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Versions: 00 01 02 03 04 draft-ietf-mpls-ldp-mldp-yang

MPLS Working Group                                               K. Raza
Internet-Draft                                                  R. Asati
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: January 9, 2017
                                                                  X. Liu
                                                                Ericsson

                                                                S. Esale
                                                        Juniper Networks

                                                                 X. Chen
                                                     Huawei Technologies

                                                                 H. Shah
                                                       Ciena Corporation

                                                            July 8, 2016


                 YANG Data Model for MPLS LDP and mLDP
                    draft-raza-mpls-ldp-mldp-yang-04

Abstract

   This document describes a YANG data model for Multi-Protocol Label
   Switching (MPLS) Label Distribution Protocol (LDP) and Multipoint LDP
   (mLDP).

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 http://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on January 9, 2017.







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Copyright Notice

   Copyright (c) 2016 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Specification of Requirements . . . . . . . . . . . . . . . .   3
   3.  LDP YANG Model  . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Configuration . . . . . . . . . . . . . . . . . . . . . .   7
       3.2.1.  Configuration Hierarchy . . . . . . . . . . . . . . .  11
       3.2.2.  All-VRFs Configuration  . . . . . . . . . . . . . . .  14
     3.3.  Operational State . . . . . . . . . . . . . . . . . . . .  14
       3.3.1.  Derived States  . . . . . . . . . . . . . . . . . . .  21
     3.4.  Notifications . . . . . . . . . . . . . . . . . . . . . .  26
     3.5.  Actions . . . . . . . . . . . . . . . . . . . . . . . . .  26
   4.  mLDP YANG Model . . . . . . . . . . . . . . . . . . . . . . .  27
     4.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  27
     4.2.  Configuration . . . . . . . . . . . . . . . . . . . . . .  28
       4.2.1.  Configuration Hierarchy . . . . . . . . . . . . . . .  28
       4.2.2.  mldp container  . . . . . . . . . . . . . . . . . . .  30
       4.2.3.  Leveraging LDP containers . . . . . . . . . . . . . .  31
       4.2.4.  YANG tree . . . . . . . . . . . . . . . . . . . . . .  31
     4.3.  Operational State . . . . . . . . . . . . . . . . . . . .  33
       4.3.1.  Derived states  . . . . . . . . . . . . . . . . . . .  38
     4.4.  Notifications . . . . . . . . . . . . . . . . . . . . . .  42
     4.5.  Actions . . . . . . . . . . . . . . . . . . . . . . . . .  43
   5.  Open Items  . . . . . . . . . . . . . . . . . . . . . . . . .  43
   6.  YANG Specification  . . . . . . . . . . . . . . . . . . . . .  43
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . 110
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . 110
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 110
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . 110
     10.1.  Normative References . . . . . . . . . . . . . . . . . . 110
     10.2.  Informative References . . . . . . . . . . . . . . . . . 113
   Appendix A.  Additional Contributors  . . . . . . . . . . . . . . 113



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   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 113

1.  Introduction

   The Network Configuration Protocol (NETCONF) [RFC6241] is one of the
   network management protocols that defines mechanisms to manage
   network devices.  YANG [RFC6020] is a modular language that
   represents data structures in an XML tree format, and is used as a
   data modelling language for the NETCONF.

   This document introduces a YANG data model for MPLS Label
   Distribution Protocol (LDP) [RFC5036] and Multipoint LDP (mLDP)
   [RFC6388].  For LDP, it also covers LDP IPv6 [RFC7552] and LDP
   capabilities [RFC5561].

   The data model is defined for following constructs that are used for
   managing the protocol:

   o  Configuration

   o  Operational State

   o  Executables (Actions)

   o  Notifications

   This document is organized to define the data model for each of the
   above constructs (configuration, state, action, and notifications) in
   the sequence as listed earlier.  Given that mLDP is tightly coupled
   with LDP, mLDP data model is defined under LDP tree and in the same
   sequence as listed above.

2.  Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

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

3.  LDP YANG Model








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3.1.  Overview

   This document defines a new module named "ietf-mpls-ldp" for LDP/mLDP
   data model where this module augments /rt:routing/rt:control-plane-
   protocols that is defined in [I-D.ietf-netmod-routing-cfg].

   There are four main containers in "ietf-mpls-ldp" module as follows:

   o  Read-Write parameters for configuration (Discussed in Section 3.2)

   o  Read-only parameters for operational state (Discussed in
      Section 3.3)

   o  Notifications for events (Discussed in Section 3.4)

   o  RPCs for executing commands to perform some action (Discussed in
      Section 3.5)

   For the configuration and state data, this model follows the similar
   approach described in [I-D.openconfig-netmod-opstate] to represent
   the configuration (intended state) and operational (applied and
   derived) state.  This means that for every configuration (rw) item,
   there is an associated (ro) item under "state" container to represent
   the applied state.  Furthermore, protocol derived state is also kept
   under "state" tree corresponding to the protocol area (discovery,
   peer etc.).  [Ed note: This document will be (re-)aligned with
   [I-D.openconfig-netmod-opstate] once that specification is adopted as
   a WG document]

   Following diagram depicts high level LDP yang tree organization and
   hierarchy:




















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       module: ietf-mpls-ldp
            +-- rw routing
              +-- rw control-plane-protocols
                 +-- rw mpls-ldp
                     +-- rw global
                     |   +-- rw config
                     |       +-- rw ...
                     |   +-- ro state
                     |       +-- ro ...
                     |       .
                     +-- rw ...
                     |
                     |
                     +-- rw ...
                     ...

       rpcs:
          +-- x mpls-ldp-rpc
          +-- x . . . . .

       notifications:
          +--- n mpls-ldp-notif
          +--- n ...


                                 Figure 1

   Before going into data model details, it is important to take note of
   the following points:

   o  This module aims to address only the core LDP/mLDP parameters as
      per RFC specification, as well as some widely used and deployed
      non-RFC features (such as label policies, session authentication
      etc).  Any vendor specific feature should be defined in a vendor-
      specific augmentation of this model.

   o  Multi-topology LDP [RFC7307] and Multi-topology mLDP
      [I-D.iwijnand-mpls-mldp-multi-topology] are beyond the scope of
      this document.

   o  This module does not cover any applications running on top of LDP
      and mLDP, nor does it cover any OAM procedures for LDP and mLDP.

   o  This model is a VPN Forwarding and Routing (VRF)-centric model.
      It is important to note that [RFC4364] defines VRF tables and
      default forwarding tables as different, however from a yang
      modelling perspective this introduces unnecessary complications,




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      hence we are treating the default forwarding table as just another
      VRF.

   o  A "network-instance" as defined in [I-D.rtgyangdt-rtgwg-ni-model]
      refers to a VRF instance (both default and non-default) within the
      scope of this model.

   o  This model supports two address-families, namely "ipv4" and
      "ipv6".

   o  This model assumes platform-wide label space (i.e. label space Id
      of zero).  However, when Upstream Label assignment [RFC6389] is in
      use, an upstream assigned label is looked up in a Context-Specific
      label space as defined in [RFC5331].

   o  The label and peer policies (including filters) are defined using
      a prefix-list.  When used for a peer policy, the prefix refers to
      the LSR Id of the peer.  The prefix-list is referenced from
      routing-policy model as defined in [I-D.ietf-rtgwg-policy-model].

   o  The use of grouping (templates) for bundling and grouping the
      configuration items is not employed in current revision, and is a
      subject for consideration in future.

   o  This model uses the terms LDP "neighbor"/"adjacency", "session",
      and "peer" with the following semantics:

      *  Neighbor/Adjacency: An LDP enabled LSR that is discovered
         through LDP discovery mechanisms.

      *  Session: An LDP neighbor with whom a TCP connection has been
         established.

      *  Peer: An LDP session which has successfully progressed beyond
         its initialization phase and is either already exchanging the
         bindings or is ready to do so.

      It is to be noted that LDP Graceful Restart mechanisms defined in
      [RFC3478] allow keeping the exchanged bindings for some time after
      a session goes down with a peer.  We call such a state -- i.e.
      keeping peer bindings without established or recovered peering --
      a "stale" peer.  When used in this document, the above terms will
      refer strictly to the semantics and definitions defined for them.

   A graphical representation of LDP YANG data model is presented in
   Figure 3, Figure 5, Figure 11, and Figure 12.  Whereas, the actual
   model definition in YANG is captured in Section 6.




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

3.2.  Configuration

   This specification defines the configuration parameters for base LDP
   as specified in [RFC5036] and LDP IPv6 [RFC7552].  Moreover, it
   incorporates provisions to enable LDP Capabilities [RFC5561], and
   defines some of the most significant and commonly used capabilities
   such as Typed Wildcard FEC [RFC5918], End-of-LIB [RFC5919], and LDP
   Upstream Label Assignment [RFC6389].

   This specification supports VRF-centric configuration.  For
   implementations that support protocol-centric configuration, with
   provision for inheritance and items that apply to all vrfs, we
   recommend an augmentation of this model such that any protocol-
   centric or all-vrf configuration is defined under their designated
   containers within the standard network-instance (please see
   Section 3.2.2)

   This model augments /rt:routing/rt:control-plane-protocols that is
   defined in [I-D.ietf-netmod-routing-cfg].  For LDP interfaces, this
   model refers the MPLS interface as defined under MPLS base
   specification [I-D.saad-mpls-base-yang].  Furthermore, as mentioned
   earlier, the configuration tree presents read-write intended
   configuration leave/items as well as read-only state of the applied
   configuration.  The former is listed under "config" container and
   latter under "state" container.

   Following is high-level configuration organization for LDP/mLDP:




















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       module: ietf-mpls-ldp
          +-- routing
           +-- control-plane-protocols
                 +-- mpls-ldp
                     +-- global
                     |    +-- ...
                     |    +-- ...
                     |    +-- address-family* [afi]
                     |        +-- . . .
                     |        +-- . . .
                     |    +-- discovery
                     |        +-- . . .
                     +-- peers
                          +-- ...
                          +-- ...


                                 Figure 2

   Given the configuration hierarchy, the model allows inheritance such
   that an item in a child tree is able to derive value from a similar
   or related item in one of the parent.  For instance, hello holdtime
   can be configured per-VRF or per-VRF-interface, thus allowing
   inheritance as well flexibility to override with a different value at
   any child level.

   Following is a simplified graphical representation of the data model
   for LDP configuration


   +--rw mpls-ldp!
      +--rw global
      |  +--rw config
      |  |  +--rw capability
      |  |  |  +--rw end-of-lib {capability-end-of-lib}?
      |  |  |  |  +--rw enable?   boolean
      |  |  |  +--rw typed-wildcard-fec {capability-typed-wildcard-fec}?
      |  |  |  |  +--rw enable?   boolean
      |  |  |  +--rw upstream-label-assignment {capability-upstream-label-assignment}?
      |  |  |     +--rw enable?   boolean
      |  |  +--rw graceful-restart
      |  |  |  +--rw enable?                boolean
      |  |  |  +--rw helper-enable?         boolean {graceful-restart-helper-mode}?
      |  |  |  +--rw reconnect-time?        uint16
      |  |  |  +--rw recovery-time?         uint16
      |  |  |  +--rw forwarding-holdtime?   uint16
      |  |  +--rw igp-synchronization-delay?   uint16
      |  |  +--rw lsr-id?                      yang:dotted-quad



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      |  +--rw address-family* [afi]
      |  |  +--rw afi       ldp-address-family
      |  |  +--rw config
      |  |     +--rw enable?         boolean
      |  |     +--rw label-policy
      |  |     |  +--rw independent-mode
      |  |     |  |  +--rw assign {policy-label-assignment-config}?
      |  |     |  |  |  +--rw (prefix-option)?
      |  |     |  |  |     |  +--rw prefix-list?        prefix-list-ref
      |  |     |  |  |        +--rw host-routes-only?   boolean
      |  |     |  |  +--rw advertise
      |  |     |  |  |  +--rw explicit-null
      |  |     |  |  |  |  +--rw enable?        boolean
      |  |     |  |  |  |  +--rw prefix-list?   prefix-list-ref
      |  |     |  |  |  +--rw prefix-list?     prefix-list-ref
      |  |     |  |  +--rw accept
      |  |     |  |     +--rw prefix-list?   prefix-list-ref
      |  |     |  +--rw ordered-mode {policy-ordered-label-config}?
      |  |     |     +--rw egress-lsr
      |  |     |     |  +--rw prefix-list?   prefix-list-ref
      |  |     |     +--rw advertise
      |  |     |     |  +--rw prefix-list?   prefix-list-ref
      |  |     |     +--rw accept
      |  |     |        +--rw prefix-list?   prefix-list-ref
      |  |     +--rw ipv4
      |  |     |  +--rw transport-address?   inet:ipv4-address
      |  |     +--rw ipv6
      |  |        +--rw transport-address?   inet:ipv6-address
      |  +--rw discovery
      |  |  +--rw interfaces
      |  |  |  +--rw config
      |  |  |  |  +--rw hello-holdtime?   uint16
      |  |  |  |  +--rw hello-interval?   uint16
      |  |  |  +--rw interface* [interface]
      |  |  |     +--rw interface         mpls-interface-ref
      |  |  |     +--rw config
      |  |  |     |  +--rw hello-holdtime?              uint16
      |  |  |     |  +--rw hello-interval?              uint16
      |  |  |     |  +--rw igp-synchronization-delay?   uint16 {per-interface-timer-config}?
      |  |  |     +--rw address-family* [afi]
      |  |  |        +--rw afi       ldp-address-family
      |  |  |        +--rw config
      |  |  |           +--rw enable?   boolean
      |  |  |           +--rw ipv4
      |  |  |           |  +--rw transport-address?   union
      |  |  |           +--rw ipv6
      |  |  |              +--rw transport-address?   union
      |  |  +--rw targeted



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      |  |     +--rw config
      |  |     |  +--rw hello-holdtime?   uint16
      |  |     |  +--rw hello-interval?   uint16
      |  |     |  +--rw hello-accept {policy-extended-discovery-config}?
      |  |     |     +--rw enable?          boolean
      |  |     |     +--rw neighbor-list?   neighbor-list-ref
      |  |     +--rw address-family* [afi]
      |  |        +--rw afi      ldp-address-family
      |  |        +--rw ipv4
      |  |        |  +--rw target* [adjacent-address]
      |  |        |     +--rw adjacent-address    inet:ipv4-address
      |  |        |     +--rw config
      |  |        |        +--rw enable?          boolean
      |  |        |        +--rw local-address?   inet:ipv4-address
      |  |        +--rw ipv6
      |  |           +--rw target* [adjacent-address]
      |  |              +--rw adjacent-address    inet:ipv6-address
      |  |              +--rw config
      |  |                 +--rw enable?          boolean
      |  |                 +--rw local-address?   inet:ipv6-address
      |  +--rw forwarding-nexthop {forwarding-nexthop-config}?
      |  |  +--rw interfaces
      |  |     +--rw interface* [interface]
      |  |        +--rw interface         mpls-interface-ref
      |  |        +--rw address-family* [afi]
      |  |           +--rw afi       ldp-address-family
      |  |           +--rw config
      |  |              +--rw ldp-disable?    boolean
      |  +--rw label-policy
      |     +--rw independent-mode
      |     |  +--rw assign {policy-label-assignment-config}?
      |     |  |  +--rw (prefix-option)?
      |     |  |        +--rw prefix-list?        prefix-list-ref
      |     |  |        +--rw host-routes-only?   boolean
      |     |  +--rw advertise
      |     |  |  +--rw explicit-null
      |     |  |  |  +--rw enable?        boolean
      |     |  |  |  +--rw prefix-list?   prefix-list-ref
      |     |  |  +--rw prefix-list?     prefix-list-ref
      |     |  +--rw accept
      |     |     +--rw prefix-list?   prefix-list-ref
      |     +--rw ordered-mode {policy-ordered-label-config}?
      |        +--rw egress-lsr
      |        |  +--rw prefix-list?   prefix-list-ref
      |        +--rw advertise
      |        |  +--rw prefix-list?   prefix-list-ref
      |        +--rw accept
      |           +--rw prefix-list?   prefix-list-ref



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      +--rw peers
         +--rw config
         |  +--rw session-authentication-md5-password?   string
         |  +--rw session-ka-holdtime?                   uint16
         |  +--rw session-ka-interval?                   uint16
         |  +--rw session-downstream-on-demand {session-downstream-on-demand-config}?
         |     +--rw enable?      boolean
         |     +--rw peer-list?   peer-list-ref
         +--rw peer* [lsr-id]
            +--rw lsr-id    yang:dotted-quad
            +--rw config
               +--rw admin-down?                            boolean
               +--rw capability
               +--rw label-policy
               |  +--rw advertise
               |  |  +--rw prefix-list?   prefix-list-ref
               |  +--rw accept
               |     +--rw prefix-list?   prefix-list-ref
               +--rw session-authentication-md5-password?   string
               +--rw graceful-restart
               |  +--rw enable?           boolean
               |  +--rw reconnect-time?   uint16
               |  +--rw recovery-time?    uint16
               +--rw session-ka-holdtime?                   uint16
               +--rw session-ka-interval?                   uint16
               +--rw address-family
                  +--rw ipv4
                  |  +--rw label-policy
                  |     +--rw advertise
                  |     |  +--rw prefix-list?   prefix-list-ref
                  |     +--rw accept
                  |        +--rw prefix-list?   prefix-list-ref
                  +--rw ipv6
                     +--rw label-policy
                        +--rw advertise
                        |  +--rw prefix-list?   prefix-list-ref
                        +--rw accept
                           +--rw prefix-list?   prefix-list-ref


                                 Figure 3

3.2.1.  Configuration Hierarchy

   The LDP configuration container is logically divided into following
   high-level config areas:





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      Per-VRF parameters
          o Global parameters
          o Per-address-family parameters
          o LDP Capabilities parameters
          o Hello Discovery parameters
              - interfaces
                 - Per-interface:
                    Global
                    Per-address-family
              - targeted
                 - Per-target
         o Peer parameters
              - Global
              - Per-peer
                 Per-address-family
                 Capabilities parameters
         o Forwarding parameters


                                 Figure 4

   Following subsections briefly explain these configuration areas.

