A YANG Data Model for Automatic Multicast Tunneling (AMT)

AMT YANG Module

Prefixes summarizes the prefixes used in this document. Prefixes and Corresponding YANG Modules

Prefix	YANG module	Reference
inet	ietf-inet-types
rt-types	ietf-routing-types
rt	ietf-routing
yang	ietf-yang-types
if	ietf-interfaces

Tree View The full tree diagram of the "ietf-amt" YANG module is provided in . The following subsections list the subtree structures.

Overall Structure The overall tree structure of the AMT YANG module is shown in . The AMT YANG module augments the core routing YANG module "ietf- routing" specified in . Specifically, the AMT YANG module augments "/rt:routing/rt:control-plane-protocols".

Overall AMT Tree Structure The 'amt' container encapsulates all AMT functionality and serves as the primary entry point for its configuration and state. The 'amt' container consists of two functional components: the relay and the gateway. Support of relay or gateway is indicated by dedicated YANG features. The 'relay' container manages the AMT Relay function on the multicast source side. It provides the configuration and operational state for AMT Relay devices that receive multicast traffic, tunnel it to AMT Gateways over unicast, and act as tunnel termination points. This container is conditionally present only if the device implements the 'amt-relay' feature, typically on service provider edge routers or data center gateways. The 'gateway' container manages the AMT Gateway function on the multicast receiver side. It provides the configuration and operational state for AMT Gateway devices that discover AMT Relays, establish tunnels to receive multicast traffic, and forward it to local receivers. This container is conditionally present only if the device implements the 'amt-gateway' feature, typically on enterprise edge routers or Customer Premises Equipment (CPE).

Relay The overall structure of 'relay' is shown in .

AMT Relay Subtree Structure The 'relay' data nodes are described as follows:

'addresses':: Indicates the core address configurations for AMT Relay.
: This data node includes 'family', 'anycast-prefix', and 'local- address'. The 'family' indicates the address family (IPv4 or IPv6). The 'anycast-prefix' indicates the address prefix used by the Gateway to discover the Relay. The 'local-address' indicates the local interface address the Relay actually listens on and sends AMT messages on, or the actual communication address after the tunnel is established.
'tunnel-limit':: Indicates the maximum number of endpoint Gateways that a Relay can serve simultaneously.
'secret-key-timeout':: Indicates the maximum recommended validity period or rotation interval for the private secret (or key) used by a AMT Relay to compute Response MAC values. In addition, the private secret (or key) is known only to the AMT relay, and the provisioning of the private secret (or key) is out of scope.
'relay-dns-resource-records':: Indicates the DNS RR configuration for AMT relay discovery. Each DNS RR configuration ('record') includes the specific multicast source IP address to which this DNS RR applies ('source-address'), the priority value of this DNS RR ('precedence'), the discovery optional flag ('d-bit'), the type of AMT relay address ('relay-type'), the directly specified IP address of AMT relay discovery address ('discovery-address'), and the wire-encoded domain name of AMT relay ('domain-name').
'tunnels' ():: Indicates tunnel information from various AMT gateways connected to this AMT relay.
: Each tunnel entry ('tunnel') includes the IP address and port number of the tunnel opposite end ('gateway') ('gateway-address' and 'gateway-port'), the local IP address and UDP port number used by the local ('relay') end for this tunnel ('local-address' and 'local- port'), the tunnel status ('state'), the multicast flow information ('multicast-flows') carried by the tunnel, the number of different multicast groups currently carried by this tunnel ('multicast-group- num'), the message counter carried by the tunnel ('request-message- count', 'membership-query-message-count', and 'membership-update- message-count'), and the time on the most recent occasion at which any one or more of the tunnel's counters suffered a discontinuity ('discontinuity-time').
: Each multicast flow information ('flow') has multicast source address ('source-address') and multicast group address ('group-address').

