draft-ietf-pce-pcep-yang-11.xml

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<rfc ipr="trust200902" category="std" docName="draft-ietf-pce-pcep-yang-11" obsoletes="" updates="" submissionType="IETF" xml:lang="en">
  <front>
    <title abbrev="PCE-YANG">A YANG Data Model for Path Computation Element Communications Protocol (PCEP)</title>

    <author initials="D" surname="Dhody" fullname="Dhruv Dhody" role="editor">
      <organization>Huawei Technologies</organization>
      <address>
        <postal>
          <street>Divyashree Techno Park, Whitefield</street>
          <city>Bangalore</city>
          <region>Karnataka</region>
          <code>560066</code>
          <country>India</country>
        </postal>
        <email>dhruv.ietf@gmail.com</email>
      </address>
    </author>
    <author fullname="Jonathan Hardwick" initials="J." surname="Hardwick">
      <organization>Metaswitch</organization>
      <address>
        <postal>
          <street>100 Church Street</street>
          <city>Enfield</city>
          <code>EN2 6BQ</code>
          <country>UK</country>
        </postal>
        <email> jonathan.hardwick@metaswitch.com </email>
      </address>
    </author>
    <author fullname="Vishnu Pavan Beeram" initials="V." surname="Beeram">
      <organization>Juniper Networks</organization>
      <address>
        <postal>
          <street></street>
          <city></city>
          <code></code>
          <country>USA</country>
        </postal>
        <email> vbeeram@juniper.net </email>
      </address>
    </author>

    <author fullname="Jeff Tantsura" initials="J." surname="Tantsura">
      <organization></organization>

      <address>
        <postal>
          <street></street>

          <city></city>

          <region></region>

          <code></code>

          <country>USA</country>
        </postal>

        <email>jefftant@gmail.com</email>
      </address>
    </author>

    <date year="2019" />
    <area>Routing</area>
    <workgroup>PCE Working Group</workgroup>
    <abstract>
    <t>This document defines a YANG data model for the management of
    Path Computation Element communications Protocol (PCEP) for
    communications between a Path Computation Client (PCC) and a Path
    Computation Element (PCE), or between two PCEs. The data model
    includes configuration and state data.</t>
    </abstract>
  </front>
  <middle>
    <section title="Introduction" toc="default">
    <t>The Path Computation Element (PCE) defined in <xref target="RFC4655"/>
    is an entity that is capable of computing a network path or route
    based on a network graph, and applying computational constraints.
    A Path Computation Client (PCC) may make requests to a PCE for paths
    to be computed.</t>

   <t>PCEP is the communication protocol between a PCC and PCE and is
   defined in <xref target="RFC5440"/>. PCEP interactions include path
   computation requests and path computation replies as well as
   notifications of specific states related to the use of a PCE in the
   context of Multiprotocol Label Switching (MPLS) and Generalized MPLS
   (GMPLS) Traffic Engineering (TE). <xref target='RFC8231'/>
   specifies extensions to PCEP to enable stateful control of MPLS TE LSPs. </t>

   <t>This document defines a YANG <xref target="RFC7950"/> data model
   for the management of PCEP speakers. It is important to
   establish a common data model for how PCEP speakers are identified,
   configured, and monitored. The data model includes configuration data
   and state data.</t>

   <t>This document contains a specification of the PCEP YANG module,
   "ietf-pcep" which provides the PCEP <xref target="RFC5440"/> data
   model.</t>

   <t>The PCEP operational state is included in the same tree as the PCEP
    configuration consistent with Network Management Datastore
   Architecture <xref target="RFC8342"/>. 
   The origin of the data is indicated as per the origin metadata 
   annotation.</t>

    </section>
<section title="Requirements Language" toc="default">
        <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
      "MAY", and "OPTIONAL" in this document are to be interpreted as
      described in BCP 14 <xref target="RFC2119" /> <xref target="RFC8174"/> when, and only when, they
      appear in all capitals, as shown here.</t>
      </section>
    <section title="Terminology and Notation" toc="default">
<t>
          This document uses the terminology defined in <xref target="RFC4655"/>
          and <xref target="RFC5440"/>.  In particular, it uses the following
          acronyms.
          <list style='symbols'>
            <t>
              Path Computation Request message (PCReq).
            </t>
            <t>
              Path Computation Reply message (PCRep).
            </t>
            <t>
              Notification message (PCNtf).
            </t>
            <t>
              Error message (PCErr).
            </t>
            <t>
              Request Parameters object (RP).
            </t>
            <t>
              Synchronization Vector object (SVEC).
            </t>
            <t>
              Explicit Route object (ERO).
            </t>
          </list>
        </t>
        <t>
          This document also uses the following terms defined in
          <xref target="RFC7420"/>:
          <list style='symbols'>
            <t>
            PCEP entity: a local PCEP speaker.
            </t>
            <t>
            PCEP peer: to refer to a remote PCEP speaker.
            </t>
            <t>PCEP speaker: where it is not necessary to distinguish between local
          and remote.
        </t>
        </list>
        </t>
      <t>
          Further, this document also uses the following terms defined in
          <xref target='RFC8231'/> :
          <list style='symbols'>
            <t>
            Stateful PCE, Passive Stateful PCE, Active Stateful PCE
            </t>
            <t>
            Delegation, Revocation, Redelegation
            </t>
            <t>LSP State Report, Path Computation Report message (PCRpt).</t>
            <t>LSP State Update, Path Computation Update message (PCUpd).</t>
        </list>
        </t>
      <t>
          <xref target='RFC8281'/> :
          <list style='symbols'>
            <t>PCE-initiated LSP, Path Computation LSP Initiate Message (PCInitiate).</t>
        </list>
        </t>
      <t>
          <xref target='RFC8408'/> :
          <list style='symbols'>
            <t>Path Setup Type (PST).</t>
        </list>
        </t>