3.2.1.1.  Per-VRF parameters

   LDP module resides under an network-instance and the scope of any LDP
   configuration defined under this tree is per network-instance (per-
   VRF).  This configuration is further divided into sub categories as
   follows.

3.2.1.1.1.  Per-VRF global parameters

   There are configuration items that are available directly under a VRF
   instance and do not fall under any other sub tree.  Example of such a
   parameter is LDP LSR id that is typically configured per VRF.  To
   keep legacy LDP features and applications working in an LDP IPv4
   networks with this model, this document recommends an operator to
   pick a routable IPv4 unicast address as an LSR Id.

3.2.1.1.2.  Per-VRF Capabilities parameters

   This container falls under global tree and holds the LDP capabilities
   that are to be enabled for certain features.  By default, an LDP
   capability is disabled unless explicitly enabled.  These capabilities
   are typically used to negotiate with LDP peer(s) the support/non-
   support related to a feature and its parameters.  The scope of a
   capability enabled under this container applies to all LDP peers in
   the given VRF instance.  There is also a peer level capability



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   container that is provided to override a capability that is enabled/
   specified at VRF level.

3.2.1.1.3.  Per-VRF Per-Address-Family parameters

   Any LDP configuration parameter related to IP address family (AF)
   whose scope is VRF wide is configured under this tree.  The examples
   of per-AF parameters include enabling LDP for an address family,
   prefix-list based label policies, and LDP transport address.

3.2.1.1.4.  Per-VRF Hello Discovery parameters

   This container is used to hold LDP configuration related to Hello and
   discovery process for both basic (link) and extended (targeted)
   discovery.

   The "interfaces" is a container to configure parameters related to
   VRF interfaces.  There are parameters that apply to all interfaces
   (such as hello timers), as well as parameters that can be configured
   per-interface.  Hence, an interface list is defined under
   "interfaces" container.  The model defines parameters to configure
   per-interface non AF related items, as well as per-interface per-AF
   items.  The example of former is interface hello timers, and example
   of latter is enabling hellos for a given AF under an interface.

   The "targeted" container under a VRF instance allows to configure LDP
   targeted discovery related parameters.  Within this container, the
   "target" list provides a mean to configure multiple target addresses
   to perform extended discovery to a specific destination target, as
   well as to fine-tune the per-target parameters.

3.2.1.1.5.  Per-VRF Peer parameters

   This container is used to hold LDP configuration related to LDP
   sessions and peers under a VRF instance.  This container allows to
   configure parameters that either apply on VRF's all peers or a subset
   (peer-list) of VRF peers.  The example of such parameters include
   authentication password, session KA timers etc.  Moreover, the model
   also allows per-peer parameter tuning by specifying a "peer" list
   under the "peers" container.  A peer is uniquely identified using its
   LSR Id and hence LSR Id is the key for peer list

   Like per-interface parameters, some per-peer parameters are AF-
   agnostic (i.e. either non AF related or apply to both IP address
   families), and some that belong to an AF.  The example of former is
   per-peer session password configuration, whereas the example of
   latter is prefix-list based label policies (inbound and outbound)
   that apply to a given peer.



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3.2.1.1.6.  Per-VRF Forwarding parameters

   This container is used to hold configuration used to control LDP
   forwarding behavior under a VRF instance.  One example of a
   configuration under this container is when a user wishes to enable
   neighbor discovery on an interface but wishes to disable use of the
   same interface as forwarding nexthop.  This example configuration
   makes sense only when there are more than one LDP enabled interfaces
   towards the neighbor.

3.2.2.  All-VRFs Configuration

   [Ed note: TODO]

3.3.  Operational State

   Operational state of LDP can be queried and obtained from read-only
   state containers that fall under the same tree (/rt:routing/
   rt:control-plane-protocols/) as the configuration.

   Please note this state tree refers both the configuration "applied"
   state as well as the "derived" state related to the protocol.  [Ed
   note: This is where this model differs presently from
   [I-D.openconfig-netmod-opstate] and subject to alignment in later
   revisions]

   Following is a simplified graphical representation of the data model
   for LDP operational state.


module: ietf-mpls-ldp
augment /rt:routing/rt:control-plane-protocols:
   +--rw mpls-ldp!
      +--rw global
      |  +--ro state
      |  |  +--ro capability
      |  |  |  +--ro end-of-lib {capability-end-of-lib}?
      |  |  |  |  +--ro enable?   boolean
      |  |  |  +--ro typed-wildcard-fec {capability-typed-wildcard-fec}?
      |  |  |  |  +--ro enable?   boolean
      |  |  |  +--ro upstream-label-assignment {capability-upstream-label-assignment}?
      |  |  |  |  +--ro enable?   boolean
      |  |  +--ro graceful-restart
      |  |  |  +--ro enable?                boolean
      |  |  |  +--ro helper-enable?         boolean {graceful-restart-helper-mode}?
      |  |  |  +--ro reconnect-time?        uint16
      |  |  |  +--ro recovery-time?         uint16
      |  |  |  +--ro forwarding-holdtime?   uint16



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      |  |  +--ro igp-synchronization-delay?   uint16
      |  |  +--ro lsr-id?                      yang:dotted-quad
      |  +--rw address-family* [afi]
      |  |  +--rw afi       ldp-address-family
      |  |  +--ro state
      |  |     +--ro enable?         boolean
      |  |     +--ro label-policy
      |  |     |  +--ro independent-mode
      |  |     |  |  +--ro assign {policy-label-assignment-config}?
      |  |     |  |  |  +--ro (prefix-option)?
      |  |     |  |  |     +--:(prefix-list)
      |  |     |  |  |     |  +--ro prefix-list?        prefix-list-ref
      |  |     |  |  |     +--:(host-routes-only)
      |  |     |  |  |        +--ro host-routes-only?   boolean
      |  |     |  |  +--ro advertise
      |  |     |  |  |  +--ro explicit-null
      |  |     |  |  |  |  +--ro enable?        boolean
      |  |     |  |  |  |  +--ro prefix-list?   prefix-list-ref
      |  |     |  |  |  +--ro prefix-list?     prefix-list-ref
      |  |     |  |  +--ro accept
      |  |     |  |     +--ro prefix-list?   prefix-list-ref
      |  |     |  +--ro ordered-mode {policy-ordered-label-config}?
      |  |     |     +--ro egress-lsr
      |  |     |     |  +--ro prefix-list?   prefix-list-ref
      |  |     |     +--ro advertise
      |  |     |     |  +--ro prefix-list?   prefix-list-ref
      |  |     |     +--ro accept
      |  |     |        +--ro prefix-list?   prefix-list-ref
      |  |     +--ro ipv4
      |  |     |  +--ro transport-address?   inet:ipv4-address
      |  |     |  +--ro bindings
      |  |     |     +--ro address* [address]
      |  |     |     |  +--ro address      inet:ipv4-address
      |  |     |     |  +--ro advertisement-type?   advertised-received
      |  |     |     |  +--ro peer?        leafref
      |  |     |     +--ro fec-label* [fec]
      |  |     |        +--ro fec     inet:ipv4-prefix
      |  |     |        +--ro peer* [peer advertisement-type]
      |  |     |           +--ro peer                  leafref
      |  |     |           +--ro advertisement-type    advertised-received
      |  |     |           +--ro label?                mpls:mpls-label
      |  |     |           +--ro used-in-forwarding?   boolean
      |  |     +--ro ipv6
      |  |        +--ro transport-address?   inet:ipv6-address
      |  |        +--ro binding
      |  |           +--ro address* [address]
      |  |           |  +--ro address      inet:ipv6-address
      |  |           |  +--ro advertisement-type?   advertised-received



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      |  |           |  +--ro peer?        leafref
      |  |           +--ro fec-label* [fec]
      |  |              +--ro fec     inet:ipv6-prefix
      |  |              +--ro peer* [peer advertisement-type]
      |  |                 +--ro peer                  leafref
      |  |                 +--ro advertisement-type    advertised-received
      |  |                 +--ro label?                mpls:mpls-label
      |  |                 +--ro used-in-forwarding?   boolean
      |  +--rw discovery
      |  |  +--rw interfaces
      |  |  |  +--ro state
      |  |  |  |  +--ro hello-holdtime?   uint16
      |  |  |  |  +--ro hello-interval?   uint16
      |  |  |  +--rw interface* [interface]
      |  |  |     +--ro state
      |  |  |     |  +--ro hello-holdtime?              uint16
      |  |  |     |  +--ro hello-interval?              uint16
      |  |  |     |  +--ro igp-synchronization-delay?   uint16 {per-interface-timer-config}?
      |  |  |     |  +--ro next-hello?                  uint16
      |  |  |     +--rw address-family* [afi]
      |  |  |        +--rw afi       ldp-address-family
      |  |  |        +--ro state
      |  |  |           +--ro enable?   boolean
      |  |  |           +--ro ipv4
      |  |  |           |  +--ro transport-address?   union
      |  |  |           |  +--ro hello-adjacencies* [adjacent-address]
      |  |  |           |     +--ro adjacent-address    inet:ipv4-address
      |  |  |           |     +--ro flag*               identityref
      |  |  |           |     +--ro hello-holdtime
      |  |  |           |     |  +--ro adjacent?     uint16
      |  |  |           |     |  +--ro negotiated?   uint16
      |  |  |           |     |  +--ro remaining?    uint16
      |  |  |           |     +--ro next-hello?         uint16
      |  |  |           |     +--ro statistics
      |  |  |           |     |  +--ro discontinuity-time    yang:date-and-time
      |  |  |           |     |  +--ro hello-received?       yang:counter64
      |  |  |           |     |  +--ro hello-dropped?        yang:counter64
      |  |  |           |     +--ro peer?               leafref
      |  |  |           +--ro ipv6
      |  |  |              +--ro transport-address?   union
      |  |  |              +--ro hello-adjacencies* [adjacent-address]
      |  |  |                 +--ro adjacent-address    inet:ipv6-address
      |  |  |                 +--ro flag*               identityref
      |  |  |                 +--ro hello-holdtime
      |  |  |                 |  +--ro adjacent?     uint16
      |  |  |                 |  +--ro negotiated?   uint16
      |  |  |                 |  +--ro remaining?    uint16
      |  |  |                 +--ro next-hello?         uint16



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      |  |  |                 +--ro statistics
      |  |  |                 |  +--ro discontinuity-time    yang:date-and-time
      |  |  |                 |  +--ro hello-received?       yang:counter64
      |  |  |                 |  +--ro hello-dropped?        yang:counter64
      |  |  |                 +--ro peer?               leafref
      |  |  +--rw targeted
      |  |     +--ro state
      |  |     |  +--ro hello-holdtime?   uint16
      |  |     |  +--ro hello-interval?   uint16
      |  |     |  +--ro hello-accept {policy-extended-discovery-config}?
      |  |     |     +--ro enable?          boolean
      |  |     |     +--ro neighbor-list?   neighbor-list-ref
      |  |     +--rw address-family* [afi]
      |  |        +--rw afi      ldp-address-family
      |  |        +--ro state
      |  |        |  +--ro ipv4
      |  |        |  |  +--ro hello-adjacencies* [local-address adjacent-address]
      |  |        |  |     +--ro local-address       inet:ipv4-address
      |  |        |  |     +--ro adjacent-address    inet:ipv4-address
      |  |        |  |     +--ro flag*               identityref
      |  |        |  |     +--ro hello-holdtime
      |  |        |  |     |  +--ro adjacent?     uint16
      |  |        |  |     |  +--ro negotiated?   uint16
      |  |        |  |     |  +--ro remaining?    uint16
      |  |        |  |     +--ro next-hello?         uint16
      |  |        |  |     +--ro statistics
      |  |        |  |     |  +--ro discontinuity-time    yang:date-and-time
      |  |        |  |     |  +--ro hello-received?       yang:counter64
      |  |        |  |     |  +--ro hello-dropped?        yang:counter64
      |  |        |  |     +--ro peer?               leafref
      |  |        |  +--ro ipv6
      |  |        |     +--ro hello-adjacencies* [local-address adjacent-address]
      |  |        |        +--ro local-address       inet:ipv6-address
      |  |        |        +--ro adjacent-address    inet:ipv6-address
      |  |        |        +--ro flag*               identityref
      |  |        |        +--ro hello-holdtime
      |  |        |        |  +--ro adjacent?     uint16
      |  |        |        |  +--ro negotiated?   uint16
      |  |        |        |  +--ro remaining?    uint16
      |  |        |        +--ro next-hello?         uint16
      |  |        |        +--ro statistics
      |  |        |        |  +--ro discontinuity-time    yang:date-and-time
      |  |        |        |  +--ro hello-received?       yang:counter64
      |  |        |        |  +--ro hello-dropped?        yang:counter64
      |  |        |        +--ro peer?               leafref
      |  |        +--rw ipv4
      |  |        |  +--rw target* [adjacent-address]
      |  |        |     +--rw adjacent-address    inet:ipv4-address



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      |  |        |     +--ro state
      |  |        |        +--ro enable?          boolean
      |  |        |        +--ro local-address?   inet:ipv4-address
      |  |        +--rw ipv6
      |  |           +--rw target* [adjacent-address]
      |  |              +--rw adjacent-address    inet:ipv6-address
      |  |              +--ro state
      |  |                 +--ro enable?          boolean
      |  |                 +--ro local-address?   inet:ipv6-address
      |  +--rw forwarding-nexthop {forwarding-nexthop-config}?
      |  |  +--rw interfaces
      |  |     +--rw interface* [interface]
      |  |        +--rw interface         mpls-interface-ref
      |  |        +--rw address-family* [afi]
      |  |           +--rw afi       ldp-address-family
      |  |           +--ro state
      |  |              +--ro ldp-disable?    boolean
      +--rw peers
         +--ro state
         |  +--ro session-authentication-md5-password?   string
         |  +--ro session-ka-holdtime?                   uint16
         |  +--ro session-ka-interval?                   uint16
         |  +--ro session-downstream-on-demand {session-downstream-on-demand-config}?
         |     +--ro enable?      boolean
         |     +--ro peer-list?   peer-list-ref
         +--rw peer* [lsr-id]
            +--rw lsr-id    yang:dotted-quad
            +--ro state
               +--ro admin-down?                            boolean
               +--ro capability
               +--ro label-policy
               |  +--ro advertise
               |  |  +--ro prefix-list?   prefix-list-ref
               |  +--ro accept
               |     +--ro prefix-list?   prefix-list-ref
               +--ro session-authentication-md5-password?   string
               +--ro graceful-restart
               |  +--ro enable?           boolean
               |  +--ro reconnect-time?   uint16
               |  +--ro recovery-time?    uint16
               +--ro session-ka-holdtime?                   uint16
               +--ro session-ka-interval?                   uint16
               +--ro address-family
               |  +--ro ipv4
               |  |  +--ro label-policy
               |  |  |  +--ro advertise
               |  |  |  |  +--ro prefix-list?   prefix-list-ref
               |  |  |  +--ro accept