Design note: The four data nodes ('gateway-address', 'gateway-port', 'local-address', and 'local-port) do not reuse the standard "udp-client" grouping defined in because AMT requires the gateway to be a specific IP address (inet:ip-address), while the "udp-client" grouping allows the use of domain names (inet:host). Reuse could lead to configuration errors or runtime risks, so a custom structure must be defined to enforce this constraint.

AMT Relay Tunnel Subtree Structure

'relay-message-statistics':: Indicates various messages and error statistics handled by AMT relay as shown in .

AMT Relay Statistics Subtree Structure

Gateway The structure of 'gateway' is shown in .

AMT Gateway Subtree Structure The 'gateway' data nodes are described as follows:

'pseudo-interfaces':: Indicates the configuration and operational state of pseudo interfaces used to establish AMT tunnels between gateways and relays.
'gateway-message-statistics':: Indicates the message statistics of the AMT gateway. It has the time on the most recent occasion at which any one or more of the AMT gateway message counters suffered a discontinuity ('discontinuity-time'), the received message statistics of AMT gateway ('received'), and the sent message statistics of AMT gateway ('sent').
: 'received' container includes the number of AMT relay advertisement messages received ('relay-advertisement') and the number of AMT membership query messages received ('membership-query').
: 'sent' container includes the number of AMT relay discovery messages sent ('relay- discovery'), the number of AMT membership request messages sent ('request'), the number of AMT membership update messages sent ('membership-update'), and the number of AMT teardown messages sent ('teardown').

