\
MPLS Working Group                                          K. Raza, Ed.
Internet-Draft                                             Cisco Systems
Intended status: Standards Track
Expires: 15 May 2022                                             X. Liu
                                                         Volta Networks

                                                                S. Esale
                                                        Juniper Networks

                                                            L. Andersson
                                                     Huawei Technologies

                                                             J. Tantsura
                                                   Microsoft Corporation

                                                         S. Krishnaswamy
                                                              Individual


                                                        11 November 2021


                     YANG Data Model for MPLS mLDP
                      draft-ietf-mpls-mldp-yang-10

Abstract

   This document describes a YANG data model for the Multiprotocol Label
   Switching (MPLS) Multipoint Label Distribution Protocol (mLDP).  The
   mLDP YANG data model augments the MPLS LDP YANG data model.

   The YANG modules in this document conform to the Network Management
   Datastore Architecture (NMDA).

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."




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   This Internet-Draft will expire on 15 May 2022.

Copyright Notice

   Copyright (c) 2021 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Base and Extended . . . . . . . . . . . . . . . . . . . .   3
   2.  Specification of Requirements . . . . . . . . . . . . . . . .   4
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  The Complete Tree . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Configuration . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.1.  High-level Hierarchy  . . . . . . . . . . . . . . . . . .  17
     5.2.  Base Parameters . . . . . . . . . . . . . . . . . . . . .  19
     5.3.  Capabilities Parameters . . . . . . . . . . . . . . . . .  20
     5.4.  Forwarding Parameters . . . . . . . . . . . . . . . . . .  20
   6.  Operational State . . . . . . . . . . . . . . . . . . . . . .  20
     6.1.  Root State  . . . . . . . . . . . . . . . . . . . . . . .  21
     6.2.  Bindings State  . . . . . . . . . . . . . . . . . . . . .  22
     6.3.  Capabilities State  . . . . . . . . . . . . . . . . . . .  25
   7.  Notifications . . . . . . . . . . . . . . . . . . . . . . . .  27
   8.  Actions . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
   9.  YANG Specification  . . . . . . . . . . . . . . . . . . . . .  27
     9.1.  Base  . . . . . . . . . . . . . . . . . . . . . . . . . .  27
     9.2.  Extended  . . . . . . . . . . . . . . . . . . . . . . . .  37
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  60
     10.1.  YANG Data Model  . . . . . . . . . . . . . . . . . . . .  60
       10.1.1.  Writable Nodes . . . . . . . . . . . . . . . . . . .  61
       10.1.2.  Readable Nodes . . . . . . . . . . . . . . . . . . .  61
       10.1.3.  Notifications  . . . . . . . . . . . . . . . . . . .  62
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  62
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  62
   13. Informative References  . . . . . . . . . . . . . . . . . . .  65
   Appendix A.  Data Tree Example  . . . . . . . . . . . . . . . . .  65
   Appendix B.  Acknowledgments  . . . . . . . . . . . . . . . . . .  74
   Appendix C.  Contributors . . . . . . . . . . . . . . . . . . . .  74



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   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  74

1.  Introduction

   This document introduces a YANG data model for the MPLS Multipoint
   Label Distribution Protocol (mLDP).  The mLDP YANG data model being
   defined here is dependent on the LDP YANG data model
   [I-D.ietf-mpls-ldp-yang].  This implies that an operator will need to
   use the LDP base YANG data model to configure and manage the control
   plane for mLDP.  For example, an operator would enable LDP discovery
   on MPLS interface to establish LDP session for mLDP peering on which
   mLDP bindings could be exchanged.  Similarly, an operator could query
   state information for an LDP peer in order to verify peering
   attributes, etc.

   Moreover, it is important to note here that any assumptions made in
   the LDP YANG data model also hold true in this document, unless
   otherwise explicitly stated.

   Like its parent LDP data model, this mLDP model also defines the
   following constructs for managing the mLDP protocol:

   *  Configuration

   *  Operational State

   *  Executables (Actions)

   *  Notifications

   This document is organized to define the data model for each of the
   above constructs in the sequence as listed above.

1.1.  Base and Extended

   Like the LDP model, the configuration and state items are divided
   into the following two broad categories:

   *  Base

   *  Extended










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   The "base" category contains the basic and fundamental features that
   are covered in the mLDP base specification [RFC6388] (and some
   important extensions like the targeted mLDP [RFC7060]) and constitute
   the minumum requirements for a typical base mLDP deployment, whereas
   the "extended" category contains all other non-base features.  All
   the items in the base category are mandatory and, hence, no "if-
   feature" is allowed under the "base" category.  The base and extended
   categories are defined in their own modules as described later.

   The examples of base mLDP features include the enablement of mLDP and
   its capabilities, and static configuration of leaf IPv4 LSPs with
   generic LSP Id, whereas the examples of extended mLDP feature include
   enhanced mLDP capabilities, Recursive FEC [RFC6512], traffic
   protection [RFC7715] [RFC7431], static leaf IPv6 LSPs with generic
   LSP Id, and static leaf IPv4/IPv6 LSPs of all other opaque types
   (transit, bidir, recursive).  It is worth highlighting that any IPv6
   related feature support is categorized as an extended feature.

   While "base" model support will suffice for small deployments, it is
   expected that large deployments will require both the "base" and
   "extended" model support from the vendors.

2.  Specification of Requirements

   In this document, the word "IP" is used to refer to both IPv4 and
   IPv6, unless otherwise explicitly stated.  For example, "IP address
   family" should be read as "IPv4 and/or IPv6 address family".

3.  Overview

   This document defines two new modules for mLDP YANG support:

   *  "ietf-mpls-mldp" module that specifies the base mLDP features

   *  "ietf-mpls-mldp-extended" module that specifies the extended mLDP
      features

   Both the modules augment the LDP module (/rt:routing/rt:control-
   plane-protocols/rt:control-plane- protocol/ldp:mpls-ldp) as defined
   in [I-D.ietf-mpls-ldp-yang]

   There are four types of containers in our module(s):

   *  Read-write parameters for configuration (Section 5)

   *  Read-only parameters for operational state (Section 6)

   *  Notifications for events (Section 7)



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   Currently, no RPCs for executing commands to perform some action are
   defined in our mLDP modules.

   The modules in this document conform to the Network Management
   Datastore Architecture (NMDA) defined in [RFC8342].  The operational
   state data is combined with the associated configuration data in the
   same hierarchy [RFC8407].  When protocol states are retrieved from
   the NMDA operational state datastore, the returned states cover all
   "config true" (rw) and "config false" (ro) nodes defined in the
   schema.

   The following diagram depicts high-level mLDP yang tree organization
   and hierarchy with respect to LDP:


            +-- rw routing
              +-- rw control-plane-protocols
               +-- rw control-plane-protocol
                 +-- rw mpls-ldp
                     +-- rw some_ldp_container
                     |   +-- rw mldp
                     |       +-- rw ...                 // mldp base
                     |       |   +-- rw ...
                     |       |   +-- ro ...
                     |       |   +--
                     |       +-- rw mldp-ext:...        // mldp extended
                     |       |   +-- rw ...
                     |       |   +-- ro ...
                     |       |   +--
                     +-- ro someother_ldp_container
                         +-- ro mldp
                             +-- ro ...                 // mldp base
                             |   +-- ro ...
                             |   +--
                             +-- ro mldp-ext:...        // mldp extended
                                 +-- ro ...
                                 +--

       notifications:
          +--- n mpls-mldp-some_event
          +--- n ...


                   Figure 1: mLDP YANG Tree Organization

   The mLDP areas and features that are within the scope of this
   modeling effort are as follows:




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   *  Base:

      -  mLDP Base Specification [RFC6388]

      -  Targeted mLDP [RFC7060]

      -  Configured Leaf LSPs (manually provisioned)

   *  Extended:

      -  mLDP Recursive FEC [RFC6512]

      -  mLDP Fast-Reroute (FRR):

         o  Node Protection [RFC7715]

         o  Multicast-only [RFC7431]

      -  Hub-and-Spoke Multipoint LSPs [RFC7140]

      -  In-band Signaling:

         o  mLDP In-band Signaling [RFC6826]

         o  mLDP In-band signaling in a VRF [RFC7246]

         o  mLDP In-band Signaling with Wildcards [RFC7438]

   [Ed Note: Some of the topics in the above list are to be addressed/
   extended in a later revision of this document].

   For manually provisioned Multipoint LSPs, we represent its associated
   FEC as (root-address, opaque-element) tuple.  The following table
   lists various type of opaque elements with their keys, as later used
   in the configuration and state model:
















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        +========================+===================+===========+
        | Opaque Type            | Key               | RFC       |
        +========================+===================+===========+
        | Generic LSP Identifier | LSP Id            | [RFC6388] |
        +------------------------+-------------------+-----------+
        | Transit IPv4 Source    | Source, Group     | [RFC6826] |
        +------------------------+-------------------+-----------+
        | Transit IPv6 Source    | Source, Group     | [RFC6826] |
        +------------------------+-------------------+-----------+
        | Transit IPv4 Bidir     | RP, Group         | [RFC6826] |
        +------------------------+-------------------+-----------+
        | Transit IPv6 Bidir     | RP, Group         | [RFC6826] |
        +------------------------+-------------------+-----------+
        | Transit VPNv4 Source   | Source, Group, RD | [RFC7246] |
        +------------------------+-------------------+-----------+
        | Transit VPNv6 Source   | Source, Group, RD | [RFC7246] |
        +------------------------+-------------------+-----------+
        | Transit VPNv4 Bidir    | RP, Group, RD     | [RFC7246] |
        +------------------------+-------------------+-----------+
        | Transit VPNv6 Bidir    | RP, Group, RD     | [RFC7246] |
        +------------------------+-------------------+-----------+
        | Recursive Opaque       | Root              | [RFC6512] |
        +------------------------+-------------------+-----------+
        | VPN-Recursive Opaque   | Root, RD          | [RFC6512] |
        +------------------------+-------------------+-----------+

                              Table 1: URIs

   It should be noted that there are three basic types (LSP Id, Source,
   and Bidir) and then there are variants (VPN, recursive, VPN-
   recursive) on top of these basic types.  The "base" data model
   includes only the "Generic LSP Identifier" opaque type (for ipv4),
   while rest of the above types are covered by the "extended" model.

   A simplified graphical tree representation of base and extended mLDP
   YANG data models is presented in Figure 2.  The meaning of the
   symbols in these tree diagrams is defined in [RFC8340].

   The actual YANG specification for base and extended modules is
   captured in Section 9.

   While presenting the YANG tree view and actual specification, this
   document assumes readers are familiar with the concepts of YANG
   modeling, its presentation and its compilation.







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4.  The Complete Tree

   The following is a complete tree representation of configuration,
   state, and notification items under mLDP base and extended modules.
   Since mLDP modules augement LDP module, the mLDP tree view is shown
   with respective to LDP.


module: ietf-mpls-ldp
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol:
    +--rw mpls-ldp
       +--rw global
       |  +--rw capability
       |  |  +--rw mldp:mldp
       |  |     +--rw mldp:p2mp
       |  |     |  +--rw mldp:enabled?   boolean
       |  |     +--rw mldp:mp2mp
       |  |     |  +--rw mldp:enabled?   boolean
       |  |     +--rw mldp:make-before-break
       |  |     |  +--rw mldp:enabled?            boolean
       |  |     |  +--rw mldp:switchover-delay?   uint16
       |  |     |  +--rw mldp:timeout?            uint16
       |  |     +--rw mldp-ext:hub-and-spoke {capability-mldp-hsmp}?
       |  |     |  +--rw mldp-ext:enabled?   boolean
       |  |     +--rw mldp-ext:node-protection
       |  |             {capability-mldp-node-protection}?
       |  |        +--rw mldp-ext:plr?           boolean
       |  |        +--rw mldp-ext:merge-point
       |  |           +--rw mldp-ext:enabled?
       |  |           |       boolean
       |  |           +--rw mldp-ext:targeted-session-teardown-delay?
       |  |                   uint16
       |  +--rw ldp-ext:forwarding-nexthop
       |  |       {forwarding-nexthop-config}?
       |  |  +--rw ldp-ext:interfaces
       |  |     +--rw ldp-ext:interface* [name]
       |  |        +--rw ldp-ext:name              if:interface-ref
       |  |        +--rw ldp-ext:address-family* [afi]
       |  |           +--rw ldp-ext:afi               identityref
       |  |           +--rw mldp-ext:mldp-disable?   boolean
       |  +--rw mldp:mldp
       |     +--rw mldp:enabled?            boolean
       |     +--rw mldp:address-families
       |        +--rw mldp:ipv4!
       |        |  +--ro mldp:roots
       |        |  |  +--ro mldp:root* [root-address]
       |        |  |     +--ro mldp:root-address    inet:ipv4-address



