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PROPOSED STANDARD

Internet Engineering Task Force (IETF)                            X. Liu
Request for Comments: 8652                                Volta Networks
Category: Standards Track                                         F. Guo
ISSN: 2070-1721                                                   Huawei
                                                            M. Sivakumar
                                                                 Juniper
                                                           P. McAllister
                                                     Metaswitch Networks
                                                                A. Peter
                                                       IP Infusion India
                                                           November 2019


  A YANG Data Model for the Internet Group Management Protocol (IGMP)
                 and Multicast Listener Discovery (MLD)

Abstract

   This document defines a YANG data model that can be used to configure
   and manage Internet Group Management Protocol (IGMP) and Multicast
   Listener Discovery (MLD) devices.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8652.

Copyright Notice

   Copyright (c) 2019 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 extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Terminology
     1.2.  Conventions Used in This Document
     1.3.  Tree Diagrams
     1.4.  Prefixes in Data Node Names
   2.  Design of the Data Model
     2.1.  Scope of Model
       2.1.1.  Parameters Not Covered at the Global Level
       2.1.2.  Parameters Not Covered at the Interface Level
     2.2.  Optional Capabilities
     2.3.  Position of Address Family in Hierarchy
   3.  Module Structure
     3.1.  IGMP Configuration and Operational State
     3.2.  MLD Configuration and Operational State
     3.3.  IGMP and MLD Actions
   4.  IGMP and MLD YANG Module
   5.  Security Considerations
   6.  IANA Considerations
   7.  References
     7.1.  Normative References
     7.2.  Informative References
   Acknowledgments
   Contributors
   Authors' Addresses

1.  Introduction

   YANG [RFC6020] [RFC7950] is a data definition language that was
   introduced to model the configuration and running state of a device
   managed using network management protocols such as NETCONF [RFC6241]
   or RESTCONF [RFC8040].  YANG is now also being used as a component of
   wider management interfaces, such as command-line interfaces (CLIs).

   This document defines a YANG data model that can be used to configure
   and manage Internet Group Management Protocol (IGMP) and Multicast
   Listener Discovery (MLD) devices.  The protocol versions include
   IGMPv1 [RFC1112], IGMPv2 [RFC2236], IGMPv3 [RFC3376], MLDv1
   [RFC2710], and MLDv2 [RFC3810].  The core features of the IGMP and
   MLD protocols are defined as required.  Non-core features are defined
   as optional in the provided data model.

   The YANG data model in this document conforms to the Network
   Management Datastore Architecture (NMDA) [RFC8342].

1.1.  Terminology

   The terminology for describing YANG data models is found in [RFC6020]
   and [RFC7950], including:

   *  augment

   *  data model

   *  data node

   *  identity

   *  module

   The following abbreviations are used in this document and the defined
   model:

   IGMP:  Internet Group Management Protocol [RFC3376].

   MLD:  Multicast Listener Discovery [RFC3810].

   SSM:  Source-Specific Multicast service model [RFC3569] [RFC4607].

1.2.  Conventions Used in This Document

   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.

1.3.  Tree Diagrams

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

1.4.  Prefixes in Data Node Names

   In this document, names of data nodes, actions, and other data model
   objects are often used without a prefix, as long as it is clear from
   the context in which YANG module each name is defined.  Otherwise,
   names are prefixed using the standard prefix associated with the
   corresponding YANG module, as shown in Table 1.

            +----------+--------------------------+-----------+
            | Prefix   | YANG module              | Reference |
            +==========+==========================+===========+
            | yang     | ietf-yang-types          | [RFC6991] |
            +----------+--------------------------+-----------+
            | inet     | ietf-inet-types          | [RFC6991] |
            +----------+--------------------------+-----------+
            | if       | ietf-interfaces          | [RFC8343] |
            +----------+--------------------------+-----------+
            | ip       | ietf-ip                  | [RFC8344] |
            +----------+--------------------------+-----------+
            | rt       | ietf-routing             | [RFC8349] |
            +----------+--------------------------+-----------+
            | rt-types | ietf-routing-types       | [RFC8294] |
            +----------+--------------------------+-----------+
            | acl      | ietf-access-control-list | [RFC8519] |
            +----------+--------------------------+-----------+

              Table 1: Prefixes and Corresponding YANG Modules

2.  Design of the Data Model

2.1.  Scope of Model

   The model covers IGMPv1 [RFC1112], IGMPv2 [RFC2236], IGMPv3
   [RFC3376], MLDv1 [RFC2710], and MLDv2 [RFC3810].

   This model does not cover other IGMP- and MLD-related protocols such
   as IGMP/MLD Proxy [RFC4605] or IGMP/MLD Snooping [RFC4541] etc.,
   which will be specified in separate documents.

   This model can be used to configure and manage various versions of
   IGMP and MLD protocols.  The operational state data and statistics
   can be retrieved by this model.  Even though no protocol-specific
   notifications are defined in this model, the subscription and push
   mechanism defined in [RFC8639] and [RFC8641] can be implemented by
   the user to subscribe to notifications on the data nodes in this
   model.

   The model contains all the basic configuration parameters to operate
   the protocols listed above.  Depending on the implementation choices,
   some systems may not allow some of the advanced parameters to be
   configurable.  The occasionally implemented parameters are modeled as
   optional features in this model, while the rarely implemented
   parameters are not included in this model and left for augmentation.
   This model can be extended, and it has been structured in a way that
   such extensions can be conveniently made.

   The protocol parameters covered in this model can been seen from the
   model structure described in Section 3.

   The protocol parameters that were considered but are not covered in
   this model are described in the following sections.

2.1.1.  Parameters Not Covered at the Global Level

   The configuration parameters and operational states not covered on an
   IGMP instance or an MLD instance are:

   *  Explicit tracking

   *  Maximum transmit rate

   *  Last member query count

   *  Other querier present time

   *  Send router alert

   *  Startup query interval

   *  Startup query count

2.1.2.  Parameters Not Covered at the Interface Level

   The configuration parameters and operational states not covered on an
   IGMP interface or an MLD interface are:

   *  Disable router alert check

   *  Drop IGMP version 1, IGMP version 2, or MLD version 1

   *  Last member query count

   *  Maximum number of sources

   *  Other querier present time

   *  Passive mode

   *  Promiscuous mode

   *  Query before immediate leave

   *  Send router alert

2.2.  Optional Capabilities

   This model is designed to represent the capabilities of IGMP and MLD
   devices with various specifications, including the basic capability
   subsets of the IGMP and MLD protocols.  The main design goals of this
   document are that the basic capabilities described in the model are
   supported by any major now-existing implementation, and that the
   configuration of all implementations meeting the specifications is
   easy to express through some combination of the optional features in
   the model and simple vendor augmentations.

   There is also value in widely supported features being standardized,
   to provide a standardized way to access these features, to save work
   for individual vendors, and so that mapping between different
   vendors' configuration is not needlessly complicated.  Therefore,
   this model declares a number of features representing capabilities
   that not all deployed devices support.

   The extensive use of feature declarations should also substantially
   simplify the capability negotiation process for a vendor's IGMP and
   MLD implementations.

   On the other hand, operational state parameters are not so widely
   designated as features, as there are many cases where the defaulting
   of an operational state parameter would not cause any harm to the
   system, and it is much more likely that an implementation without
   native support for a piece of operational state would be able to
   derive a suitable value for a state variable that is not natively
   supported.

2.3.  Position of Address Family in Hierarchy

   The protocol IGMP only supports IPv4, while the protocol MLD only
   supports IPv6.  The data model defined in this document can be used
   for both IPv4 and IPv6 address families.

   This document defines IGMP and MLD as separate schema branches in the
   structure.  The benefits are:

   *  The model can support IGMP (IPv4), MLD (IPv6), or both optionally
      and independently.  Such flexibility cannot be achieved cleanly
      with a combined branch.

   *  The structure is consistent with other YANG data models such as
      RFC 8344, which uses separate branches for IPv4 and IPv6.

   *  The separate branches for IGMP and MLD can accommodate their
      differences better and cleaner.  The two branches can better
      support different features and node types.