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               |  |  |     +--ro prefix-list?   prefix-list-ref
               |  |  +--ro hello-adjacencies* [local-address adjacent-address]
               |  |     +--ro local-address       inet:ipv4-address
               |  |     +--ro adjacent-address    inet:ipv4-address
               |  |     +--ro flag*               identityref
               |  |     +--ro hello-holdtime
               |  |     |  +--ro adjacent?     uint16
               |  |     |  +--ro negotiated?   uint16
               |  |     |  +--ro remaining?    uint16
               |  |     +--ro next-hello?         uint16
               |  |     +--ro statistics
               |  |     |  +--ro discontinuity-time    yang:date-and-time
               |  |     |  +--ro hello-received?       yang:counter64
               |  |     |  +--ro hello-dropped?        yang:counter64
               |  |     +--ro interface?          mpls-interface-ref
               |  +--ro ipv6
               |     +--ro label-policy
               |     |  +--ro advertise
               |     |  |  +--ro prefix-list?   prefix-list-ref
               |     |  +--ro accept
               |     |     +--ro prefix-list?   prefix-list-ref
               |     +--ro hello-adjacencies* [local-address adjacent-address]
               |        +--ro local-address       inet:ipv6-address
               |        +--ro adjacent-address    inet:ipv6-address
               |        +--ro flag*               identityref
               |        +--ro hello-holdtime
               |        |  +--ro adjacent?     uint16
               |        |  +--ro negotiated?   uint16
               |        |  +--ro remaining?    uint16
               |        +--ro next-hello?         uint16
               |        +--ro statistics
               |        |  +--ro discontinuity-time    yang:date-and-time
               |        |  +--ro hello-received?       yang:counter64
               |        |  +--ro hello-dropped?        yang:counter64
               |        +--ro interface?          mpls-interface-ref
               +--ro label-advertisement-mode
               |  +--ro local?        label-adv-mode
               |  +--ro peer?         label-adv-mode
               |  +--ro negotiated?   label-adv-mode
               +--ro next-keep-alive?                       uint16
               +--ro peer-ldp-id?                           yang:dotted-quad
               +--ro received-peer-state
               |  +--ro graceful-restart
               |  |  +--ro enable?           boolean
               |  |  +--ro reconnect-time?   uint16
               |  |  +--ro recovery-time?    uint16
               |  +--ro capability
               |     +--ro end-of-lib



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               |     |  +--ro enable?   boolean
               |     +--ro typed-wildcard-fec
               |     |  +--ro enable?   boolean
               |     +--ro upstream-label-assignment
               |        +--ro enable?   boolean
               +--ro session-holdtime
               |  +--ro peer?         uint16
               |  +--ro negotiated?   uint16
               |  +--ro remaining?    uint16
               +--ro session-state?                         enumeration
               +--ro tcp-connection
               |  +--ro local-address?    inet:ip-address
               |  +--ro local-port?       inet:port-number
               |  +--ro remote-address?   inet:ip-address
               |  +--ro remote-port?      inet:port-number
               +--ro up-time?                               string
               +--ro statistics
                  +--ro discontinuity-time          yang:date-and-time
                  +--ro received
                  |  +--ro total-octets?          yang:counter64
                  |  +--ro total-messages?        yang:counter64
                  |  +--ro address?               yang:counter64
                  |  +--ro address-withdraw?      yang:counter64
                  |  +--ro initialization?        yang:counter64
                  |  +--ro keepalive?             yang:counter64
                  |  +--ro label-abort-request?   yang:counter64
                  |  +--ro label-mapping?         yang:counter64
                  |  +--ro label-release?         yang:counter64
                  |  +--ro label-request?         yang:counter64
                  |  +--ro label-withdraw?        yang:counter64
                  |  +--ro notification?          yang:counter64
                  +--ro sent
                  |  +--ro total-octets?          yang:counter64
                  |  +--ro total-messages?        yang:counter64
                  |  +--ro address?               yang:counter64
                  |  +--ro address-withdraw?      yang:counter64
                  |  +--ro initialization?        yang:counter64
                  |  +--ro keepalive?             yang:counter64
                  |  +--ro label-abort-request?   yang:counter64
                  |  +--ro label-mapping?         yang:counter64
                  |  +--ro label-release?         yang:counter64
                  |  +--ro label-request?         yang:counter64
                  |  +--ro label-withdraw?        yang:counter64
                  |  +--ro notification?          yang:counter64
                  +--ro total-addresses?            uint32
                  +--ro total-labels?               uint32
                  +--ro total-fec-label-bindings?   uint32




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                                 Figure 5

3.3.1.  Derived States

   Following are main areas for which LDP operational "derived" state is
   defined:

      Neighbor Adjacencies

      Peer

      Bindings (FEC-label and address)

      Capabilities

3.3.1.1.  Adjacency state

   Neighbor adjacencies are per address-family hello adjacencies that
   are formed with neighbors as result of LDP basic or extended
   discovery.  In terms of organization, there is a source of discovery
   (e.g. interface or target address) along with its associated
   parameters and one or more discovered neighbors along with neighbor
   discovery related parameters.  For the basic discovery, there could
   be more than one discovered neighbor for a given source (interface),
   whereas there is at most one discovered neighbor for an extended
   discovery source (local-address and target-address).  This is also to
   be noted that the reason for a targeted neighbor adjacency could be
   either an active source (locally configured targeted) or passive
   source (to allow any incoming extended/targeted hellos).  A neighbor/
   adjacency record also contains session-state that helps highlight
   whether a given adjacency has progressed to subsequent session level
   or to eventual peer level.

   Following captures high level tree hierarchy for neighbor adjacency
   state.
















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   +--rw mpls-ldp!
      +--rw discovery
         +--rw interfaces
         |  +--rw interface* [interface]
         |     +--rw address-family* [af]
         |        +--ro state
         |           +--ro ipv4 (or ipv6)
         |              +--ro hello-adjacencies* [adjacent-address]
         |                 +--ro adjacent-address
         |                    . . . .
         |                    . . . .
         +--rw targeted
            +--rw address-family* [afi]
                +--rw afi      address-family
                   +--ro state
                      +--ro ipv4 (or ipv6)
                         +--ro hello-adjacencies* [local-address adjacent-address]
                            +--ro local-address
                            +--ro adjacent-address
                               . . . .
                               . . . .


                                 Figure 6

3.3.1.2.  Peer state

   Peer related derived state is presented under peers tree.  This is
   one of the core state that provides info on the session related
   parameters (mode, authentication, KA timeout etc.), TCP connection
   info, hello adjacencies for the peer, statistics related to messages
   and bindings, and capabilities exchange info.

   Following captures high level tree hierarchy for peer state.

















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  +--rw mpls-ldp!
      +--rw peers
         +--rw peer* [lsr-id]
            +--rw lsr-id
            +--ro state
               +--ro session-ka-holdtime?
               +-- . . . .
               +-- . . . .
               +--ro capability
               +  +ro -- . . .
               +--ro address-family
               |  +--ro ipv4 (or ipv6)
               |     +--ro hello-adjacencies* [local-address adjacent-address]
               |        . . . .
               |        . . . .
               +--ro received-peer-state
               |  +--ro . . . .
               |  +--ro capability
               |     +--ro . . . .
               +--ro statistics
                  +-- . . . .
                  +-- . . . .


                                 Figure 7

3.3.1.3.  Bindings state

   Binding state provides information on LDP FEC-label bindings as well
   as address binding for both inbound (received) as well as outbound
   (advertised) direction.  FEC-label bindings are presented as a FEC-
   centric view, and address bindings are presented as an address-
   centric view:


















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        FEC-Label bindings:
            FEC 200.1.1.1/32:
              advertised: local-label 16000
                peer 192.168.0.2:0
                peer 192.168.0.3:0
                peer 192.168.0.4:0
              received:
                peer 192.168.0.2:0, label 16002, used-in-forwarding=Yes
                peer 192.168.0.3:0, label 17002, used-in-forwarding=No
            FEC 200.1.1.2/32:
               . . . .
            FEC 201.1.0.0/16:
               . . . .


        Address bindings:
            Addr 1.1.1.1:
              advertised
            Addr 1.1.1.2:
              advertised
            Addr 2.2.2.2:
              received, peer 192.168.0.2
            Addr 2.2.2.22:
              received, peer 192.168.0.2
            Addr 3.3.3.3:
              received, peer 192.168.0.3
            Addr 3.3.3.33:
              received, peer 192.168.0.3


                                 Figure 8

   Note that all local addresses are advertised to all peers and hence
   no need to provide per-peer information for local address
   advertisement.  Furthermore, note that it is easy to derive a peer-
   centric view for the bindings from the information already provided
   in this model.

   Following captures high level tree hierarchy for bindings state.












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   +--rw mpls-ldp!
      +--rw global
         +--rw address-family* [afi]
            +--rw afi       address-family
            +--ro state
               +--ro ipv4 (or ipv6)
                  +--ro bindings
                     +--ro address* [address]
                     |  +--ro address
                     |  +--ro direction?   advertised-received
                     |  +--ro peer?        leafref
                     +--ro fec-label* [fec]
                        +--ro fec     inet:ipv4-prefix
                        +--ro peer* [peer advertisement-type]
                           +--ro peer                  leafref
                           +--ro advertisement-type    advertised-received
                           +--ro label?                mpls:mpls-label
                           +--ro used-in-forwarding?   boolean


                                 Figure 9

3.3.1.4.  Capabilities state

   LDP capabilities state comprise two types of information - global
   information (such as timer etc.), and per-peer information.

   Following captures high level tree hierarchy for LDP capabilities
   state.


      +--rw mpls-ldp!
         +--rw global
         |  +--ro state
         |     +--ro capability
         |        +--ro . . . .
         |        +--ro . . . .
         +--rw peers
            +--rw peer* [lsr-id]
               +--rw lsr-id    yang:dotted-quad
               +--ro state
                  +--ro received-peer-state
                     +--ro capability
                        +--ro . . . .
                        +--ro . . . .


                                 Figure 10



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3.4.  Notifications

   This model defines a list of notifications to inform client of
   important events detected during the protocol operation.  These
   events include events related to changes in the operational state of
   an LDP peer, hello adjacency, and FEC etc.  It is to be noted that an
   LDP FEC is treated as operational (up) as long as it has at least 1
   NHLFE with outgoing label.

   Following is a simplified graphical representation of the data model
   for LDP notifications.

   module: ietf-mpls-ldp
   notifications:
      +---n mpls-ldp-peer-event
      |  +--ro event-type?   oper-status-event-type
      |  +--ro peer-ref?     leafref
      +---n mpls-ldp-hello-adjacency-event
      |  +--ro event-type?   oper-status-event-type
      |  +--ro (hello-adjacency-type)?
      |     +--:(targeted)
      |     |  +--ro targeted
      |     |     +--ro target-address?   inet:ip-address
      |     +--:(link)
      |        +--ro link
      |           +--ro next-hop-interface?   mpls-interface-ref
      |           +--ro next-hop-address?     inet:ip-address
      +---n mpls-ldp-fec-event
         +--ro event-type?   oper-status-event-type
         +--ro prefix?       inet:ip-prefix


                                 Figure 11

3.5.  Actions

   This model defines a list of rpcs that allow performing an action or
   executing a command on the protocol.  For example, it allows to clear
   (reset) LDP peers, hello-adjacencies, and statistics.  The model
   makes an effort to provide different level of control so that a user
   is able to either clear all, or clear all for a given type, or clear
   a specific entity.

   Following is a simplified graphical representation of the data model
   for LDP actions.






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   module: ietf-mpls-ldp
   rpcs:
      +---x mpls-ldp-clear-peer
      |  +---w input
      |     +---w lsr-id?   union
      +---x mpls-ldp-clear-hello-adjacency
      |  +---w input
      |     +---w hello-adjacency
      |        +---w (hello-adjacency-type)?
      |           +--:(targeted)
      |           |  +---w targeted!
      |           |     +---w target-address?   inet:ip-address
      |           +--:(link)
      |              +---w link!
      |                 +---w next-hop-interface?   mpls-interface-ref
      |                 +---w next-hop-address?     inet:ip-address
      +---x mpls-ldp-clear-peer-statistics
         +---w input
            +---w lsr-id?   union

                                 Figure 12

4.  mLDP YANG Model

4.1.  Overview

   Due to tight dependency of mLDP on LDP, mLDP model builds on top of
   LDP model defined earlier in the document.  Following are the main
   mLDP areas and documents that are within the scope of this model:

   o  mLDP Base Specification [RFC6388]

   o  mLDP Recursive FEC [RFC6512]

   o  Targeted mLDP [RFC7060]

   o  mLDP Fast-Reroute (FRR)

      *  Node Protection [RFC7715]

      *  Multicast-only

   o  Hub-and-Spoke Multipoint LSPs [RFC7140]

   o  mLDP In-band Signaling [RFC6826] (future revision)

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




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   o  mLDP In-band Signaling with Wildcards [RFC7438] (future revision)

   o  Configured Leaf LSPs (manually provisioned)

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

4.2.  Configuration

4.2.1.  Configuration Hierarchy

   In terms of overall configuration layout, following figure highlights
   extensions to LDP configuration model to incorporate mLDP:






































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      +-- mpls-ldp
         +-- ...
         +-- ...
         +-- mldp
         |  +-- ...
         |  +-- ...
         |  +-- address-family* [af]
         |     +-- af
         |        +-- ...
         |        +-- ...
         +-- global
         |  +-- ...
         |  +-- capability
         |     +-- ...
         |     +-- ...
         |     +-- mldp
         |        +-- ...
         |        +-- ...
         +-- discovery
         |  +-- ...
         |  +-- ...
         +-- forwarding-nexthop
         |  +-- interfaces
         |     +-- interface* [interface]
         |        +-- interface
         |        +-- address-family* [af]
         |           +-- af
         |           +-- ...
         |           +-- mldp-disable
         +-- peers
            +-- ...
            +-- ...
            +-- peer* [lsr-id]
                +-- ...
                +-- ...
                +-- capability
                    +-- ...
                    +-- ...
                    +-- mldp
                        +-- ...
                        +-- ...


                                 Figure 13

   From above hierarchy, we can categorize mLDP configuration parameters
   into two types:




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   o  Parameters that leverage/extend LDP containers and parameters

   o  Parameters that are mLDP specific

   Following subsections first describe mLDP specific configuration
   parameters, followed by those leveraging LDP.

4.2.2.  mldp container

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

   o  mLDP enabling: To enable mLDP under a (VRF) routing instance, mldp
      container is enabled under LDP.  Given that mLDP requires LDP
      signalling, it is not sensible to allow disabling LDP control
      plane under a (VRF) network-instance while requiring mLDP to be
      enabled for the same.  However, if a user wishes only to allow
      signalling for multipoint FECs on an LDP/mLDP enabled VRF
      instance, he/she can use LDP label-policies to disable unicast
      FECs under the VRF.

   o  mLDP per-AF 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 LSP
         manually, a container is provided per-AF 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] do not require any mLDP
   specific configuration.  It, however, requires LDP upstream-label-
   assignment capability [RFC6389] to be enabled.








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4.2.3.  Leveraging LDP containers

   mLDP configuration model leverages following configuration areas and
   containers that are already defined for LDP:

   o  Capabilities: A new container "mldp" is defined under Capabilities
      container.  This new container specifies any mLDP specific
      capabilities and their parameters.  Moreover, a new "mldp"
      container is also added under per-peer capability container to
      override/control mLDP specific capabilities on a peer level.  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.

   o  Discovery and Peer: mLDP requires LDP discovery and peer
      procedures to form mLDP peering.  A peer is treated as mLDP peer
      only when either P2MP or MP2MP capabilities have been successfully
      exchanged with the peer.  If a user wish to selectively enable or
      disable mLDP with a LDP-enabled peer, he/she may use per-peer mLDP
      capabilities configuration.  [Ed Note: The option to control mLDP
      enabling/disabling on a peer-list is being explored for future ].
      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 targeted
      only.  In future revision, a configuration option for this support
      will also be provided.

   o  Forwarding: By default, mLDP is allowed to select any of the LDP
      enabled interface as a downstream interface towards a nexthop
      (LDP/mLDP peer) for MP LSP programming.  However, a configuration
      option is provided to allow mLDP to exclude a given interface from
      such a selection.  Note that such a configuration option will be
      useful only when there are more than one interfaces available for
      the downstream selection.

   This goes without saying that mLDP configuration tree follows the
   same approach as LDP, where the tree comprise leafs for intended
   configuration.

4.2.4.  YANG tree

   The following figure captures the YANG tree for mLDP configuration.
   To keep the focus, the figure has been simplified to display only
   mLDP items without any LDP items.

module: ietf-mpls-ldp
augment /rt:routing/rt:control-plane-protocols:
   +--rw mpls-ldp!