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       |        |  |     +--ro mldp:is-self?        boolean
       |        |  |     +--ro mldp:reachability* [address interface]
       |        |  |     |  +--ro mldp:address      inet:ipv4-address
       |        |  |     |  +--ro mldp:interface    if:interface-ref
       |        |  |     |  +--ro mldp:peer?        leafref
       |        |  |     +--ro mldp:bindings
       |        |  |        +--ro mldp:opaque-element-lspid
       |        |  |        |  +--ro mldp:fec-label* [lsp-id]
       |        |  |        |     +--ro mldp:lsp-id
       |        |  |        |     |       uint32
       |        |  |        |     +--ro mldp:multipoint-type?
       |        |  |        |     |       multipoint-type
       |        |  |        |     +--ro mldp:peer*
       |        |  |        |     |       [direction peer advertisement-type]
       |        |  |        |     |  +--ro mldp:peer                  leafref
       |        |  |        |     |  +--ro mldp:direction
       |        |  |        |     |  |       ldp:downstream-upstream
       |        |  |        |     |  +--ro mldp:advertisement-type
       |        |  |        |     |  |       ldp:advertised-received
       |        |  |        |     |  +--ro mldp:label?
       |        |  |        |     |  |       rt-types:mpls-label
       |        |  |        |     |  +--ro mldp:mbb-role?
       |        |  |        |     |  |       enumeration
       |        |  |        |     |  +--ro mldp-ext:mofrr-role?
       |        |  |        |     |          mofrr-role
       |        |  |        |     +--ro mldp-ext:recursive-fec*
       |        |  |        |             [recur-root-address recur-rd]
       |        |  |        |        +--ro mldp-ext:recur-root-address
       |        |  |        |        |       inet:ip-address
       |        |  |        |        +--ro mldp-ext:recur-rd
       |        |  |        |        |       rt-types:route-distinguisher
       |        |  |        |        +--ro mldp-ext:multipoint-type?
       |        |  |        |        |       mldp:multipoint-type
       |        |  |        |        +--ro mldp-ext:peer*
       |        |  |        |                [direction peer advertisement-type]
       |        |  |        |           +--ro mldp-ext:peer                  leafref
       |        |  |        |           +--ro mldp-ext:direction
       |        |  |        |           |       ldp:downstream-upstream
       |        |  |        |           +--ro mldp-ext:advertisement-type
       |        |  |        |           |       ldp:advertised-received
       |        |  |        |           +--ro mldp-ext:label?
       |        |  |        |           |       rt-types:mpls-label
       |        |  |        |           +--ro mldp-ext:mbb-role?
       |        |  |        |           |       enumeration
       |        |  |        |           +--ro mldp-ext:mofrr-role?
       |        |  |        |                   mofrr-role
       |        |  |        +--ro mldp-ext:opaque-element-transit
       |        |  |        |  +--ro mldp-ext:fec-label*



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       |        |  |        |          [source-address group-address rd recur-root-address recur-rd]
       |        |  |        |     +--ro mldp-ext:source-address
       |        |  |        |     |       inet:ip-address
       |        |  |        |     +--ro mldp-ext:group-address
       |        |  |        |     |       inet:ip-address-no-zone
       |        |  |        |     +--ro mldp-ext:rd
       |        |  |        |     |       rt-types:route-distinguisher
       |        |  |        |     +--ro mldp-ext:recur-root-address
       |        |  |        |     |       inet:ip-address
       |        |  |        |     +--ro mldp-ext:recur-rd
       |        |  |        |     |       rt-types:route-distinguisher
       |        |  |        |     +--ro mldp-ext:multipoint-type?
       |        |  |        |     |       mldp:multipoint-type
       |        |  |        |     +--ro mldp-ext:peer*
       |        |  |        |             [direction peer advertisement-type]
       |        |  |        |        +--ro mldp-ext:peer                  leafref
       |        |  |        |        +--ro mldp-ext:direction
       |        |  |        |        |       ldp:downstream-upstream
       |        |  |        |        +--ro mldp-ext:advertisement-type
       |        |  |        |        |       ldp:advertised-received
       |        |  |        |        +--ro mldp-ext:label?
       |        |  |        |        |       rt-types:mpls-label
       |        |  |        |        +--ro mldp-ext:mbb-role?
       |        |  |        |        |       enumeration
       |        |  |        |        +--ro mldp-ext:mofrr-role?
       |        |  |        |                mofrr-role
       |        |  |        +--ro mldp-ext:opaque-element-bidir
       |        |  |           +--ro mldp-ext:fec-label*
       |        |  |                   [rp group-address rd recur-root-address recur-rd]
       |        |  |              +--ro mldp-ext:rp
       |        |  |              |       inet:ip-address
       |        |  |              +--ro mldp-ext:group-address
       |        |  |              |       inet:ip-address-no-zone
       |        |  |              +--ro mldp-ext:rd
       |        |  |              |       rt-types:route-distinguisher
       |        |  |              +--ro mldp-ext:recur-root-address
       |        |  |              |       inet:ip-address
       |        |  |              +--ro mldp-ext:recur-rd
       |        |  |              |       rt-types:route-distinguisher
       |        |  |              +--ro mldp-ext:multipoint-type?
       |        |  |              |       mldp:multipoint-type
       |        |  |              +--ro mldp-ext:peer*
       |        |  |                      [direction peer advertisement-type]
       |        |  |                 +--ro mldp-ext:peer                  leafref
       |        |  |                 +--ro mldp-ext:direction
       |        |  |                 |       ldp:downstream-upstream
       |        |  |                 +--ro mldp-ext:advertisement-type
       |        |  |                 |       ldp:advertised-received



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       |        |  |                 +--ro mldp-ext:label?
       |        |  |                 |       rt-types:mpls-label
       |        |  |                 +--ro mldp-ext:mbb-role?
       |        |  |                 |       enumeration
       |        |  |                 +--ro mldp-ext:mofrr-role?
       |        |  |                         mofrr-role
       |        |  +--rw mldp:configured-leaf-lsps
       |        |  |  +--rw mldp:opaque-element-lspid
       |        |  |  |  +--rw mldp:fec-label* [root-address lsp-id]
       |        |  |  |     +--rw mldp:root-address
       |        |  |  |     |       inet:ipv4-address
       |        |  |  |     +--rw mldp:lsp-id               uint32
       |        |  |  |     +--rw mldp:multipoint-type?
       |        |  |  |     |       multipoint-type
       |        |  |  |     +--rw mldp-ext:recursive-fec*
       |        |  |  |             [recur-root-address recur-rd]
       |        |  |  |        +--rw mldp-ext:recur-root-address
       |        |  |  |        |       inet:ip-address
       |        |  |  |        +--rw mldp-ext:recur-rd
       |        |  |  |        |       rt-types:route-distinguisher
       |        |  |  |        +--rw mldp-ext:multipoint-type?
       |        |  |  |                mldp:multipoint-type
       |        |  |  +--rw mldp-ext:opaque-element-transit
       |        |  |  |  +--rw mldp-ext:fec-label*
       |        |  |  |          [root-address source-address group-address rd recur-root-address recur-rd]
       |        |  |  |     +--rw mldp-ext:root-address
       |        |  |  |     |       inet:ipv4-address
       |        |  |  |     +--rw mldp-ext:source-address
       |        |  |  |     |       inet:ip-address
       |        |  |  |     +--rw mldp-ext:group-address
       |        |  |  |     |       inet:ip-address-no-zone
       |        |  |  |     +--rw mldp-ext:rd
       |        |  |  |     |       rt-types:route-distinguisher
       |        |  |  |     +--rw mldp-ext:recur-root-address
       |        |  |  |     |       inet:ip-address
       |        |  |  |     +--rw mldp-ext:recur-rd
       |        |  |  |     |       rt-types:route-distinguisher
       |        |  |  |     +--rw mldp-ext:multipoint-type?
       |        |  |  |             mldp:multipoint-type
       |        |  |  +--rw mldp-ext:opaque-element-bidir
       |        |  |     +--rw mldp-ext:fec-label*
       |        |  |             [root-address rp group-address rd recur-root-address recur-rd]
       |        |  |        +--rw mldp-ext:root-address
       |        |  |        |       inet:ipv4-address
       |        |  |        +--rw mldp-ext:rp
       |        |  |        |       inet:ip-address
       |        |  |        +--rw mldp-ext:group-address
       |        |  |        |       inet:ip-address-no-zone



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       |        |  |        +--rw mldp-ext:rd
       |        |  |        |       rt-types:route-distinguisher
       |        |  |        +--rw mldp-ext:recur-root-address
       |        |  |        |       inet:ip-address
       |        |  |        +--rw mldp-ext:recur-rd
       |        |  |        |       rt-types:route-distinguisher
       |        |  |        +--rw mldp-ext:multipoint-type?
       |        |  |                mldp:multipoint-type
       |        |  +--rw mldp-ext:multicast-only-frr {mldp-mofrr}?
       |        |  |  +--rw mldp-ext:prefix-list?
       |        |  |          ldp-ext:prefix-list-ref
       |        |  +--rw mldp-ext:recursive-fec
       |        |     +--rw mldp-ext:prefix-list?
       |        |             ldp-ext:prefix-list-ref
       |        +--rw mldp-ext:ipv6!
       |           +--ro mldp-ext:roots
       |           |  +--ro mldp-ext:root* [root-address]
       |           |     +--ro mldp-ext:root-address
       |           |     |       inet:ipv6-address
       |           |     +--ro mldp-ext:is-self?        boolean
       |           |     +--ro mldp-ext:reachability*
       |           |     |       [address interface]
       |           |     |  +--ro mldp-ext:address
       |           |     |  |       inet:ipv6-address
       |           |     |  +--ro mldp-ext:interface
       |           |     |  |       if:interface-ref
       |           |     |  +--ro mldp-ext:peer?        leafref
       |           |     +--ro mldp-ext:bindings
       |           |        +--ro mldp-ext:opaque-element-lspid
       |           |        |  +--ro mldp-ext:fec-label* [lsp-id]
       |           |        |     +--ro mldp-ext:lsp-id
       |           |        |     |       uint32
       |           |        |     +--ro mldp-ext:multipoint-type?
       |           |        |     |       mldp:multipoint-type
       |           |        |     +--ro mldp-ext:peer*
       |           |        |     |       [direction peer advertisement-type]
       |           |        |     |  +--ro mldp-ext:peer                  leafref
       |           |        |     |  +--ro mldp-ext:direction
       |           |        |     |  |       ldp:downstream-upstream
       |           |        |     |  +--ro mldp-ext:advertisement-type
       |           |        |     |  |       ldp:advertised-received
       |           |        |     |  +--ro mldp-ext:label?
       |           |        |     |  |       rt-types:mpls-label
       |           |        |     |  +--ro mldp-ext:mbb-role?
       |           |        |     |  |       enumeration
       |           |        |     |  +--ro mldp-ext:mofrr-role?
       |           |        |     |          mofrr-role
       |           |        |     +--ro mldp-ext:recursive-fec*



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       |           |        |             [recur-root-address recur-rd]
       |           |        |        +--ro mldp-ext:recur-root-address
       |           |        |        |       inet:ip-address
       |           |        |        +--ro mldp-ext:recur-rd
       |           |        |        |       rt-types:route-distinguisher
       |           |        |        +--ro mldp-ext:multipoint-type?
       |           |        |        |       mldp:multipoint-type
       |           |        |        +--ro mldp-ext:peer*
       |           |        |                [direction peer advertisement-type]
       |           |        |           +--ro mldp-ext:peer                  leafref
       |           |        |           +--ro mldp-ext:direction
       |           |        |           |       ldp:downstream-upstream
       |           |        |           +--ro mldp-ext:advertisement-type
       |           |        |           |       ldp:advertised-received
       |           |        |           +--ro mldp-ext:label?
       |           |        |           |       rt-types:mpls-label
       |           |        |           +--ro mldp-ext:mbb-role?
       |           |        |           |       enumeration
       |           |        |           +--ro mldp-ext:mofrr-role?
       |           |        |                   mofrr-role
       |           |        +--ro mldp-ext:opaque-element-transit
       |           |        |  +--ro mldp-ext:fec-label*
       |           |        |          [source-address group-address rd recur-root-address recur-rd]
       |           |        |     +--ro mldp-ext:source-address
       |           |        |     |       inet:ip-address
       |           |        |     +--ro mldp-ext:group-address
       |           |        |     |       inet:ip-address-no-zone
       |           |        |     +--ro mldp-ext:rd
       |           |        |     |       rt-types:route-distinguisher
       |           |        |     +--ro mldp-ext:recur-root-address
       |           |        |     |       inet:ip-address
       |           |        |     +--ro mldp-ext:recur-rd
       |           |        |     |       rt-types:route-distinguisher
       |           |        |     +--ro mldp-ext:multipoint-type?
       |           |        |     |       mldp:multipoint-type
       |           |        |     +--ro mldp-ext:peer*
       |           |        |             [direction peer advertisement-type]
       |           |        |        +--ro mldp-ext:peer                  leafref
       |           |        |        +--ro mldp-ext:direction
       |           |        |        |       ldp:downstream-upstream
       |           |        |        +--ro mldp-ext:advertisement-type
       |           |        |        |       ldp:advertised-received
       |           |        |        +--ro mldp-ext:label?
       |           |        |        |       rt-types:mpls-label
       |           |        |        +--ro mldp-ext:mbb-role?
       |           |        |        |       enumeration
       |           |        |        +--ro mldp-ext:mofrr-role?
       |           |        |                mofrr-role