      <t>
          <xref target='I-D.ietf-pce-segment-routing'/> :
          <list style='symbols'>
            <t>Segment Routing (SR).</t>


        </list>
        </t>
        <t>
          <xref target='RFC6241'/> :
          <list style='symbols'>
            <t>Configuration data.</t>
            <t>State data.</t>


        </list>
        </t>

    <section anchor="sec.tree-symbols" title="Tree Diagrams" toc="default">
      <t>A simplified graphical representation of the data model is used in this
       document. The meaning of the symbols in these diagrams is defined in <xref target="RFC8340"/>. 
      </t>
      <!--
      <list style="symbols">
        <t>Brackets "[" and "]" enclose list keys.</t>
        <t>Abbreviations before data node names: "rw" means
        configuration (read-write) and "ro" state data
        (read-only).</t>
        <t>Symbols after data node names: "?" means an optional node, "!"
      means a presence container, and "*" denotes a list and leaf-list.</t>


        <t>Parentheses enclose choice and case nodes, and case nodes
        are also marked with a colon (":").</t>
        <t>Ellipsis ("...") stands for contents of subtrees that are
        not shown.</t>
      </list></t>-->
    </section>
    <section title="Prefixes in Data Node Names" toc="default">
      <t>In this document, names of data nodes and other data
   model objects are often used without a prefix, as long as it is clear
   from the context in which YANG module each name is defined.
   Otherwise, names are prefixed using the standard prefix associated
   with the corresponding YANG module, as shown in <xref target="tab.prefixes" pageno="false" format="default"/>.</t>

      <texttable anchor="tab.prefixes" title="Prefixes and corresponding YANG modules" suppress-title="false" align="center" style="full">
        <ttcol align="left">Prefix</ttcol>
        <ttcol align="left">YANG module</ttcol>
        <ttcol align="left">Reference</ttcol>
        <c>yang</c><c>ietf-yang-types</c><c><xref target="RFC6991" pageno="false" format="default"/></c>
        <c>inet</c><c>ietf-inet-types</c><c><xref target="RFC6991" pageno="false" format="default"/></c>
        <c>te</c><c>ietf-te</c><c><xref target="I-D.ietf-teas-yang-te" pageno="false" format="default"/></c>
        <c>te-types</c><c>ietf-te-types</c><c><xref target="I-D.ietf-teas-yang-te" pageno="false" format="default"/></c>
        <c>key-chain</c><c>ietf-key-chain</c><c><xref target="RFC8177" pageno="false" format="default"/></c>
        <c>nacm</c><c>ietf-netconf-acm</c><c><xref target="RFC8341" pageno="false" format="default"/></c>
        <c>tls-server</c><c>ietf-tls-server</c><c><xref target="I-D.ietf-netconf-tls-client-server" pageno="false" format="default"/></c>
        <c>tls-client</c><c>ietf-tls-client</c><c><xref target="I-D.ietf-netconf-tls-client-server" pageno="false" format="default"/></c>
        <c>ospf</c><c>ietf-ospf</c><c><xref target="I-D.ietf-ospf-yang" pageno="false" format="default"/></c>
        <c>isis</c><c>ietf-isis</c><c><xref target="I-D.ietf-isis-yang-isis-cfg" pageno="false" format="default"/></c>
      </texttable>
    </section>
    <section title="Refrences in the Model" toc="default">
      <t>Following documents are refrenced in the model defined in this document - </t>
        <texttable anchor="tab.ref" title="Refrences in the YANG modules" suppress-title="false" align="center" style="full">
        <ttcol align="left">Documents</ttcol>
        <ttcol align="left">Reference</ttcol>
        <c>RSVP-TE: Extensions to RSVP for LSP Tunnels</c><c><xref target="RFC3209" pageno="false" format="default"/></c>
        <c>OSPF Protocol Extensions for Path Computation Element (PCE) Discovery</c><c><xref target="RFC5088" pageno="false" format="default"/></c>
        <c>IS-IS Protocol Extensions for Path Computation Element (PCE) Discovery</c><c><xref target="RFC5089" pageno="false" format="default"/></c>
        <c>Path Computation Element (PCE) Communication Protocol (PCEP)</c><c><xref target="RFC5440" pageno="false" format="default"/></c>
        <c>Preserving Topology Confidentiality in Inter-Domain Path Computation Using a Path-Key-Based Mechanism</c><c><xref target="RFC5520" pageno="false" format="default"/></c>
        <c>Encoding of Objective Functions in the Path Computation Element Communication Protocol (PCEP)</c><c><xref target="RFC5541" pageno="false" format="default"/></c>
        <c>Path Computation Element Communication Protocol (PCEP) Requirements and Protocol Extensions in Support of Global Concurrent Optimization</c><c><xref target="RFC5557" pageno="false" format="default"/></c>
        <c>Common YANG Data Types</c><c><xref target="RFC6991" pageno="false" format="default"/></c>
        <c>YANG Data Model for Key Chains</c><c><xref target="RFC8177" pageno="false" format="default"/></c>
        <c>Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE</c><c><xref target="RFC8231" pageno="false" format="default"/></c>
        <c>Optimizations of Label Switched Path State Synchronization Procedures for a Stateful PCE</c><c><xref target="RFC8232" pageno="false" format="default"/></c>
        <c>PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)</c><c><xref target="RFC8253" pageno="false" format="default"/></c>
        <c>Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model</c><c><xref target="RFC8281" pageno="false" format="default"/></c>
        <c>Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths</c><c><xref target="RFC8306" pageno="false" format="default"/></c>
        <c>Network Configuration Access Control Model</c><c><xref target="RFC8341" pageno="false" format="default"/></c>
        <c>Conveying Path Setup Type in PCE Communication Protocol (PCEP) Messages</c><c><xref target="RFC8408" pageno="false" format="default"/></c>