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      +--rw global
      |  +--rw config
      |  |  +--rw capability
      |  |     +--rw mldp {mldp}?
      |  |        +--rw p2mp
      |  |        |  +--rw enable?   boolean
      |  |        +--rw mp2mp
      |  |        |  +--rw enable?   boolean
      |  |        +--rw make-before-break
      |  |        |  +--rw enable?             boolean
      |  |        |  +--rw switchover-delay?   uint16
      |  |        |  +--rw timeout?            uint16
      |  |        +--rw hub-and-spoke {capability-mldp-hsmp}?
      |  |        |  +--rw enable?   boolean
      |  |        +--rw node-protection {capability-mldp-node-protection}?
      |  |           +--rw plr?           boolean
      |  |           +--rw merge-point
      |  |              +--rw enable?                            boolean
      |  |              +--rw targeted-session-teardown-delay?   uint16
      |  +--rw mldp {mldp}?
      |  |  +--rw config
      |  |  |  +--rw enable?   boolean
      |  |  +--rw address-family* [afi]
      |  |     +--rw afi                     ldp-address-family
      |  |     +--rw config
      |  |     |  +--rw multicast-only-frr {mldp-mofrr}?
      |  |     |  |  +--rw prefix-list?   prefix-list-ref
      |  |     |  +--rw recursive-fec
      |  |     |     +--rw prefix-list?   prefix-list-ref
      |  |     +--rw configured-leaf-lsps
      |  |        +--rw p2mp
      |  |        |  +--rw roots-ipv4
      |  |        |  |  +--rw root* [root-address]
      |  |        |  |     +--rw root-address    inet:ipv4-address
      |  |        |  |     +--rw lsp* [lsp-id source-address group-address]
      |  |        |  |        +--rw lsp-id            uint16
      |  |        |  |        +--rw source-address    inet:ipv4-address
      |  |        |  |        +--rw group-address     inet:ipv4-address-no-zone
      |  |        |  +--rw roots-ipv6
      |  |        |     +--rw root* [root-address]
      |  |        |        +--rw root-address    inet:ipv6-address
      |  |        |        +--rw lsp* [lsp-id source-address group-address]
      |  |        |           +--rw lsp-id            uint16
      |  |        |           +--rw source-address    inet:ipv6-address
      |  |        |           +--rw group-address     inet:ipv6-address-no-zone
      |  |        +--rw mp2mp
      |  |           +--rw roots-ipv4
      |  |           |  +--rw root* [root-address]



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      |  |           |     +--rw root-address    inet:ipv4-address
      |  |           |     +--rw lsp* [lsp-id source-address group-address]
      |  |           |        +--rw lsp-id            uint16
      |  |           |        +--rw source-address    inet:ipv4-address
      |  |           |        +--rw group-address     inet:ipv4-address-no-zone
      |  |           +--rw roots-ipv6
      |  |              +--rw root* [root-address]
      |  |                 +--rw root-address    inet:ipv6-address
      |  |                 +--rw lsp* [lsp-id source-address group-address]
      |  |                    +--rw lsp-id            uint16
      |  |                    +--rw source-address    inet:ipv6-address
      |  |                    +--rw group-address     inet:ipv6-address-no-zone
      |  +--rw forwarding-nexthop {forwarding-nexthop-config}?
      |     +--rw interfaces
      |        +--rw interface* [interface]
      |           +--rw interface         if:interface-ref
      |           +--rw address-family* [afi]
      |              +--rw afi       address-family
      |              +--rw config
      |                 +--rw mldp-disable?   boolean {mldp}?
      +--rw peers
         +--rw peer* [lsr-id]
               +--rw capability
                  +--rw mldp {mldp}?
                     +--rw p2mp
                     |  +--rw enable?   boolean
                     +--rw mp2mp
                     |  +--rw enable?   boolean
                     +--rw make-before-break
                     |  +--rw enable?             boolean
                     |  +--rw switchover-delay?   uint16
                     |  +--rw timeout?            uint16
                     +--rw hub-and-spoke {capability-mldp-hsmp}?
                     |  +--rw enable?   boolean
                      +--rw node-protection {capability-mldp-node-protection}?
                        +--rw plr?           boolean
                        +--rw merge-point
                           +--rw enable?                            boolean
                           +--rw targeted-session-teardown-delay?   uint16


                                 Figure 14

4.3.  Operational State

   Operational state of mLDP can be queried and obtained from this read-
   only container "mldp" which resides under mpls-ldp container.




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   Please note this state tree refers both the configuration "applied"
   state as well as the "derived" state related to the mLDP protocol.

   Following is a simplified graphical representation of the data model
   for mLDP operational state:


module: ietf-mpls-ldp
augment /rt:routing/rt:control-plane-protocols:
   +--rw mpls-ldp!
      +--rw global
      |  +--ro state
      |  |  +--ro capability
      |  |     +--ro mldp {mldp}?
      |  |        +--ro p2mp
      |  |        |  +--ro enable?   boolean
      |  |        +--ro mp2mp
      |  |        |  +--ro enable?   boolean
      |  |        +--ro make-before-break
      |  |        |  +--ro enable?             boolean
      |  |        |  +--ro switchover-delay?   uint16
      |  |        |  +--ro timeout?            uint16
      |  |        +--ro hub-and-spoke {capability-mldp-hsmp}?
      |  |        |  +--ro enable?   boolean
      |  |        +--ro node-protection {capability-mldp-node-protection}?
      |  |           +--ro plr?           boolean
      |  |           +--ro merge-point
      |  |              +--ro enable?                            boolean
      |  |              +--ro targeted-session-teardown-delay?   uint16
      |  |
      |  +--rw mldp {mldp}?
      |  |  +--ro state
      |  |     +--ro enable?   boolean
      |  |  +--rw address-family* [afi]
      |  |     +--rw afi                     ldp-address-family
      |  |     +--ro state
      |  |        +--ro multicast-only-frr {mldp-mofrr}?
      |  |        |  +--ro prefix-list?   prefix-list-ref
      |  |        +--ro recursive-fec
      |  |        |  +--ro prefix-list?   prefix-list-ref
      |  |        +--ro ipv4
      |  |        |  +--ro roots
      |  |        |  |  +--ro root* [root-address]
      |  |        |  |     +--ro root-address    inet:ipv4-address
      |  |        |  |     +--ro is-self?        boolean
      |  |        |  |     +--ro reachability* [address interface]
      |  |        |  |        +--ro address      inet:ipv4-address
      |  |        |  |        +--ro interface    mpls-interface-ref



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      |  |        |  |        +--ro peer?        leafref
      |  |        |  +--ro bindings
      |  |        |     +--ro opaque-type-lspid
      |  |        |     |  +--ro fec-label* [root-address lsp-id recur-root-address recur-rd]
      |  |        |     |     +--ro root-address          inet:ipv4-address
      |  |        |     |     +--ro lsp-id                uint32
      |  |        |     |     +--ro recur-root-address    inet:ip-address
      |  |        |     |     +--ro recur-rd              route-distinguisher
      |  |        |     |     +--ro multipoint-type?      multipoint-type
      |  |        |     |     +--ro peer* [direction peer advertisement-type]
      |  |        |     |        +--ro direction             downstream-upstream
      |  |        |     |        +--ro peer                  leafref
      |  |        |     |        +--ro advertisement-type    advertised-received
      |  |        |     |        +--ro label?                mpls:mpls-label
      |  |        |     |        +--ro mbb-role?             enumeration
      |  |        |     |        +--ro mofrr-role?           enumeration
      |  |        |     +--ro opaque-type-src
      |  |        |     |  +--ro fec-label* [root-address source-address group-address rd recur-root-address recur-rd]
      |  |        |     |     +--ro root-address          inet:ipv4-address
      |  |        |     |     +--ro source-address        inet:ip-address
      |  |        |     |     +--ro group-address         inet:ip-address-no-zone
      |  |        |     |     +--ro rd                    route-distinguisher
      |  |        |     |     +--ro recur-root-address    inet:ip-address
      |  |        |     |     +--ro recur-rd              route-distinguisher
      |  |        |     |     +--ro multipoint-type?      multipoint-type
      |  |        |     |     +--ro peer* [direction peer advertisement-type]
      |  |        |     |        +--ro direction             downstream-upstream
      |  |        |     |        +--ro peer                  leafref
      |  |        |     |        +--ro advertisement-type    advertised-received
      |  |        |     |        +--ro label?                mpls:mpls-label
      |  |        |     |        +--ro mbb-role?             enumeration
      |  |        |     |        +--ro mofrr-role?           enumeration
      |  |        |     +--ro opaque-type-bidir
      |  |        |        +--ro fec-label* [root-address rp group-address rd recur-root-address recur-rd]
      |  |        |           +--ro root-address          inet:ipv4-address
      |  |        |           +--ro rp                    inet:ip-address
      |  |        |           +--ro group-address         inet:ip-address-no-zone
      |  |        |           +--ro rd                    route-distinguisher
      |  |        |           +--ro recur-root-address    inet:ip-address
      |  |        |           +--ro recur-rd              route-distinguisher
      |  |        |           +--ro multipoint-type?      multipoint-type
      |  |        |           +--ro peer* [direction peer advertisement-type]
      |  |        |              +--ro direction             downstream-upstream
      |  |        |              +--ro peer                  leafref
      |  |        |              +--ro advertisement-type    advertised-received
      |  |        |              +--ro label?                mpls:mpls-label
      |  |        |              +--ro mbb-role?             enumeration
      |  |        |              +--ro mofrr-role?           enumeration



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      |  |        +--ro ipv6
      |  |           +--ro roots
      |  |           |  +--ro root* [root-address]
      |  |           |     +--ro root-address    inet:ipv6-address
      |  |           |     +--ro is-self?        boolean
      |  |           |     +--ro reachability* [address interface]
      |  |           |        +--ro address      inet:ipv6-address
      |  |           |        +--ro interface    mpls-interface-ref
      |  |           |        +--ro peer?        leafref
      |  |           +--ro bindings
      |  |              +--ro opaque-type-lspid
      |  |              |  +--ro fec-label* [root-address lsp-id recur-root-address recur-rd]
      |  |              |     +--ro root-address          inet:ipv6-address
      |  |              |     +--ro lsp-id                uint32
      |  |              |     +--ro recur-root-address    inet:ip-address
      |  |              |     +--ro recur-rd              route-distinguisher
      |  |              |     +--ro multipoint-type?      multipoint-type
      |  |              |     +--ro peer* [direction peer advertisement-type]
      |  |              |        +--ro direction             downstream-upstream
      |  |              |        +--ro peer                  leafref
      |  |              |        +--ro advertisement-type    advertised-received
      |  |              |        +--ro label?                mpls:mpls-label
      |  |              |        +--ro mbb-role?             enumeration
      |  |              |        +--ro mofrr-role?           enumeration
      |  |              +--ro opaque-type-src
      |  |              |  +--ro fec-label* [root-address source-address group-address rd recur-root-address recur-rd]
      |  |              |     +--ro root-address          inet:ipv6-address
      |  |              |     +--ro source-address        inet:ip-address
      |  |              |     +--ro group-address         inet:ip-address-no-zone
      |  |              |     +--ro rd                    route-distinguisher
      |  |              |     +--ro recur-root-address    inet:ip-address
      |  |              |     +--ro recur-rd              route-distinguisher
      |  |              |     +--ro multipoint-type?      multipoint-type
      |  |              |     +--ro peer* [direction peer advertisement-type]
      |  |              |        +--ro direction             downstream-upstream
      |  |              |        +--ro peer                  leafref
      |  |              |        +--ro advertisement-type    advertised-received
      |  |              |        +--ro label?                mpls:mpls-label
      |  |              |        +--ro mbb-role?             enumeration
      |  |              |        +--ro mofrr-role?           enumeration
      |  |              +--ro opaque-type-bidir
      |  |                 +--ro fec-label* [root-address rp group-address rd recur-root-address recur-rd]
      |  |                    +--ro root-address          inet:ipv6-address
      |  |                    +--ro rp                    inet:ip-address
      |  |                    +--ro group-address         inet:ip-address-no-zone
      |  |                    +--ro rd                    route-distinguisher
      |  |                    +--ro recur-root-address    inet:ip-address
      |  |                    +--ro recur-rd              route-distinguisher



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      |  |                    +--ro multipoint-type?      multipoint-type
      |  |                    +--ro peer* [direction peer advertisement-type]
      |  |                       +--ro direction             downstream-upstream
      |  |                       +--ro peer                  leafref
      |  |                       +--ro advertisement-type    advertised-received
      |  |                       +--ro label?                mpls:mpls-label
      |  |                       +--ro mbb-role?             enumeration
      |  |                       +--ro mofrr-role?           enumeration
      |  +--rw forwarding-nexthop {forwarding-nexthop-config}?
      |     +--rw interfaces
      |        +--rw interface* [interface]
      |           +--rw address-family* [afi]
      |              +--ro state
      |                 +--ro mldp-disable?   boolean {mldp}?
      +--rw peers
         +--rw peer* [lsr-id]
            +--ro state
               +--ro capability
               |   +--ro mldp {mldp}?
               |     +--ro p2mp
               |     |  +--ro enable?   boolean
               |     +--ro mp2mp
               |     |  +--ro enable?   boolean
               |     +--ro make-before-break
               |     |  +--ro enable?             boolean
               |     |  +--ro switchover-delay?   uint16
               |     |  +--ro timeout?            uint16
               |     +--ro hub-and-spoke {capability-mldp-hsmp}?
               |     |  +--ro enable?   boolean
               |     +--ro node-protection {capability-mldp-node-protection}?
               |        +--ro plr?           boolean
               |        +--ro merge-point
               |           +--ro enable?                            boolean
               |           +--ro targeted-session-teardown-delay?   uint16
               +--ro received-peer-state
                  +--ro capability
                     +--ro mldp {mldp}?
                        +--ro p2mp
                        |  +--ro enable?   boolean
                        +--ro mp2mp
                        |  +--ro enable?   boolean
                        +--ro make-before-break
                        |  +--ro enable?   boolean
                        +--ro hub-and-spoke
                        |  +--ro enable?   boolean
                        +--ro node-protection
                           +--ro plr?           boolean
                           +--ro merge-point?   boolean



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                                 Figure 15

4.3.1.  Derived states

   Following are main areas for which mLDP operational derived state is
   defined:

   o  Root

   o  Bindings (FEC-label)

   o  Capabilities

4.3.1.1.  Root state

   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 information on the root reachability (as
   learnt from RIB).  In case of multi-path reachability to a root, the
   selection of upstream path is done on per-LSP basis at the time of
   LSP setup.  Similarly, when protection mechanisms like MBB or MoFRR
   are in place, the path designation as active/standby or primary/
   backup is also done on per LSP basis.  It is to 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 RNR
   purposes.

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






















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        root 1.1.1.1:
            path1:
                RIB: GigEthernet 1/0, 12.1.0.2;
                LDP: peer 192.168.0.1:0
            path2:
                RIB: GigEthernet 2/0, 12.2.0.2;
                LDP: peer 192.168.0.3:0

        root 2.2.2.2:
            path1:
                RIB: 3.3.3.3;             (NOTE: This is a recursive path)
                LDP: peer 192.168.0.3:0   (NOTE: T-mLDP peer)

         root 9.9.9.9:
            . . . .


                                 Figure 16

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


           root 9.9.9.9:
               is-self


                                 Figure 17

4.3.1.2.  Bindings state

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

   This document covers following type of opaque values with their keys
   in the operational model of mLDP bindings:









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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: MP Opaque Types and keys

   It is to 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.

   Following captures high level tree hierarchy for mLDP bindings state:

   +--rw mpls-ldp!
       +--rw mldp
         +--rw address-family* [afi]
            +--rw afi       address-family
            +--ro state
               +--ro ipv4 (or ipv6)
                  +--ro bindings
                     +--ro opaque-type-xxx [root-address, type-specific-key]
                        +--ro root-address
                        +--ro ...
                        +--ro recur-root-address    inet:ipv4-address
                        +--ro recur-rd              route-distinguisher
                        +--ro multipoint-type?      multipoint-type
                        +--ro peer* [direction peer advertisement-type]
                           +--ro direction             downstream-upstream
                           +--ro peer                  leafref
                           +--ro advertisement-type    advertised-received
                           +--ro label?                mpls:mpls-label
                           +--ro mbb-role?             enumeration
                           +--ro mofrr-role?           enumeration

                                 Figure 18





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   In the above tree, the type-specific-key varies with the base type as
   listed in earlier Table 1.  For example, if the opaque type is
   Generic LSP Identifier, then the type-specific-key will be a uint32
   value corresponding to the LSP.  Please see the complete model for
   all other types.

   Moreover, the binding tree defines only three types of sub-trees
   (i.e. lspid, src, and bidir) which is able to map the respective
   variants (vpn, recursive, and vpn-recusrive) accordingly.  For
   example, the key for opaque-type-src is [R, S, G, rd, recur-R, recur-
   RD], where basic type will specify (R, S,G,-, -, -), VPN type will
   specify (R, S,G, rd, -, -), recursive type will specify [R, S,G, -,
   recur-R, -] and VPN-recursive type will specify [R, S,G, -, recur-R,
   recur-rd].

   It is important to take note of the following:

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

   o  The "recur-root-address" field applies to Recursive opaque type,
      and (recur-root-address, recur-rd) fields applies to VPN-Recursive
      opaque types as defined in [RFC6512]

   o  In case of a recursive FEC, the address-family of the recur-root-
      address could be different than the address-family of the root
      address of original encapsulated MP FEC

   The following diagram illustrates the FEC-label binding information
   structure for a P2MP (Transit IPv4 Source type) LSP on a branch/
   transit LSR:


            FEC (root 2.2.2.2, S=192.168.1.1, G=224.1.1.1):
              type: p2mp
              upstream:
                advertised:
                  peer 192.168.0.1:0, label 16000 (local)
              downstream:
                received:
                  peer 192.168.0.2:0, label 17000 (remote)
                  peer 192.168.0.3:0, label 18000  (remote)



                                 Figure 19




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   The following diagram illustrates the FEC-label binding information
   structure for a similar MP2MP LSP on a branch/transit LSR:


         FEC (root 2.2.2.2, RP=192.168.9.9, G=224.1.1.1):
           type: mp2mp
           upstream:
             advertised:
               peer 192.168.0.1:0, label 16000 (local)
             received:
               peer 192.168.0.1:0, label 17000 (remote)
           downstream:
             advertised:
               peer 192.168.0.2:0, label 16001 (local), MBB role=active
               peer 192.168.0.3:0, label 16002 (local), MBB role=standby
             received:
               peer 192.168.0.2:0, label 17001 (remote)
               peer 192.168.0.3:0, label 18001 (remote)


                                 Figure 20

4.3.1.3.  Capabilities state

   Like LDP, mLDP capabilities state comprise two types of information -
   global information and per-peer information.