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       |           |        +--ro mldp-ext:opaque-element-bidir
       |           |           +--ro mldp-ext:fec-label*
       |           |                   [rp group-address rd recur-root-address recur-rd]
       |           |              +--ro mldp-ext:rp
       |           |              |       inet:ip-address
       |           |              +--ro mldp-ext:group-address
       |           |              |       inet:ip-address-no-zone
       |           |              +--ro mldp-ext:rd
       |           |              |       rt-types:route-distinguisher
       |           |              +--ro mldp-ext:recur-root-address
       |           |              |       inet:ip-address
       |           |              +--ro mldp-ext:recur-rd
       |           |              |       rt-types:route-distinguisher
       |           |              +--ro mldp-ext:multipoint-type?
       |           |              |       mldp:multipoint-type
       |           |              +--ro mldp-ext:peer*
       |           |                      [direction peer advertisement-type]
       |           |                 +--ro mldp-ext:peer                  leafref
       |           |                 +--ro mldp-ext:direction
       |           |                 |       ldp:downstream-upstream
       |           |                 +--ro mldp-ext:advertisement-type
       |           |                 |       ldp:advertised-received
       |           |                 +--ro mldp-ext:label?
       |           |                 |       rt-types:mpls-label
       |           |                 +--ro mldp-ext:mbb-role?
       |           |                 |       enumeration
       |           |                 +--ro mldp-ext:mofrr-role?
       |           |                         mofrr-role
       |           +--rw mldp-ext:configured-leaf-lsps
       |           |  +--rw mldp-ext:opaque-element-lspid
       |           |  |  +--rw mldp-ext:fec-label*
       |           |  |          [root-address lsp-id]
       |           |  |     +--rw mldp-ext:root-address
       |           |  |     |       inet:ipv6-address
       |           |  |     +--rw mldp-ext:lsp-id             uint32
       |           |  |     +--rw mldp-ext:multipoint-type?
       |           |  |     |       mldp:multipoint-type
       |           |  |     +--rw mldp-ext:recursive-fec*
       |           |  |             [recur-root-address recur-rd]
       |           |  |        +--rw mldp-ext:recur-root-address
       |           |  |        |       inet:ip-address
       |           |  |        +--rw mldp-ext:recur-rd
       |           |  |        |       rt-types:route-distinguisher
       |           |  |        +--rw mldp-ext:multipoint-type?
       |           |  |                mldp:multipoint-type
       |           |  +--rw mldp-ext:opaque-element-transit
       |           |  |  +--rw mldp-ext:fec-label*
       |           |  |          [root-address source-address group-address rd recur-root-address recur-rd]



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       |           |  |     +--rw mldp-ext:root-address
       |           |  |     |       inet:ipv6-address
       |           |  |     +--rw mldp-ext:source-address
       |           |  |     |       inet:ip-address
       |           |  |     +--rw mldp-ext:group-address
       |           |  |     |       inet:ip-address-no-zone
       |           |  |     +--rw mldp-ext:rd
       |           |  |     |       rt-types:route-distinguisher
       |           |  |     +--rw mldp-ext:recur-root-address
       |           |  |     |       inet:ip-address
       |           |  |     +--rw mldp-ext:recur-rd
       |           |  |     |       rt-types:route-distinguisher
       |           |  |     +--rw mldp-ext:multipoint-type?
       |           |  |             mldp:multipoint-type
       |           |  +--rw mldp-ext:opaque-element-bidir
       |           |     +--rw mldp-ext:fec-label*
       |           |             [root-address rp group-address rd recur-root-address recur-rd]
       |           |        +--rw mldp-ext:root-address
       |           |        |       inet:ipv6-address
       |           |        +--rw mldp-ext:rp
       |           |        |       inet:ip-address
       |           |        +--rw mldp-ext:group-address
       |           |        |       inet:ip-address-no-zone
       |           |        +--rw mldp-ext:rd
       |           |        |       rt-types:route-distinguisher
       |           |        +--rw mldp-ext:recur-root-address
       |           |        |       inet:ip-address
       |           |        +--rw mldp-ext:recur-rd
       |           |        |       rt-types:route-distinguisher
       |           |        +--rw mldp-ext:multipoint-type?
       |           |                mldp:multipoint-type
       |           +--rw mldp-ext:multicast-only-frr {mldp-mofrr}?
       |           |  +--rw mldp-ext:prefix-list?
       |           |          ldp-ext:prefix-list-ref
       |           +--rw mldp-ext:recursive-fec
       |              +--rw mldp-ext:prefix-list?
       |                      ldp-ext:prefix-list-ref
       +--rw peers
          +--rw peer* [lsr-id label-space-id]
             +--rw lsr-id                         rt-types:router-id
             +--rw label-space-id                 uint16
             +--rw address-families
             +--ro received-peer-state
                +--ro capability
                   +--ro mldp:mldp
                      +--ro mldp:p2mp
                      |  +--ro mldp:enabled?   boolean
                      +--ro mldp:mp2mp



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                      |  +--ro mldp:enabled?   boolean
                      +--ro mldp:make-before-break
                      |  +--ro mldp:enabled?   boolean
                      +--ro mldp-ext:hub-and-spoke
                      |  +--ro mldp-ext:enabled?   boolean
                      +--ro mldp-ext:node-protection
                         +--ro mldp-ext:plr?           boolean
                         +--ro mldp-ext:merge-point?   boolean

module: ietf-mpls-mldp

  notifications:
    +---n mpls-mldp-fec-event
       +--ro event-type?
       |       ldp:oper-status-event-type
       +--ro (opaque-element)?
          +--:(opaque-element-lspid)
          |  +--ro opaque-element-lspid
          |     +--ro root-address?             inet:ip-address
          |     +--ro lsp-id?                   uint32
          |     +--ro multipoint-type?          multipoint-type
          |     +--ro mldp-ext:recursive-fec
          |        +--ro mldp-ext:recur-root-address?
          |        |       inet:ip-address
          |        +--ro mldp-ext:recur-rd?
          |        |       rt-types:route-distinguisher
          |        +--ro mldp-ext:multipoint-type?
          |                mldp:multipoint-type
          +--:(mldp-ext:opaque-element-transit)
          |  +--ro mldp-ext:opaque-element-transit
          |     +--ro mldp-ext:root-address?         inet:ip-address
          |     +--ro mldp-ext:source-address?       inet:ip-address
          |     +--ro mldp-ext:group-address?
          |     |       inet:ip-address-no-zone
          |     +--ro mldp-ext:rd?
          |     |       rt-types:route-distinguisher
          |     +--ro mldp-ext:recur-root-address?   inet:ip-address
          |     +--ro mldp-ext:recur-rd?
          |     |       rt-types:route-distinguisher
          |     +--ro mldp-ext:multipoint-type?
          |             mldp:multipoint-type
          +--:(mldp-ext:opaque-element-bidir)
             +--ro mldp-ext:opaque-element-bidir
                +--ro mldp-ext:root-address?         inet:ip-address
                +--ro mldp-ext:rp?                   inet:ip-address
                +--ro mldp-ext:group-address?
                |       inet:ip-address-no-zone
                +--ro mldp-ext:rd?



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                |       rt-types:route-distinguisher
                +--ro mldp-ext:recur-root-address?   inet:ip-address
                +--ro mldp-ext:recur-rd?
                |       rt-types:route-distinguisher
                +--ro mldp-ext:multipoint-type?
                        mldp:multipoint-type


                       Figure 2: Complete Tree

5.  Configuration

   This specification defines the parameters for configuring the base
   and extended mLDP features.  As stated earlier, mLDP configuration
   items augment relevant LDP configuration hiearchy.

5.1.  High-level Hierarchy

   The following presents a high-level view of configuration hierarchy
   for mLDP with respect to LDP:































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        augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol:
              +-- mpls-ldp
                  +-- global
                       +-- ...
                       +-- ...
                       +-- mldp
                       |   +-- ...
                       |   +-- ...
                       |   +-- address-families
                       |       +-- ipv4
                       |       |   +-- ...
                       |       |   +-- mldp-ext: ...
                       |       |   +-- ...
                       |       |   +-- configured-leaf-lsps
                       |       |       +-- ...
                       |       |       +-- ...
                       |       |       +-- mldp-ext: ...
                       |       |       +-- ...
                       |       |
                       |       +-- mldp-ext: ipv6
                       |           +-- ...
                       |           +-- ...
                       |           +-- configured-leaf-lsps
                       |               +-- ...
                       |               +-- ...
                       +-- capability
                       |   +-- mldp
                       |       +-- ...
                       |       +-- mldp-ext: ...
                       |       +-- ...
                       |
                       +-- forwarding-nexthop
                           +--- interfaces
                                +--- interface* [name]
                                     +--- mldp-ext: ...


                  Figure 3: Configuration Hierarchy

   The above hierarchy illustrates that mLDP configuation parameters are
   distributed amongst the following three sections:

   *  mldp base

   *  mldp capabilities

   *  mldp forwarding




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   The following subsections describe the above mLDP sub-tree alongwith
   their configuration items.

5.2.  Base Parameters

   mldp container falls directly under mpls-ldp:global and holds the
   configuration related to items that are mLDP specific.  The main
   items under this container are:

   *  mLDP enablement: To enable mLDP under a (VRF) routing instance,
      mldp is enabled in the mldp container under LDP.  It is to remind
      that the LDP modules reside under a network-instance and the scope
      of any configuration defined under this tree is network-instance
      (VRF) scoped.  Given that mLDP requires LDP signaling, it is not
      sensible to allow disabling the LDP control plane under a (VRF)
      network-instance while requiring mLDP to be enabled for the same.
      However, if a user wants to only allow signaling for multipoint
      FECs on an LDP/mLDP enabled VRF instance, he/she can use LDP
      label-policies to disable unicast FECs under the VRF.
      Alteratively, the same can be acheived by advertising the
      capabilities and the procedures defined in [RFC7473].

   *  Per address-family mLDP features: mLDP manages its own list of IP
      address-families and the features enabled underneath.  The per-AF
      mLDP configuration items include:

      -  Multicast-only FRR: This enables Multicast-only FRR
         functionality for a given AF under mLDP.  The feature allows
         route-policy to be configured for finer control/applicability
         of the feature.

      -  Recursive FEC: The recursive-fec feature [RFC6512] can be
         enabled per-AF with a route-policy.

      -  Configured Leaf LSPs: To provision multipoint leaf LSPs
         manually, a per-AF container is provided under LDP.  The
         configuration is flexible and allows a user to specify MP LSPs
         of type p2mp or mp2mp with IPv4 or IPv6 root address(es) by
         using either LSP-Id or (S,G).

   Targeted mLDP feature specification [RFC7060] does not require any
   mLDP specific configuration.  It, however, requires LDP upstream-
   label-assignment capability [RFC6389] to be enabled.








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5.3.  Capabilities Parameters

   mldp capabilities are enabled under mldp specific container under
   ldp:global:capability container.  In the scope of this document, the
   most important capabilities related to mLDP are p2mp, mp2mp, make-
   before-break, hub-and-spoke, and node-protection.

   It is worth reminding that mLDP requires LDP discovery and peer
   procedures to form mLDP peering but a peer is considered as an mLDP
   peer only when either p2mp or mp2mp capabilities have been
   successfully exchanged with the peer.

   In most common deployments, it is desirable to disable mLDP
   (capabilities announcements) on a targeted-only LDP peering, where
   targeted-only peer is the one whose discovery sources are the
   targeted type only.

5.4.  Forwarding Parameters

   The container ldp:global:forwarding-nexthop is used to hold
   configuration to controlling LDP/mLDP forwarding behavior.  One
   example of a such a configuration is to allow a user in disabling the
   use of LDP interface(s) as an mLDP forwarding egress interface for MP
   LSPs(s).  This example configuration makes sense only when there are
   more than one interface available for the selection.

