other- | | | | |config-flag | +---------+----------------------+--------------+-----------------+ |4861 |AdvLinkMTU |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:link-mtu | +---------+----------------------+--------------+-----------------+ |4861 |AdvReachableTime |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:reachable- | | | | |time | +---------+----------------------+--------------+-----------------+ |4861 |AdvRetransTimer |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:retrans- | | | | |timer | +---------+----------------------+--------------+-----------------+ |4861 |AdvCurHopLimit |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:cur-hop- | | | | |limit | +---------+----------------------+--------------+-----------------+ |4861 |AdvDefaultLifetime |ietf-ipv6- |/if:interfaces | |s6.2.1 | |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:default- | | | | |lifetime | +---------+----------------------+--------------+-----------------+ |4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces | |s6.2.1 |AdvValidLifetime |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:prefix-list| | | | |/v6ur:prefix | Zhang, et al. Expires 5 March 2027 [Page 23] Internet-Draft ND YANG model September 2026 | | | |/v6ur:control-adv| | | | |-prefixes | | | | |/v6ur:advertise | | | | |/v6ur:valid | | | | |-lifetime | +---------+----------------------+--------------+-----------------+ |4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces | |s6.2.1 |AdvOnLinkFlag |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:prefix-list| | | | |/v6ur:prefix | | | | |/v6ur:control-adv| | | | |-prefixes | | | | |/v6ur:advertise/ | | | | |v6ur:on-link-flag| +---------+----------------------+--------------+-----------------+ |4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces | |s6.2.1 |AdvPreferredLifetime |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:prefix-list| | | | |/v6ur:prefix | | | | |/v6ur:control-adv| | | | |-prefixes | | | | |/v6ur:advertise | | | | |/v6ur:preferred | | | | |-lifetime | +---------+----------------------+--------------+-----------------+ |4861 |AdvPrefixList/ |ietf-ipv6- |/if:interfaces | |s6.2.1 |AdvAutonomousFlag |router- |/if:interface | | | |advertisements|/ip:ipv6 | | | | |/v6ur:prefix-list| | | | |/v6ur:prefix | | | | |/v6ur:control-adv| | | | |-prefixes | | | | |/v6ur:advertise | | | | |/v6ur:autonomous | | | | |-flag | +---------+----------------------+--------------+-----------------+ |4861 |LinkMTU |- |- | |s6.3.2 | | | | +---------+----------------------+--------------+-----------------+ |4861 |CurHopLimit |- |- | |s6.3.2 | | | | +---------+----------------------+--------------+-----------------+ |4861 |BaseReachableTime |ietf-ipv6-nd |/if:interfaces | |s6.3.2 | | |/if:interface | | | | |/ip:ipv6/v6nd:nd | | | | |/v6nd:reachable | Zhang, et al. Expires 5 March 2027 [Page 24] Internet-Draft ND YANG model September 2026 | | | |-time | +---------+----------------------+--------------+-----------------+ |4861 |ReachableTime |- |- | |s6.3.2 | | | | +---------+----------------------+--------------+-----------------+ |4861 |RetransTimer |ietf-ipv6-nd |/if:interfaces | |s6.3.2 | | |/if:interface | |/4862 | | |/ip:ipv6/v6nd:nd | |s5.1 | | |/v6nd:retrans | | | | |-timer | +---------+----------------------+--------------+-----------------+ |4861 |Proxy Neighbor |ietf-ipv6-nd |/if:interfaces | |s7.2.8 |Advertisements | |/if:interface | | | | |/ip:ipv6/v6nd:nd | | | | |/v6nd:proxy-na | +---------+----------------------+--------------+-----------------+ |4861 |Redirect |ietf-ipv6-nd |/if:interfaces | |s8 | | |/if:interface | | | | |/ip:ipv6/v6nd:nd | | | | |/v6nd:redirect | +---------+----------------------+--------------+-----------------+ |4862 |DupAddrDetectTransmits|ietf-ip |/if:interfaces | |s5.1 | | |/if:interface | | | | |/ip:ipv6/ip:dup | | | | |-addr-detect | | | | |-transmits | +---------+----------------------+--------------+-----------------+ |4862 |Creation of Global |ietf-ip |/if:interfaces | |s5.5 |Addresses | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:autoconf | | | | |/ip:create- | | | | |global- | | | | |addresses | +---------+----------------------+--------------+-----------------+ |8981 |Creation of Temporary |ietf-ip |/if:interfaces | |s3.4 |Addresses | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:autoconf | | | | |/ip:create- | | | | |temporary- | | | | |addresses | +---------+----------------------+--------------+-----------------+ |8981 |TEMP_VALID_LIFETIME |ietf-ip |/if:interfaces | |s3.4 | | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:autoconf | | | | |/ip:temporary- | Zhang, et al. Expires 5 March 2027 [Page 25] Internet-Draft ND YANG model September 2026 | | | |valid-lifetime | +---------+----------------------+--------------+-----------------+ |8981 |TEMP_PREFERRED_ |ietf-ip |/if:interfaces | |s3.4 |LIFETIME | |/if:interface | | | | |/ip:ipv6 | | | | |/ip:autoconf | | | | |/ip:temporary- | | | | |preferred- | | | | |lifetime | +---------+----------------------+--------------+-----------------+ |7527 |Enhanced Duplicate |ietf-ipv6-nd |/if:interfaces | |s4 |Address Detection | |/if:interface | | | | |/ip:ipv6/v6nd:nd/| | | | |v6nd:enhanced-dad| +---------+----------------------+--------------+-----------------+ |7527 |Automated Resolving |ietf-ipv6-nd |/if:interfaces | |s5 |of Duplicates | |/if:interface | | | | |/ip:ipv6/v6nd:nd/| | | | |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 Zhang, et al. Expires 5 March 2027 [Page 26] Internet-Draft ND YANG model September 2026 Bo Wu Huawei China Email: lana.wubo@huawei.com Jiayuan Hu China Telecom Guangzhou China Email: hujy5@chinatelecom.cn Zhang, et al. Expires 5 March 2027 [Page 27]