        <c>Traffic Engineering Common YANG Types</c><c><xref target="I-D.ietf-teas-yang-te-types" pageno="false" format="default"/></c>
        <c>A YANG Data Model for Traffic Engineering Tunnels and Interfaces</c><c><xref target="I-D.ietf-teas-yang-te" pageno="false" format="default"/></c>
        <c>YANG Groupings for TLS Clients and TLS Servers</c><c><xref target="I-D.ietf-netconf-tls-client-server" pageno="false" format="default"/></c>
        <c>PCEP Extensions for Segment Routing</c><c><xref target="I-D.ietf-pce-segment-routing" pageno="false" format="default"/></c>
        <c>PCEP Extensions for Establishing Relationships Between Sets of LSPs</c><c><xref target="I-D.ietf-pce-association-group" pageno="false" format="default"/></c>
        <c>YANG Data Model for OSPF Protocol</c><c><xref target="I-D.ietf-ospf-yang" pageno="false" format="default"/></c>
        <c>YANG Data Model for IS-IS Protocol</c><c><xref target="I-D.ietf-isis-yang-isis-cfg" pageno="false" format="default"/></c>
        <c>PCEP extensions for GMPLS</c><c><xref target="I-D.ietf-pce-gmpls-pcep-extensions" pageno="false" format="default"/></c>
      </texttable>
      
    </section>
    </section>

    <section title="Objectives" toc="default">
    <t>This section describes some of the design objectives for the model:
    <list style="symbols">
    <t>In case of existing implementations, it needs to map
      the data model defined in this document to their proprietary
      native data model.  To facilitate such mappings, the data model
      should be simple.</t>
    <t>The data model should be suitable for new implementations to use
      as is.</t>
    <t>Mapping to the PCEP MIB Module should be clear.</t>
    <t>The data model should allow for static configurations of peers.</t>
    <t>The data model should include read-only counters in order to
      gather statistics for sent and received PCEP messages,
      received messages with errors, and messages that could not be sent
      due to errors. This could be in a separate model which
      augments the base data model.</t>
    <t>It should be fairly straightforward to augment the base data model
    for advanced PCE features.</t>
    </list>
    </t>
    </section>

    <section title="The Design of PCEP Data Model" toc="default" anchor="sec.data-tree">
<section title="The Overview of PCEP Data Model" toc="default" anchor="sec.overview.data-tree">
<t>The PCEP YANG module defined in this document has all the common
   building blocks for the PCEP protocol.
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep
    +--rw pcep!
       +--rw entity
          +--rw addr                          inet:ip-address
          +--rw enabled?                      boolean
          +--rw role                          pcep-role
          +--rw description?                  string
          +--rw speaker-entity-id?            string
          |       {stateful-sync-opt}?
          +--rw admin-status?                 pcep-admin-status
          +--ro index?                        uint32
          +--ro oper-status?                  pcep-oper-status
          +--rw domain
          |  +--rw domain* [domain-type domain]
          |        ...
          +--rw capability

          |        ...
          +--rw pce-info
          |  +--rw scope
          |  |     ...
          |  +--rw neigh-domains
          |  |     ...
          |  +--rw path-key {path-key}?
          |        ...

          +--ro lsp-db {stateful}?
          |  +--ro db-ver?             uint64
          |  |       {stateful-sync-opt}?
          |  +--ro association-list*
          |  |       [id source global-source extended-id]
          |  |     ...
          |  +--ro lsp* [plsp-id pcc-id]
          |        ...
          +--ro path-keys {path-key}?
          |  +--ro path-keys* [path-key]
          |        ...
          +--rw peers
             +--rw peer* [addr]
                   
                +--ro sessions
                   +--ro session* [initiator]
                      ...

  rpcs:
    +---x trigger-resync {stateful,stateful-sync-opt}?
       +---w input
          +---w pcc?   -> /pcep/entity/peers/peer/addr

  notifications:
    +---n pcep-session-up
    |  ...
    +---n pcep-session-down
    |  ...
    +---n pcep-session-local-overload
    |  ...
    +---n pcep-session-local-overload-clear
    |  ...
    +---n pcep-session-peer-overload
    |  ...
    +---n pcep-session-peer-overload-clear
       ...
                  ]]></artwork>
        </figure>
      </t>
</section>