6.  Operational State

   The mLDP modules conform to the NMDA where the operational state data
   is combined with the associated configuration data in the same
   hierarchy.  This means that When protocol states are retrieved from
   the NMDA operational state datastore, the returned states cover all
   "config true" (rw) and "config false" (ro) nodes defined in the
   schema.

   The following are the main areas for which mLDP operational state is
   defined:

   *  Root

   *  Bindings (FEC-label)

   *  Capabilities








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6.1.  Root State

   The root address is a fundamental construct for MP FEC bindings and
   LSPs.  The root state provides information on all the known roots in
   a given address-familty and their root reachability information (as
   learnt from RIB).  In case of multi-path reachability to a root, the
   selection of the upstream path is done on per-LSP basis at the time
   of LSP setup.  Similarly, when protection mechanisms like Make-
   before-break (MBB) or Multicast-only FRR (MoFRR) are in place, the
   path designation as active/standby or primary/backup is also done on
   per-LSP basis.  It should be noted that a given root can be shared
   amongst multiple P2MP and/or MP2MP LSPs.  Moreover, an LSP can be
   signaled to more than one root for Root Node Redundancy (RNR)
   purposes.

   The following example illustrates a root database on a branch/transit
   LSR:


        root 203.0.113.1:
            path1:
                RIB: GigEthernet 1/0, 198.51.100.1;
                LDP: peer 192.0.2.1:0
            path2:
                RIB: GigEthernet 2/0, 198.51.100.16;
                LDP: peer 192.0.2.2:0

        root 203.0.113.2:
            path1:
                RIB: 198.51.100.100;      (NOTE: This is a recursive path)
                LDP: peer 192.0.2.100:0   (NOTE: T-mLDP peer)

        root 2001:db8:0:9::1:
            path1:
                RIB: GigEthernet 1/0, 2001:db8:0:1::1
                LDP: peer 192.0.2.1:0

        root . . . .


                   Figure 4: Example Root database

   A root entry on a root LSR itself will be presented as follows:








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           root 203.0.113.10:
               is-self

           root 2001:db8:0:9::1:
               is-self


                Figure 5: Example Root entry on a Root node

   The following digram captures the high-level tree hierarchy for state
   of an mLDP root The tree is shown for ipv4 roots only; a similar tree
   exists for ipv6 roots as well.

       +--rw mpls-ldp
          +--rw global
             +--rw mldp:mldp
                +--rw mldp:address-families
                   +--rw mldp:ipv4!
                      +--ro mldp:roots
                         +--ro mldp:root* [root-address]
                            +--ro mldp:root-address    inet:ipv4-address
                            +--ro mldp:is-self?        boolean
                            +--ro mldp:reachability* [address interface]
                               +--ro mldp:address      inet:ipv4-address
                               +--ro mldp:interface    if:interface-ref
                               +--ro mldp:peer?        leafref


                         Figure 6: Root state tree

6.2.  Bindings State

   Binding state provides information on mLDP FEC-label bindings for
   both the P2MP and MP2MP FEC types.  The state includes both the
   inbound (received) and the outbound (advertised) bindings.  Like LDP,
   the state of FEC-label binding is presented per address-family in a
   FEC-centric view per address-family.  An mLDP FEC is presented as
   (root-address, opaque-element-data) tuple as described earlier in
   Section 3, alongwith its direction (upstream or downstream) as picked
   with respect to the root reachability.  The role of a given peer
   binding is also provided in case of MBB (as active or standby) and/or
   MoFRR (as primary or backup).

   The following example illustrates a FEC-label binding database on a
   branch/transit LSR for both P2MP and MP2MP FECs of Transit Source
   type:





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        Transit IPv4 Source:

           FEC (root 203.0.113.1, S=198.51.100.1, G=224.1.1.1):
             type: p2mp
             upstream:
               advertised:
                 peer 192.0.2.1:0, label 16000 (local)
             downstream:
               received:
                 peer 192.0.2.2:0, label 17000 (remote)
                 peer 192.0.2.3:0, label 18000  (remote)


           FEC (root 203.0.113.1, S=198.51.100.2, G=224.1.1.1):
             type: mp2mp
             upstream:
               advertised:
                 peer 192.0.2.1:0, label 26000 (local)
               received:
                 peer 192.0.2.1:0, label 27000 (remote)
             downstream:
               advertised:
                 peer 192.0.2.2:0, label 26001 (local), MBB role=active
                 peer 192.0.2.3:0, label 26002 (local), MBB role=standby
               received:
                 peer 192.0.2.2:0, label 27001 (remote)
                 peer 192.0.2.3:0, label 28001 (remote)


        Transit IPv6 Source:

           FEC (root 203.0.113.1, S=2001:db8:0:9::1, G=ff39:1::1):
             type: p2mp
             upstream:
               advertised:
                 peer 192.0.2.1:0, label 16100 (local)
             downstream:
               received:
                 peer 192.0.2.2:0, label 17100 (remote)
                 peer 192.0.2.3:0, label 18100  (remote)


           FEC (root 203.0.113.1, S=2001:db8:0:9::2, G=ff39:1::1):
             type: mp2mp
             upstream:
               advertised:
                 peer 192.0.2.1:0, label 26100 (local)
               received:



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                 peer 192.0.2.1:0, label 27100 (remote)
             downstream:
               advertised:
                 peer 192.0.2.2:0, label 26101 (local), MBB role=active
                 peer 192.0.2.3:0, label 26102 (local), MBB role=standby
               received:
                 peer 192.0.2.2:0, label 27101 (remote)
                 peer 192.0.2.3:0, label 28101 (remote)


                    Figure 7: Example Binding database

   The following captures the high-level tree hierarchy for mLDP
   bindings state.  The tree shown below is for ipv4 root only; a
   similar tree exists for ipv6 root as well.



   +--rw mpls-ldp
       +--rw global
          +--rw mldp:mldp
             +--rw mldp:address-families
                +--rw mldp:ipv4!
                      +--ro mldp:root* [root-address]
                         +--ro mldp:root-address    inet:ipv4-address
                         +--ro mldp:bindings
                            +--ro mldp:opaque-element-xxx
                            |  +--ro mldp:fec-label* [key1 key2 ...]
                            |     +--ro mldp:key1
                            |     +--ro mldp:key2
                            |     +--ro mldp:...
                            |     +--ro mldp:multipoint-type? multipoint-type
                            |     +--ro mldp:peer* [direction peer advertisement-type]
                            |        +--ro mldp:peer      leafref
                            |        +--ro mldp:direction ldp:downstream-upstream
                            |        +--ro mldp:advertisement-type ldp:advertised-received
                            |        +--ro mldp:label? rt-types:mpls-label
                            |        +--ro mldp:mbb-role? enumeration
                            |        +--ro mldp-ext:mofrr-role? mofrr-role
                            +--ro mldp:opaque-element-yyy
                              +--ro mldp:fec-label* [keya keyb ...]
                                  +--ro mldp: . . .


               Figure 8: Binding state tree (ipv4 root)






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   mLDP binding state is organized and presented per root address;
   hence, the bindings container is under a root node in the model.  The
   bindings state is made available for FECs pertaining to different
   types of opaque elements, with some state avaiable under the "base"
   tree and the rest under the "extended" tree.

   In the above tree, the various opaque types along with their type
   specific key(s) refer to the table Table 1 as captured earlier in the
   document.  For example, if the opaque type is a Generic LSP
   Identifier, then the type-specific-key will be a uint32 LSP-Id key.
   Please see the complete model for all other types.

   It is worth higlighting that:

   *  The address-family ipv4/ipv6 applies to "root" address in the mLDP
      binding tree.  The other addresses (source, group, Rendezvous-
      Point etc.) do not have to be of the same address family type as
      the root.

   *  In case of a recursive FECs, the "recur-root-address" field is
      applicable.  In case of VPN-Recursive type, "recur-rd" field is
      also applicable.

6.3.  Capabilities State

   Like LDP, mLDP capabilities state comprises two types of information:

   *  global: augments ldp:global/ldp:capability

   *  per-peer: augments ldp:peers/ldp:peer/ldp:capability

   The following tree captures the high-level tree hierarchy for mLDP
   capabilities state.


















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       +--rw mpls-ldp
          +--rw global
          |  +--rw capability
          |  |  +--rw mldp:mldp
          |  |     +--rw mldp:p2mp
          |  |     |  +--rw mldp:enabled?   boolean
          |  |     +--rw mldp:mp2mp
          |  |     |  +--rw mldp:enabled?   boolean
          |  |     +--rw mldp:make-before-break
          |  |     |  +--rw mldp:enabled?            boolean
          |  |     |  +--rw mldp:switchover-delay?   uint16
          |  |     |  +--rw mldp:timeout?            uint16
          |  |     +--rw mldp-ext:hub-and-spoke {capability-mldp-hsmp}?
          |  |     |  +--rw mldp-ext:enabled?   boolean
          |  |     +--rw mldp-ext:node-protection
          |  |             {capability-mldp-node-protection}?
          |  |        +--rw mldp-ext:plr?           boolean
          |  |        +--rw mldp-ext:merge-point
          |  |           +--rw mldp-ext:enabled?
          |  |           |       boolean
          |  |           +--rw mldp-ext:targeted-session-teardown-delay?
          |  |                   uint16
          |  . . .
          |  . . .
          +--rw peers
             +--rw peer* [lsr-id label-space-id]
                +--rw lsr-id                         rt-types:router-id
                +--rw label-space-id                 uint16
                +--rw address-families
                +--ro received-peer-state
                   +--ro capability
                      +--ro mldp:mldp
                         +--ro mldp:p2mp
                         |  +--ro mldp:enabled?   boolean
                         +--ro mldp:mp2mp
                         |  +--ro mldp:enabled?   boolean
                         +--ro mldp:make-before-break
                         |  +--ro mldp:enabled?   boolean
                         +--ro mldp-ext:hub-and-spoke
                         |  +--ro mldp-ext:enabled?   boolean
                         +--ro mldp-ext:node-protection
                            +--ro mldp-ext:plr?           boolean
                            +--ro mldp-ext:merge-point?   boolean


                      Figure 9: Capabilites state tree





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7.  Notifications

   The mLDP notification model consists of notifications related to
   changes in the operational state of an mLDP FEC.  The "base" mLDP
   data model includes only the "Generic LSP Identifier" opaque FEC type
   (for ipv4), while rest of the FEC types are covered by the "extended"
   mLDP model.

   A simplified graphical representation of the data model for mLDP
   notifications is shown in Figure 2.

8.  Actions

   Currently, no RPCs/actions are defined for mLDP.

9.  YANG Specification

   The following sections specify the actual YANG (module) specification
   for mLDP constructs defined earlier in the document.

9.1.  Base

   This YANG module imports types defined in [RFC6991], [RFC8343],
   [RFC8349], [I-D.ietf-mpls-ldp-yang], and [RFC8294].



   <CODE BEGINS> file "ietf-mpls-mldp@2021-11-11.yang"

   // RFC Editor: replace the above date with the date of
   // publication and remove this note.

   module ietf-mpls-mldp {
     yang-version 1.1;

     namespace "urn:ietf:params:xml:ns:yang:ietf-mpls-mldp";
     prefix "mldp";

     import ietf-inet-types {
       prefix "inet";
       reference "RFC 6991: Common YANG Data Types";
     }

     import ietf-interfaces {
       prefix "if";
       reference "RFC 8343: A YANG Data Model for Interface Management";
     }




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     import ietf-mpls-ldp {
       prefix "ldp";
       reference "RFC XXXX: A YANG Data Model for MPLS LDP";
   // RFC Editor: replace the XXXX with actual LDP YANG RFC number at
   // time of publication and remove this note.
     }

     import ietf-routing {
       prefix "rt";
       reference
         "RFC 8349: A YANG Data Model for Routing Management (NMDA
          version)";
     }

     import ietf-routing-types {
       prefix "rt-types";
       reference
         "RFC 8294: Common YANG Data Types for the Routing Area";
     }

     organization
       "IETF MPLS Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/mpls/>
        WG List:  <mailto:mpls@ietf.org>

        Editor:   Kamran Raza
                  <mailto:skraza@cisco.com>

        Editor:   Sowmya Krishnaswamy
                  <mailto:krishnaswamy.sowmya@gmail.com>

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

        Editor:   Santosh Esale
                  <mailto:santosh_easale@berkeley.edu>

        Editor:   Loa Andersson
                  <mailto:loa@pi.nu>

        Editor:   Jeff Tantsura
                  <mailto:jefftant.ietf@gmail.com>";

     description
       "This YANG module defines the essential components for the
        management of Multiprotocol Label Switching (MPLS) Multipoint
        LDP (mLDP).