3.  Module Structure

   This model augments the core routing data model specified in
   [RFC8349].

         +--rw routing
            +--rw router-id?
            +--rw control-plane-protocols
            |  +--rw control-plane-protocol* [type name]
            |     +--rw type
            |     +--rw name
            |     +--rw igmp     <= Augmented by this Model
                        ...
            |     +--rw mld      <= Augmented by this Model
                        ...

   The "igmp" container instantiates an IGMP protocol of version IGMPv1,
   IGMPv2, or IGMPv3.  The "mld" container instantiates an MLD protocol
   of version MLDv1 or MLDv2.

   The YANG data model defined in this document conforms to the Network
   Management Datastore Architecture (NMDA) [RFC8342].  The operational
   state data is combined with the associated configuration data in the
   same hierarchy [RFC8407].

   A configuration data node is marked as mandatory only when its value
   must be provided by the user.  Where nodes are not essential to
   protocol operation, they are marked as optional.  Some other nodes
   are essential but have a default specified, so that they are also
   optional and need not be configured explicitly.

3.1.  IGMP Configuration and Operational State

   The IGMP data is modeled as a schema subtree augmenting the "control-
   plane-protocol" data node under "/rt:routing/rt:control-plane-
   protocols" in the module ietf-routing, following the convention
   described in [RFC8349].  The augmentation to the module ietf-routing
   allows this model to support multiple instances of IGMP, but a
   restriction MAY be added depending on the implementation and the
   device.  The identity "igmp" is derived from the "rt:control-plane-
   protocol" base identity and indicates that a control-plane-protocol
   instance is IGMP.

   The IGMP subtree is a three-level hierarchy structure as listed
   below:

   Global level:  Including IGMP configuration and operational state
      attributes for the entire IGMP protocol instance in this router.

   Interface-global level:  Including configuration data nodes that are
      applicable to all the interfaces whose corresponding nodes are not
      defined or not configured at the interface level.  For such a node
      at the interface level, the system uses the same value of the
      corresponding node at the interface-global level.

   Interface level:  Including IGMP configuration and operational state
      attributes specific to the given interface.  For a configuration
      node at the interface level, there may exist a corresponding
      configuration node with the same name at the interface-global
      level.  The value configured on a node at the interface level
      overrides the value configured on the corresponding node at the
      interface-global level.

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw igmp {feature-igmp}?
          +--rw global
          |  +--rw enabled?         boolean {global-admin-enable}?
          |  +--rw max-entries?     uint32 {global-max-entries}?
          |  +--rw max-groups?      uint32 {global-max-groups}?
          |  +--ro entries-count?   uint32
          |  +--ro groups-count?    uint32
          |  +--ro statistics
          |     +--ro discontinuity-time?   yang:date-and-time
          |     +--ro error
          |     |  +--ro total?       yang:counter64
          |     |  +--ro query?       yang:counter64
          |     |  +--ro report?      yang:counter64
          |     |  +--ro leave?       yang:counter64
          |     |  +--ro checksum?    yang:counter64
          |     |  +--ro too-short?   yang:counter64
          |     +--ro received
          |     |  +--ro total?    yang:counter64
          |     |  +--ro query?    yang:counter64
          |     |  +--ro report?   yang:counter64
          |     |  +--ro leave?    yang:counter64
          |     +--ro sent
          |        +--ro total?    yang:counter64
          |        +--ro query?    yang:counter64
          |        +--ro report?   yang:counter64
          |        +--ro leave?    yang:counter64
          +--rw interfaces
             +--rw last-member-query-interval?   uint16
             +--rw query-interval?               uint16
             +--rw query-max-response-time?      uint16
             +--rw require-router-alert?         boolean
             |       {intf-require-router-alert}?
             +--rw robustness-variable?          uint8
             +--rw version?                      uint8
             +--rw max-groups-per-interface?     uint32
             |       {intf-max-groups}?
             +--rw interface* [interface-name]
                +--rw interface-name                if:interface-ref
                +--rw last-member-query-interval?   uint16
                +--rw query-interval?               uint16
                +--rw query-max-response-time?      uint16
                +--rw require-router-alert?         boolean
                |       {intf-require-router-alert}?
                +--rw robustness-variable?          uint8
                +--rw version?                      uint8
                +--rw enabled?                      boolean
                |       {intf-admin-enable}?
                +--rw group-policy?
                |       -> /acl:acls/acl/name
                +--rw immediate-leave?              empty
                |       {intf-immediate-leave}?
                +--rw max-groups?                   uint32
                |       {intf-max-groups}?
                +--rw max-group-sources?            uint32
                |       {intf-max-group-sources}?
                +--rw source-policy?
                |       -> /acl:acls/acl/name {intf-source-policy}?
                +--rw verify-source-subnet?         empty
                |       {intf-verify-source-subnet}?
                +--rw explicit-tracking?            empty
                |       {intf-explicit-tracking}?
                +--rw lite-exclude-filter?          empty
                |       {intf-lite-exclude-filter}?
                +--rw join-group*
                |       rt-types:ipv4-multicast-group-address
                |       {intf-join-group}?
                +--rw ssm-map*
                |       [ssm-map-source-addr ssm-map-group-policy]
                |       {intf-ssm-map}?
                |  +--rw ssm-map-source-addr     ssm-map-ipv4-addr-type
                |  +--rw ssm-map-group-policy    string
                +--rw static-group* [group-addr source-addr]
                |       {intf-static-group}?
                |  +--rw group-addr
                |  |       rt-types:ipv4-multicast-group-address
                |  +--rw source-addr
                |          rt-types:ipv4-multicast-source-address
                +--ro oper-status                   enumeration
                +--ro querier                       inet:ipv4-address
                +--ro joined-group*
                |       rt-types:ipv4-multicast-group-address
                |       {intf-join-group}?
                +--ro group* [group-address]
                   +--ro group-address
                   |       rt-types:ipv4-multicast-group-address
                   +--ro expire           uint32
                   +--ro filter-mode      enumeration
                   +--ro up-time          uint32
                   +--ro last-reporter?   inet:ipv4-address
                   +--ro source* [source-address]
                      +--ro source-address    inet:ipv4-address
                      +--ro expire            uint32
                      +--ro up-time           uint32
                      +--ro host-count?       uint32
                      |       {intf-explicit-tracking}?
                      +--ro last-reporter?    inet:ipv4-address
                      +--ro host* [host-address]
                              {intf-explicit-tracking}?
                         +--ro host-address        inet:ipv4-address
                         +--ro host-filter-mode    enumeration

3.2.  MLD Configuration and Operational State

   The MLD data is modeled as a schema subtree augmenting the "control-
   plane-protocol" data node under "/rt:routing/rt:control-plane-
   protocols" in the module ietf-routing, following the convention
   described in [RFC8349].  The augmentation to the module ietf-routing
   allows this model to support multiple instances of MLD, but a
   restriction MAY be added depending on the implementation and the
   device.  The identity "mld" is derived from the "rt:control-plane-
   protocol" base identity and indicates that a control-plane-protocol
   instance is MLD.

   The MLD subtree is a three-level hierarchy structure as listed below:

   Global level:  Including MLD configuration and operational state
      attributes for the entire MLD protocol instance in this router.

   Interface-global level:  Including configuration data nodes that are
      applicable to all the interfaces whose corresponding nodes are not
      defined or not configured at the interface level.  For such a node
      at the interface level, the system uses the same value of the
      corresponding node at the interface-global level.

   Interface level:  Including MLD configuration and operational state
      attributes specific to the given interface.  For a configuration
      node at the interface level, there may exist a corresponding
      configuration node with the same name at the interface-global
      level.  The value configured on a node at the interface level
      overrides the value configured on the corresponding node at the
      interface-global level.