4.4.  Notifications

   mLDP notification module consists of notification related to changes
   in the operational state of an mLDP FEC.  Following is a simplified
   graphical representation of the data model for mLDP notifications:


   notifications:
      +---n mpls-mldp-fec-event
         +--ro event-type?       oper-status-event-type
         +--ro tree-type?        multipoint-type
         +--ro root?             inet:ip-address
         +--ro (lsp-key-type)?
            +--:(lsp-id-based)
            |  +--ro lsp-id?           uint16
            +--:(source-group-based)
               +--ro source-address?   inet:ip-address
               +--ro group-address?    inet:ip-address


                                 Figure 21



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4.5.  Actions

   Currently, no RPCs/actions are defined for mLDP.

5.  Open Items

   Following is a list of open items that are to be discussed and
   addressed in future revisions of this document:

   o  Close on augmentation off "mpls" list in "ietf-mpls" defined in
      [I-D.saad-mpls-base-yang]

   o  Align operational state modeling with other routing procols and
      [I-D.openconfig-netmod-opstate]

   o  Complete the section on Protocol-centric implementations and all-
      vrfs

   o  Specify default values for configuration parameters

   o  Revisit and cut down on the scope of the document and number of
      features it is trying to cover

   o  Split the model into a base and extended items

   o  Add statistics for mLDP root LSPs and bindings

   o  Extend the "Configured Leaf LSPs" for various type of opaque-types

   o  Extend mLDP notifications for other types of opaque values as well

   o  Close on single vs separate document for mLDP Yang

6.  YANG Specification

   Following are actual YANG definition for LDP and mLDP constructs
   defined earlier in the document.



 <CODE BEGINS> file "ietf-mpls-ldp@2016-07-08.yang" -->

 module ietf-mpls-ldp {
   namespace "urn:ietf:params:xml:ns:yang:ietf-mpls-ldp";
   // replace with IANA namespace when assigned
   prefix ldp;

   import ietf-inet-types {



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     prefix "inet";
   }

   import ietf-yang-types {
     prefix "yang";
   }

   import ietf-interfaces {
     prefix "if";
   }

   import ietf-ip {
     prefix "ip";
   }

   import ietf-routing {
     prefix "rt";
   }

   import ietf-mpls {
     prefix "mpls";
   }

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

      WG Chair: Loa Andersson
                <mailto:loa@pi.nu>

      WG Chair: Ross Callon
                <mailto:rcallon@juniper.net>

      WG Chair: George Swallow
                <mailto:swallow.ietf@gmail.com>

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

      Editor:   Rajiv Asati
                <mailto:rajiva@cisco.com>

      Editor:   Xufeng Liu
                <mailto:xliu@kuatrotech.com>

      Editor:   Santosh Esale



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                <mailto:sesale@juniper.net>

      Editor:   Xia Chen
                <mailto:jescia.chenxia@huawei.com>

      Editor:   Himanshu Shah
                <mailto:hshah@ciena.com>";

   description
     "This YANG module defines the essential components for the
      management of Multi-Protocol Label Switching (MPLS) Label
      Distribution Protocol (LDP) and Multipoint LDP (mLDP).";

   revision 2016-07-08 {
     description
       "Initial revision.";
     reference
       "RFC XXXX: YANG Data Model for MPLS LDP and mLDP.";
   }

   /*
    * Features
    */

   feature admin-down-config {
     description
       "This feature indicates that the system allows to configure
        administrative down on a VRF instance and a peer.";
   }

   feature all-af-policy-config {
     description
       "This feature indicates that the system allows to configure
        policies that are applied to all address families.";
   }

   feature capability-end-of-lib {
     description
       "This feature indicates that the system allows to configure
        LDP end-of-lib capability.";
   }

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




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

   feature capability-typed-wildcard-fec {
     description
       "This feature indicates that the system allows to configure
        LDP typed-wildcard-fec capability.";
   }

   feature capability-upstream-label-assignment {
     description
       "This feature indicates that the system allows to configure
        LDP upstream label assignment capability.";
   }

   feature forwarding-nexthop-config {
     description
       "This feature indicates that the system allows to configure
        forwarding nexthop on interfaces.";
   }

   feature global-session-authentication {
     description
       "This feature indicates that the system allows to configure
        authentication at global level.";
   }

   feature graceful-restart-helper-mode {
     description
       "This feature indicates that the system supports graceful
        restart helper mode.";
   }

   feature mldp {
     description
       "This feature indicates that the system supports Multicast
        LDP (mLDP).";
   }

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




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   feature per-interface-timer-config {
     description
       "This feature indicates that the system allows to configure
        interface hello timers at the per-interface level.";
   }

   feature per-peer-graceful-restart-config {
     description
       "This feature indicates that the system allows to configure
        graceful restart at the per-peer level.";
   }

   feature per-peer-session-attributes-config {
     description
       "This feature indicates that the system allows to configure
        session attributes at the per-peer level.";
   }

   feature policy-extended-discovery-config {
     description
       "This feature indicates that the system allows to configure
        policies to control the acceptance of extended neighbor
        discovery hello messages.";
   }

   feature policy-label-assignment-config {
     description
       "This feature indicates that the system allows to configure
        policies to assign labels according to certain prefixes.";
   }

   feature policy-ordered-label-config {
     description
       "This feature indicates that the system allows to configure
        ordered label policies.";
   }

   feature session-downstream-on-demand-config {
     description
       "This feature indicates that the system allows to configure
        session downstream-on-demand";
   }

   /*
    * Typedefs
    */
   typedef ldp-address-family {
     type identityref {



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       base rt:address-family;
     }
     description
       "LDP address family type.";
   }

   typedef duration32-inf {
     type union {
       type uint32;
       type enumeration {
         enum "infinite" {
           description "The duration is infinite.";
         }
       }
     }
     units seconds;
     description
       "Duration represented as 32 bit seconds with infinite.";
   }

   typedef advertised-received {
     type enumeration {
       enum advertised {
         description "Advertised information.";
       }
       enum received {
         description "Received information.";
       }
     }
     description
       "Received or advertised.";
   }

   typedef downstream-upstream {
     type enumeration {
       enum downstream {
         description "Downstream information.";
       }
       enum upstream {
         description "Upstream information.";
       }
     }
     description
       "Received or advertised.";
   }

   typedef label-adv-mode {
     type enumeration {



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       enum downstream-unsolicited {
         description "Downstream Unsolicited.";
       }
       enum downstream-on-demand {
         description "Downstream on Demand.";
       }
     }
     description
       "Label Advertisement Mode.";
   }

   typedef mpls-interface-ref {
     type leafref {
       path "/rt:routing/mpls:mpls/mpls:interface/mpls:name";
     }
     description
       "This type is used by data models that need to reference
        mpls interfaces.";
   }

   typedef multipoint-type {
     type enumeration {
       enum p2mp {
         description "Point to multipoint.";
       }
       enum mp2mp {
         description "Multipoint to multipoint.";
       }
     }
     description
       "p2mp or mp2mp.";
   }

   typedef neighbor-list-ref {
     type string;
     description
       "A type for a reference to a neighbor list.";
   }

   typedef peer-list-ref {
     type string;
     description
       "A type for a reference to a peer list.";
   }

   typedef prefix-list-ref {
     type string;
     description



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       "A type for a reference to a prefix list.";
   }

   typedef oper-status-event-type {
     type enumeration {
       enum up {
         value 1;
         description
           "Operational status changed to up.";
       }
       enum down {
         value 2;
         description
           "Operational status changed to down.";
       }
     }
     description "Operational status event type for notifications.";
   }

   typedef route-distinguisher {
     type string {
     }
     description
       "Type definition for route distinguisher.";
     reference
       "RFC4364: BGP/MPLS IP Virtual Private Networks (VPNs).";
   }

   /*
    * Identities
    */
   identity adjacency-flag-base {
     description "Base type for adjacency flags.";
   }

   identity adjacency-flag-active {
     base "adjacency-flag-base";
     description
       "This adjacency is configured and actively created.";
   }

   identity adjacency-flag-passive {
     base "adjacency-flag-base";
     description
       "This adjacency is not configured and passively accepted.";
   }

   /*



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    * Groupings
    */

   grouping adjacency-state-attributes {
     description
       "Adjacency state attributes.";

     leaf-list flag {
       type identityref {
         base "adjacency-flag-base";
       }
       description "Adjacency flags.";
     }
     container hello-holdtime {
       description "Hello holdtime state.";
       leaf adjacent {
         type uint16;
         units seconds;
         description "Peer holdtime.";
       }
       leaf negotiated {
         type uint16;
         units seconds;
         description "Negotiated holdtime.";
       }
       leaf remaining {
         type uint16;
         units seconds;
         description "Remaining holdtime.";
       }
     }

     leaf next-hello {
       type uint16;
       units seconds;
       description "Time to send the next hello message.";
     }

     container statistics {
       description
         "Statistics objects.";

       leaf discontinuity-time {
         type yang:date-and-time;
         mandatory true;
         description
           "The time on the most recent occasion at which any one or
            more of this interface's counters suffered a



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            discontinuity.  If no such discontinuities have occurred
            since the last re-initialization of the local management
            subsystem, then this node contains the time the local
            management subsystem re-initialized itself.";
       }

       leaf hello-received {
         type yang:counter64;
         description
           "The number of hello messages received.";
       }
       leaf hello-dropped {
         type yang:counter64;
         description
           "The number of hello messages received.";
       }
     } // statistics
   } // adjacency-state-attributes

   grouping basic-discovery-timers {
     description
       "Basic discovery timer attributes.";
     leaf hello-holdtime {
       type uint16 {
         range 15..3600;
       }
       units seconds;
       description
         "The time interval for which a LDP link Hello adjacency
          is maintained in the absence of link Hello messages from
          the LDP neighbor";
     }
     leaf hello-interval {
       type uint16 {
         range 5..1200;
       }
       units seconds;
       description
         "The interval between consecutive LDP link Hello messages
          used in basic LDP discovery";
     }
   } // basic-discovery-timers

   grouping binding-address-state-attributes {
     description
       "Address binding attributes";
     leaf advertisement-type {
       type advertised-received;



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       description
         "Received or advertised.";
     }
     leaf peer {
       type leafref {
         path "../../../../../../../peers/peer/lsr-id";
       }
       must "../advertisement-type = 'received'" {
         description
           "Applicable for received address.";
       }
       description
         "LDP peer from which this address is received.";
     } // peer
   } // binding-address-state-attributes

   grouping binding-label-state-attributes {
     description
       "Label binding attributes";
     list peer {
       key "peer advertisement-type";
       description
         "List of advertised and received peers.";
       leaf peer {
         type leafref {
           path "../../../../../../../../peers/peer/lsr-id";
         }
         description
           "LDP peer from which this binding is received,
            or to which this binding is advertised.";
       }
       leaf advertisement-type {
         type advertised-received;
         description
           "Received or advertised.";
       }
       leaf label {
         type mpls:mpls-label;
         description
           "Advertised (outbound) or received (inbound)
            label.";
       }
       leaf used-in-forwarding {
         type boolean;
         description
           "'true' if the lable is used in forwarding.";
       }
     } // peer



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   } // binding-label-state-attributes

   grouping extended-discovery-policy-attributes {
     description
       "LDP policy to control the acceptance of extended neighbor
        discovery hello messages.";
     container hello-accept {
       if-feature policy-extended-discovery-config;
       description
         "Extended discovery acceptance policies.";

       leaf enable {
         type boolean;
         description
           "'true' to accept; 'false' to deny.";
       }
       leaf neighbor-list {
         type neighbor-list-ref;
         description

           "The name of a peer ACL.";
       }
     } // hello-accept
   } // extended-discovery-policy-attributes

   grouping extended-discovery-timers {
     description
       "Extended discovery timer attributes.";
     leaf hello-holdtime {
       type uint16 {
         range 15..3600;
       }
       units seconds;
       description
         "The time interval for which LDP targeted Hello adjacency

          is maintained in the absence of targeted Hello messages
          from an LDP neighbor.";
     }
     leaf hello-interval {
       type uint16 {
         range 5..3600;
       }
       units seconds;
       description
         "The interval between consecutive LDP targeted Hello
          messages used in extended LDP discovery.";
     }



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   } // extended-discovery-timers

   grouping global-attributes {
     description "Configuration attributes at global level.";

     uses instance-attributes;
   } // global-attributes

   grouping graceful-restart-attributes {
     description
       "Graceful restart configuration attributes.";
     container graceful-restart {
       description
         "Attributes for graceful restart.";
       leaf enable {
         type boolean;
         description
           "Enable or disable graceful restart.";
       }
       leaf helper-enable {
         if-feature graceful-restart-helper-mode;
         type boolean;
         description
           "Enable or disable graceful restart helper mode.";
       }
       leaf reconnect-time {
         type uint16 {
           range 10..1800;
         }
         units seconds;
         description
           "Specifies the time interval that the remote LDP peer
            must wait for the local LDP peer to reconnect after the
            remote peer detects the LDP communication failure.";
       }
       leaf recovery-time {
         type uint16 {
           range 30..3600;
         }
         units seconds;
         description
           "Specifies the time interval, in seconds, that the remote
            LDP peer preserves its MPLS forwarding state after
            receiving the Initialization message from the restarted
            local LDP peer.";
       }
       leaf forwarding-holdtime {
         type uint16 {



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           range 30..3600;
         }
         units seconds;
         description
           "Specifies the time interval, in seconds, before the
            termination of the recovery phase.";
       }
     } // graceful-restart
   } // graceful-restart-attributes

   grouping graceful-restart-attributes-per-peer {
     description
       "Per peer graceful restart configuration attributes.";
     container graceful-restart {
       description
         "Attributes for graceful restart.";
       leaf enable {
         type boolean;
         description
           "Enable or disable graceful restart.";
       }
       leaf reconnect-time {
         type uint16 {
           range 10..1800;
         }
         units seconds;
         description
           "Specifies the time interval that the remote LDP peer
            must wait for the local LDP peer to reconnect after the
            remote peer detects the LDP communication failure.";
       }
       leaf recovery-time {
         type uint16 {
           range 30..3600;
         }
         units seconds;
         description
           "Specifies the time interval, in seconds, that the remote
            LDP peer preserves its MPLS forwarding state after
            receiving the Initialization message from the restarted
            local LDP peer.";
       }
     } // graceful-restart
   } // graceful-restart-attributes-per-peer

   grouping instance-attributes {
     description "Configuration attributes at instance level.";




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     container capability {
       description "Configure capability.";
       container end-of-lib {
         if-feature capability-end-of-lib;
         description
           "Configure end-of-lib capability.";
         leaf enable {
           type boolean;
           description
             "Enable end-of-lib capability.";
         }
       }
       container typed-wildcard-fec {
         if-feature capability-typed-wildcard-fec;
         description
           "Configure typed-wildcard-fec capability.";
         leaf enable {
           type boolean;
           description
             "Enable typed-wildcard-fec capability.";
         }
       }
       container upstream-label-assignment {
         if-feature capability-upstream-label-assignment;
         description
           "Configure upstream label assignment capability.";
         leaf enable {
           type boolean;
           description
             "Enable upstream label assignment.";
         }
       }
       container mldp {
         if-feature mldp;

         description
           "Multipoint capabilities.";
         uses mldp-capabilities;
       }
     } // capability

     uses graceful-restart-attributes;

     leaf igp-synchronization-delay {
       type uint16 {
         range 3..60;
       }
       units seconds;



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       description
         "Sets the interval that the LDP waits before notifying the
          Interior Gateway Protocol (IGP) that label exchange is
          completed so that IGP can start advertising the normal
          metric for the link.";
     }
     leaf lsr-id {
       type yang:dotted-quad;
       description "Router ID.";
     }
   } // instance-attributes

   grouping ldp-adjacency-ref {
     description
       "An absolute reference to an LDP adjacency.";
     choice hello-adjacency-type {
       description
         "Interface or targeted adjacency.";
       case targeted {
         container targeted {
           description "Targeted adjacency.";
           leaf target-address {
             type inet:ip-address;
             description
               "The target address.";
           }
         } // targeted
       }
       case link {
         container link {
           description "Link adjacency.";
           leaf next-hop-interface {
             type mpls-interface-ref;
             description
               "Interface connecting to next-hop.";
           }
           leaf next-hop-address {
             type inet:ip-address;
             must "../next-hop-interface" {
               description
                 "Applicable when interface is specified.";