    <section title="The Entity" toc="default">
    <t>The PCEP yang module may contain status information for the
    local PCEP entity.</t>
    <t>The entity has an IP address
   (using ietf-inet-types <xref target="RFC6991"/>) and a "role"
   leaf (the local entity PCEP role) as mandatory. </t>
    <t>Note that, the PCEP MIB module <xref target="RFC7420"/> uses an
    entity list and a system generated entity index as a primary index
    to the read only entity
    table. If the device implements the PCEP MIB, the "index" leaf MUST contain
    the value of the corresponding pcePcepEntityIndex and only one entity
    is assumed.</t>
    <t>The various information related to this entity such as its domain, capcabilities etc. 
      Further incase when the entity is PCE it could also have path-key and the LSP-DB information.</t>  
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep
  +--rw pcep!
     +--rw entity
        +--rw addr                          inet:ip-address
        +--rw enabled?                      boolean
        +--rw role                          pcep-role
        +--rw description?                  string
        +--rw speaker-entity-id?            string {sync-opt}?
        +--rw admin-status?                 boolean
        +--ro index?                        uint32
        +--ro oper-status?                  pcep-oper-status
        +--rw domain
        |  +--rw domain* [domain-type domain]
        |     +--rw domain-type    domain-type
        |     +--rw domain         domain
        +--rw capability
        |  +--rw capability?             bits
        |  +--rw pce-initiated?          boolean {pce-initiated}?
        |  +--rw include-db-ver?         boolean
        |  |       {stateful,sync-opt}?
        |  +--rw trigger-resync?         boolean
        |  |       {stateful,sync-opt}?
        |  +--rw trigger-initial-sync?   boolean
        |  |       {stateful,sync-opt}?
        |  +--rw incremental-sync?       boolean
        |  |       {stateful,sync-opt}?
        |  +--rw sr {sr}?
        |     +--rw enabled?     boolean
        |     +--rw msd-limit?   boolean
        |     +--rw nai?         boolean
        +--rw msd?                          uint8 {sr}?
        +--rw pce-info
        |  +--rw scope
        |  |  +--rw path-scope?         bits
        |  |  +--rw intra-area-pref?    uint8
        |  |  +--rw inter-area-pref?    uint8
        |  |  +--rw inter-as-pref?      uint8
        |  |  +--rw inter-layer-pref?   uint8
        |  +--rw neigh-domains
        |  |  +--rw domain* [domain-type domain]
        |  |     +--rw domain-type    domain-type
        |  |     +--rw domain         domain
        |  +--rw path-key {path-key}?
        |     +--rw enabled?         boolean
        |     +--rw discard-timer?   uint32
        |     +--rw reuse-time?      uint32
        |     +--rw pce-id?          inet:ip-address
        +--rw connect-timer?                uint16
        +--rw connect-max-retry?            uint32
        +--rw init-backoff-timer?           uint16
        +--rw max-backoff-timer?            uint32
        +--rw open-wait-timer?              uint16
        +--rw keep-wait-timer?              uint16
        +--rw keep-alive-timer?             uint8
        +--rw dead-timer?                   uint8
        +--rw allow-negotiation?            boolean
        +--rw max-keep-alive-timer?         uint8
        +--rw max-dead-timer?               uint8
        +--rw min-keep-alive-timer?         uint8
        +--rw min-dead-timer?               uint8
        +--rw sync-timer?                   uint16 {svec}?
        +--rw request-timer?                uint16
        +--rw max-sessions?                 uint32
        +--rw max-unknown-reqs?             uint32
        +--rw max-unknown-msgs?             uint32
        +--rw pcep-notification-max-rate    uint32
        +--rw stateful-parameter {stateful}?
        |  +--rw state-timeout?          uint32
        |  +--rw redelegation-timeout?   uint32
        |  +--rw rpt-non-pcep-lsp?       boolean
        +--rw of-list {objective-function}?
        |  +--rw objective-function* [of]
        |     +--rw of    identityref
        +--ro lsp-db {stateful}?
        |  +--ro db-ver?             uint64 {sync-opt}?
        |  +--ro association-list*
        |  |       [type id source global-source extended-id]
        |  |       {association}?
        |  |  +--ro type             identityref
        |  |  +--ro id               uint16
        |  |  +--ro source           inet:ip-address
        |  |  +--ro global-source    uint32
        |  |  +--ro extended-id      string
        |  |  +--ro lsp* [plsp-id pcc-id]
        |  |     +--ro plsp-id    -> /pcep/entity/lsp-db/lsp/plsp-id
        |  |     +--ro pcc-id     -> /pcep/entity/lsp-db/lsp/pcc-id
        |  +--ro lsp* [plsp-id pcc-id]
        |     +--ro plsp-id               uint32
        |     +--ro pcc-id                inet:ip-address
        |     +--ro lsp-ref
        |     |  +--ro source?
        |     |  |       -> /te:te/lsps-state/lsp/source
        |     |  +--ro destination?
        |     |  |       -> /te:te/lsps-state/lsp/destination
        |     |  +--ro tunnel-id?
        |     |  |       -> /te:te/lsps-state/lsp/tunnel-id
        |     |  +--ro lsp-id?
        |     |  |       -> /te:te/lsps-state/lsp/lsp-id
        |     |  +--ro extended-tunnel-id?
        |     |          -> /te:te/lsps-state/lsp/extended-tunnel-id
        |     +--ro admin-state?          boolean
        |     +--ro operational-state?    operational-state
        |     +--ro delegated
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     |  +--ro srp-id?    uint32
        |     +--ro initiation {pce-initiated}?
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     +--ro symbolic-path-name?   string
        |     +--ro last-error?           identityref
        |     +--ro pst?                  identityref
        |     +--ro association-list*
        |             [type id source global-source extended-id]
        |             {association}?
        |        +--ro type
        |        |       -> /pcep/entity/lsp-db/association-list/type
        |        +--ro id
        |        |       -> /pcep/entity/lsp-db/association-list/id
        |        +--ro source           leafref
        |        +--ro global-source    leafref
        |        +--ro extended-id      leafref
        +--ro path-keys {path-key}?
        |  +--ro path-keys* [path-key]
        |     +--ro path-key         uint16
        |     +--ro cps
        |     |  +--ro explicit-route-objects* [index]
        |     |     +--ro index                        uint32
        |     |     +--ro (type)?
        |     |        +--:(numbered-node-hop)
        |     |        |  +--ro numbered-node-hop
        |     |        |     +--ro node-id     te-node-id
        |     |        |     +--ro hop-type?   te-hop-type
        |     |        +--:(numbered-link-hop)
        |     |        |  +--ro numbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(unnumbered-link-hop)
        |     |        |  +--ro unnumbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro node-id       te-node-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(as-number)
        |     |        |  +--ro as-number-hop
        |     |        |     +--ro as-number    inet:as-number
        |     |        |     +--ro hop-type?    te-hop-type
        |     |        +--:(label)
        |     |           +--ro label-hop
        |     |              +--ro te-label
        |     |                    ...
        |     +--ro pcc-original?    -> /pcep/entity/peers/peer/addr
        |     +--ro req-id?          uint32
        |     +--ro retrieved?       boolean
        |     +--ro pcc-retrieved?   -> /pcep/entity/peers/peer/addr
        |     +--ro creation-time?   yang:timestamp
        |     +--ro discard-time?    uint32
        |     +--ro reuse-time?      uint32
        +--rw peers
           +--rw peer* [addr]
                 ...
                  ]]></artwork>
        </figure>