YANG Module This document imports modules defined in , , , and . WG List: MBONED Editor: Yisong Liu Editor: Changwang Lin Editor: Zheng(Sandy) Zhang Editor: Xuesong Geng Editor: Vinod Kumar Nagaraj "; description "This module describes a YANG data model for managing the Automatic Multicast Tunneling (AMT) protocol. 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. 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."; revision 2026-03-10 { description "Initial Version"; reference "RFC XXXX: A YANG Data Model for Automatic Multicast Tunneling (AMT)"; } feature amt-gateway { description "Indicates support of AMT Gateway functionality."; reference "RFC 7450: Automatic Multicast Tunneling, Section 4.1.2"; } feature amt-relay { description "Indicates support of AMT Relay functionality."; reference "RFC 7450: Automatic Multicast Tunneling, Section 4.1.3"; } typedef ip-multicast-source-address { type union { type rt-types:ipv4-multicast-source-address; type rt-types:ipv6-multicast-source-address; } description "This type represents a version-neutral IP multicast source address. The format of the textual representation implies the IP address family."; } identity tunnel-state-base { description "Base identity for AMT tunnel states."; } identity up { base tunnel-state-base; description "The AMT tunnel has been successfully established."; } identity establishing { base tunnel-state-base; description "The AMT tunnel is being established."; } identity initial { base tunnel-state-base; description "Initial AMT tunnel state."; } identity discoverying { base tunnel-state-base; description "The Relay Discovery message has been sent and is waiting for the Advertisement message."; } identity requesting { base tunnel-state-base; description "The Request message has been sent, waiting for the Query message."; } identity discovery-method-base { description "Base identity for all methods used to discover an AMT relay address. New discovery methods should be defined by creating new identities derived from this base identity."; } identity by-amt-solicit { base discovery-method-base; description "Find the relay address by sending an AMT Discovery message. This method involves sending an AMT Discovery message to discover available relays in the network."; reference "RFC 7450: Automatic Multicast Tunneling, Section 5.1.1"; } identity by-dns-reverse-ip { base discovery-method-base; description "Find the relay address by DNS reverse IP AMT Discovery. This method uses DNS reverse IP lookup to discover AMT relays based on the client's IP address."; reference "RFC 8777: DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery"; } augment "/rt:routing/rt:control-plane-protocols" { description "AMT augmentation to the routing instance model."; container amt { description "Management parameters for the AMT protocol."; container relay { if-feature "amt-relay"; description "Parameters of the AMT relay service."; container addresses { description "Parameters of AMT relay addresses."; list address { key "family"; description "Each entry contains parameters for an AMT relay address identified by the 'family' key. Under normal operation, these addresses SHOULD belong to the same address family indicated by 'family'. Any mismatch is an indication of abnormal configuration and is therefore allowed to be reported. The 'anycast-prefix' serve as the discovery entry for AMT relays, while unicast IP addresses 'local-address' are the actual communication entities of AMT relays. The AMT gateway first locates the AMT relay via the 'anycast-prefix' and then uses its 'local-address' to complete all subsequent AMT interactions."; leaf family { type identityref { base rt:address-family; } description "Indicates the address family for the entry."; } leaf anycast-prefix { type inet:ip-prefix; description "An anycast IP prefix of the AMT relay discovery address which is used when sending discovery messages to a relay. If 'family' is IPv4, it SHOULD be an IPv4 prefix; If 'family' is IPv6, it SHOULD be an IPv6 prefix. Any mismatch is an indication of abnormal configuration and is therefore allowed to be reported."; } leaf local-address { type inet:ip-address; description "A unicast IP address of the AMT relay address which is obtained as a result of the discovery process. If 'family' is IPv4, it SHOULD be an IPv4 address; If 'family' is IPv6, it SHOULD be an IPv6 address. Any mismatch is an indication of abnormal configuration and is therefore allowed to be reported."; } } } leaf tunnel-limit { type uint32; description "The total number of endpoints."; } leaf secret-key-timeout { type uint32; description "The timeout interval of secret key."; } container relay-dns-resource-records { description "The DNS Resource Records (RRs) of the AMT relay."; list record { key "source-address"; description "Specifies an RR entry."; leaf source-address { type inet:ip-address; description "The unicast IP address of multicast sender."; } leaf precedence { type uint32; description "The precedence value of this record, used for relay selection priority. Lower values indicate higher priority. Relays listed in AMT relay records with a lower value for precedence are to be attempted first."; reference "RFC 8777: DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery, Section 4.2.1"; } leaf d-bit { type boolean; default false; description "If the D-bit is set to true, the gateway MAY send an AMT Request message directly to the discovered relay address without first sending an AMT Discovery message. If the D-bit is set to false, the gateway MUST receive an AMT relay advertisement message for an address before sending an AMT Request message to that address."; reference "RFC 8777: DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery, Section 4.2.2"; } leaf relay-type { type enumeration { enum empty { value 0; description "The relay field is empty."; } enum ipv4-address { value 1; description "The relay field contains a 4-octet IPv4 address."; } enum ipv6-address { value 2; description "The relay field contains a 16-octet IPv6 address."; } enum domain-name { value 3; description "The relay field contains a wire-encoded domain name."; } } description "Indicates the type of relay in the AMT relay RR. Value 0 indicates that no AMT relay should be used for multicast traffic from this source. Values 1 and 2 indicate that the IP address is used to describe the AMT relay. Value 3 indicates that the domain name is used to describe the AMT relay."; reference "RFC 8777: DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery, Section 4.2.3"; } leaf discovery-address { type inet:ip-address; description "The IP address of AMT relay discovery address. When the 'relay-type' value is 1 or 2, this data node is used to indicate the AMT relay of the AMT relay RR."; } leaf domain-name { type inet:domain-name; description "The wire-encoded domain name of the AMT relay. When the 'relay-type' value is 3, this data node is used to indicate the AMT relay of the AMT relay RR."; } } } container tunnels { config false; description "AMT tunnel session information, which contains session parameters, state, and statistics for all AMT tunnels established between gateways and this relay."; list tunnel { key "gateway-address gateway-port"; description "Records a tunnel entry."; leaf gateway-address { type inet:ip-address; description "The IP address of an AMT gateway."; } leaf gateway-port { type inet:port-number; description "The UDP port number of an AMT gateway."; } leaf local-address { type inet:ip-address; description "The local IP address of the AMT relay."; } leaf local-port { type inet:port-number; description "The local UDP port number of the AMT relay."; } leaf state { type identityref { base tunnel-state-base; } description "The state of AMT tunnel."; } container multicast-flows { config false; description "The multicast flow information in the AMT tunnel. Contains operational data for all multicast flows being forwarded through AMT tunnels between this relay and connected gateways."; list flow { key "source-address group-address"; description "Records the characteristics of a multicast flow."; leaf source-address { type ip-multicast-source-address; description "The source IP address of a multicast flow. It MUST belong to the same address family as group-address."; } leaf group-address { type rt-types:ip-multicast-group-address; description "The group IP address of a multicast flow. It MUST belong to the same address family as source-address."; } } } leaf multicast-group-num { type yang:gauge32; description "Number of multicast groups."; } leaf request-message-count { type yang:zero-based-counter64; description "Number of AMT Request messages received in the tunnel."; } leaf membership-query-message-count { type yang:zero-based-counter64; description "Number of AMT membership Query messages sent in the tunnel."; } leaf membership-update-message-count { type yang:zero-based-counter64; description "Number of AMT membership Update messages received in the tunnel."; } leaf discontinuity-time { type yang:date-and-time; description "The time on the most recent occasion at which any one or more of this AMT tunnel's counters suffered a discontinuity. If no such discontinuities have occurred since the last re-initialization of the AMT tunnel, then this node contains the time when the AMT tunnel was last initialized or the tunnel was established."; } } } container relay-message-statistics { config false; description "Message statistics of an AMT relay."; container received { description "Received message statistics of AMT relay."; leaf relay-discovery { type yang:zero-based-counter64; description "Number of AMT relay discovery messages received."; } leaf request { type yang:zero-based-counter64; description "Number of AMT membership Request messages received."; } leaf membership-update { type yang:zero-based-counter64; description "Number of AMT membership Update messages received."; } leaf teardown { type yang:zero-based-counter64; description "Number of AMT Teardown messages received."; } } container sent { description "Sent message statistics of AMT relay."; leaf relay-advertisement { type yang:zero-based-counter64; description "Number of AMT relay advertisement messages sent."; } leaf membership-query { type yang:zero-based-counter64; description "Number of AMT membership Query messages sent."; } } container error { description "Error message statistics of AMT relay."; leaf incomplete-packet { type yang:zero-based-counter64; description "Number of messages received with length errors so severe that further classification could not occur."; } leaf invalid-mac { type yang:zero-based-counter64; description "Number of messages received with an invalid Message Authentication Code (MAC)."; } leaf unexpected-type { type yang:zero-based-counter64; description "Number of messages received with an unknown message type specified."; } leaf invalid-relay-discovery-address { type yang:zero-based-counter64; description "Number of AMT relay discovery messages received with an address other than the configured anycast address."; } leaf invalid-membership-request-address { type yang:zero-based-counter64; description "Number of AMT membership request messages received with an address other than the configured AMT local address."; } leaf invalid-membership-update-address { type yang:zero-based-counter64; description "Number of AMT membership update messages received with an