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw mld {feature-mld}?
          +--rw global
          |  +--rw enabled?         boolean {global-admin-enable}?
          |  +--rw max-entries?     uint32 {global-max-entries}?
          |  +--rw max-groups?      uint32 {global-max-groups}?
          |  +--ro entries-count?   uint32
          |  +--ro groups-count?    uint32
          |  +--ro statistics
          |     +--ro discontinuity-time?   yang:date-and-time
          |     +--ro error
          |     |  +--ro total?       yang:counter64
          |     |  +--ro query?       yang:counter64
          |     |  +--ro report?      yang:counter64
          |     |  +--ro leave?       yang:counter64
          |     |  +--ro checksum?    yang:counter64
          |     |  +--ro too-short?   yang:counter64
          |     +--ro received
          |     |  +--ro total?    yang:counter64
          |     |  +--ro query?    yang:counter64
          |     |  +--ro report?   yang:counter64
          |     |  +--ro leave?    yang:counter64
          |     +--ro sent
          |        +--ro total?    yang:counter64
          |        +--ro query?    yang:counter64
          |        +--ro report?   yang:counter64
          |        +--ro leave?    yang:counter64
          +--rw interfaces
             +--rw last-member-query-interval?   uint16
             +--rw query-interval?               uint16
             +--rw query-max-response-time?      uint16
             +--rw require-router-alert?         boolean
             |       {intf-require-router-alert}?
             +--rw robustness-variable?          uint8
             +--rw version?                      uint8
             +--rw max-groups-per-interface?     uint32
             |       {intf-max-groups}?
             +--rw interface* [interface-name]
                +--rw interface-name                if:interface-ref
                +--rw last-member-query-interval?   uint16
                +--rw query-interval?               uint16
                +--rw query-max-response-time?      uint16
                +--rw require-router-alert?         boolean
                |       {intf-require-router-alert}?
                +--rw robustness-variable?          uint8
                +--rw version?                      uint8
                +--rw enabled?                      boolean
                |       {intf-admin-enable}?
                +--rw group-policy?
                |       -> /acl:acls/acl/name
                +--rw immediate-leave?              empty
                |       {intf-immediate-leave}?
                +--rw max-groups?                   uint32
                |       {intf-max-groups}?
                +--rw max-group-sources?            uint32
                |       {intf-max-group-sources}?
                +--rw source-policy?
                |       -> /acl:acls/acl/name {intf-source-policy}?
                +--rw verify-source-subnet?         empty
                |       {intf-verify-source-subnet}?
                +--rw explicit-tracking?            empty
                |       {intf-explicit-tracking}?
                +--rw lite-exclude-filter?          empty
                |       {intf-lite-exclude-filter}?
                +--rw join-group*
                |       rt-types:ipv6-multicast-group-address
                |       {intf-join-group}?
                +--rw ssm-map*
                |       [ssm-map-source-addr ssm-map-group-policy]
                |       {intf-ssm-map}?
                |  +--rw ssm-map-source-addr     ssm-map-ipv6-addr-type
                |  +--rw ssm-map-group-policy    string
                +--rw static-group* [group-addr source-addr]
                |       {intf-static-group}?
                |  +--rw group-addr
                |  |       rt-types:ipv6-multicast-group-address
                |  +--rw source-addr
                |          rt-types:ipv6-multicast-source-address
                +--ro oper-status                   enumeration
                +--ro querier                       inet:ipv6-address
                +--ro joined-group*
                |       rt-types:ipv6-multicast-group-address
                |       {intf-join-group}?
                +--ro group* [group-address]
                   +--ro group-address
                   |       rt-types:ipv6-multicast-group-address
                   +--ro expire           uint32
                   +--ro filter-mode      enumeration
                   +--ro up-time          uint32
                   +--ro last-reporter?   inet:ipv6-address
                   +--ro source* [source-address]
                      +--ro source-address    inet:ipv6-address
                      +--ro expire            uint32
                      +--ro up-time           uint32
                      +--ro host-count?       uint32
                      |       {intf-explicit-tracking}?
                      +--ro last-reporter?    inet:ipv6-address
                      +--ro host* [host-address]
                              {intf-explicit-tracking}?
                         +--ro host-address        inet:ipv6-address
                         +--ro host-filter-mode    enumeration

3.3.  IGMP and MLD Actions

   IGMP and MLD each have one action that clears the group membership
   cache entries for that protocol.

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw igmp {feature-igmp}?
          +---x clear-groups {action-clear-groups}?
             +---w input
                +---w (interface)
                |  +--:(name)
                |  |  +---w interface-name?   leafref
                |  +--:(all)
                |     +---w all-interfaces?   empty
                +---w group-address           union
                +---w source-address
                        rt-types:ipv4-multicast-source-address

     augment /rt:routing/rt:control-plane-protocols
               /rt:control-plane-protocol:
       +--rw mld {feature-mld}?
          +---x clear-groups {action-clear-groups}?
             +---w input
                +---w (interface)
                |  +--:(name)
                |  |  +---w interface-name?   leafref
                |  +--:(all)
                |     +---w all-interfaces?   empty
                +---w group-address?          union
                +---w source-address?
                        rt-types:ipv6-multicast-source-address

4.  IGMP and MLD YANG Module

   This module references [RFC1112], [RFC2236], [RFC2710], [RFC3376],
   [RFC3810], [RFC5790], [RFC6636], [RFC6991], [RFC8294], [RFC8343],
   [RFC8344], [RFC8349], and [RFC8519].

   <CODE BEGINS> file "ietf-igmp-mld@2019-11-01.yang"
   module ietf-igmp-mld {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-igmp-mld";
     prefix igmp-mld;

     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-routing-types {
       prefix rt-types;
       reference
         "RFC 8294: Common YANG Data Types for the Routing Area";
     }
     import ietf-access-control-list {
       prefix acl;
       reference
         "RFC 8519: YANG Data Model for Network Access Control Lists
          (ACLs)";
     }
     import ietf-routing {
       prefix rt;
       reference
         "RFC 8349: A YANG Data Model for Routing Management (NMDA
          Version)";
     }
     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 PIM Working Group";
     contact
       "WG Web:   <http://datatracker.ietf.org/wg/pim/>
        WG List:  <mailto:pim@ietf.org>

        Editor:   Xufeng Liu
                  <mailto:xufeng.liu.ietf@gmail.com>

        Editor:   Feng Guo
                  <mailto:guofeng@huawei.com>

        Editor:   Mahesh Sivakumar
                  <mailto:sivakumar.mahesh@gmail.com>

        Editor:   Pete McAllister
                  <mailto:pete.mcallister@metaswitch.com>

        Editor:   Anish Peter
                  <mailto:anish.ietf@gmail.com>";
     description
       "The module defines the configuration and operational state for
        the Internet Group Management Protocol (IGMP) and Multicast
        Listener Discovery (MLD) protocols.

        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) 2019 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 Simplified BSD License set
        forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC 8652; see the
        RFC itself for full legal notices.";

     revision 2019-11-01 {
       description
         "Initial revision.";
       reference
         "RFC 8652: A YANG Data Model for the Internet Group Management
          Protocol (IGMP) and Multicast Listener Discovery (MLD)";
     }

     /*
      * Features
      */

     feature feature-igmp {
       description
         "Support IGMP protocol for IPv4 group membership record.";
     }

     feature feature-mld {
       description
         "Support MLD protocol for IPv6 group membership record.";
     }

     feature global-admin-enable {
       description
         "Support global configuration to enable or disable protocol.";
     }

     feature global-max-entries {
       description
         "Support configuration of global max-entries.";
     }

     feature global-max-groups {
       description
         "Support configuration of global max-groups.";
     }

     feature interface-global-config {
       description
         "Support global configuration applied for all interfaces.";
     }

     feature intf-admin-enable {
       description
         "Support configuration of interface administrative enabling.";
     }

     feature intf-immediate-leave {
       description
         "Support configuration of interface immediate-leave.";
     }

     feature intf-join-group {
       description
         "Support configuration of interface join-group.";
     }

     feature intf-max-groups {
       description
         "Support configuration of interface max-groups.";
     }

     feature intf-max-group-sources {
       description
         "Support configuration of interface max-group-sources.";
     }

     feature intf-require-router-alert {
       description
         "Support configuration of interface require-router-alert.";
     }

     feature intf-source-policy {
       description
         "Support configuration of interface source policy.";
     }

     feature intf-ssm-map {
       description
         "Support configuration of interface ssm-map.";
     }

     feature intf-static-group {
       description
         "Support configuration of interface static-group.";
     }

     feature intf-verify-source-subnet {
       description
         "Support configuration of interface verify-source-subnet.";
     }

     feature intf-explicit-tracking {
       description
         "Support configuration of interface explicit-tracking hosts.";
     }

     feature intf-lite-exclude-filter {
       description
         "Support configuration of interface lite-exclude-filter.";
     }

     feature per-interface-config {
       description
         "Support per-interface configuration.";
     }

     feature action-clear-groups {
       description
         "Support actions to clear groups.";
     }