    </section>
    <section title="The Peer Lists" toc="default">
        <t>
          The peer list contains peer(s) that the
          local PCEP entity knows about. A PCEP speaker is identified by its
          IP address.  If there is a PCEP
          speaker in the network that uses multiple IP addresses
          then it looks like multiple distinct peers to the other PCEP
          speakers in the network.
        </t>
        <t>
          Since PCEP sessions
          can be ephemeral, the peer list tracks a peer even when no
          PCEP session currently exists to that peer.  The statistics contained
          are an aggregate of the statistics for all
          successive sessions to that peer.
        </t>
        <t>
          To limit the quantity of information that is stored, an
          implementation MAY choose to discard this information
          if and only if no PCEP session exists to the corresponding peer.
        </t>

   <t>The data model for PCEP peer presented in this document uses a flat
   list of peers.  Each peer in the list is identified by its
   IP address (addr-type, addr).</t>
   <t> There is a list for static peer configuration and operational state of
   all peers (i.e.static as well as discovered)("/pcep/entity/peers"). The list
   is used to enable remote PCE configuration at PCC (or PCE) and has the
   operational state of these peers as well as the remote PCE peer which were
   discovered and PCC peers that have initiated session.</t>


<figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep
  +--rw pcep!
     +--rw entity
        ...
        +--rw peers
           +--rw peer* [addr]
              +--rw addr                    inet:ip-address
              +--rw role                    pcep-role
              +--rw description?            string
              +--rw domain
              |  +--rw domain* [domain-type domain]
              |     +--rw domain-type    domain-type
              |     +--rw domain         domain
              +--rw capability
              |  +--rw capability?             bits
              |  +--rw pce-initiated?          boolean
              |  |       {pce-initiated}?
              |  +--rw include-db-ver?         boolean
              |  |       {stateful,sync-opt}?
              |  +--rw trigger-resync?         boolean
              |  |       {stateful,sync-opt}?
              |  +--rw trigger-initial-sync?   boolean
              |  |       {stateful,sync-opt}?
              |  +--rw incremental-sync?       boolean
              |  |       {stateful,sync-opt}?
              |  +--rw sr {sr}?
              |     +--rw enabled?     boolean
              |     +--rw msd-limit?   boolean
              |     +--rw nai?         boolean
              +--rw msd?                    uint8 {sr}?
              +--rw pce-info
              |  +--rw scope
              |  |  +--rw path-scope?         bits
              |  |  +--rw intra-area-pref?    uint8
              |  |  +--rw inter-area-pref?    uint8
              |  |  +--rw inter-as-pref?      uint8
              |  |  +--rw inter-layer-pref?   uint8
              |  +--rw neigh-domains
              |     +--rw domain* [domain-type domain]
              |        +--rw domain-type    domain-type
              |        +--rw domain         domain
              +--rw delegation-pref?        uint8 {stateful}?
              +--rw auth
              |  +--rw (auth-type-selection)?
              |     +--:(auth-key-chain)
              |     |  +--rw key-chain?
              |     |          key-chain:key-chain-ref
              |     +--:(auth-key)
              |     |  +--rw crypto-algorithm            identityref
              |     |  +--rw (key-string-style)?
              |     |     +--:(keystring)
              |     |     |  +--rw keystring?            string
              |     |     +--:(hexadecimal)
              |     |              {key-chain:hex-key-string}?
              |     |        +--rw hexadecimal-string?
              |     |                yang:hex-string
              |     +--:(auth-tls) {tls}?
              |        +--rw (role)?
              |           +--:(server)
              |           |  +--rw tls-server
              |           |        ...
              |           +--:(client)
              |              +--rw tls-client
              |                    ...
              +--ro discontinuity-time?     yang:timestamp
              +--ro initiate-session?       boolean
              +--ro session-exists?         boolean
              +--ro session-up-time?        yang:timestamp
              +--ro session-fail-time?      yang:timestamp
              +--ro session-fail-up-time?   yang:timestamp
              +--ro sessions
                 +--ro session* [initiator]
                       ...            
                  ]]></artwork>
        </figure>
    </section>
    <section title="The Session Lists" toc="default">
 <t>
          The session list contains PCEP session that the
          PCEP entity (PCE or PCC) is currently participating in.
          The statistics in
          session are semantically different from those in
          peer since the former applies to the current session only,
          whereas the latter is the aggregate for all sessions that have
          existed to that peer.
        </t>
        <t>
          Although <xref target="RFC5440"/> forbids more than one
          active PCEP session between a given pair of PCEP entities
          at any given time, there is a window during session
          establishment where two sessions may exist for a given pair,
          one representing a session initiated by the local PCEP
          entity and the other representing a session initiated by
          the peer.  If either of these sessions reaches active state
          first, then the other is discarded.
        </t>
<t>The data model for PCEP session presented in this document uses a flat
   list of sessions.  Each session in the list is identified by its
   initiator. This index allows two sessions to exist transiently for a
          given peer, as discussed above.</t>
          <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep
  +--rw pcep!
     +--rw entity
           ...
        +--rw peers
           +--rw peer* [addr]
                 ...
              +--ro sessions
                 +--ro session* [initiator]
                    +--ro initiator               pcep-initiator
                    +--ro role?
                    |       -> /pcep/entity/role
                    +--ro state-last-change?      yang:timestamp
                    +--ro state?                  pcep-sess-state
                    +--ro session-creation?       yang:timestamp
                    +--ro connect-retry?          yang:counter32
                    +--ro local-id?               uint8
                    +--ro remote-id?              uint8
                    +--ro keepalive-timer?        uint8
                    +--ro peer-keepalive-timer?   uint8
                    +--ro dead-timer?             uint8
                    +--ro peer-dead-timer?        uint8
                    +--ro ka-hold-time-rem?       uint8
                    +--ro overloaded?             boolean
                    +--ro overload-time?          uint32
                    +--ro peer-overloaded?        boolean
                    +--ro peer-overload-time?     uint32
                    +--ro lspdb-sync?             sync-state
                    |       {stateful}?
                    +--ro recv-db-ver?            uint64
                    |       {stateful,sync-opt}?
                    +--ro of-list {objective-function}?
                    |  +--ro objective-function* [of]
                    |     +--ro of    identityref
                    +--ro pst-list
                    |  +--ro path-setup-type* [pst]
                    |     +--ro pst    identityref
                    +--ro assoc-type-list {association}?
                    |  +--ro assoc-type* [at]
                    |     +--ro at    identityref
                    +--ro speaker-entity-id?      string {sync-opt}?
                    +--ro discontinuity-time?     yang:timestamp