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        Copyright (c) 2021 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 XXXX; see the
        RFC itself for full legal notices.";

        // RFC Editor: replace XXXX with actual RFC number and remove
        // this note

     revision 2021-11-11 {
       // RFC Editor: replace the above date 2021-11-11 with the date of
       // publication and remove this note.

       description
         "Initial revision.";
       reference
         "RFC XXXX: Base YANG Data Model for MPLS mLDP";
        // RFC Editor: replace XXXX with actual RFC number and remove
        // this note
     }

     /*
      * Typedefs
      */
     typedef multipoint-type {
       type enumeration {
         enum p2mp {
           description "Point to multipoint";
         }
         enum mp2mp {
           description "Multipoint to multipoint";
         }
       }
       description
         "The type of a multipoint LSP: either Point to multipoint
          (p2mp) or Multipoint to multipoint (mp2mp)";
     }

     /*
      * Groupings
      */



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     grouping mldp-capabilities {
       description
         "A grouping describing the protocol capabilities of mLDP";
       container p2mp {
         description
           "Configuration and state information for the
            point-to-multipoint capability";
         leaf enabled {
           type boolean;
           description
             "'true' to enable the point-to-multipoint capability";
         }
       }
       container mp2mp {
         description
           "Configuration and state information for the
            multipoint-to-multipoint capability";
         leaf enabled {
           type boolean;
           description
             "'true' to enable the multipoint-to-multipoint capability";
         }
       }
       container make-before-break {
         description
           "Configuration and state information for the
            make-before-break capability.";
         leaf enabled {
           type boolean;
           description
             "'true' to enable the make-before-break capability";
         }
         leaf switchover-delay {
           type uint16;
           units seconds;
           description
             "Switchover delay in seconds";
         }
         leaf timeout {
           type uint16;
           units seconds;
           description
             "Timeout in seconds";
         }
       }
     } // mldp-capabilities

     grouping  mldp-binding-label-peer-state-attributes {



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       description
         "mLDP label binding per peer attributes";
       leaf direction {
         type ldp:downstream-upstream;
         description
           "Downstream or upstream";
       }
       leaf advertisement-type {
         type ldp:advertised-received;
         description
           "Advertised or received";
       }
       leaf label {
         type rt-types:mpls-label;
         description
           "Advertised (outbound) or received (inbound) label";
       }
       leaf mbb-role {
         when "../direction = 'upstream'" {
           description
             "This leaf is used for upstream only.";
         }
         type enumeration {
           enum none {
             description "Make-Before-Break (MBB) is not enabled";
           }
           enum active {
             description "This LSP is active.";
           }
           enum inactive {
             description "This LSP is inactive.";
           }
         }
         description
           "The MBB status of this LSP";
       }
     } // mldp-binding-label-peer-state-attributes

     grouping  mldp-binding-label-state-attributes {
       description
         "mLDP label binding attributes";
       list peer {
         key "direction peer advertisement-type";
         description
           "List of advertised and received peers";
         leaf peer {
           type leafref {
             path



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               "../../../../../../../../../../../ldp:peers/ldp:peer/"
             + "ldp:lsr-id";
           }
           description
             "LDP peer from which this binding is received,
            or to which this binding is advertised.";
         }
         uses mldp-binding-label-peer-state-attributes;
       } // peer
     } // mldp-binding-label-state-attributes

     /*
      * Configuration data and operational state data nodes
      */
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
       + "ldp:capability" {
       description "Augmentation for MLDP global capability";
       container mldp {
         description
           "This container contains the configruation and state
            information for multipoint LDP capabilities.";
         uses mldp-capabilities;
       }
     }

     /*
      * Operational state data nodes
      */
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/ldp:peer/"
       + "ldp:received-peer-state/ldp:capability" {
       description
         "Augmentation for MLDP received peer state capability";
       container mldp {
         description
           "Operational state information for the protocol capabilities
            of mLDP";

         container p2mp {
           description
             "Operational state information for the point-to-multipoint
              capability";
           leaf enabled {
             type boolean;
             description
               "'true' to enable the point-to-multipoint capability";
           }



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         }
         container mp2mp {
           description
             "Operational state information for the
              multipoint-to-multipoint capability";
           leaf enabled {
             type boolean;
             description
               "'true' to enable the multipoint-to-multipoint
                capability";
           }
         }
         container make-before-break {
           description
             "Operational state information for the make-before-break
              capability";
           leaf enabled {
             type boolean;
             description
               "'true' to enable the make-before-break capability";
           }
         }
       } // mldp
     }

     /*
      * Global augmentation
      */
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global" {
       description "MLDP global augmentation.";
       container mldp {
         description
           "mLDP attributes at per instance level. Defining
            attributes here does not enable any MP capabilities.
            MP capabilities need to be explicitly enabled under
            container capability.";

         leaf enabled {
           type boolean;
           description
             "'true' to enable mLDP";
         }

         container address-families {
           description
             "Per address family parameters";




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           container ipv4 {
             presence
               "Present if IPv4 is enabled.";
             description
                 "IPv4 information";
             container roots {
               config false;
               description
                 "IPv4 multicast LSP roots";
               list root {
                 key "root-address";
                 description
                   "List of roots for configured multicast LSPs";

                 leaf root-address {
                   type inet:ipv4-address;
                   description
                     "Root address.";
                 }

                 leaf is-self {
                   type boolean;
                   description
                     "I am the root node.";
                 }

                 list reachability {
                   key "address interface";
                   description
                     "A next-hop for reachability to root,
                      as a RIB view";
                   leaf address {
                     type inet:ipv4-address;
                     description
                       "The next-hop address to reach root";
                   }
                   leaf interface {
                     type if:interface-ref;
                     description
                       "Interface connecting to next-hop";
                   }
                   leaf peer {
                     type leafref {
                       path
                         "../../../../../../../../ldp:peers/"
                         + "ldp:peer/ldp:lsr-id";
                     }
                     description



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                       "LDP peer from which this next-hop can be
                        reached";
                   }
                 }

                 container bindings {
                   description
                     "mLDP FEC to label bindings";
                   container opaque-element-lspid {
                     description
                       "The type of opaque value element is the generic
                        LSP identifier";
                     reference
                       "RFC6388: Label Distribution Protocol
                        Extensions for Point-to-Multipoint and
                        Multipoint-to-Multipoint Label Switched
                        Paths.";
                     list fec-label {
                       key
                         "lsp-id";
                       description
                         "List of FEC to label bindings";
                       leaf lsp-id {
                         type uint32;
                         description "ID to identify the LSP";
                       }
                       leaf multipoint-type {
                         type multipoint-type;
                         description
                           "The type of mutipoint: p2mp or mp2mp";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-element-lspid
                 } // bindings
               } // list root
             } // roots

             container configured-leaf-lsps {
               description
                 "Configured multicast LSPs.";
               container opaque-element-lspid {
                 description
                   "The type of opaque value element is
                    the generic LSP identifier";
                 reference
                   "RFC6388: Label Distribution Protocol
                    Extensions for Point-to-Multipoint and



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                    Multipoint-to-Multipoint Label Switched
                    Paths.";
                 list fec-label {
                   key
                     "root-address lsp-id";
                   description
                     "List of FEC to label bindings.";
                   leaf root-address {
                     type inet:ipv4-address;
                     description
                       "Root address";
                   }
                   leaf lsp-id {
                     type uint32;
                     description "ID to identify the LSP";
                   }
                   leaf multipoint-type {
                     type multipoint-type;
                     description
                       "The type of mutipoint: p2mp or mp2mp";
                   }
                 } // fec-label
               } // opaque-element-lspid
             } // configured-leaf-lsps
           } // ipv4
         } // list address-family
       } // mldp
     }

     /*
      * Notifications
      */
     notification mpls-mldp-fec-event {
       description
         "Notification event for a change of FEC status";
       leaf event-type {
         type ldp:oper-status-event-type;
         description "Event type";
       }
       choice opaque-element {
         description
           "The type of opaque value element";
         case opaque-element-lspid {
           container opaque-element-lspid {
             description
               "The type of opaque value element is
                the generic LSP identifier";
             reference



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               "RFC6388: Label Distribution Protocol
                Extensions for Point-to-Multipoint and
                Multipoint-to-Multipoint Label Switched
                Paths.";
             leaf root-address {
               type inet:ip-address;
               description
                 "Root address.";
             }
             leaf lsp-id {
               type uint32;
               description "ID to identify the LSP";
             }
             leaf multipoint-type {
               type multipoint-type;
               description
                 "The type of mutipoint: p2mp or mp2mp";
             }
           } // container opaque-element-lspid
         }
       }
     }
   }

   <CODE ENDS>


                        Figure 10: mLDP base module

9.2.  Extended

   This YANG module imports types defined in [RFC6991], [RFC8343],
   [RFC8349], [I-D.ietf-mpls-ldp-yang], and [RFC8294].



   <CODE BEGINS> file "ietf-mpls-mldp-extended@2021-11-11.yang"

   // RFC Editor: replace the above date with the date of
   // publication and remove this note.

   module ietf-mpls-mldp-extended {
     yang-version 1.1;

     namespace "urn:ietf:params:xml:ns:yang:ietf-mpls-mldp-extended";
     prefix "mldp-ext";

     import ietf-inet-types {



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       prefix "inet";
       reference "RFC 6991: Common YANG Data Types";
     }

     import ietf-interfaces {
       prefix "if";
       reference "RFC 8343: A YANG Data Model for Interface Management";
     }

     import ietf-routing {
       prefix "rt";
       reference
         "RFC 8349: A YANG Data Model for Routing Management (NMDA
          version)";
     }

     import ietf-routing-types {
       prefix "rt-types";
       reference
         "RFC 8294: Common YANG Data Types for the Routing Area";
     }

     import ietf-mpls-ldp {
       prefix "ldp";
       reference "RFC XXXX: A YANG Data Model for MPLS LDP";
   // RFC Editor: replace the XXXX with actual LDP YANG RFC number at
   // time of publication and remove this note.
     }

     import ietf-mpls-ldp-extended {
       prefix "ldp-ext";
      reference "RFC XXXX: A YANG Data Model for MPLS LDP";
   // RFC Editor: replace the XXXX with actual LDP YANG RFC number at
   // time of publication and remove this note.
     }
     import ietf-mpls-mldp {
       prefix "mldp";
      reference "RFC XXXX: Base YANG Data Model for MPLS mLDP";
   // RFC Editor: replace the XXXX with actual mLDP YANG RFC number at
   // time of publication and remove this note.
     }

     organization
       "IETF MPLS Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/mpls/>
        WG List:  <mailto:mpls@ietf.org>




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        Editor:   Kamran Raza
                  <mailto:skraza@cisco.com>

        Editor:   Sowmya Krishnaswamy
                  <mailto:krishnaswamy.sowmya@gmail.com>

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

        Editor:   Santosh Esale
                  <mailto:santosh_easale@berkeley.edu>

        Editor:   Loa Andersson
                  <mailto:loa@pi.nu>

        Editor:   Jeff Tantsura
                  <mailto:jefftant.ietf@gmail.com>";

     description
       "This YANG module defines the extended components for the
        management of Multiprotocol Label Switching (MPLS) Multipoint
        LDP (mLDP).