     /*
      * Typedefs
      */

     typedef ssm-map-ipv4-addr-type {
       type union {
         type enumeration {
           enum policy {
             description
               "Source address is specified in SSM map policy.";
           }
         }
         type inet:ipv4-address;
       }
       description
         "Multicast source IP address type for SSM map.";
     }
     // source-ipv4-addr-type

     typedef ssm-map-ipv6-addr-type {
       type union {
         type enumeration {
           enum policy {
             description
               "Source address is specified in SSM map policy.";
           }
         }
         type inet:ipv6-address;
       }
       description
         "Multicast source IP address type for SSM map.";
     }
     // source-ipv6-addr-type

     /*
      * Identities
      */

     identity igmp {
       if-feature "feature-igmp";
       base rt:control-plane-protocol;
       description
         "IGMP protocol.";
       reference
         "RFC 3376: Internet Group Management Protocol, Version 3";
     }

     identity mld {
       if-feature "feature-mld";
       base rt:control-plane-protocol;
       description
         "MLD protocol.";
       reference
         "RFC 3810: Multicast Listener Discovery Version 2 (MLDv2) for
          IPv6";
     }

     /*
      * Groupings
      */

     grouping global-config-attributes {
       description
         "This grouping is used in either IGMP schema or MLD schema.
          When used in IGMP schema, this grouping contains the global
          configuration for IGMP;
          when used in MLD schema, this grouping contains the global
          configuration for MLD.";
       leaf enabled {
         if-feature "global-admin-enable";
         type boolean;
         default "true";
         description
           "When this grouping is used for IGMP, this leaf indicates
            whether IGMP is enabled ('true') or disabled ('false')
            in the routing instance.
            When this grouping is used for MLD, this leaf indicates
            whether MLD is enabled ('true') or disabled ('false')
            in the routing instance.";
       }
       leaf max-entries {
         if-feature "global-max-entries";
         type uint32;
         description
           "When this grouping is used for IGMP, this leaf indicates
            the maximum number of entries in the IGMP instance.
            When this grouping is used for MLD, this leaf indicates
            the maximum number of entries in the MLD instance.
            If this leaf is not specified, the number of entries is not
            limited.";
       }
       leaf max-groups {
         if-feature "global-max-groups";
         type uint32;
         description
           "When this grouping is used for IGMP, this leaf indicates
            the maximum number of groups in the IGMP instance.
            When this grouping is used for MLD, this leaf indicates
            the maximum number of groups in the MLD instance.
            If this leaf is not specified, the number of groups is not
            limited.";
       }
     }
     // global-config-attributes

     grouping global-state-attributes {
       description
         "This grouping is used in either IGMP schema or MLD schema.
          When used in IGMP schema, this grouping contains the global
          IGMP state attributes;
          when used in MLD schema, this grouping contains the global
          MLD state attributes.";
       leaf entries-count {
         type uint32;
         config false;
         description
           "When this grouping is used for IGMP, this leaf indicates
            the number of entries in the IGMP instance.
            When this grouping is used for MLD, this leaf indicates
            the number of entries in the MLD instance.";
       }
       leaf groups-count {
         type uint32;
         config false;
         description
           "When this grouping is used for IGMP, this leaf indicates
            the number of existing groups in the IGMP instance.
            When this grouping is used for MLD, this leaf indicates
            the number of existing groups in the MLD instance.";
       }
       container statistics {
         config false;
         description
           "When this grouping is used for IGMP, this container contains
            the statistics for the IGMP instance.
            When this grouping is used for MLD, this leaf indicates
            the statistics for the MLD instance.";
         leaf discontinuity-time {
           type yang:date-and-time;
           description
             "The time on the most recent occasion at which any one
              or more of the statistic counters suffered a
              discontinuity.  If no such discontinuities have occurred
              since the last re-initialization of the local
              management subsystem, then this node contains the time
              the local management subsystem re-initialized itself.";
         }
         container error {
           description
             "Statistics of errors.";
           uses global-statistics-error;
         }
         container received {
           description
             "Statistics of received messages.";
           uses global-statistics-sent-received;
         }
         container sent {
           description
             "Statistics of sent messages.";
           uses global-statistics-sent-received;
         }
       }
       // statistics
     }
     // global-state-attributes

     grouping global-statistics-error {
       description
         "A grouping defining statistics attributes for errors.";
       uses global-statistics-sent-received;
       leaf checksum {
         type yang:counter64;
         description
           "The number of checksum errors.";
       }
       leaf too-short {
         type yang:counter64;
         description
           "The number of messages that are too short.";
       }
     }
     // global-statistics-error

     grouping global-statistics-sent-received {
       description
         "A grouping defining statistics attributes.";
       leaf total {
         type yang:counter64;
         description
           "The number of total messages.";
       }
       leaf query {
         type yang:counter64;
         description
           "The number of query messages.";
       }
       leaf report {
         type yang:counter64;
         description
           "The number of report messages.";
       }
       leaf leave {
         type yang:counter64;
         description
           "The number of leave messages.";
       }
     }
     // global-statistics-sent-received

     grouping interface-global-config-attributes {
       description
         "Configuration attributes applied to the interface-global level
          whose per-interface attributes are not configured.";
       leaf max-groups-per-interface {
         if-feature "intf-max-groups";
         type uint32;
         description
           "The maximum number of groups associated with each interface.
            If this leaf is not specified, the number of groups is not
            limited.";
       }
     }
     // interface-global-config-attributes

     grouping interface-common-config-attributes {
       description
         "Configuration attributes applied to both the interface-global
          level and interface level.";
       leaf last-member-query-interval {
         type uint16 {
           range "1..1023";
         }
         units "seconds";
         description
           "When used in IGMP schema, this leaf indicates the Last
            Member Query Interval, which may be tuned to modify the
            leave latency of the network;
            when used in MLD schema, this leaf indicates the Last
            Listener Query Interval, which may be tuned to modify the
            leave latency of the network.
            This leaf is not applicable for version 1 of the IGMP.  For
            version 2 and version 3 of the IGMP, and for all versions of
            the MLD, the default value of this leaf is 1.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "Section 8.8 of RFC 2236: Internet Group Management Protocol,
            Version 2.
            Section 8.8 of RFC 3376: Internet Group Management Protocol,
            Version 3.
            Section 7.8 of RFC 2710: Multicast Listener Discovery (MLD)
            for IPv6.
            Section 9.8 of RFC 3810: Multicast Listener Discovery
            Version 2 (MLDv2) for IPv6.";
       }
       leaf query-interval {
         type uint16 {
           range "1..31744";
         }
         units "seconds";
         description
           "The Query Interval is the interval between General Queries
            sent by the Querier.  In RFC 3376, the Querier's Query
            Interval (QQI) is represented from the Querier's Query
            Interval Code (QQIC) in query message as follows:
            If QQIC < 128, QQI = QQIC.
            If QQIC >= 128, QQIC represents a floating-point value as
            follows:
             0 1 2 3 4 5 6 7
            +-+-+-+-+-+-+-+-+
            |1| exp | mant  |
            +-+-+-+-+-+-+-+-+
            QQI = (mant | 0x10) << (exp + 3).
            The maximum value of QQI is 31744.
            The default value is 125.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "Sections 4.1.7, 8.2, and 8.14.2 of RFC 3376: Internet Group
            Management Protocol, Version 3";
       }
       leaf query-max-response-time {
         type uint16 {
           range "1..1023";
         }
         units "seconds";
         description
           "Query maximum response time specifies the maximum time
            allowed before sending a responding report.
            The default value is 10.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "Sections 4.1.1, 8.3, and 8.14.3 of RFC 3376: Internet Group
            Management Protocol, Version 3";
       }
       leaf require-router-alert {
         if-feature "intf-require-router-alert";
         type boolean;
         description
           "Protocol packets should contain the router alert IP option.
            When this leaf is not configured, the server uses the
            following rules to determine the operational value of this
            leaf:
            if this grouping is used in IGMP schema and the value of the
            leaf 'version' is 1, the value 'false' is operationally used
            by the server;
            if this grouping is used in IGMP schema and the value of the
            leaf 'version' is 2 or 3, the value 'true' is operationally
            used by the server;
            if this grouping is used in MLD schema, the value 'true' is
            operationally used by the server.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
       }
       leaf robustness-variable {
         type uint8 {
           range "1..7";
         }
         description
           "The Querier's Robustness Variable allows tuning for the
            expected packet loss on a network.
            The default value is 2.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "Sections 4.1.6, 8.1, and 8.14.1 of RFC 3376: Internet Group
            Management Protocol, Version 3";
       }
     }
     // interface-common-config-attributes