                  ]]></artwork>
        </figure>          
    </section>
    <section title="Notifications" toc="default">
    <t>This YANG model defines a list of notifications to inform client of
   important events detected during the protocol operation.  The
   notifications defined cover the PCEP MIB notifications.</t>
          <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
  notifications:
    +---n pcep-session-up
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro state-last-change?   yang:timestamp
    |  +--ro state?               pcep-sess-state
    +---n pcep-session-down
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?   pcep-initiator
    |  +--ro state-last-change?   yang:timestamp
    |  +--ro state?               pcep-sess-state
    +---n pcep-session-local-overload
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro overloaded?          boolean
    |  +--ro overload-time?       uint32
    +---n pcep-session-local-overload-clear
    |  +--ro peer-addr?    -> /pcep/entity/peers/peer/addr
    |  +--ro overloaded?   boolean
    +---n pcep-session-peer-overload
    |  +--ro peer-addr?            -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro peer-overloaded?      boolean
    |  +--ro peer-overload-time?   uint32
    +---n pcep-session-peer-overload-clear
       +--ro peer-addr?         -> /pcep/entity/peers/peer/addr
       +--ro peer-overloaded?   boolean
                  ]]></artwork>
        </figure>    
    </section>
    <section title="RPC" toc="default">
    <t>This YANG model defines a RPC to trigger state resynchronization to
      a particular PCEP peer.</t>
          <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
  rpcs:
    +---x trigger-resync {stateful,sync-opt}?
       +---w input
          +---w pcc?   -> /pcep/entity/peers/peer/addr
            