             }
             description
               "IP address of next-hop.";
           }
         } // link
       }



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     }
   } // ldp-adjacency-ref

   grouping ldp-fec-event {
     description
       "A LDP FEC event.";
     leaf prefix {
       type inet:ip-prefix;
       description
         "FEC.";
     }
   } // ldp-fec-event

   grouping ldp-peer-ref {
     description
       "An absolute reference to an LDP peer.";
     leaf peer-ref {
       type leafref {
         path "/rt:routing/rt:control-plane-protocols/mpls-ldp/"
           + "peers/peer/lsr-id";
       }
       description
         "Reference to an LDP peer.";
     }
   } // ldp-peer-ref

   grouping mldp-capabilities {
     description
       "mLDP capabilities.";
     container p2mp {
       description
         "Configure point-to-multipoint capability.";
       leaf enable {
         type boolean;
         description
           "Enable point-to-multipoint.";
       }
     }
     container mp2mp {
       description
         "Configure multipoint-to-multipoint capability.";
       leaf enable {
         type boolean;
         description
           "Enable multipoint-to-multipoint.";
       }
     }
     container make-before-break {



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       description
         "Configure make-before-break capability.";
       leaf enable {
         type boolean;
         description
           "Enable make-before-break.";
       }
       leaf switchover-delay {
         type uint16;
         units seconds;
         description
           "Switchover delay in seconds.";
       }
       leaf timeout {
         type uint16;
         units seconds;
         description
           "Timeout in seconds.";
       }
     }
     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 enable {
         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 capable for MP LSP node
            protection.";
       }
       container merge-point {
         description
           "Merge Point capable for MP LSP node protection.";



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         leaf enable {
           type boolean;
           description
             "Enable merge point capability.";
         }
         leaf targeted-session-teardown-delay {
           type uint16;
           units seconds;
           description
             "Targeted session teardown delay.";
         }
       } // merge-point
     }
   } // mldp-capabilities

   grouping  mldp-configured-lsp-roots {
     description
       "mLDP roots containers.";

     container roots-ipv4 {

       when "../../../af = 'ipv4'" {
         description
           "Only for IPv4.";
       }
       description
         "Configured IPv4 multicast LSPs.";
       list root {
         key "root-address";
         description
           "List of roots for configured multicast LSPs.";

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

         list lsp {
           must "(lsp-id = 0 and source-address != '0.0.0.0' and "
             + "group-address != '0.0.0.0') or "
             + "(lsp-id != 0 and source-address = '0.0.0.0' and "
             + "group-address = '0.0.0.0')" {
             description
               "A LSP can be identified by either <lsp-id> or
                <source-address, group-address>.";
           }
           key "lsp-id source-address group-address";



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           description
             "List of LSPs.";
           leaf lsp-id {
             type uint16;
             description "ID to identify the LSP.";
           }
           leaf source-address {
             type inet:ipv4-address;
             description
               "Source address.";
           }
           leaf group-address {
             type inet:ipv4-address-no-zone;
             description
               "Group address.";
           }
         } // list lsp
       } // list root
     } // roots-ipv4

     container roots-ipv6 {

       when "../../../af = 'ipv6'" {
         description
           "Only for IPv6.";
       }
       description
         "Configured IPv6 multicast LSPs.";

       list root {
         key "root-address";
         description
           "List of roots for configured multicast LSPs.";

         leaf root-address {
           type inet:ipv6-address;
           description
             "Root address.";
         }

         list lsp {
           must "(lsp-id = 0 and source-address != '::' and "
             + "group-address != '::') or "
             + "(lsp-id != 0 and source-address = '::' and "
             + "group-address = '::')" {
             description
               "A LSP can be identified by either <lsp-id> or
                <source-address, group-address>.";



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           }
           key "lsp-id source-address group-address";
           description
             "List of LSPs.";
           leaf lsp-id {
             type uint16;
             description "ID to identify the LSP.";
           }
           leaf source-address {
             type inet:ipv6-address;
             description
               "Source address.";
           }
           leaf group-address {
             type inet:ipv6-address-no-zone;
             description
               "Group address.";
           }
         } // list lsp
       } // list root
     } // roots-ipv6
   } // mldp-configured-lsp-roots

   grouping mldp-fec-event {
     description
       "A mLDP FEC event.";
     leaf tree-type {
       type multipoint-type;
       description
         "p2mp or mp2mp.";
     }
     leaf root {
       type inet:ip-address;
       description
         "Root address.";
     }
     choice lsp-key-type {
       description
         "LSP ID based or source-group based .";
       case lsp-id-based {
         leaf lsp-id {
           type uint16;
           description
             "ID to identify the LSP.";
         }
       }
       case source-group-based {
         leaf source-address {



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           type inet:ip-address;
           description

             "LSP source address.";
         }
         leaf group-address {
           type inet:ip-address;
           description
             "Multicast group address.";
         }
       } // case source-group-based
     }
   } // mldp-fec-event

   grouping  mldp-binding-label-state-attributes {
     description
       "mLDP label binding attributes.";

     leaf multipoint-type {
       type multipoint-type;
       description
         "The type of mutipoint, p2mp or mp2mp.";
     }
     list peer {
       key "direction peer advertisement-type";
       description
         "List of advertised and received peers.";
       leaf direction {
         type downstream-upstream;
         description
           "Downstream or upstream.";
       }
       leaf peer {
         type leafref {
           path
             "../../../../../../../../../../peers/peer/lsr-id";
         }
         description
           "LDP peer from which this binding is received,
            or to which this binding is advertised.";
       }
       leaf advertisement-type {
         type advertised-received;
         description
           "Advertised or received.";
       }
       leaf label {
         type mpls:mpls-label;



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         description
           "Advertised (outbound) or received (inbound) label.";
       }
       leaf mbb-role {
         when "../direction = 'upstream'" {
           description
             "For upstream.";
         }
         type enumeration {
           enum none {
             description "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.";
       }
       leaf mofrr-role {
         when "../direction = 'upstream'" {
           description
             "For upstream.";
         }
         type enumeration {
           enum none {
             description "MOFRR is not enabled.";
           }
           enum primary {
             description "This LSP is primary.";
           }
           enum backup {
             description "This LSP is backup.";
           }
         }
         description
           "The MOFRR status of this LSP.";
       }
     } // peer
   } // mldp-binding-label-state-attributes

   grouping peer-af-policy-container {
     description
       "LDP policy attribute container under peer address-family.";
     container label-policy {



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       description
         "Label policy attributes.";
       container advertise {
         description
           "Label advertising policies.";
         leaf prefix-list {
           type prefix-list-ref;
             description
               "Applies the prefix list to outgoing label
                advertisements.";
         }
       }
       container accept {
         description
           "Label advertisement acceptance policies.";
         leaf prefix-list {
           type prefix-list-ref;
           description
             "Applies the prefix list to incoming label
              advertisements.";
         }
       } // accept
     } // label-policy
   } // peer-af-policy-container

   grouping peer-attributes {
     description "Peer configuration attributes.";

     leaf session-ka-holdtime {
       type uint16 {
         range 45..3600;
       }
       units seconds;
       description
         "The time interval after which an inactive LDP session
          terminates and the corresponding TCP session closes.
          Inactivity is defined as not receiving LDP packets from the
          peer.";
     }
     leaf session-ka-interval {
       type uint16 {
         range 15..1200;
       }
       units seconds;
       description
         "The interval between successive transmissions of keepalive
          packets. Keepalive packets are only sent in the absence of
          other LDP packets transmitted over the LDP session.";



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     }
   } // peer-attributes

   grouping peer-authentication {
     description
       "Peer authentication attributes.";
     leaf session-authentication-md5-password {
       type string {
         length "1..80";
       }
       description
         "Assigns an encrypted MD5 password to an LDP
          peer";
     } // md5-password
   } // peer-authentication

   grouping peer-state-derived {
     description "Peer derived state attributes.";

     container label-advertisement-mode {
       description "Label advertisement mode state.";
       leaf local {
         type label-adv-mode;
         description
           "Local Label Advertisement Mode.";
       }
       leaf peer {
         type label-adv-mode;
         description
           "Peer Label Advertisement Mode.";
       }
       leaf negotiated {
         type label-adv-mode;
         description
           "Negotiated Label Advertisement Mode.";
       }
     }
     leaf next-keep-alive {
       type uint16;
       units seconds;
       description "Time to send the next KeepAlive message.";
     }

     leaf peer-ldp-id {
       type yang:dotted-quad;
       description "Peer LDP ID.";
     }




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     container received-peer-state {
       description "Peer features.";

       uses graceful-restart-attributes-per-peer;

       container capability {
         description "Configure capability.";
         container end-of-lib {
           description
             "Configure end-of-lib capability.";
           leaf enable {
             type boolean;
             description
               "Enable end-of-lib capability.";
           }
         }
         container typed-wildcard-fec {
           description
             "Configure typed-wildcard-fec capability.";
           leaf enable {
             type boolean;
             description
               "Enable typed-wildcard-fec capability.";
           }
         }
         container upstream-label-assignment {
           description
             "Configure upstream label assignment capability.";
           leaf enable {
             type boolean;
             description
               "Enable upstream label assignment.";
           }
         }
         container mldp {
           if-feature mldp;
           description
             "Multipoint capabilities.";

           container p2mp {
             description
               "Configure point-to-multipoint capability.";
             leaf enable {
               type boolean;
               description
                 "Enable point-to-multipoint.";
             }
           }



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           container mp2mp {
             description
               "Configure multipoint-to-multipoint capability.";
             leaf enable {
               type boolean;
               description
                 "Enable multipoint-to-multipoint.";
             }
           }
           container make-before-break {
             description
               "Configure make-before-break capability.";
             leaf enable {
               type boolean;
               description
                 "Enable make-before-break.";
             }
           }
           container hub-and-spoke {
             description
               "Configure hub-and-spoke-multipoint capability.";
             reference
               "RFC7140: LDP Extensions for Hub and Spoke Multipoint
                Label Switched Path";
             leaf enable {
               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 capable for MP LSP node
                  protection.";
             }
             leaf merge-point {
               type boolean;
               description
                 "Merge Point capable for MP LSP node protection.";
             } // merge-point
           } // node-protection
         } // mldp



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       } // capability
     } // received-peer-state

     container session-holdtime {
       description "Session holdtime state.";
       leaf peer {
         type uint16;
         units seconds;
         description "Peer holdtime.";
       }
       leaf negotiated {
         type uint16;
         units seconds;
         description "Negotiated holdtime.";
       }
       leaf remaining {
         type uint16;
         units seconds;
         description "Remaining holdtime.";
       }
     } // session-holdtime

     leaf session-state {
       type enumeration {
         enum non-existent {
           description "NON EXISTENT state. Transport disconnected.";
         }
         enum initialized {
           description "INITIALIZED state.";
         }
         enum openrec {
           description "OPENREC state.";
         }
         enum opensent {
           description "OPENSENT state.";
         }
         enum operational {
           description "OPERATIONAL state.";
         }
       }
       description
         "Representing the operational status.";
     }

     container tcp-connection {
       description "TCP connection state.";
       leaf local-address {
         type inet:ip-address;



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         description "Local address.";
       }
       leaf local-port {
         type inet:port-number;
         description "Local port.";
       }
       leaf remote-address {
         type inet:ip-address;
         description "Remote address.";
       }
       leaf remote-port {
         type inet:port-number;
         description "Remote port.";
       }
     } // tcp-connection

     leaf up-time {
       type string;
       description "Up time. The interval format in ISO 8601.";
     }

     container statistics {
       description
         "Statistics objects.";

       leaf discontinuity-time {
         type yang:date-and-time;
         mandatory true;
         description
           "The time on the most recent occasion at which any one or
            more of this interface's counters suffered a
            discontinuity.  If no such discontinuities have occurred
            since the last re-initialization of the local management
            subsystem, then this node contains the time the local
            management subsystem re-initialized itself.";
       }

       container received {
         description "Inbound statistics.";
         uses statistics-peer-received-sent;
       }
       container sent {
         description "Outbound statistics.";
         uses statistics-peer-received-sent;
       }

       leaf total-addresses {
         type uint32;



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         description
           "The number of learned addresses.";
       }
       leaf total-labels {
         type uint32;
         description
           "The number of learned labels.";
       }
       leaf total-fec-label-bindings {
         type uint32;
         description
           "The number of learned label-address bindings.";
       }
     } // statistics
   } // peer-state-derived

   grouping policy-container {
     description
       "LDP policy attributes.";
     container label-policy {
       description
         "Label policy attributes.";
       container independent-mode {
         description
           "Independent label policy attributes.";
         container assign {

           if-feature policy-label-assignment-config;
           description
             "Label assignment policies";
           choice prefix-option {
             description
               "Use either prefix-list or host-routes-only.";
             case prefix-list {
               leaf prefix-list {
                 type prefix-list-ref;
                 description
                   "Assign labels according to certain prefixes.";
               }
             }
             case host-routes-only {
               leaf host-routes-only {
                 type boolean;
                 description
                   "'true' to apply host routes only.";
               }
             }
           } // prefix-option



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         }
         container advertise {
           description
             "Label advertising policies.";
           container explicit-null {
             description
               "Enables an egress router to advertise an
                explicit null label (value 0) in place of an
                implicit null label (value 3) to the
                penultimate hop router.";
             leaf enable {
               type boolean;
               description
                 "'true' to enable explicit null.";
             }
             leaf prefix-list {
               type prefix-list-ref;
               description
                 "Prefix list name. Applies the filters in the
                  specified prefix list to label
                  advertisements.
                  If the prefix list is not specified, explicit
                  null label advertisement is enabled for all
                  directly connected prefixes.";
             }
           }
           leaf prefix-list {
             type prefix-list-ref;
             description
               "Applies the prefix list to outgoing label
                advertisements.";

           }
         }
         container accept {
           description
             "Label advertisement acceptance policies.";
           leaf prefix-list {
             type prefix-list-ref;
             description
               "Applies the prefix list to incoming label
                advertisements.";
           }
         }
       } // independent-mode
       container ordered-mode {
         if-feature policy-ordered-label-config;
         description



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           "Ordered label policy attributes.";
         container egress-lsr {
           description
             "Egress LSR label assignment policies";
           leaf prefix-list {
             type prefix-list-ref;
             description
               "Assign labels according to certain prefixes.";
           }
         }
         container advertise {
           description
             "Label advertising policies.";
           leaf prefix-list {
             type prefix-list-ref;
             description
               "Applies the prefix list to outgoing label
                advertisements.";
           }
         }
         container accept {
           description
             "Label advertisement acceptance policies.";
           leaf prefix-list {
             type prefix-list-ref;
             description
               "Applies the prefix list to incoming label
                advertisements.";
           }
         }
       } // ordered-mode
     } // label-policy
   } // policy-container

   grouping statistics-peer-received-sent {
     description
       "Inbound and outbound statistic counters.";
     leaf total-octets {
       type yang:counter64;
       description
         "The total number of octets sent or received.";
     }
     leaf total-messages {
       type yang:counter64;
       description
         "The number of messages sent or received.";
     }
     leaf address {



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       type yang:counter64;
       description
         "The number of address messages sent or received.";
     }
     leaf address-withdraw {
       type yang:counter64;
       description
         "The number of address-withdraw messages sent or received.";
     }
     leaf initialization {
       type yang:counter64;
       description
         "The number of initialization messages sent or received.";
     }
     leaf keepalive {
       type yang:counter64;
       description
         "The number of keepalive messages sent or received.";
     }
     leaf label-abort-request {
       type yang:counter64;
       description
         "The number of label-abort-request messages sent or
          received.";
     }
     leaf label-mapping {
       type yang:counter64;
       description
         "The number of label-mapping messages sent or received.";
     }
     leaf label-release {
       type yang:counter64;
       description
         "The number of label-release messages sent or received.";
     }
     leaf label-request {
       type yang:counter64;
       description
         "The number of label-request messages sent or received.";
     }
     leaf label-withdraw {
       type yang:counter64;
       description
         "The number of label-withdraw messages sent or received.";
     }
     leaf notification {
       type yang:counter64;
       description



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         "The number of messages sent or received.";
     }
   } // statistics-peer-received-sent

   /*
    * Configuration data nodes
    */

   augment "/rt:routing/rt:control-plane-protocols" {
     description "LDP augmentation.";

     container mpls-ldp {
       presence "Container for LDP protocol.";
       description
         "Container for LDP protocol.";

       container global {
         description
           "Global attributes for LDP.";
         container config {
           description
             "Configuration data.";
           uses global-attributes;
         }
         container state {
           config false;
           description
             "Operational state data.";
           uses global-attributes;
         }

         container mldp {
           if-feature 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.";

           container config {
             description
               "Configuration data.";
             leaf enable {
               type boolean;
               description
                 "Enable mLDP.";
             }
           }



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           container state {
             config false;
             description