        Copyright (c) 2021 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 XXXX; see the
        RFC itself for full legal notices.";

        // RFC Editor: replace XXXX with actual RFC number and remove
        // this note

     revision 2021-11-11 {
       // RFC Editor: replace the above date 2021-11-11 with the date of
       // publication and remove this note.

       description
         "Initial revision.";
       reference
         "RFC XXXX: Extended YANG Data Model for MPLS mLDP";
        // RFC Editor: replace XXXX with actual RFC number and remove



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        // this note
     }

     /*
      * Features
      */
     feature capability-mldp-hsmp {
       description
         "This feature indicates that the system allows to configure
          mLDP hub-and-spoke-multipoint capability.";
     }

     feature capability-mldp-node-protection {
       description
         "This feature indicates that the system allows to configure
          mLDP node-protection capability.";
     }

     feature mldp-mofrr {
       description
         "This feature indicates that the system supports mLDP
          Multicast only FRR (MoFRR).";
     }

     feature per-peer-capability {
       description
         "This feature indicates that the system allows to configure
          mLDP capabilities at the per peer level.";
     }

     /*
      * Typedefs
      */
     typedef mofrr-role {
       type enumeration {
         enum none {
           description "MOFRR is not enabled.";
         }
         enum primary {
           description "This LSP is primary.";
         }
         enum backup {
           description "This LSP is backup.";
         }
       }
       description
         "This type represents the MOFRR (Multicast only FRR) role
          status of a LSP.";



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     }

     /*
      * Groupings
      */
     grouping  mldp-ext-binding-label-peer-state {
       description
         "mLDP label binding peer state.";

       list peer {
         key "direction peer advertisement-type";
         description
           "List of advertised and received peers";
         leaf peer {
           type leafref {
             path
               "../../../../../../../../../../../ldp:peers/ldp:peer/"
             + "ldp:lsr-id";
           }
           description
             "LDP peer from which this binding is received,
              or to which this binding is advertised.";
         }
         uses mldp:mldp-binding-label-peer-state-attributes;

         leaf mofrr-role {
           when "../direction = 'upstream'" {
             description
               "For upstream.";
           }
           type mofrr-role;
           description
             "The MOFRR status of this LSP";
         }
       } // peer
     } // mldp-ext-binding-label-peer-state

     grouping  mldp-ext-binding-label-recursive-fec-peer-state {
       description
         "mLDP label binding peer state for recursive FECs.";

       list peer {
         key "direction peer advertisement-type";
         description
           "List of advertised and received peers";
         leaf peer {
           type leafref {
             path



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               "../../../../../../../../../../../../ldp:peers/ldp:peer/"
             + "ldp:lsr-id";
           }
           description
             "LDP peer from which this binding is received,
              or to which this binding is advertised.";
         }
         uses mldp:mldp-binding-label-peer-state-attributes;

         leaf mofrr-role {
           when "../direction = 'upstream'" {
             description
               "For upstream.";
           }
           type mofrr-role;
           description
             "The MOFRR status of this LSP";
         }
       } // peer
     } // mldp-ext-binding-label-recursive-fec-peer-state

     grouping mldp-ext-capabilities {
       description
         "mLDP extended capabilities";
       container hub-and-spoke {
         if-feature capability-mldp-hsmp;
         description
           "Configure hub-and-spoke-multipoint capability";
         reference
           "RFC7140: LDP Extensions for Hub and Spoke Multipoint
            Label Switched Path";
         leaf enabled {
           type boolean;
           description
             "Enable hub-and-spoke-multipoint";
         }
       }
       container node-protection {
         if-feature capability-mldp-node-protection;
         description
           "Configure node-protection capability.";
         reference
           "RFC7715: mLDP Node Protection.";
         leaf plr {
           type boolean;
           description
             "Point of Local Repair (PLR) capable for Multipoimt LSP
              node protection";



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         }
         container merge-point {
           description
             "Merge Point capable for Multipoint LSP node protection";
           leaf enabled {
             type boolean;
             description
               "Enable merge point capability";
           }
           leaf targeted-session-teardown-delay {
             type uint16;
             units seconds;
             description
               "Targeted session teardown delay";
           }
         } // merge-point
       }
     } // mldp-ext-capabilities

     grouping mldp-ext-per-af-config-attibutes {
       description
         "mLDP per address family configuration attibutes";
       container multicast-only-frr {
         if-feature mldp-mofrr;
         description
           "Multicast-only FRR (MoFRR) policy";
         leaf prefix-list {
           type ldp-ext:prefix-list-ref;
           description
             "Enables Multicast-only FRR (MoFRR) for the specified
              access list";
         }
       } // multicast-only-frr
       container recursive-fec {
         description
           "Recursive FEC policy";
         leaf prefix-list {
           type ldp-ext:prefix-list-ref;
           description
             "Enables recursive FEC for the specified prefix-list";
         }
       } // recursive-fec
     } // mldp-ext-per-af-config-attibutes

     grouping recursive-fec-attibutes {
       description
         "mLDP recursive FEC attibutes.";
       leaf recur-root-address {



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         type inet:ip-address;
         description
           "Recursive root address";
         reference
           "RFC6512: Using Multipoint LDP When the
            Backbone Has No Route to the Root";
       }
       leaf recur-rd {
         type rt-types:route-distinguisher;
         description
           "Route Distinguisher in the VPN-Recursive
            Opaque Value";
         reference
           "RFC6512: Using Multipoint LDP When the
            Backbone Has No Route to the Root";
       }
       leaf multipoint-type {
         type mldp:multipoint-type;
         description
           "The type of mutipoint: p2mp or mp2mp";
       }
     } // recursive-fec-attibutes

     /*
      * Configuration data and operational state data nodes
      */
     // Global capability
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
       + "ldp:capability/mldp:mldp" {
       description "Augmentation for MLDP global capability.";

       uses mldp-ext-capabilities;
     }

     /* TODO: FIXME
     // Peer capability
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/ldp:peer/"
       + "ldp:capability" {
       description "Augmentation for MLDP peer capability.";
       container mldp {
         if-feature per-peer-capability;
         description
           "mLDP capabilities";
         uses mldp:mldp-capabilities;
       }
     } */



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     // IPv4 config
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4" {
       description "Augmentation for MLDP IPv4 configuration";
       uses mldp-ext-per-af-config-attibutes;
     }

     // IPv4 configured-leaf-lsps config
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4/mldp:configured-leaf-lsps/"
       + "mldp:opaque-element-lspid/mldp:fec-label" {
       description
         "Augmentation for MLDP IPv4 configured-leaf-lsps
          configuration for opaque-element-lspid";
       list recursive-fec {
         key
           "recur-root-address recur-rd";
         description
           "List of recursive opaque values";
         uses recursive-fec-attibutes;
       } // fec-label
     }

     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4/mldp:configured-leaf-lsps" {
       description
         "Augmentation for MLDP IPv4 configured-leaf-lsps
          configuration";

       container opaque-element-transit {
         description
           "The type of opaque value element is the transit IPv4
            source.";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched Paths.";
         list fec-label {
           key
             "root-address source-address group-address " +
             "rd recur-root-address recur-rd";
           description
             "List of FEC to label bindings";
           leaf root-address {
             type inet:ipv4-address;



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             description
               "Root address";
           }
           leaf source-address {
             type inet:ip-address;
             description
               "Source address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
         } // fec-label
       } // opaque-element-transit

       container opaque-element-bidir {
         description
           "The type of opaque value element is
            the generic LSP identifier";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched
            Paths.";
         list fec-label {
           key
             "root-address rp group-address rd recur-root-address "
           + "recur-rd";
           description
             "List of FEC to label bindings";
           leaf root-address {
             type inet:ipv4-address;
             description
               "Root address";
           }
           leaf rp {



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             type inet:ip-address;
             description
               "Rendezvous-Point (RP) address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
         } // fec-label
       } // opaque-element-bidir
     }

     // IPv6 config
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/ipv6" {
       description "Augmentation for MLDP IPv4 configuration";
       uses mldp-ext-per-af-config-attibutes;
     }

     // Global forwarding-nexthop
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
       + "ldp-ext:forwarding-nexthop/ldp-ext:interfaces/"
       + "ldp-ext:interface/ldp-ext:address-family" {
       description
         "Augmentation for MLDP nexthop forwarding interface";
       leaf mldp-disable {
         type boolean;
         description
           "Disable mLDP forwarding on this interface";
       }
     }

     /*
      * Operational state data nodes



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      */
     // IPv4 state for per peer bindings
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4/mldp:roots/mldp:root/"
       + "mldp:bindings/mldp:opaque-element-lspid/mldp:fec-label/"
       + "mldp:peer" {
       description "Augmentation for MLDP IPv4 state";

       leaf mofrr-role {
         when "../mldp:direction = 'upstream'" {
           description
             "For upstream";
         }
         type mofrr-role;
         description
           "The MOFRR status of this LSP";
       }
     }

     // Peer capability state
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/ldp:peer/"
       + "ldp:received-peer-state/ldp:capability/mldp:mldp" {
       description
         "Augmentation for MLDP received peer state capability.";
       container hub-and-spoke {
         description
           "Configure hub-and-spoke-multipoint capability.";
         reference
           "RFC7140: LDP Extensions for Hub and Spoke Multipoint
            Label Switched Path";
         leaf enabled {
           type boolean;
           description
             "Enable hub-and-spoke-multipoint";
         }
       }
       container node-protection {
         description
           "Configure node-protection capability";
         reference
           "RFC7715: mLDP Node Protection.";
         leaf plr {
           type boolean;
           description
             "Point of Local Repair (PLR) capable for Multipoint LSP
              node protection";



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         }
         leaf merge-point {
           type boolean;
           description
             "Merge Point capable for Multipoint LSP node protection";
         } // merge-point
       } // node-protection
     }

     // IPv4 bindings state
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4/mldp:roots/mldp:root/"
       + "mldp:bindings" {
       description "Augmentation for MLDP IPv4 bindings.";
       container opaque-element-transit {
         description
           "The type of opaque value element is the transit IPv4
            source.";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched Paths.";
         list fec-label {
           key
             "source-address group-address "
           + "rd recur-root-address recur-rd";
           description
             "List of FEC to label bindings";
           leaf source-address {
             type inet:ip-address;
             description
               "Source address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";



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           }
           uses recursive-fec-attibutes;
           uses mldp-ext-binding-label-peer-state;
         } // fec-label
       } // opaque-element-transit

       container opaque-element-bidir {
         description
           "The type of opaque value element is
            the generic LSP identifier.";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched
            Paths.";
         list fec-label {
           key
             "rp group-address rd recur-root-address recur-rd";
           description
             "List of FEC to label bindings";
           leaf rp {
             type inet:ip-address;
             description
               "Rendezvous Point (RP) address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
           uses mldp-ext-binding-label-peer-state;
         } // fec-label
       } // opaque-element-bidir
     }

     // IPv6 bindings state
     augment "/rt:routing/rt:control-plane-protocols/"



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       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/ipv6/roots/root/bindings" {
       description "Augmentation for MLDP IPv6 bindings.";
       container opaque-element-transit {
         config false;
         description
           "The type of opaque value element is the transit IPv6
            source.";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched
            Paths.";
         list fec-label {
           key
             "source-address group-address "
           + "rd recur-root-address recur-rd";
           description
             "List of FEC to label bindings";
           leaf source-address {
             type inet:ip-address;
             description
               "Source address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
           uses mldp-ext-binding-label-peer-state;
         } // fec-label
       } // opaque-element-transit

       container opaque-element-bidir {
         config false;
         description
           "The type of opaque value element is



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            the generic LSP identifier";
         reference
           "RFC6826: Multipoint LDP In-Band Signaling for
            Point-to-Multipoint and
            Multipoint-to-Multipoint Label Switched
            Paths.";
         list fec-label {
           key
             "rp group-address rd recur-root-address recur-rd";
           description
             "List of FEC to label bindings";
           leaf rp {
             type inet:ip-address;
             description
               "Rendezvous Point (RP) address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
           uses mldp-ext-binding-label-peer-state;
         } // fec-label
       } // opaque-element-bidir
     }

     // IPv4 bindings opaque-element-lspid state
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/mldp:ipv4/mldp:roots/mldp:root/"
       + "mldp:bindings/mldp:opaque-element-lspid/mldp:fec-label" {
       description
         "Augmentation for MLDP IPv4 bindings with opaque type LSP ID.";
       list recursive-fec {
         key
           "recur-root-address recur-rd";
         description



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           "List of recursive opaque values";
         uses recursive-fec-attibutes;
         uses mldp-ext-binding-label-recursive-fec-peer-state;
       } // fec-label
     }

     // IPv6 bindings opaque-element-lspid state
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families/ipv6/roots/root/bindings/"
       + "opaque-element-lspid/fec-label" {
       description
         "Augmentation for MLDP IPv6 bindings with opaque type LSP ID.";
       list recursive-fec {
         key "recur-root-address recur-rd";
         config false;
         description
           "List of recursive opaque values";
         uses recursive-fec-attibutes;
         uses mldp-ext-binding-label-recursive-fec-peer-state;
       } // fec-label
     }

     /*
      * Per AF augmentation
      */
     // IPv6 augmentation
     augment "/rt:routing/rt:control-plane-protocols/"
       + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/mldp:mldp/"
       + "mldp:address-families" {
       description "Augmentation for MLDP IPv6 address family.";
       container ipv6 {
         presence
           "Present if IPv6 is enabled.";
         description
           "IPv6 information";

         container roots {
           config false;
           description
             "IPv6 multicast LSP roots";
           list root {
             key "root-address";
             description
               "List of roots for configured multicast LSPs";

             leaf root-address {
               type inet:ipv6-address;