                  ]]></artwork>
        </figure>                 
    </section>
<section title="The Full PCEP Data Model" toc="default" anchor="sec.full.data-tree">
    <t>The module, "ietf-pcep", defines the basic components of a PCE speaker. The tree depth in the tree is set to 10. 
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep
  +--rw pcep!
     +--rw entity
        +--rw addr                          inet:ip-address
        +--rw enabled?                      boolean
        +--rw role                          pcep-role
        +--rw description?                  string
        +--rw speaker-entity-id?            string {sync-opt}?
        +--rw admin-status?                 boolean
        +--ro index?                        uint32
        +--ro oper-status?                  pcep-oper-status
        +--rw domain
        |  +--rw domain* [domain-type domain]
        |     +--rw domain-type    domain-type
        |     +--rw domain         domain
        +--rw capability
        |  +--rw capability?             bits
        |  +--rw pce-initiated?          boolean {pce-initiated}?
        |  +--rw include-db-ver?         boolean
        |  |       {stateful,sync-opt}?
        |  +--rw trigger-resync?         boolean
        |  |       {stateful,sync-opt}?
        |  +--rw trigger-initial-sync?   boolean
        |  |       {stateful,sync-opt}?
        |  +--rw incremental-sync?       boolean
        |  |       {stateful,sync-opt}?
        |  +--rw sr {sr}?
        |     +--rw enabled?     boolean
        |     +--rw msd-limit?   boolean
        |     +--rw nai?         boolean
        +--rw msd?                          uint8 {sr}?
        +--rw pce-info
        |  +--rw scope
        |  |  +--rw path-scope?         bits
        |  |  +--rw intra-area-pref?    uint8
        |  |  +--rw inter-area-pref?    uint8
        |  |  +--rw inter-as-pref?      uint8
        |  |  +--rw inter-layer-pref?   uint8
        |  +--rw neigh-domains
        |  |  +--rw domain* [domain-type domain]
        |  |     +--rw domain-type    domain-type
        |  |     +--rw domain         domain
        |  +--rw path-key {path-key}?
        |     +--rw enabled?         boolean
        |     +--rw discard-timer?   uint32
        |     +--rw reuse-time?      uint32
        |     +--rw pce-id?          inet:ip-address
        +--rw connect-timer?                uint16
        +--rw connect-max-retry?            uint32
        +--rw init-backoff-timer?           uint16
        +--rw max-backoff-timer?            uint32
        +--rw open-wait-timer?              uint16
        +--rw keep-wait-timer?              uint16
        +--rw keep-alive-timer?             uint8
        +--rw dead-timer?                   uint8
        +--rw allow-negotiation?            boolean
        +--rw max-keep-alive-timer?         uint8
        +--rw max-dead-timer?               uint8
        +--rw min-keep-alive-timer?         uint8
        +--rw min-dead-timer?               uint8
        +--rw sync-timer?                   uint16 {svec}?
        +--rw request-timer?                uint16
        +--rw max-sessions?                 uint32
        +--rw max-unknown-reqs?             uint32
        +--rw max-unknown-msgs?             uint32
        +--rw pcep-notification-max-rate    uint32
        +--rw stateful-parameter {stateful}?
        |  +--rw state-timeout?          uint32
        |  +--rw redelegation-timeout?   uint32
        |  +--rw rpt-non-pcep-lsp?       boolean
        +--rw of-list {objective-function}?
        |  +--rw objective-function* [of]
        |     +--rw of    identityref
        +--ro lsp-db {stateful}?
        |  +--ro db-ver?             uint64 {sync-opt}?
        |  +--ro association-list*
        |  |       [type id source global-source extended-id]
        |  |       {association}?
        |  |  +--ro type             identityref
        |  |  +--ro id               uint16
        |  |  +--ro source           inet:ip-address
        |  |  +--ro global-source    uint32
        |  |  +--ro extended-id      string
        |  |  +--ro lsp* [plsp-id pcc-id]
        |  |     +--ro plsp-id    -> /pcep/entity/lsp-db/lsp/plsp-id
        |  |     +--ro pcc-id     -> /pcep/entity/lsp-db/lsp/pcc-id
        |  +--ro lsp* [plsp-id pcc-id]
        |     +--ro plsp-id               uint32
        |     +--ro pcc-id                inet:ip-address
        |     +--ro lsp-ref
        |     |  +--ro source?
        |     |  |       -> /te:te/lsps-state/lsp/source
        |     |  +--ro destination?
        |     |  |       -> /te:te/lsps-state/lsp/destination
        |     |  +--ro tunnel-id?
        |     |  |       -> /te:te/lsps-state/lsp/tunnel-id
        |     |  +--ro lsp-id?
        |     |  |       -> /te:te/lsps-state/lsp/lsp-id
        |     |  +--ro extended-tunnel-id?
        |     |          -> /te:te/lsps-state/lsp/extended-tunnel-id
        |     +--ro admin-state?          boolean
        |     +--ro operational-state?    operational-state
        |     +--ro delegated
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     |  +--ro srp-id?    uint32
        |     +--ro initiation {pce-initiated}?
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     +--ro symbolic-path-name?   string
        |     +--ro last-error?           identityref
        |     +--ro pst?                  identityref
        |     +--ro association-list*
        |             [type id source global-source extended-id]
        |             {association}?
        |        +--ro type
        |        |       -> /pcep/entity/lsp-db/association-list/type
        |        +--ro id
        |        |       -> /pcep/entity/lsp-db/association-list/id
        |        +--ro source           leafref
        |        +--ro global-source    leafref
        |        +--ro extended-id      leafref
        +--ro path-keys {path-key}?
        |  +--ro path-keys* [path-key]
        |     +--ro path-key         uint16
        |     +--ro cps
        |     |  +--ro explicit-route-objects* [index]
        |     |     +--ro index                        uint32
        |     |     +--ro (type)?
        |     |        +--:(numbered-node-hop)
        |     |        |  +--ro numbered-node-hop
        |     |        |     +--ro node-id     te-node-id
        |     |        |     +--ro hop-type?   te-hop-type
        |     |        +--:(numbered-link-hop)
        |     |        |  +--ro numbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(unnumbered-link-hop)
        |     |        |  +--ro unnumbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro node-id       te-node-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(as-number)
        |     |        |  +--ro as-number-hop
        |     |        |     +--ro as-number    inet:as-number