address other than the configured AMT local address."; } leaf incomplete-relay-discovery-messages { type yang:zero-based-counter64; description "Number of AMT relay discovery messages received that are not fully formed."; } leaf incomplete-membership-request-messages { type yang:zero-based-counter64; description "Number of AMT membership request messages received that are not fully formed."; } leaf incomplete-membership-update-messages { type yang:zero-based-counter64; description "Number of AMT membership update messages received that are not fully formed."; } leaf no-active-gateway { type yang:zero-based-counter64; description "Number of AMT membership update messages received for a tunnel that does not exist for the gateway that sent the message."; } leaf invalid-inner-header-checksum { type yang:zero-based-counter64; description "Number of AMT membership update messages received with an invalid IP checksum."; } leaf gateways-timed-out { type yang:gauge64; description "Number of gateways that timed out because of inactivity."; } } leaf discontinuity-time { type yang:date-and-time; description "The time on the most recent occasion at which any one or more of this AMT tunnel's message counters suffered a discontinuity. If no such discontinuities have occurred since the last re-initialization of the AMT tunnel, then this node contains the time when the AMT tunnel was last initialized or the tunnel was established."; } } } // relay container gateway { if-feature "amt-gateway"; description "Parameters of AMT gateway service."; container pseudo-interfaces { description "Parameters of AMT pseudo-interface."; list interface { key "name"; description "An entry of AMT pseudo-interface."; leaf name { type if:interface-ref; description "Indicates the name of a pseudo interface."; } leaf discovery-method { type identityref { base discovery-method-base; } description "The method used to discover the relay address."; } leaf relay-discovery-address { type inet:ip-address; description "Specifies the AMT relay discovery address."; } leaf relay-address { type inet:ip-address; description "Specifies the IP address of the AMT relay."; } leaf relay-port { type inet:port-number; description "The UDP port number of the AMT relay."; } leaf local-address { type inet:ip-address; config false; description "The local IP address of this AMT tunnel."; } leaf local-port { type inet:port-number; config false; description "The local UDP port number of this AMT tunnel."; } leaf upstream-interface { type if:interface-ref; description "Indicates the upstream interface to reach the AMT relay."; } leaf discovery-timeout { type uint32; description "Initial time to wait for a response to a Relay Discovery message."; } leaf discovery-retrans-count { type uint32; description "Maximum number of Relay Discovery retransmissions to allow before terminating relay discovery and reporting an error."; } leaf request-timeout { type uint32; description "Initial time to wait for a response to a Request message"; } leaf request-retrans-count { type uint32; description "Maximum number of Request retransmissions to allow before abandoning a relay and restarting relay discovery or reporting an error."; } leaf dest-unreach-retry-count { type uint32; description "The maximum number of times a gateway should attempt to send the same Request or Membership Update message after receiving an ICMP Destination Unreachable message."; } leaf tunnel-state { type identityref { base tunnel-state-base; } config false; description "The tunnel's state."; } leaf relay-discovery-message-count { type yang:zero-based-counter64; config false; description "Number of AMT relay discovery messages sent on the interface."; } leaf relay-advertisement-message-count { type yang:zero-based-counter64; config false; description "Number of AMT relay advertisement messages received on the interface."; } leaf request-message-count { type yang:zero-based-counter64; config false; description "Number of AMT membership request messages sent on the interface."; } leaf membership-query-message-count { type yang:zero-based-counter64; config false; description "Number of AMT membership query messages received on the interface."; } leaf membership-update-message-count { type yang:zero-based-counter64; config false; description "Number of AMT membership update messages sent on the interface."; } } } container gateway-message-statistics { config false; description "Message statistics of the AMT Gateway."; leaf discontinuity-time { type yang:date-and-time; description "The time on the most recent occasion at which the AMT gateway message counters suffered a discontinuity. If no such discontinuities have occurred since the last re-initialization of the gateway, then this data node contains the time when the gateway was last initialized."; } container received { description "Received message statistics of the AMT Gateway."; leaf relay-advertisement { type yang:zero-based-counter64; description "Number of AMT relay advertisement messages received."; } leaf membership-query { type yang:zero-based-counter64; description "Number of AMT membership query messages received."; } } container sent { description "Sent message statistics of the AMT Gateway."; leaf relay-discovery { type yang:zero-based-counter64; description "Number of AMT relay discovery messages sent."; } leaf request { type yang:zero-based-counter64; description "Number of AMT membership request messages sent."; } leaf membership-update { type yang:zero-based-counter64; description "Number of AMT membership update messages sent."; } leaf teardown { type yang:zero-based-counter64; description "Number of AMT teardown messages sent."; } } } } // gateway } // amt } // augment } ]]>