     grouping interface-common-config-attributes-igmp {
       description
         "Configuration attributes applied to both the interface-global
          level and interface level for IGMP.";
       uses interface-common-config-attributes;
       leaf version {
         type uint8 {
           range "1..3";
         }
         description
           "IGMP version.
            The default value is 2.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "RFC 1112: Host Extensions for IP Multicasting,
            RFC 2236: Internet Group Management Protocol, Version 2,
            RFC 3376: Internet Group Management Protocol, Version 3.";
       }
     }

     grouping interface-common-config-attributes-mld {
       description
         "Configuration attributes applied to both the interface-global
          level and interface level for MLD.";
       uses interface-common-config-attributes;
       leaf version {
         type uint8 {
           range "1..2";
         }
         description
           "MLD version.
            The default value is 2.
            This leaf may be configured at the interface level or the
            interface-global level, with precedence given to the value
            at the interface level.  If the leaf is not configured at
            either level, the default value is used.";
         reference
           "RFC 2710: Multicast Listener Discovery (MLD) for IPv6,
            RFC 3810: Multicast Listener Discovery Version 2 (MLDv2)
            for IPv6.";
       }
     }

     grouping interfaces-config-attributes-igmp {
       description
         "Configuration attributes applied to the interface-global
          level for IGMP.";
       uses interface-common-config-attributes-igmp;
       uses interface-global-config-attributes;
     }

     grouping interfaces-config-attributes-mld {
       description
         "Configuration attributes applied to the interface-global
          level for MLD.";
       uses interface-common-config-attributes-mld;
       uses interface-global-config-attributes;
     }

     grouping interface-level-config-attributes {
       description
         "This grouping is used in either IGMP schema or MLD schema.
          When used in IGMP schema, this grouping contains the IGMP
          configuration attributes that are defined at the interface
          level but are not defined at the interface-global level;
          when used in MLD schema, this grouping contains the MLD
          configuration attributes that are defined at the interface
          level but are not defined at the interface-global level.";
       leaf enabled {
         if-feature "intf-admin-enable";
         type boolean;
         default "true";
         description
           "When this grouping is used for IGMP, this leaf indicates
            whether IGMP is enabled ('true') or disabled ('false')
            on the interface.
            When this grouping is used for MLD, this leaf indicates
            whether MLD is enabled ('true') or disabled ('false')
            on the interface.";
       }
       leaf group-policy {
         type leafref {
           path "/acl:acls/acl:acl/acl:name";
         }
         description
           "When this grouping is used for IGMP, this leaf specifies
            the name of the access policy used to filter the
            IGMP membership.
            When this grouping is used for MLD, this leaf specifies
            the name of the access policy used to filter the
            MLD membership.
            The value space of this leaf is restricted to the existing
            policy instances defined by the referenced schema in
            RFC 8519.
            As specified by RFC 8519, the length of the name is between
            1 and 64; a device MAY further restrict the length of this
            name; space and special characters are not allowed.
            If this leaf is not specified, no policy is applied, and
            all packets received from this interface are accepted.";
         reference
           "RFC 8519: YANG Data Model for Network Access Control Lists
            (ACLs)";
       }
       leaf immediate-leave {
         if-feature "intf-immediate-leave";
         type empty;
         description
           "When this grouping is used for IGMP, the presence of this
            leaf requests IGMP to perform an immediate leave upon
            receiving an IGMPv2 leave message.
            If the router is IGMP-enabled, it sends an IGMP last member
            query with a last member query response time.  However, the
            router does not wait for the response time before it prunes
            the group.
            When this grouping is used for MLD, the presence of this
            leaf requests MLD to perform an immediate leave upon
            receiving an MLDv1 leave message.
            If the router is MLD-enabled, it sends an MLD last member
            query with a last member query response time.  However, the
            router does not wait for the response time before it prunes
            the group.";
       }
       leaf max-groups {
         if-feature "intf-max-groups";
         type uint32;
         description
           "When this grouping is used for IGMP, this leaf indicates
            the maximum number of groups associated with the IGMP
            interface.
            When this grouping is used for MLD, this leaf indicates
            the maximum number of groups associated with the MLD
            interface.
            If this leaf is not specified, the number of groups is not
            limited.";
       }
       leaf max-group-sources {
         if-feature "intf-max-group-sources";
         type uint32;
         description
           "The maximum number of group sources.
            If this leaf is not specified, the number of group sources
            is not limited.";
       }
       leaf source-policy {
         if-feature "intf-source-policy";
         type leafref {
           path "/acl:acls/acl:acl/acl:name";
         }
         description
           "Name of the access policy used to filter sources.
            The value space of this leaf is restricted to the existing
            policy instances defined by the referenced schema in
            RFC 8519.
            As specified by RFC 8519, the length of the name is between
            1 and 64; a device MAY further restrict the length of this
            name; space and special characters are not allowed.
            If this leaf is not specified, no policy is applied, and
            all packets received from this interface are accepted.";
       }
       leaf verify-source-subnet {
         if-feature "intf-verify-source-subnet";
         type empty;
         description
           "If present, the interface accepts packets with matching
            source IP subnet only.";
       }
       leaf explicit-tracking {
         if-feature "intf-explicit-tracking";
         type empty;
         description
           "When this grouping is used for IGMP, the presence of this
            leaf enables an IGMP-based explicit membership tracking
            function for multicast routers and IGMP proxy devices
            supporting IGMPv3.
            When this grouping is used for MLD, the presence of this
            leaf enables an MLD-based explicit membership tracking
            function for multicast routers and MLD proxy devices
            supporting MLDv2.
            The explicit membership tracking function contributes to
            saving network resources and shortening leave latency.";
         reference
           "Section 3 of RFC 6636: Tuning the Behavior of the Internet
            Group Management Protocol (IGMP) and Multicast Listener
            Discovery (MLD) for Routers in Mobile and Wireless
            Networks";
       }
       leaf lite-exclude-filter {
         if-feature "intf-lite-exclude-filter";
         type empty;
         description
           "When this grouping is used for IGMP, the presence of this
            leaf enables the support of the simplified EXCLUDE filter
            in the Lightweight IGMPv3 protocol, which simplifies the
            standard versions of IGMPv3.
            When this grouping is used for MLD, the presence of this
            leaf enables the support of the simplified EXCLUDE filter
            in the Lightweight MLDv2 protocol, which simplifies the
            standard versions of MLDv2.";
         reference
           "RFC 5790: Lightweight Internet Group Management Protocol
            Version 3 (IGMPv3) and Multicast Listener Discovery
            Version 2 (MLDv2) Protocols";
       }
     }
     // interface-level-config-attributes