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               description
                 "Root address";
             }

             leaf is-self {
               type boolean;
               description
                 "This is the root";
             }

             list reachability {
               key "address interface";
               description
                 "A next-hop for reachability to root,
                  as a RIB view";
               leaf address {
                 type inet:ipv6-address;
                 description
                   "The next-hop address to reach root";
               }
               leaf interface {
                 type if:interface-ref;
                 description
                   "Interface connecting to next-hop";
               }
               leaf peer {
                 type leafref {
                   path
                     "../../../../../../../../ldp:peers/"
                     + "ldp:peer/ldp:lsr-id";
                 }
                 description
                   "LDP peer from which this next-hop can be
                    reached";
               }
             }

             container bindings {
               description
                 "mLDP FEC to label bindings";
               container opaque-element-lspid {
                 description
                   "The type of opaque value element is
                    the generic LSP identifier";
                 reference
                   "RFC6388: Label Distribution Protocol
                    Extensions for Point-to-Multipoint and
                    Multipoint-to-Multipoint Label Switched



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                    Paths.";
                 list fec-label {
                   key
                     "lsp-id";
                   description
                     "List of FEC to label bindings";
                   leaf lsp-id {
                     type uint32;
                     description "ID to identify the LSP";
                   }
                   leaf multipoint-type {
                     type mldp:multipoint-type;
                     description
                       "The type of mutipoint: p2mp or mp2mp";
                   }

                   uses mldp-ext-binding-label-peer-state;
                 } // fec-label
               } // opaque-element-lspid
             } // bindings
           } // list root
         } // roots

         container configured-leaf-lsps {
           description
             "Configured multicast LSPs";

           container opaque-element-lspid {
             description
               "The type of opaque value element is
                the generic LSP identifier";
             reference
               "RFC6388: Label Distribution Protocol
                Extensions for Point-to-Multipoint and
                Multipoint-to-Multipoint Label Switched
                Paths.";
             list fec-label {
               key
                 "root-address lsp-id";
               description
                 "List of FEC to label bindings";
               leaf root-address {
                 type inet:ipv6-address;
                 description
                   "Root address";
               }
               leaf lsp-id {
                 type uint32;



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                 description "ID to identify the LSP";
               }
               leaf multipoint-type {
                 type mldp:multipoint-type;
                 description
                   "The type of mutipoint: p2mp or mp2mp";
               }
               list recursive-fec {
                 key
                   "recur-root-address recur-rd";
                 description
                   "List of recursive opaque values";
                 uses recursive-fec-attibutes;
               } // fec-label
             } // fec-label
           } // opaque-element-lspid

           container opaque-element-transit {
             description
               "The type of opaque value element is the transit IPv4
                source.";
             reference
               "RFC6826: Multipoint LDP In-Band Signaling for
                Point-to-Multipoint and
                Multipoint-to-Multipoint Label Switched Paths.";
             list fec-label {
               key
                 "root-address source-address group-address "
                 + "rd recur-root-address recur-rd";
               description
                 "List of FEC to label bindings";
               leaf root-address {
                 type inet:ipv6-address;
                 description
                   "Root address";
               }
               leaf source-address {
                 type inet:ip-address;
                 description
                   "Source address";
               }
               leaf group-address {
                 type inet:ip-address-no-zone;
                 description
                   "Group address";
               }
               leaf rd {
                 type rt-types:route-distinguisher;



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                 description
                   "Route Distinguisher";
                 reference
                   "RFC7246: Multipoint Label Distribution
                    Protocol In-Band Signaling in a Virtual
                    Routing and Forwarding (VRF) Table
                    Context.";
               }
               uses recursive-fec-attibutes;
             } // fec-label
           } // opaque-element-transit

           container opaque-element-bidir {
             description
               "The type of opaque value element is
                the generic LSP identifier";
             reference
               "RFC6826: Multipoint LDP In-Band Signaling for
                Point-to-Multipoint and
                Multipoint-to-Multipoint Label Switched
                Paths.";
             list fec-label {
               key
                 "root-address rp group-address rd recur-root-address "
               + "recur-rd";
               description
                 "List of FEC to label bindings.";
               leaf root-address {
                 type inet:ipv6-address;
                 description
                   "Root address";
               }
               leaf rp {
                 type inet:ip-address;
                 description
                   "Rendezvous Point (RP) address";
               }
               leaf group-address {
                 type inet:ip-address-no-zone;
                 description
                   "Group address";
               }
               leaf rd {
                 type rt-types:route-distinguisher;
                 description
                   "Route Distinguisher";
                 reference
                   "RFC7246: Multipoint Label Distribution



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                    Protocol In-Band Signaling in a Virtual
                    Routing and Forwarding (VRF) Table
                    Context.";
               }
               uses recursive-fec-attibutes;
             } // fec-label
           } // opaque-element-bidir
         } // configured-leaf-lsps
       } // ipv6
     }

     /*
      * Global augmentation
      */
     /*
      * Notifications
      */
     augment "/mldp:mpls-mldp-fec-event/mldp:opaque-element/"
       + "mldp:opaque-element-lspid/mldp:opaque-element-lspid" {
       description
         "Augmentation for MLDP notification for opaque-element-lspid.";
       container recursive-fec {
         description
           "Container of recursive opaque values";
         uses recursive-fec-attibutes;
       } // fec-label
     }

     augment "/mldp:mpls-mldp-fec-event/mldp:opaque-element" {
       description
         "Augmentation for MLDP notification.";
       case opaque-element-transit {
         container opaque-element-transit {
           description
             "The type of opaque value element is the transit IPv4
              source.";
           reference
             "RFC6826: Multipoint LDP In-Band Signaling for
              Point-to-Multipoint and
              Multipoint-to-Multipoint Label Switched Paths.";
           leaf root-address {
             type inet:ip-address;
             description
               "Root address";
           }
           leaf source-address {
             type inet:ip-address;
             description



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               "Source address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;
             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
         } // opaque-element-transit
       } // opaque-element-transit

       case opaque-element-bidir {
         container opaque-element-bidir {
           description
             "The type of opaque value element is
              the generic LSP identifier";
           reference
             "RFC6826: Multipoint LDP In-Band Signaling for
              Point-to-Multipoint and
              Multipoint-to-Multipoint Label Switched
              Paths.";
           leaf root-address {
             type inet:ip-address;
             description
               "Root address";
           }
           leaf rp {
             type inet:ip-address;
             description
               "Rendezvous Point (RP) address";
           }
           leaf group-address {
             type inet:ip-address-no-zone;
             description
               "Group address";
           }
           leaf rd {
             type rt-types:route-distinguisher;



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             description
               "Route Distinguisher";
             reference
               "RFC7246: Multipoint Label Distribution
                Protocol In-Band Signaling in a Virtual
                Routing and Forwarding (VRF) Table
                Context.";
           }
           uses recursive-fec-attibutes;
         } // opaque-element-bidir
       } // opaque-element-bidir
     }
   }

   <CODE ENDS>

                      Figure 11: mLDP extended module

10.  Security Considerations

   This specification also inherits the security considerations captured
   in [RFC5920] and mLDP protocol specification documents, namely base
   mLDP [RFC6388], targeted mLDP [RFC7060], mLDP Recursive FEC
   [RFC6512], Multicast-only FRR [RFC7431], mLDP Node Protection
   [RFC7715], mLDP In-band Signaling [RFC6826] [RFC7246] [RFC7438], and
   Hub-and-Spoke Multipoint LSPs [RFC7140].

10.1.  YANG Data Model

   The YANG modules specified in this document define 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.

   The following sub sections capture the security considerations with
   respect to mLDP data nodes defined in mLDP YANG modules.  This goes
   without saying that LDP data nodes security considerations, as
   captured in in LDP YANG specification [I-D.ietf-mpls-ldp-yang], apply
   orthogonally to mLDP as well.



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10.1.1.  Writable Nodes

   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.

   For mLDP, the ability to modify MPLS mLDP configuration may allow the
   entire MPLS mLDP domain to be compromised including forming LDP
   adjacencies and/or peer sessions with unauthorized routers to mount a
   massive Denial-of-Service (DoS) attack.

   In particular, the subtrees and data nodes that are sensitivite and
   vulnerable are same as captured in [I-D.ietf-mpls-ldp-yang] section
   10.1.1

10.1.2.  Readable Nodes

   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.  The following text lists the
   subtrees and data nodes alongwith their sensitivity/vulnerability:

   The exposure of mLDP databases (such as mLDP peers, mLDP Roots, mLDP
   FEC-Label bindings) as well LDP databases (such as hello adjacencies,
   TCP sessions, and address bindings) beyond the scope of the mLDP
   admin domain may be undesirable.  The relevant subtrees and data
   nodes for LDP are captured in [I-D.ietf-mpls-ldp-yang] section
   10.1.2, whereas the relevant subtrees and data nodes for mLDP are as
   follows:

   *  /mpls-ldp/global/mldp/address-families/ipv4/roots

   *  /mpls-ldp/global/mldp/address-families/ipv6/roots

   *  /mpls-ldp/global/mldp/address-families/ipv4/roots/root/bindings

   *  /mpls-ldp/global/mldp/address-families/ipv6/roots/root/bindings

   *  /mpls-ldp/peers/peer/received-peer-state/capability/mldp








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10.1.3.  Notifications

   The mLDP implementations must rate-limit the generation of mLDP
   notifications to avoid creating significant notification load and
   possible side effects on the system stability.

11.  IANA Considerations

   This document requests the registration of the following URIs in the
   IETF "XML registry" [RFC3688]:

   +====================================================+==========+===+
   |URI                                                 |Registrant|XML|
   +====================================================+==========+===+
   |urn:ietf:params:xml:ns:yang:ietf-mpls-mldp          |The IESG  |N/A|
   +----------------------------------------------------+----------+---+
   |urn:ietf:params:xml:ns:yang:ietf-mpls-mldp-extended |The IESG  |N/A|
   +----------------------------------------------------+----------+---+

                               Table 2: URIs

   This document requests the registration of the following YANG modules
   in the "YANG Module Names" registry [RFC6020]:

   +==========+===================================+========+===========+
   |Name      | Namespace                         |Prefix  | Reference |
   +==========+===================================+========+===========+
   |ietf-mpls-| urn:ietf:params:xml:ns:yang:ietf- |mldp    | This      |
   |mldp      | mpls-mldp                         |        | document  |
   +----------+-----------------------------------+--------+-----------+
   |ietf-mpls-| urn:ietf:params:xml:ns:yang:ietf- |mldp-ext| This      |
   |mldp-     | mpls-mldp-extended                |        | document  |
   |extended  |                                   |        |           |
   +----------+-----------------------------------+--------+-----------+

                           Table 3: YANG Modules

   -- RFC Editor: Replace "This document" with the document RFC number
   at time of publication, and remove this note.

12.  Normative References

   [I-D.ietf-mpls-ldp-yang]
              Raza, K., Asati, R., Liu, X., Esale, S., Chen, X., and H.
              Shah, "YANG Data Model for MPLS LDP", Work in Progress,
              Internet-Draft, draft-ietf-mpls-ldp-yang-09, 20 March
              2020, <https://datatracker.ietf.org/doc/html/draft-ietf-
              mpls-ldp-yang-09>.



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

   [RFC5920]  Fang, L., Ed., "Security Framework for MPLS and GMPLS
              Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
              <https://www.rfc-editor.org/info/rfc5920>.

   [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>.

   [RFC6388]  Wijnands, IJ., Ed., Minei, I., Ed., Kompella, K., and B.
              Thomas, "Label Distribution Protocol Extensions for Point-
              to-Multipoint and Multipoint-to-Multipoint Label Switched
              Paths", RFC 6388, DOI 10.17487/RFC6388, November 2011,
              <https://www.rfc-editor.org/info/rfc6388>.

   [RFC6389]  Aggarwal, R. and JL. Le Roux, "MPLS Upstream Label
              Assignment for LDP", RFC 6389, DOI 10.17487/RFC6389,
              November 2011, <https://www.rfc-editor.org/info/rfc6389>.

   [RFC6512]  Wijnands, IJ., Rosen, E., Napierala, M., and N. Leymann,
              "Using Multipoint LDP When the Backbone Has No Route to
              the Root", RFC 6512, DOI 10.17487/RFC6512, February 2012,
              <https://www.rfc-editor.org/info/rfc6512>.

   [RFC6826]  Wijnands, IJ., Ed., Eckert, T., Leymann, N., and M.
              Napierala, "Multipoint LDP In-Band Signaling for Point-to-
              Multipoint and Multipoint-to-Multipoint Label Switched
              Paths", RFC 6826, DOI 10.17487/RFC6826, January 2013,
              <https://www.rfc-editor.org/info/rfc6826>.

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





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   [RFC7060]  Napierala, M., Rosen, E., and IJ. Wijnands, "Using LDP
              Multipoint Extensions on Targeted LDP Sessions", RFC 7060,
              DOI 10.17487/RFC7060, November 2013,
              <https://www.rfc-editor.org/info/rfc7060>.