               "Operational state data.";
             leaf enable {
               type boolean;
               description
                 "Enable mLDP.";
             }
           }

           list address-family {
             key "afi";
             description
               "Per-af params.";
             leaf afi {
               type ldp-address-family;
               description
                 "Address family type value.";
             }

             container config {
               description
                 "Configuration data.";
               container multicast-only-frr {
                 if-feature mldp-mofrr;
                 description
                   "Multicast only FRR (MoFRR) policy.";
                 leaf prefix-list {
                   type prefix-list-ref;
                   description
                     "Enables MoFRR for the specified access list.";
                 }
               } // multicast-only-frr
               container recursive-fec {
                 description
                   "Recursive FEC policy.";
                 leaf prefix-list {
                   type prefix-list-ref;
                   description
                     "Enables recursive FEC for the specified access
                      list.";
                 }
               } // recursive-for
             }
             container state {
               config false;



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               description
                 "Operational state data.";
               container multicast-only-frr {
                 if-feature mldp-mofrr;

                 description
                   "Multicast only FRR (MoFRR) policy.";
                 leaf prefix-list {
                   type prefix-list-ref;
                   description
                     "Enables MoFRR for the specified access list.";
                 }
               } // multicast-only-frr
               container recursive-fec {
                 description
                   "Recursive FEC policy.";
                 leaf prefix-list {
                   type prefix-list-ref;
                   description
                     "Enables recursive FEC for the specified access
                      list.";
                 }
               } // recursive-fec

               container ipv4 {
                 when "../../afi = 'ipv4'" {
                   description
                     "Only for IPv4.";
                 }
                 description
                   "IPv4 state information.";
                 container roots {
                   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



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                         "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:ipv4-address;
                         description
                           "The next hop address to reach root.";
                       }
                       leaf interface {
                         type mpls-interface-ref;
                         description
                           "Interface connecting to next-hop.";
                       }
                       leaf peer {
                         type leafref {
                           path
                             "../../../../../../../../../peers/peer/"
                             + "lsr-id";
                         }
                         description
                           "LDP peer from which this next hop can be
                            reached.";
                       }
                     }
                   } // list root
                 } // roots
                 container bindings {
                   description
                     "mLDP FEC to label bindings.";
                   container opaque-type-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 "
                         + "recur-root-address recur-rd";
                       description



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                         "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 recur-root-address {
                         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 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";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-lspid

                   container opaque-type-src {
                     description
                       "The type of opaque value element is
                        the transit source TLV";
                     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 route-distinguisher;
                         description
                           "Route Distinguisher.";
                         reference
                           "RFC7246: Multipoint Label Distribution
                            Protocol In-Band Signaling in a Virtual
                            Routing and Forwarding (VRF) Table
                            Context.";
                       }
                       leaf recur-root-address {
                         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 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";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-src

                   container opaque-type-bidir {
                     description
                       "The type of opaque value element is
                        the generic LSP identifier";



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                     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 {
                         type inet:ip-address;
                         description
                           "RP address.";
                       }
                       leaf group-address {
                         type inet:ip-address-no-zone;
                         description
                           "Group address.";
                       }
                       leaf rd {
                         type route-distinguisher;
                         description
                           "Route Distinguisher.";
                         reference
                           "RFC7246: Multipoint Label Distribution
                            Protocol In-Band Signaling in a Virtual
                            Routing and Forwarding (VRF) Table
                            Context.";
                       }
                       leaf recur-root-address {
                         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 route-distinguisher;
                         description
                           "Route Distinguisher in the VPN-Recursive



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                            Opaque Value.";
                         reference
                           "RFC6512: Using Multipoint LDP When the
                            Backbone Has No Route to the Root";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-bidir
                 } // bindings
               } // ipv4

               container ipv6 {
                 when "../../afi = 'ipv6'" {
                   description
                     "Only for IPv6.";
                 }
                 description
                   "IPv6 state information.";
                 container roots {
                   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;
                       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.";
                       }



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                       leaf interface {
                         type mpls-interface-ref;
                         description
                           "Interface connecting to next-hop.";
                       }
                       leaf peer {
                         type leafref {
                           path
                             "../../../../../../../../../peers/peer/"
                             + "lsr-id";
                         }
                         description
                           "LDP peer from which this next hop can be
                            reached.";
                       }
                     }
                   } // list root
                 } // roots
                 container bindings {
                   description
                     "mLDP FEC to label bindings.";
                   container opaque-type-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 "
                         + "recur-root-address recur-rd";
                       description
                         "List of FEC to label bindings.";
                       leaf root-address {
                         type inet:ipv6-address;
                         description
                           "Root address.";
                       }
                       leaf lsp-id {
                         type uint32;
                         description "ID to identify the LSP.";
                       }
                       leaf recur-root-address {
                         type inet:ip-address;
                         description



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                           "Recursive root address.";
                         reference
                           "RFC6512: Using Multipoint LDP When the
                            Backbone Has No Route to the Root";
                       }
                       leaf recur-rd {
                         type 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";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-lspid

                   container opaque-type-src {
                     description
                       "The type of opaque value element is
                        the transit Source TLV";
                     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.";
                       }



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                       leaf rd {
                         type route-distinguisher;
                         description
                           "Route Distinguisher.";
                         reference
                           "RFC7246: Multipoint Label Distribution
                            Protocol In-Band Signaling in a Virtual
                            Routing and Forwarding (VRF) Table
                            Context.";
                       }
                       leaf recur-root-address {
                         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 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";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-src

                   container opaque-type-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;



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                         description
                           "Root address.";
                       }
                       leaf rp {
                         type inet:ip-address;
                         description
                           "RP address.";
                       }
                       leaf group-address {
                         type inet:ip-address-no-zone;
                         description
                           "Group address.";
                       }
                       leaf rd {
                         type route-distinguisher;
                         description
                           "Route Distinguisher.";
                         reference
                           "RFC7246: Multipoint Label Distribution
                            Protocol In-Band Signaling in a Virtual
                            Routing and Forwarding (VRF) Table
                            Context.";
                       }
                       leaf recur-root-address {
                         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 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";
                       }
                       uses mldp-binding-label-state-attributes;
                     } // fec-label
                   } // opaque-type-bidir
                 } // bindings
               } // ipv6
             } // state

             container configured-leaf-lsps {



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               description
                 "Configured multicast LSPs.";

               container p2mp {
                 description
                   "Configured point-to-multipoint LSPs.";
                 uses mldp-configured-lsp-roots;
               }
               container mp2mp {
                 description
                   "Configured multipoint-to-multipoint LSPs.";
                 uses mldp-configured-lsp-roots;
               }
             } // configured-leaf-lsps
           } // list address-family
         } // mldp

         list address-family {
           key "afi";
           description
             "Per-vrf per-af params.";
           leaf afi {
             type ldp-address-family;
             description
               "Address family type value.";
           }

           container config {
             description
               "Configuration data.";
             leaf enable {
               type boolean;
               description
                 "'true' to enable the address family.";
             }
             uses policy-container;

             container ipv4 {
               when "../../afi = 'ipv4'" {
                 description
                   "Only for IPv4.";
               }
               description
                 "IPv4 address family.";
               leaf transport-address {
                 type inet:ipv4-address;
                 description
                   "The transport address advertised in LDP Hello



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                    messages.";
               }
             } // ipv4
             container ipv6 {
               when "../../afi = 'ipv6'" {
                 description
                   "Only for IPv6.";
               }
               description
                 "IPv6 address family.";
               leaf transport-address {
                 type inet:ipv6-address;
                 description
                   "The transport address advertised in LDP Hello
                    messages.";
               }
             } // ipv6
           }
           container state {
             config false;
             description
               "Operational state data.";
             leaf enable {
               type boolean;
               description
                 "'true' to enable the address family.";
             }

             uses policy-container;

             container ipv4 {
               when "../../afi = 'ipv4'" {
                 description
                   "Only for IPv4.";
               }
               description
                 "IPv4 address family.";
               leaf transport-address {
                 type inet:ipv4-address;
                 description
                   "The transport address advertised in LDP Hello
                    messages.";
               }

               container bindings {
                 description
                   "LDP address and label binding information.";
                 list address {



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                   key "address";
                   description
                     "List of address bindings.";
                   leaf address {
                     type inet:ipv4-address;
                     description
                       "Binding address.";
                   }
                   uses binding-address-state-attributes;
                 } // binding-address

                 list fec-label {
                   key "fec";
                   description
                     "List of label bindings.";
                   leaf fec {
                     type inet:ipv4-prefix;
                     description
                       "Prefix FEC.";
                   }
                   uses binding-label-state-attributes;
                 } // fec-label
               } // binding
             } // ipv4
             container ipv6 {
               when "../../afi = 'ipv6'" {
                 description
                   "Only for IPv6.";
               }
               description
                 "IPv6 address family.";
               leaf transport-address {
                 type inet:ipv6-address;
                 description
                   "The transport address advertised in LDP Hello
                    messages.";
               }

               container binding {
                 description
                   "LDP address and label binding information.";
                 list address {
                   key "address";
                   description
                     "List of address bindings.";
                   leaf address {
                     type inet:ipv6-address;
                     description



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                       "Binding address.";
                   }
                   uses binding-address-state-attributes;
                 } // binding-address

                 list fec-label {
                   key "fec";
                   description
                     "List of label bindings.";
                   leaf fec {
                     type inet:ipv6-prefix;
                     description
                       "Prefix FEC.";
                   }
                   uses binding-label-state-attributes;
                 } // fec-label
               } // binding
             } // ipv6
           } // state
         } // address-family

         container discovery {
           description
             "Neibgbor discovery configuration.";

           container interfaces {
             description
               "A list of interfaces for basic descovery.";
             container config {
               description
                 "Configuration data.";
               uses basic-discovery-timers;
             }
             container state {
               config false;
               description

                 "Operational state data.";
               uses basic-discovery-timers;
             }

             list interface {
               key "interface";
               description
                 "List of LDP interfaces.";
               leaf interface {
                 type mpls-interface-ref;
                 description



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                   "Interface.";
               }
               container config {
                 description
                   "Configuration data.";
                 uses basic-discovery-timers {
                   if-feature per-interface-timer-config;
                 }
                 leaf igp-synchronization-delay {
                   if-feature per-interface-timer-config;
                   type uint16 {
                     range 3..60;
                   }
                   units seconds;
                   description
                     "Sets the interval that the LDP waits before
                      notifying the Interior Gateway Protocol (IGP)
                      that label exchange is completed so that IGP
                      can start advertising the normal metric for
                      the link.";
                 }
               }
               container state {
                 config false;
                 description
                   "Operational state data.";
                 uses basic-discovery-timers {
                   if-feature per-interface-timer-config;
                 }
                 leaf igp-synchronization-delay {
                   if-feature per-interface-timer-config;
                   type uint16 {
                     range 3..60;
                   }
                   units seconds;
                   description
                     "Sets the interval that the LDP waits before
                      notifying the Interior Gateway Protocol (IGP)
                      that label exchange is completed so that IGP
                      can start advertising the normal metric for
                      the link.";
                 }
                 leaf next-hello {
                   type uint16;
                   units seconds;
                   description "Time to send the next hello message.";
                 }
               } // state



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               list address-family {
                 key "afi";
                 description
                   "Per-vrf per-af params.";
                 leaf afi {
                   type ldp-address-family;
                   description
                     "Address family type value.";
                 }
                 container config {
                   description
                     "Configuration data.";
                   leaf enable {
                     type boolean;
                     description
                       "Enable the address family on the interface.";
                   }

                   container ipv4 {
                     must "/if:interfaces/if:interface"
                       + "[name = current()/../../../interface]/"
                       + "ip:ipv4" {
                       description
                         "Only if IPv4 is enabled on the interface.";
                     }
                     description
                       "IPv4 address family.";
                     leaf transport-address {
                       type union {
                         type enumeration {
                           enum "use-interface-address" {
                             description
                             "Use interface address as the transport
                              address.";
                           }
                         }
                         type inet:ipv4-address;
                       }
                       description
                         "IP address to be advertised as the LDP
                          transport address.";
                     }
                   }

                   container ipv6 {
                     must "/if:interfaces/if:interface"
                       + "[name = current()/../../../interface]/"
                       + "ip:ipv6" {



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                       description
                         "Only if IPv6 is enabled on the interface.";
                     }
                     description
                       "IPv6 address family.";
                     leaf transport-address {
                       type union {
                         type enumeration {
                           enum "use-interface-address" {
                             description
                               "Use interface address as the transport
                                address.";
                           }
                         }
                         type inet:ipv4-address;
                       }
                       description
                         "IP address to be advertised as the LDP
                          transport address.";
                     }
                   } // ipv6
                 }
                 container state {
                   config false;
                   description
                     "Operational state data.";
                   leaf enable {
                     type boolean;
                     description
                       "Enable the address family on the interface.";
                   }

                   container ipv4 {
                     must "/if:interfaces/if:interface"
                       + "[name = current()/../../../interface]/"
                       + "ip:ipv4" {
                       description
                         "Only if IPv4 is enabled on the interface.";
                     }
                     description
                       "IPv4 address family.";
                     leaf transport-address {
                       type union {
                         type enumeration {

                           enum "use-interface-address" {
                             description
                               "Use interface address as the transport



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                                address.";
                           }
                         }
                         type inet:ipv4-address;
                       }
                       description
                         "IP address to be advertised as the LDP
                          transport address.";
                     }

                     list hello-adjacencies {
                       key "adjacent-address";
                       description "List of hello adjacencies.";

                       leaf adjacent-address {
                         type inet:ipv4-address;
                         description
                           "Neighbor address of the hello adjacency.";
                       }

                       uses adjacency-state-attributes;

                       leaf peer {
                         type leafref {
                           path "../../../../../../../../../peers/peer/"
                             + "lsr-id";
                         }
                         description
                           "LDP peer from this adjacency.";
                       }
                     } // hello-adjacencies
                   }
                   container ipv6 {
                     must "/if:interfaces/if:interface"
                       + "[name = current()/../../../interface]/"
                       + "ip:ipv6" {
                       description
                         "Only if IPv6 is enabled on the interface.";
                     }
                     description
                       "IPv6 address family.";
                     leaf transport-address {
                       type union {
                         type enumeration {
                           enum "use-interface-address" {
                             description
                             "Use interface address as the transport
                              address.";



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                           }
                         }
                         type inet:ipv4-address;
                       }
                       description
                         "IP address to be advertised as the LDP
                          transport address.";
                     }

                     list hello-adjacencies {
                       key "adjacent-address";
                       description "List of hello adjacencies.";

                       leaf adjacent-address {
                         type inet:ipv6-address;
                         description
                           "Neighbor address of the hello adjacency.";
                       }

                       uses adjacency-state-attributes;

                       leaf peer {
                         type leafref {
                           path "../../../../../../../../../peers/peer/"
                             + "lsr-id";
                         }
                         description
                           "LDP peer from this adjacency.";
                       }
                     } // hello-adjacencies
                   } // ipv6
                 }
               } // address-family
             } // list interface
           } // interfaces

           container targeted
           {
             description
               "A list of targeted neighbors for extended discovery.";
             container config {

               description
                 "Configuration data.";
               uses extended-discovery-timers;
               uses extended-discovery-policy-attributes;
             }
             container state {



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               config false;
               description
                 "Operational state data.";
               uses extended-discovery-timers;
               uses extended-discovery-policy-attributes;
             }

             list address-family {
               key "afi";
               description
                 "Per-af params.";
               leaf afi {
                 type ldp-address-family;
                 description
                   "Address family type value.";
               }

               container state {
                 config false;
                 description
                   "Operational state data.";

                 container ipv4 {
                   when "../../afi = 'ipv4'" {
                     description
                       "For IPv4.";
                   }
                   description
                     "IPv4 address family.";
                   list hello-adjacencies {
                     key "local-address adjacent-address";
                     description "List of hello adjacencies.";

                     leaf local-address {
                       type inet:ipv4-address;
                       description
                         "Local address of the hello adjacency.";
                     }
                     leaf adjacent-address {
                       type inet:ipv4-address;
                       description
                         "Neighbor address of the hello adjacency.";
                     }

                     uses adjacency-state-attributes;

                     leaf peer {
                       type leafref {



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                         path "../../../../../../../../peers/peer/"
                           + "lsr-id";
                       }
                       description
                         "LDP peer from this adjacency.";
                     }
                   } // hello-adjacencies
                 } // ipv4

                 container ipv6 {
                   when "../../afi = 'ipv6'" {
                     description
                       "For IPv6.";
                   }
                   description
                     "IPv6 address family.";
                   list hello-adjacencies {
                     key "local-address adjacent-address";
                     description "List of hello adjacencies.";

                     leaf local-address {
                       type inet:ipv6-address;
                       description
                         "Local address of the hello adjacency.";
                     }
                     leaf adjacent-address {
                       type inet:ipv6-address;
                       description
                         "Neighbor address of the hello adjacency.";
                     }

                     uses adjacency-state-attributes;

                     leaf peer {
                       type leafref {
                         path "../../../../../../../../peers/peer/"
                           + "lsr-id";
                       }
                       description
                         "LDP peer from this adjacency.";
                     }
                   } // hello-adjacencies
                 } // ipv6
               } // state

               container ipv4 {
                 when "../afi = 'ipv4'" {
                   description