     grouping interface-config-attributes-igmp {
       description
         "Per-interface configuration attributes for IGMP.";
       uses interface-common-config-attributes-igmp;
       uses interface-level-config-attributes;
       leaf-list join-group {
         if-feature "intf-join-group";
         type rt-types:ipv4-multicast-group-address;
         description
           "The router joins this multicast group on the interface.";
       }
       list ssm-map {
         if-feature "intf-ssm-map";
         key "ssm-map-source-addr ssm-map-group-policy";
         description
           "The policy for (*,G) mapping to (S,G).";
         leaf ssm-map-source-addr {
           type ssm-map-ipv4-addr-type;
           description
             "Multicast source IPv4 address.";
         }
         leaf ssm-map-group-policy {
           type string;
           description
             "Name of the policy used to define ssm-map rules.
              A device can restrict the length
              and value of this name, possibly space and special
              characters are not allowed.";
         }
       }
       list static-group {
         if-feature "intf-static-group";
         key "group-addr source-addr";
         description
           "A static multicast route, (*,G) or (S,G).
            The version of IGMP must be 3 to support (S,G).";
         leaf group-addr {
           type rt-types:ipv4-multicast-group-address;
           description
             "Multicast group IPv4 address.";
         }
         leaf source-addr {
           type rt-types:ipv4-multicast-source-address;
           description
             "Multicast source IPv4 address.";
         }
       }
     }
     // interface-config-attributes-igmp

     grouping interface-config-attributes-mld {
       description
         "Per-interface configuration attributes for MLD.";
       uses interface-common-config-attributes-mld;
       uses interface-level-config-attributes;
       leaf-list join-group {
         if-feature "intf-join-group";
         type rt-types:ipv6-multicast-group-address;
         description
           "The router joins this multicast group on the interface.";
       }
       list ssm-map {
         if-feature "intf-ssm-map";
         key "ssm-map-source-addr ssm-map-group-policy";
         description
           "The policy for (*,G) mapping to (S,G).";
         leaf ssm-map-source-addr {
           type ssm-map-ipv6-addr-type;
           description
             "Multicast source IPv6 address.";
         }
         leaf ssm-map-group-policy {
           type string;
           description
             "Name of the policy used to define ssm-map rules.
              A device can restrict the length
              and value of this name, possibly space and special
              characters are not allowed.";
         }
       }
       list static-group {
         if-feature "intf-static-group";
         key "group-addr source-addr";
         description
           "A static multicast route, (*,G) or (S,G).
            The version of MLD must be 2 to support (S,G).";
         leaf group-addr {
           type rt-types:ipv6-multicast-group-address;
           description
             "Multicast group IPv6 address.";
         }
         leaf source-addr {
           type rt-types:ipv6-multicast-source-address;
           description
             "Multicast source IPv6 address.";
         }
       }
     }
     // interface-config-attributes-mld

     grouping interface-state-attributes {
       description
         "Per-interface state attributes for both IGMP and MLD.";
       leaf oper-status {
         type enumeration {
           enum up {
             description
               "Ready to pass packets.";
           }
           enum down {
             description
               "The interface does not pass any packets.";
           }
         }
         config false;
         mandatory true;
         description
           "Indicates whether the operational state of the interface
            is up or down.";
       }
     }
     // interface-state-attributes

     grouping interface-state-attributes-igmp {
       description
         "Per-interface state attributes for IGMP.";
       uses interface-state-attributes;
       leaf querier {
         type inet:ipv4-address;
         config false;
         mandatory true;
         description
           "The querier address in the subnet.";
       }
       leaf-list joined-group {
         if-feature "intf-join-group";
         type rt-types:ipv4-multicast-group-address;
         config false;
         description
           "The routers that joined this multicast group.";
       }
       list group {
         key "group-address";
         config false;
         description
           "Multicast group membership information
            that joined on the interface.";
         leaf group-address {
           type rt-types:ipv4-multicast-group-address;
           description
             "Multicast group address.";
         }
         uses interface-state-group-attributes;
         leaf last-reporter {
           type inet:ipv4-address;
           description
             "The IPv4 address of the last host that has sent the
              report to join the multicast group.";
         }
         list source {
           key "source-address";
           description
             "List of multicast source information
              of the multicast group.";
           leaf source-address {
             type inet:ipv4-address;
             description
               "Multicast source address in group record.";
           }
           uses interface-state-source-attributes;
           leaf last-reporter {
             type inet:ipv4-address;
             description
               "The IPv4 address of the last host that has sent the
                report to join the multicast source and group.";
           }
           list host {
             if-feature "intf-explicit-tracking";
             key "host-address";
             description
               "List of hosts with the membership for the specific
                multicast source-group.";
             leaf host-address {
               type inet:ipv4-address;
               description
                 "The IPv4 address of the host.";
             }
             uses interface-state-host-attributes;
           }
           // list host
         }
         // list source
       }
       // list group
     }
     // interface-state-attributes-igmp

     grouping interface-state-attributes-mld {
       description
         "Per-interface state attributes for MLD.";
       uses interface-state-attributes;
       leaf querier {
         type inet:ipv6-address;
         config false;
         mandatory true;
         description
           "The querier address in the subnet.";
       }
       leaf-list joined-group {
         if-feature "intf-join-group";
         type rt-types:ipv6-multicast-group-address;
         config false;
         description
           "The routers that joined this multicast group.";
       }
       list group {
         key "group-address";
         config false;
         description
           "Multicast group membership information
            that joined on the interface.";
         leaf group-address {
           type rt-types:ipv6-multicast-group-address;
           description
             "Multicast group address.";
         }
         uses interface-state-group-attributes;
         leaf last-reporter {
           type inet:ipv6-address;
           description
             "The IPv6 address of the last host that has sent the
              report to join the multicast group.";
         }
         list source {
           key "source-address";
           description
             "List of multicast sources of the multicast group.";
           leaf source-address {
             type inet:ipv6-address;
             description
               "Multicast source address in group record.";
           }
           uses interface-state-source-attributes;
           leaf last-reporter {
             type inet:ipv6-address;
             description
               "The IPv6 address of the last host that has sent the
                report to join the multicast source and group.";
           }
           list host {
             if-feature "intf-explicit-tracking";
             key "host-address";
             description
               "List of hosts with the membership for the specific
                multicast source-group.";
             leaf host-address {
               type inet:ipv6-address;
               description
                 "The IPv6 address of the host.";
             }
             uses interface-state-host-attributes;
           }
           // list host
         }
         // list source
       }
       // list group
     }
     // interface-state-attributes-mld

     grouping interface-state-group-attributes {
       description
         "Per-interface state attributes for both IGMP and MLD
          groups.";
       leaf expire {
         type uint32;
         units "seconds";
         mandatory true;
         description
           "The time left before the multicast group state expires.";
       }
       leaf filter-mode {
         type enumeration {
           enum include {
             description
               "In include mode, reception of packets sent
                to the specified multicast address is requested
                only from those IP source addresses listed in the
                source-list parameter";
           }
           enum exclude {
             description
               "In exclude mode, reception of packets sent
                to the given multicast address is requested
                from all IP source addresses except those
                listed in the source-list parameter.";
           }
         }
         mandatory true;
         description
           "Filter mode for a multicast group,
            may be either include or exclude.";
       }
       leaf up-time {
         type uint32;
         units "seconds";
         mandatory true;
         description
           "The elapsed time since the device created multicast group
            record.";
       }
     }
     // interface-state-group-attributes

     grouping interface-state-source-attributes {
       description
         "Per-interface state attributes for both IGMP and MLD
          source-group records.";
       leaf expire {
         type uint32;
         units "seconds";
         mandatory true;
         description
           "The time left before multicast source-group state expires.";
       }
       leaf up-time {
         type uint32;
         units "seconds";
         mandatory true;
         description
           "The elapsed time since the device created multicast
            source-group record.";
       }
       leaf host-count {
         if-feature "intf-explicit-tracking";
         type uint32;
         description
           "The number of host addresses.";
       }
     }
     // interface-state-source-attributes

     grouping interface-state-host-attributes {
       description
         "Per-interface state attributes for both IGMP and MLD
          hosts of source-group records.";
       leaf host-filter-mode {
         type enumeration {
           enum include {
             description
               "In include mode.";
           }
           enum exclude {
             description
               "In exclude mode.";
           }
         }
         mandatory true;
         description
           "Filter mode for a multicast membership
            host may be either include or exclude.";
       }
     }
     // interface-state-host-attributes