   [RFC7140]  Jin, L., Jounay, F., Wijnands, IJ., and N. Leymann, "LDP
              Extensions for Hub and Spoke Multipoint Label Switched
              Path", RFC 7140, DOI 10.17487/RFC7140, March 2014,
              <https://www.rfc-editor.org/info/rfc7140>.

   [RFC7246]  Wijnands, IJ., Ed., Hitchen, P., Leymann, N., Henderickx,
              W., Gulko, A., and J. Tantsura, "Multipoint Label
              Distribution Protocol In-Band Signaling in a Virtual
              Routing and Forwarding (VRF) Table Context", RFC 7246,
              DOI 10.17487/RFC7246, June 2014,
              <https://www.rfc-editor.org/info/rfc7246>.

   [RFC7431]  Karan, A., Filsfils, C., Wijnands, IJ., Ed., and B.
              Decraene, "Multicast-Only Fast Reroute", RFC 7431,
              DOI 10.17487/RFC7431, August 2015,
              <https://www.rfc-editor.org/info/rfc7431>.

   [RFC7438]  Wijnands, IJ., Ed., Rosen, E., Gulko, A., Joorde, U., and
              J. Tantsura, "Multipoint LDP (mLDP) In-Band Signaling with
              Wildcards", RFC 7438, DOI 10.17487/RFC7438, January 2015,
              <https://www.rfc-editor.org/info/rfc7438>.

   [RFC7715]  Wijnands, IJ., Ed., Raza, K., Atlas, A., Tantsura, J., and
              Q. Zhao, "Multipoint LDP (mLDP) Node Protection",
              RFC 7715, DOI 10.17487/RFC7715, January 2016,
              <https://www.rfc-editor.org/info/rfc7715>.

   [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>.

   [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>.

   [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>.







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   [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>.

   [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>.

   [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>.

   [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>.

13.  Informative References

   [RFC7473]  Raza, K. and S. Boutros, "Controlling State Advertisements
              of Non-negotiated LDP Applications", RFC 7473,
              DOI 10.17487/RFC7473, March 2015,
              <https://www.rfc-editor.org/info/rfc7473>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

Appendix A.  Data Tree Example

   This section contains an example of an instance data tree in the JSON
   encoding [RFC7951], containing both configuration and state data.








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                          lo0: 2001:db8:0:200::1 (Root Address)
                                    +-------+
                                |   | Router|   |
                          eth21 +---+  R2   +---+ eth23
                                |   | (Root)|   |
                                |   +-------+   | lo0: 2001:db8:0:300::1
                 |  +-------+   |               |   +-------+  |
                 |  | Router|   |               |   | Router|  |
           eth10 +--+  R1   +---+ eth12   eth32 +---+  R3   +--+ eth30
                 |  |       |   |               |   |       |  |
                 |  +-------+   |               |   +-------+  |
                          lo0: 2001:db8:0:200::1 (Root Address)


                                 Figure 12

   The configuration instance data tree for Router R3 in the above
   figure could be as follows:

   {
     "ietf-interfaces:interfaces": {
       "interface": [
         {
           "name": "lo0",
           "description": "R3 loopback interface.",
           "type": "iana-if-type:softwareLoopback",
           "ietf-ip:ipv6": {
             "address": [
               {
                 "ip": "2001:db8:0:300::1",
                 "prefix-length": 64
               }
             ]
           }
         },
         {
           "name": "eth30",
           "description": "An interface connected to client routers.",
           "type": "iana-if-type:ethernetCsmacd",
           "ietf-ip:ipv6": {
             "forwarding": true
           }
         },
         {
           "name": "eth32",
           "description": "An interface connected to root (R2).",
           "type": "iana-if-type:ethernetCsmacd",
           "ietf-ip:ipv6": {



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             "forwarding": true
           }
         }
       ]
     },
     "ietf-routing:routing": {
       "router-id": "203.0.113.3",
       "control-plane-protocols": {
         "ietf-mpls-ldp:mpls-ldp": {
           "global": {
             "address-families": {
               "ietf-mpls-ldp-extended:ipv6": {
                 "enable": true
               }
             },
             "capability": {
               "ietf-mpls-mldp:mldp": {
                 "mp2mp": {
                   "enable": true
                 }
               }
             },
             "ietf-mpls-mldp:mldp": {
               "enable": true,
               "address-families": {
                 "ietf-mpls-mldp-extended:ipv6": {
                   "configured-leaf-lsps": {
                     "opaque-element-lspid": {
                       "fec-label": [
                         {
                           "root-address": "2001:db8:0:200::1",
                           "lsp-id": 201,
                           "multipoint-type": "mp2mp"
                         }
                       ]
                     }
                   }
                 }
               }
             }
           },
           "discovery": {
             "interfaces": {
               "interface": [
                 {
                   "name": "eth30",
                   "address-families": {
                     "ietf-mpls-ldp-extended:ipv6": {



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                       "enable": true
                     }
                   }
                 },
                 {
                   "name": "eth32",
                   "address-families": {
                     "ietf-mpls-ldp-extended:ipv6": {
                       "enable": true
                     }
                   }
                 }
               ]
             }
           }
         }
       }
     }
   }

                                 Figure 13

   The cooresponding operational state data for Router R3 could be as
   follows:

   {
     "ietf-interfaces:interfaces": {
       "interface": [
         {
           "name": "lo0",
           "description": "R3 loopback interface.",
           "type": "iana-if-type:softwareLoopback",
           "phys-address": "00:00:5e:00:53:03",
           "oper-status": "up",
           "statistics": {
             "discontinuity-time": "2018-10-15T12:34:56-05:00"
           },
           "ietf-ip:ipv6": {
             "mtu": 1500,
             "address": [
               {
                 "ip": "2001:db8:0:300::1",
                 "prefix-length": 64,
                 "origin": "static",
                 "status": "preferred"
               },
               {
                 "ip": "fe80::200:5eff:fe00:5303",



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                 "prefix-length": 64,
                 "origin": "link-layer",
                 "status": "preferred"
               }
             ],
             "neighbor": [
             ]
           }
         },
         {
           "name": "eth30",
           "description": "An interface connected to client routers.",
           "type": "iana-if-type:ethernetCsmacd",
           "phys-address": "00:00:5e:00:53:30",
           "oper-status": "up",
           "statistics": {
             "discontinuity-time": "2018-10-15T12:34:56-05:00"
           },
           "ietf-ip:ipv6": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "fe80::200:5eff:fe00:5330",
                 "prefix-length": 64,
                 "origin": "link-layer",
                 "status": "preferred"
               }
             ],
             "neighbor": [
             ]
           }
         },
         {
           "name": "eth32",
           "description": "An interface connected to root (R2).",
           "type": "iana-if-type:ethernetCsmacd",
           "phys-address": "00:00:5e:00:53:32",
           "oper-status": "up",
           "statistics": {
             "discontinuity-time": "2018-10-15T12:34:56-05:00"
           },
           "ietf-ip:ipv6": {
             "forwarding": true,
             "mtu": 1500,
             "address": [
               {
                 "ip": "fe80::200:5eff:fe00:5332",



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                 "prefix-length": 64,
                 "origin": "link-layer",
                 "status": "preferred"
               }
             ],
             "neighbor": [
               {
                 "ip": "fe80::200:5eff:fe00:5323",
                 "link-layer-address": "00:00:5e:00:53:23",
                 "origin": "dynamic",
                 "is-router": [null],
                 "state": "reachable"
               }
             ]
           }
         }
       ]
     },
     "ietf-routing:routing": {
       "router-id": "203.0.113.3",
       "interfaces": {
         "interface": [
           "lo0",
           "eth30",
           "eth32"
         ]
       },
       "control-plane-protocols": {
         "ietf-mpls-ldp:mpls-ldp": {
           "global": {
             "address-families": {
               "ietf-mpls-ldp-extended:ipv6": {
                 "enable": true
               }
             },
             "capability": {
               "ietf-mpls-mldp:mldp": {
                 "mp2mp": {
                   "enable": true
                 }
               }
             },
             "ietf-mpls-mldp:mldp": {
               "enable": true,
               "address-families": {
                 "ietf-mpls-mldp-extended:ipv6": {
                   "configured-leaf-lsps": {
                     "opaque-element-lspid": {



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                       "fec-label": [
                         {
                           "root-address": "2001:db8:0:200::1",
                           "lsp-id": 201,
                           "multipoint-type": "mp2mp"
                         }
                       ]
                     }
                   },
                   "roots": {
                     "root": [
                       {
                         "root-address": "2001:db8:0:200::1",
                         "is-self": false,
                         "reachability": [
                           {
                             "address": "fe80::200:5eff:fe00:5323",
                             "interface": "eth32",
                             "peer": "203.0.113.2"
                           }
                         ],
                         "bindings": {
                           "opaque-element-lspid": {
                             "fec-label": [
                               {
                                 "lsp-id": 201,
                                 "multipoint-type": "mp2mp",
                                 "peer": [
                                   {
                                     "direction": "upstream",
                                     "peer": "203.0.113.2",
                                     "advertisement-type": "advertised",
                                     "label": 3201
                                   },
                                   {
                                     "direction": "upstream",
                                     "peer": "203.0.113.2",
                                     "advertisement-type": "received",
                                     "label": 2301
                                   }
                                 ]
                               }
                             ]
                           }
                         }
                       }
                     ]
                   }



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                 }
               }
             }
           },
           "discovery": {
             "interfaces": {
               "interface": [
                 {
                   "name": "eth30",
                   "address-families": {
                     "ietf-mpls-ldp-extended:ipv6": {
                       "enable": true,
                       "hello-adjacencies": {
                         "hello-adjacency": [
                         ]
                       }
                     }
                   }
                 },
                 {
                   "name": "eth32",
                   "address-families": {
                     "ietf-mpls-ldp-extended:ipv6": {
                       "enable": true,
                       "hello-adjacencies": {
                         "hello-adjacency": [
                           {
                             "adjacent-address":
                               "fe80::200:5eff:fe00:5323",
                             "flag": ["adjacency-flag-active"],
                             "hello-holdtime": {
                               "adjacent": 15,
                               "negotiated": 15,
                               "remaining": 9
                             },
                             "next-hello": 3,
                             "statistics": {
                               "discontinuity-time":
                                 "2018-10-15T12:34:56-05:00"
                             },
                             "peer": {
                               "lsr-id": "203.0.113.2",
                               "label-space-id": 0
                             }
                           }
                         ]
                       }
                     }



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                   }
                 }
               ]
             }
           },
           "peers": {
             "peer": [
               {
                 "lsr-id": "203.0.113.2",
                 "label-space-id": 0,
                 "label-advertisement-mode": {
                   "local": "downstream-unsolicited",
                   "peer": "downstream-unsolicited",
                   "negotiated": "downstream-unsolicited"
                 },
                 "next-keep-alive": 5,
                 "session-holdtime": {
                   "peer": 180,
                   "negotiated": 180,
                   "remaining": 78
                 },
                 "session-state": "operational",
                 "tcp-connection": {
                   "local-address": "fe80::200:5eff:fe00:5332",
                   "local-port": 646,
                   "remote-address": "fe80::200:5eff:fe00:5323",
                   "remote-port": 646
                 },
                 "up-time": "P2H33M5S",
                 "statistics": {
                   "discontinuity-time": "2018-10-15T12:34:56-05:00"
                 },
                 "received-peer-state": {
                   "capability": {
                     "ietf-mpls-mldp:mldp": {
                       "mp2mp": {
                         "enable": true
                       }
                     }
                   }
                 }
               }
             ]
           }
         }
       }
     }
   }



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                                 Figure 14

Appendix B.  Acknowledgments

   The authors would like to acknowledge Ladislav Lhotka and Acee Lindem
   for their review and comments during WG.

Appendix C.  Contributors

   Matthew Bocci
   Nokia
   Email: matthew.bocci@nokia.com

Authors' Addresses

   Kamran Raza (editor)
   Cisco Systems
   Email: skraza@cisco.com


   Xufeng Liu
   Volta Networks
   Email: xufeng.liu.ietf@gmail.com


   Santosh Esale
   Juniper Networks
   Email: santosh_easale@berkeley.edu


   Loa Andersson
   Huawei Technologies
   Email: loa@pi.nu


   Jeff Tantsura
   Microsoft Corporation
   Email: jefftant.ietf@gmail.com


   Sowmya Krishnaswamy
   Individual
   Email: krishnaswamy.sowmya@gmail.com




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   Rajiv Asati
   Cisco Systems
   Email: rajiva@cisco.com


   Xia Chen
   Huawei Technologies
   Email: jescia.chenxia@huawei.com


   Himanshu Shah
   Ciena Corporation
   Email: hshah@ciena.com



































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