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                     "For IPv4.";
                 }
                 description
                   "IPv4 address family.";
                 list target {
                   key "adjacent-address";
                   description
                     "Targeted discovery params.";

                   leaf adjacent-address {
                     type inet:ipv4-address;
                     description
                       "Configures a remote LDP neighbor and enables
                        extended LDP discovery of the specified
                        neighbor.";
                   }
                   container config {
                     description
                       "Configuration data.";
                     leaf enable {
                       type boolean;
                       description
                         "Enable the target.";
                     }
                     leaf local-address {
                       type inet:ipv4-address;
                       description
                         "The local address.";
                     }
                   }
                   container state {
                     config false;
                     description
                       "Operational state data.";
                     leaf enable {
                       type boolean;
                       description
                         "Enable the target.";
                     }
                     leaf local-address {
                       type inet:ipv4-address;
                       description
                         "The local address.";
                     }
                   } // state
                 }
               } // ipv4
               container ipv6 {



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                 when "../afi = 'ipv6'" {
                   description
                     "For IPv6.";
                 }
                 description
                   "IPv6 address family.";
                 list target {
                   key "adjacent-address";
                   description
                     "Targeted discovery params.";

                   leaf adjacent-address {
                     type inet:ipv6-address;
                     description
                       "Configures a remote LDP neighbor and enables
                        extended LDP discovery of the specified
                        neighbor.";
                   }
                   container config {
                     description
                       "Configuration data.";
                     leaf enable {
                       type boolean;
                       description
                         "Enable the target.";
                     }
                     leaf local-address {
                       type inet:ipv6-address;
                       description
                         "The local address.";
                     }
                   }
                   container state {
                     config false;
                     description
                       "Operational state data.";
                     leaf enable {
                       type boolean;
                       description
                         "Enable the target.";
                     }
                     leaf local-address {
                       type inet:ipv6-address;
                       description
                         "The local address.";
                     }
                   } // state
                 }



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               } // ipv6
             } // address-family
           } // targeted
         } // discovery

         container forwarding-nexthop {
           if-feature forwarding-nexthop-config;
           description
             "Configuration for forwarding nexthop.";

           container interfaces {
             description
               "A list of interfaces on which forwarding is
                disabled.";

             list interface {
               key "interface";
               description
                 "List of LDP interfaces.";
               leaf interface {
                 type mpls-interface-ref;
                 description
                   "Interface.";
               }
               list address-family {
                 key "afi";
                 description
                   "Per-vrf per-af params.";
                 leaf afi {
                   type ldp-address-family;
                   description
                     "Address family type value.";
                 }
                 container config {
                   description
                     "Configuration data.";
                   leaf ldp-disable {
                     type boolean;
                     description
                       "Disable LDP forwarding on the interface.";
                   }
                   leaf mldp-disable {
                     if-feature mldp;
                     type boolean;
                     description
                       "Disable mLDP forwarding on the interface.";
                   }
                 }



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                 container state {
                   config false;
                   description
                     "Operational state data.";
                   leaf ldp-disable {
                     type boolean;
                     description
                       "Disable LDP forwarding on the interface.";
                   }
                   leaf mldp-disable {
                     if-feature mldp;

                     type boolean;
                     description
                       "Disable mLDP forwarding on the interface.";
                   }
                 }
               } // address-family
             } // list interface
           } // interfaces
         } // forwarding-nexthop
         uses policy-container {
           if-feature all-af-policy-config;
         }
       } // global

       container peers {
         description
           "Peers configuration attributes.";

         container config {
           description
             "Configuration data.";
           uses peer-authentication {
             if-feature global-session-authentication;
           }
           uses peer-attributes;

           container session-downstream-on-demand {
             if-feature session-downstream-on-demand-config;
             description
               "Session downstream-on-demand attributes.";
             leaf enable {
               type boolean;
               description
                 "'true' if session downstream-on-demand is enabled.";
             }
             leaf peer-list {



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               type peer-list-ref;
               description
                 "The name of a peer ACL.";
             }
           }
         }
         container state {
           config false;
           description
             "Operational state data.";
           uses peer-authentication {
             if-feature global-session-authentication;
           }
           uses peer-attributes;

           container session-downstream-on-demand {
             if-feature session-downstream-on-demand-config;
             description
               "Session downstream-on-demand attributes.";
             leaf enable {
               type boolean;
               description
                 "'true' if session downstream-on-demand is enabled.";
             }
             leaf peer-list {
               type peer-list-ref;
               description
                 "The name of a peer ACL.";
             }
           }
         }

         list peer {
           key "lsr-id";
           description
             "List of peers.";

           leaf lsr-id {
             type yang:dotted-quad;
             description "LSR ID.";
           }

           container config {
             description
               "Configuration data.";
             leaf admin-down {
               type boolean;
               default false;



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               description
                 "'true' to disable the peer.";
             }

             container capability {
               description
                 "Per peer capability";
               container mldp {
                 if-feature mldp;
                 description
                   "mLDP capabilities.";
                 uses mldp-capabilities;
               }
             }

             uses peer-af-policy-container {
               if-feature all-af-policy-config;
             }

             uses peer-authentication;

             uses graceful-restart-attributes-per-peer {
               if-feature per-peer-graceful-restart-config;
             }

             uses peer-attributes {
               if-feature per-peer-session-attributes-config;
             }

             container address-family {
               description
                 "Per-vrf per-af params.";
               container ipv4 {
                 description
                   "IPv4 address family.";
                 uses peer-af-policy-container;
               }
               container ipv6 {
                 description
                   "IPv6 address family.";
                 uses peer-af-policy-container;
               } // ipv6
             } // address-family
           }
           container state {
             config false;
             description
               "Operational state data.";



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             leaf admin-down {
               type boolean;
               default false;
               description
                 "'true' to disable the peer.";
             }

             container capability {
               description
                 "Per peer capability";
               container mldp {
                 if-feature mldp;
                 description
                   "mLDP capabilities.";
                 uses mldp-capabilities;
               }
             }

             uses peer-af-policy-container {
               if-feature all-af-policy-config;
             }

             uses peer-authentication;

             uses graceful-restart-attributes-per-peer {
               if-feature per-peer-graceful-restart-config;
             }

             uses peer-attributes {
               if-feature per-peer-session-attributes-config;
             }

             container address-family {
               description
                 "Per-vrf per-af params.";
               container ipv4 {
                 description
                   "IPv4 address family.";
                 uses peer-af-policy-container;

                 list hello-adjacencies {
                   key "local-address adjacent-address";
                   description "List of hello adjacencies.";

                   leaf local-address {
                     type inet:ipv4-address;
                     description
                       "Local address of the hello adjacency.";



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                   }
                   leaf adjacent-address {
                     type inet:ipv4-address;
                     description
                       "Neighbor address of the hello adjacency.";
                   }

                   uses adjacency-state-attributes;

                   leaf interface {
                     type mpls-interface-ref;
                     description "Interface for this adjacency.";
                   }
                 } // hello-adjacencies
               } // ipv4
               container ipv6 {
                 description
                   "IPv6 address family.";
                 uses peer-af-policy-container;

                 list hello-adjacencies {
                   key "local-address adjacent-address";
                   description "List of hello adjacencies.";

                   leaf local-address {
                     type inet:ipv6-address;
                     description
                       "Local address of the hello adjacency.";
                   }
                   leaf adjacent-address {
                     type inet:ipv6-address;
                     description
                       "Neighbor address of the hello adjacency.";
                   }

                   uses adjacency-state-attributes;

                   leaf interface {
                     type mpls-interface-ref;
                     description "Interface for this adjacency.";
                   }
                 } // hello-adjacencies
               } // ipv6
             } // address-family

             uses peer-state-derived;
           } // state
         } // list peer



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       } // peers
     } // container mpls-ldp
   }

   /*
    * RPCs
    */
   rpc mpls-ldp-clear-peer {
     description
       "Clears the session to the peer.";
     input {
       leaf lsr-id {
         type union {
           type yang:dotted-quad;
           type uint32;
         }
         description
           "LSR ID of peer to be cleared. If this is not provided
            then all peers are cleared";
       }
     }
   }

   rpc mpls-ldp-clear-hello-adjacency {
     description
       "Clears the hello adjacency";
     input {
       container hello-adjacency {
         description
           "Link adjacency or targettted adjacency. If this is not
            provided then all hello adjacencies are cleared";
         choice hello-adjacency-type {
           description "Adjacency type.";
           case targeted {
             container targeted {
               presence "Present to clear targeted adjacencies.";
               description
                 "Clear targeted adjacencies.";
               leaf target-address {
                 type inet:ip-address;
                 description
                   "The target address. If this is not provided then
                    all targeted adjacencies are cleared";
               }
             } // targeted
           }
           case link {
             container link {



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               presence "Present to clear link adjacencies.";
               description
                 "Clear link adjacencies.";
               leaf next-hop-interface {
                 type mpls-interface-ref;
                 description

                   "Interface connecting to next-hop. If this is not
                    provided then all link adjacencies are cleared.";
               }
               leaf next-hop-address {
                 type inet:ip-address;
                 must "../next-hop-interface" {
                   description
                     "Applicable when interface is specified.";
                 }
                 description
                   "IP address of next-hop. If this is not provided
                    then adjacencies to all next-hops on the given
                    interface are cleared.";
               } // next-hop-address
             } // link
           }
         }
       }
     }
   }

   rpc mpls-ldp-clear-peer-statistics {
     description
       "Clears protocol statistics (e.g. sent and received
        counters).";
     input {
       leaf lsr-id {
         type union {
           type yang:dotted-quad;
           type uint32;
         }
         description
           "LSR ID of peer whose statistic are to be cleared.
            If this is not provided then all peers statistics are
            cleared";
       }
     }
   }

   /*
    * Notifications



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    */
   notification mpls-ldp-peer-event {

     description
       "Notification event for a change of LDP peer operational
        status.";
     leaf event-type {
       type oper-status-event-type;
       description "Event type.";
     }
     uses ldp-peer-ref;
   }

   notification mpls-ldp-hello-adjacency-event {
     description
       "Notification event for a change of LDP adjacency operational
        status.";
     leaf event-type {
       type oper-status-event-type;
       description "Event type.";
     }
     uses ldp-adjacency-ref;
   }

   notification mpls-ldp-fec-event {
     description
       "Notification event for a change of FEC status.";
     leaf event-type {
       type oper-status-event-type;
       description "Event type.";
     }
     uses ldp-fec-event;
   }

   notification mpls-mldp-fec-event {
     description
       "Notification event for a change of FEC status.";
     leaf event-type {
       type oper-status-event-type;
       description "Event type.";
     }
     uses mldp-fec-event;
   }
 }

 <CODE ENDS>





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                                 Figure 22

7.  Security Considerations

   The configuration, state, action and notification data defined using
   YANG data models in this document are likely to be accessed via the
   protocols such as NETCONF [RFC6241] etc.

   Hence, YANG implementations MUST comply with the security
   requirements specified in section 15 of [RFC6020].  Additionally,
   NETCONF implementations MUST comply with the security requirements
   specified in sections 2.2, 2.3 and 9 of [RFC6241] as well as section
   3.7 of [RFC6536].

8.  IANA Considerations

   This document does not extend LDP or mLDP base protocol specifiction
   and hence there are no IANA considerations.

   Note to the RFC Editor: Please remove IANA section before the
   publication.

9.  Acknowledgments

   The authors would like to acknowledge Eddie Chami, Nagendra Kumar,
   Mannan Venkatesan, Pavan Beeram for their contribution to this
   document.  We also acknowledge Ladislav Lhotka for his useful
   comments as the YANG Doctor.

10.  References

10.1.  Normative References

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", draft-ietf-netmod-routing-cfg-22 (work in
              progress), July 2016.

   [I-D.rtgyangdt-rtgwg-ni-model]
              Berger, L., Hopps, C., Lindem, A., and D. Bogdanovic,
              "Network Instance Model", draft-rtgyangdt-rtgwg-ni-
              model-00 (work in progress), May 2016.

   [I-D.saad-mpls-base-yang]
              Raza, K., Gandhi, R., Liu, X., Beeram, V., Saad, T.,
              Bryskin, I., Chen, X., Jones, R., and B. Wen, "A YANG Data
              Model for MPLS Base", draft-saad-mpls-base-yang-00 (work
              in progress), May 2016.



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

   [RFC3478]  Leelanivas, M., Rekhter, Y., and R. Aggarwal, "Graceful
              Restart Mechanism for Label Distribution Protocol",
              RFC 3478, DOI 10.17487/RFC3478, February 2003,
              <http://www.rfc-editor.org/info/rfc3478>.

   [RFC5036]  Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
              "LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
              October 2007, <http://www.rfc-editor.org/info/rfc5036>.

   [RFC5331]  Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
              Label Assignment and Context-Specific Label Space",
              RFC 5331, DOI 10.17487/RFC5331, August 2008,
              <http://www.rfc-editor.org/info/rfc5331>.

   [RFC5561]  Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
              Le Roux, "LDP Capabilities", RFC 5561,
              DOI 10.17487/RFC5561, July 2009,
              <http://www.rfc-editor.org/info/rfc5561>.

   [RFC5918]  Asati, R., Minei, I., and B. Thomas, "Label Distribution
              Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class
              (FEC)", RFC 5918, DOI 10.17487/RFC5918, August 2010,
              <http://www.rfc-editor.org/info/rfc5918>.

   [RFC5919]  Asati, R., Mohapatra, P., Chen, E., and B. Thomas,
              "Signaling LDP Label Advertisement Completion", RFC 5919,
              DOI 10.17487/RFC5919, August 2010,
              <http://www.rfc-editor.org/info/rfc5919>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://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,
              <http://www.rfc-editor.org/info/rfc6241>.








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   [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,
              <http://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, <http://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,
              <http://www.rfc-editor.org/info/rfc6512>.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

   [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,
              <http://www.rfc-editor.org/info/rfc6826>.

   [RFC7060]  Napierala, M., Rosen, E., and IJ. Wijnands, "Using LDP
              Multipoint Extensions on Targeted LDP Sessions", RFC 7060,
              DOI 10.17487/RFC7060, November 2013,
              <http://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,
              <http://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,
              <http://www.rfc-editor.org/info/rfc7246>.

   [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,
              <http://www.rfc-editor.org/info/rfc7438>.




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   [RFC7552]  Asati, R., Pignataro, C., Raza, K., Manral, V., and R.
              Papneja, "Updates to LDP for IPv6", RFC 7552,
              DOI 10.17487/RFC7552, June 2015,
              <http://www.rfc-editor.org/info/rfc7552>.

   [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,
              <http://www.rfc-editor.org/info/rfc7715>.

10.2.  Informative References

   [I-D.ietf-rtgwg-policy-model]
              Shaikh, A., Shakir, R., D'Souza, K., and C. Chase,
              "Routing Policy Configuration Model for Service Provider
              Networks", draft-ietf-rtgwg-policy-model-01 (work in
              progress), April 2016.

   [I-D.iwijnand-mpls-mldp-multi-topology]
              Wijnands, I. and K. Raza, "mLDP Extensions for Multi
              Topology Routing", draft-iwijnand-mpls-mldp-multi-
              topology-03 (work in progress), June 2013.

   [I-D.openconfig-netmod-opstate]
              Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling
              of Operational State Data in YANG", draft-openconfig-
              netmod-opstate-01 (work in progress), July 2015.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <http://www.rfc-editor.org/info/rfc4364>.

   [RFC7307]  Zhao, Q., Raza, K., Zhou, C., Fang, L., Li, L., and D.
              King, "LDP Extensions for Multi-Topology", RFC 7307,
              DOI 10.17487/RFC7307, July 2014,
              <http://www.rfc-editor.org/info/rfc7307>.

Appendix A.  Additional Contributors

   Stephane Litkowski
   Orange.
   Email: stephane.litkowski@orange.com

   Reshad Rahman
   Cisco Systems Inc.
   Email: rrahman@cisco.com

   Danial Johari
   Cisco Systems Inc.
   Email: dajohari@cisco.com

Authors' Addresses

   Kamran Raza
   Cisco Systems, Inc.
   Email: skraza@cisco.com


   Rajiv Asati
   Cisco Systems, Inc.
   Email: rajiva@cisco.com


   Sowmya Krishnaswamy
   Cisco Systems, Inc.
   Email: sowkrish@cisco.com


   Xufeng Liu
   Ericsson
   Email: xliu@kuatrotech.com







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Internet-Draft      YANG Data Model for LDP and mLDP           July 2016


   Jeff Tantsura
   Ericsson
   Email: jeff.tantsura@ericsson.com


   Santosh Esale
   Juniper Networks
   Email: sesale@juniper.net


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


   Loa Andersson
   Huawei Technologies
   Email: loa@pi.nu


   Himanshu Shah
   Ciena Corporation
   Email: hshah@ciena.com


   Matthew Bocci
   Alcatel-Lucent
   Email: matthew.bocci@alcatel-lucent.com

















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