     /*
      * Configuration and Operational state data nodes (NMDA version)
      */

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol" {
       when "derived-from-or-self(rt:type, 'igmp-mld:igmp')" {
         description
           "This augmentation is only valid for a control-plane
            protocol instance of IGMP (type 'igmp').";
       }
       description
         "IGMP augmentation to routing control-plane protocol
          configuration and state.";
       container igmp {
         if-feature "feature-igmp";
         description
           "IGMP configuration and operational state data.";
         container global {
           description
             "Global attributes.";
           uses global-config-attributes;
           uses global-state-attributes;
         }
         container interfaces {
           description
             "Containing a list of interfaces.";
           uses interfaces-config-attributes-igmp {
             if-feature "interface-global-config";
             refine "query-interval" {
               default "125";
             }
             refine "query-max-response-time" {
               default "10";
             }
             refine "robustness-variable" {
               default "2";
             }
             refine "version" {
               default "2";
             }
           }
           list interface {
             key "interface-name";
             description
               "List of IGMP interfaces.";
             leaf interface-name {
               type if:interface-ref;
               must
                 '/if:interfaces/if:interface[if:name = current()]/'
               + 'ip:ipv4' {
                 error-message
                   "The interface must have IPv4 configured, either "
                 + "enabled or disabled.";
               }
               description
                 "Reference to an entry in the global interface list.";
             }
             uses interface-config-attributes-igmp {
               if-feature "per-interface-config";
               refine "last-member-query-interval" {
                 must '../version != 1 or '
                    + '(not(../version) and '
                    + '(../../version != 1 or not(../../version)))' {
                   error-message "IGMPv1 does not support "
                               + "last-member-query-interval.";
                 }
               }
               refine "max-group-sources" {
                 must '../version = 3 or '
                    + '(not(../version) and (../../version = 3))' {
                   error-message
                     "The version of IGMP must be 3 to support the "
                   + "source-specific parameters.";
                 }
               }
               refine "source-policy" {
                 must '../version = 3 or '
                    + '(not(../version) and (../../version = 3))' {
                   error-message
                     "The version of IGMP must be 3 to support the "
                   + "source-specific parameters.";
                 }
               }
               refine "explicit-tracking" {
                 must '../version = 3 or '
                    + '(not(../version) and (../../version = 3))' {
                   error-message
                     "The version of IGMP must be 3 to support the "
                   + "explicit tracking function.";
                 }
               }
               refine "lite-exclude-filter" {
                 must '../version = 3 or '
                    + '(not(../version) and (../../version = 3))' {
                   error-message
                     "The version of IGMP must be 3 to support the "
                   + "simplified EXCLUDE filter in the Lightweight "
                   + "IGMPv3 protocol.";
                 }
               }
             }
             uses interface-state-attributes-igmp;
           }
           // interface
         }
         // interfaces

         /*
          * Actions
          */
         action clear-groups {
           if-feature "action-clear-groups";
           description
             "Clears the specified IGMP cache entries.";
           input {
             choice interface {
               mandatory true;
               description
                 "Indicates the interface(s) from which the cache
                  entries are cleared.";
               case name {
                 leaf interface-name {
                   type leafref {
                     path "/rt:routing/rt:control-plane-protocols/"
                        + "rt:control-plane-protocol/"
                        + "igmp-mld:igmp/igmp-mld:interfaces/"
                        + "igmp-mld:interface/igmp-mld:interface-name";
                   }
                   description
                     "Name of the IGMP interface.";
                 }
               }
               case all {
                 leaf all-interfaces {
                   type empty;
                   description
                     "IGMP groups from all interfaces are cleared.";
                 }
               }
             }
             leaf group-address {
               type union {
                 type enumeration {
                   enum * {
                     description
                       "Any group address.";
                   }
                 }
                 type rt-types:ipv4-multicast-group-address;
               }
               mandatory true;
               description
                 "Multicast group IPv4 address.
                  If the value '*' is specified, all IGMP group entries
                  are cleared.";
             }
             leaf source-address {
               type rt-types:ipv4-multicast-source-address;
               mandatory true;
               description
                 "Multicast source IPv4 address.
                  If the value '*' is specified, all IGMP source-group
                  entries are cleared.";
             }
           }
         }
         // action clear-groups
       }
       // igmp
     }
     // augment

     augment "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol" {
       when "derived-from-or-self(rt:type, 'igmp-mld:mld')" {
         description
           "This augmentation is only valid for a control-plane
            protocol instance of IGMP (type 'mld').";
       }
       description
         "MLD augmentation to routing control-plane protocol
          configuration and state.";
       container mld {
         if-feature "feature-mld";
         description
           "MLD configuration and operational state data.";
         container global {
           description
             "Global attributes.";
           uses global-config-attributes;
           uses global-state-attributes;
         }
         container interfaces {
           description
             "Containing a list of interfaces.";
           uses interfaces-config-attributes-mld {
             if-feature "interface-global-config";
             refine "last-member-query-interval" {
               default "1";
             }
             refine "query-interval" {
               default "125";
             }
             refine "query-max-response-time" {
               default "10";
             }
             refine "require-router-alert" {
               default "true";
             }
             refine "robustness-variable" {
               default "2";
             }
             refine "version" {
               default "2";
             }
           }
           list interface {
             key "interface-name";
             description
               "List of MLD interfaces.";
             leaf interface-name {
               type if:interface-ref;
               must
                 '/if:interfaces/if:interface[if:name = current()]/'
               + 'ip:ipv6' {
                 error-message
                   "The interface must have IPv6 configured, either "
                 + "enabled or disabled.";
               }
               description
                 "Reference to an entry in the global interface list.";
             }
             uses interface-config-attributes-mld {
               if-feature "per-interface-config";
               refine "max-group-sources" {
                 must '../version = 2 or '
                    + '(not(../version) and '
                    + '(../../version = 2 or not(../../version)))' {
                   error-message
                     "The version of MLD must be 2 to support the "
                   + "source-specific parameters.";
                 }
               }
               refine "source-policy" {
                 must '../version = 2 or '
                    + '(not(../version) and '
                    + '(../../version = 2 or not(../../version)))' {
                   error-message
                     "The version of MLD must be 2 to support the "
                   + "source-specific parameters.";
                 }
               }
               refine "explicit-tracking" {
                 must '../version = 2 or '
                    + '(not(../version) and '
                    + '(../../version = 2 or not(../../version)))' {
                   error-message
                     "The version of MLD must be 2 to support the "
                   + "explicit tracking function.";
                 }
               }
               refine "lite-exclude-filter" {
                 must '../version = 2 or '
                    + '(not(../version) and '
                    + '(../../version = 2 or not(../../version)))' {
                   error-message
                     "The version of MLD must be 2 to support the "
                   + "simplified EXCLUDE filter in the Lightweight "
                   + "MLDv2 protocol.";
                 }
               }
             }
             uses interface-state-attributes-mld;
           }
           // interface
         }
         // interfaces

         /*
          * Actions
          */
         action clear-groups {
           if-feature "action-clear-groups";
           description
             "Clears the specified MLD cache entries.";
           input {
             choice interface {
               mandatory true;
               description
                 "Indicates the interface(s) from which the cache
                  entries are cleared.";
               case name {
                 leaf interface-name {
                   type leafref {
                     path "/rt:routing/rt:control-plane-protocols/"
                        + "rt:control-plane-protocol/"
                        + "igmp-mld:mld/igmp-mld:interfaces/"
                        + "igmp-mld:interface/igmp-mld:interface-name";
                   }
                   description
                     "Name of the MLD interface.";
                 }
               }
               case all {
                 leaf all-interfaces {
                   type empty;
                   description
                     "MLD groups from all interfaces are cleared.";
                 }
               }
             }
             leaf group-address {
               type union {
                 type enumeration {
                   enum * {
                     description
                       "Any group address.";
                   }
                 }
                 type rt-types:ipv6-multicast-group-address;
               }
               description
                 "Multicast group IPv6 address.
                  If the value '*' is specified, all MLD group entries
                  are cleared.";
             }
             leaf source-address {
               type rt-types:ipv6-multicast-source-address;
               description
                 "Multicast source IPv6 address.
                  If the value '*' is specified, all MLD source-group
                  entries are cleared.";
             }
           }
         }
         // action clear-mld-groups
       }
       // mld
     }
     // augment
   }
   <CODE ENDS>

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 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).  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:

   Under /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmp-mld:igmp,

   igmp-mld:global
      This subtree specifies the configuration for the IGMP attributes
      at the global level on an IGMP instance.  Modifying the
      configuration can cause IGMP membership to be deleted or
      reconstructed on all the interfaces of an IGMP instance.

   igmp-mld:interfaces
      This subtree specifies the configuration for the IGMP attributes
      at the interface-global level on an IGMP instance.  Modifying the
      configuration can cause IGMP membership to be deleted or
      reconstructed on all the interfaces of an IGMP instance.

   igmp-mld:interfaces/interface
      This subtree specifies the configuration for the IGMP attributes
      at the interface level on an IGMP instance.  Modifying the
      configuration can cause IGMP membership to be deleted or
      reconstructed on a specific interface of an IGMP instance.

   Under /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmp-mld:mld,

   igmp-mld:global
      This subtree specifies the configuration for the MLD attributes at
      the global level on an MLD instance.  Modifying the configuration
      can cause MLD membership to be deleted or reconstructed on all the
      interfaces of an MLD instance.

   igmp-mld:interfaces
      This subtree specifies the configuration for the MLD attributes at
      the interface-global level on an MLD instance.  Modifying the
      configuration can cause MLD membership to be deleted or
      reconstructed on all the interfaces of an MLD instance.

   igmp-mld:interfaces/interface
      This subtree specifies the configuration for the MLD attributes at
      the interface level on a device.  Modifying the configuration can
      cause MLD membership to be deleted or reconstructed on a specific
      interface of an MLD instance.

   Unauthorized access to any data node of these subtrees can adversely
   affect the membership records of multicast routing subsystem on the
   local device.  This may lead to network malfunctions, delivery of
   packets to inappropriate destinations, and other problems.

   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.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmmp-mld:igmp

   /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmp-mld:mld

   Unauthorized access to any data node of the above subtree can
   disclose the operational state information of IGMP or MLD on this
   device.

   Some of the action operations in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control access to these operations.  These are the
   operations and their sensitivity/vulnerability:

   /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmmp-mld:igmp/igmmp-mld:clear-groups

   /rt:routing/rt:control-plane-protocols
   /rt:control-plane-protocol/igmp-mld:mld/igmp-mld:clear-groups

   Unauthorized access to any of the above action operations can delete
   the IGMP or MLD membership records on this device.

6.  IANA Considerations

   This document registers the following namespace URIs in the IETF XML
   registry [RFC3688]:

   URI:  urn:ietf:params:xml:ns:yang:ietf-igmp-mld

   Registrant Contact:  The IESG.

   XML:  N/A; the requested URI is an XML namespace.

   This document registers the following YANG modules in the YANG Module
   Names registry [RFC6020]:

   Name:  ietf-igmp-mld

   Namespace:  urn:ietf:params:xml:ns:yang:ietf-igmp-mld

   Prefix:  igmp-mld

   Reference:  RFC 8652

7.  References

7.1.  Normative References

   [RFC1112]  Deering, S., "Host extensions for IP multicasting", STD 5,
              RFC 1112, DOI 10.17487/RFC1112, August 1989,
              <https://www.rfc-editor.org/info/rfc1112>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2236]  Fenner, W., "Internet Group Management Protocol, Version
              2", RFC 2236, DOI 10.17487/RFC2236, November 1997,
              <https://www.rfc-editor.org/info/rfc2236>.

   [RFC2710]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) for IPv6", RFC 2710,
              DOI 10.17487/RFC2710, October 1999,
              <https://www.rfc-editor.org/info/rfc2710>.

   [RFC3376]  Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
              Thyagarajan, "Internet Group Management Protocol, Version
              3", RFC 3376, DOI 10.17487/RFC3376, October 2002,
              <https://www.rfc-editor.org/info/rfc3376>.

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

   [RFC3810]  Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
              Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
              DOI 10.17487/RFC3810, June 2004,
              <https://www.rfc-editor.org/info/rfc3810>.

   [RFC4607]  Holbrook, H. and B. Cain, "Source-Specific Multicast for
              IP", RFC 4607, DOI 10.17487/RFC4607, August 2006,
              <https://www.rfc-editor.org/info/rfc4607>.

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

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

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

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

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8294]  Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger,
              "Common YANG Data Types for the Routing Area", RFC 8294,
              DOI 10.17487/RFC8294, December 2017,
              <https://www.rfc-editor.org/info/rfc8294>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8343]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
              <https://www.rfc-editor.org/info/rfc8343>.

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

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

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

   [RFC8519]  Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
              "YANG Data Model for Network Access Control Lists (ACLs)",
              RFC 8519, DOI 10.17487/RFC8519, March 2019,
              <https://www.rfc-editor.org/info/rfc8519>.

7.2.  Informative References

   [RFC3569]  Bhattacharyya, S., Ed., "An Overview of Source-Specific
              Multicast (SSM)", RFC 3569, DOI 10.17487/RFC3569, July
              2003, <https://www.rfc-editor.org/info/rfc3569>.

   [RFC4541]  Christensen, M., Kimball, K., and F. Solensky,
              "Considerations for Internet Group Management Protocol
              (IGMP) and Multicast Listener Discovery (MLD) Snooping
              Switches", RFC 4541, DOI 10.17487/RFC4541, May 2006,
              <https://www.rfc-editor.org/info/rfc4541>.

   [RFC4605]  Fenner, B., He, H., Haberman, B., and H. Sandick,
              "Internet Group Management Protocol (IGMP) / Multicast
              Listener Discovery (MLD)-Based Multicast Forwarding
              ("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605,
              August 2006, <https://www.rfc-editor.org/info/rfc4605>.

   [RFC5790]  Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet
              Group Management Protocol Version 3 (IGMPv3) and Multicast
              Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790,
              DOI 10.17487/RFC5790, February 2010,
              <https://www.rfc-editor.org/info/rfc5790>.

   [RFC6636]  Asaeda, H., Liu, H., and Q. Wu, "Tuning the Behavior of
              the Internet Group Management Protocol (IGMP) and
              Multicast Listener Discovery (MLD) for Routers in Mobile
              and Wireless Networks", RFC 6636, DOI 10.17487/RFC6636,
              May 2012, <https://www.rfc-editor.org/info/rfc6636>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

   [RFC8639]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Subscription to YANG Notifications",
              RFC 8639, DOI 10.17487/RFC8639, September 2019,
              <https://www.rfc-editor.org/info/rfc8639>.

   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

Acknowledgments

   The authors would like to thank Steve Baillargeon, Hu Fangwei, Robert
   Kebler, Tanmoy Kundu, and Stig Venaas for their valuable
   contributions.

Contributors

   Yisong Liu
   Huawei Technologies
   China

   Email: liuyisong@huawei.com

Authors' Addresses

   Xufeng Liu
   Volta Networks

   Email: xufeng.liu.ietf@gmail.com


   Feng Guo
   China
   100095
   Beijing
   Huawei Bldg., No. 156 Beiqing Rd., Haidian District
   Huawei Technologies

   Email: guofeng@huawei.com


   Mahesh Sivakumar
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, California
   United States of America

   Email: sivakumar.mahesh@gmail.com


   Pete McAllister
   Metaswitch Networks
   100 Church Street
   Enfield
   EN2 6BQ
   United Kingdom

   Email: pete.mcallister@metaswitch.com


   Anish Peter
   IP Infusion India
   RMZ Centennial, Block D 401
   Kundanahalli Main Road, Mahadevapura Post
   Bangalore
   India

   Email: anish.ietf@gmail.com


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