        |     |        |     +--ro hop-type?    te-hop-type
        |     |        +--:(label)
        |     |           +--ro label-hop
        |     |              +--ro te-label
        |     |                    ...
        |     +--ro pcc-original?    -> /pcep/entity/peers/peer/addr
        |     +--ro req-id?          uint32
        |     +--ro retrieved?       boolean
        |     +--ro pcc-retrieved?   -> /pcep/entity/peers/peer/addr
        |     +--ro creation-time?   yang:timestamp
        |     +--ro discard-time?    uint32
        |     +--ro reuse-time?      uint32
        +--rw peers
           +--rw peer* [addr]
              +--rw addr                    inet:ip-address
              +--rw role                    pcep-role
              +--rw description?            string
              +--rw domain
              |  +--rw domain* [domain-type domain]
              |     +--rw domain-type    domain-type
              |     +--rw domain         domain
              +--rw capability
              |  +--rw capability?             bits
              |  +--rw pce-initiated?          boolean
              |  |       {pce-initiated}?
              |  +--rw include-db-ver?         boolean
              |  |       {stateful,sync-opt}?
              |  +--rw trigger-resync?         boolean
              |  |       {stateful,sync-opt}?
              |  +--rw trigger-initial-sync?   boolean
              |  |       {stateful,sync-opt}?
              |  +--rw incremental-sync?       boolean
              |  |       {stateful,sync-opt}?
              |  +--rw sr {sr}?
              |     +--rw enabled?     boolean
              |     +--rw msd-limit?   boolean
              |     +--rw nai?         boolean
              +--rw msd?                    uint8 {sr}?
              +--rw pce-info
              |  +--rw scope
              |  |  +--rw path-scope?         bits
              |  |  +--rw intra-area-pref?    uint8
              |  |  +--rw inter-area-pref?    uint8
              |  |  +--rw inter-as-pref?      uint8
              |  |  +--rw inter-layer-pref?   uint8
              |  +--rw neigh-domains
              |     +--rw domain* [domain-type domain]
              |        +--rw domain-type    domain-type
              |        +--rw domain         domain
              +--rw delegation-pref?        uint8 {stateful}?
              +--rw auth
              |  +--rw (auth-type-selection)?
              |     +--:(auth-key-chain)
              |     |  +--rw key-chain?
              |     |          key-chain:key-chain-ref
              |     +--:(auth-key)
              |     |  +--rw crypto-algorithm            identityref
              |     |  +--rw (key-string-style)?
              |     |     +--:(keystring)
              |     |     |  +--rw keystring?            string
              |     |     +--:(hexadecimal)
              |     |              {key-chain:hex-key-string}?
              |     |        +--rw hexadecimal-string?
              |     |                yang:hex-string
              |     +--:(auth-tls) {tls}?
              |        +--rw (role)?
              |           +--:(server)
              |           |  +--rw tls-server
              |           |        ...
              |           +--:(client)
              |              +--rw tls-client
              |                    ...
              +--ro discontinuity-time?     yang:timestamp
              +--ro initiate-session?       boolean
              +--ro session-exists?         boolean
              +--ro session-up-time?        yang:timestamp
              +--ro session-fail-time?      yang:timestamp
              +--ro session-fail-up-time?   yang:timestamp
              +--ro sessions
                 +--ro session* [initiator]
                    +--ro initiator               pcep-initiator
                    +--ro role?
                    |       -> /pcep/entity/role
                    +--ro state-last-change?      yang:timestamp
                    +--ro state?                  pcep-sess-state
                    +--ro session-creation?       yang:timestamp
                    +--ro connect-retry?          yang:counter32
                    +--ro local-id?               uint8
                    +--ro remote-id?              uint8
                    +--ro keepalive-timer?        uint8
                    +--ro peer-keepalive-timer?   uint8
                    +--ro dead-timer?             uint8
                    +--ro peer-dead-timer?        uint8
                    +--ro ka-hold-time-rem?       uint8
                    +--ro overloaded?             boolean
                    +--ro overload-time?          uint32
                    +--ro peer-overloaded?        boolean
                    +--ro peer-overload-time?     uint32
                    +--ro lspdb-sync?             sync-state
                    |       {stateful}?
                    +--ro recv-db-ver?            uint64
                    |       {stateful,sync-opt}?
                    +--ro of-list {objective-function}?
                    |  +--ro objective-function* [of]
                    |     +--ro of    identityref
                    +--ro pst-list
                    |  +--ro path-setup-type* [pst]
                    |     +--ro pst    identityref
                    +--ro assoc-type-list {association}?
                    |  +--ro assoc-type* [at]
                    |     +--ro at    identityref
                    +--ro speaker-entity-id?      string {sync-opt}?
                    +--ro discontinuity-time?     yang:timestamp

  rpcs:
    +---x trigger-resync {stateful,sync-opt}?
       +---w input
          +---w pcc?   -> /pcep/entity/peers/peer/addr

  notifications:
    +---n pcep-session-up
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro state-last-change?   yang:timestamp
    |  +--ro state?               pcep-sess-state
    +---n pcep-session-down
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?   pcep-initiator
    |  +--ro state-last-change?   yang:timestamp
    |  +--ro state?               pcep-sess-state
    +---n pcep-session-local-overload
    |  +--ro peer-addr?           -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro overloaded?          boolean
    |  +--ro overload-time?       uint32
    +---n pcep-session-local-overload-clear
    |  +--ro peer-addr?    -> /pcep/entity/peers/peer/addr
    |  +--ro overloaded?   boolean
    +---n pcep-session-peer-overload
    |  +--ro peer-addr?            -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?
    |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
    |  +--ro peer-overloaded?      boolean
    |  +--ro peer-overload-time?   uint32
    +---n pcep-session-peer-overload-clear
       +--ro peer-addr?         -> /pcep/entity/peers/peer/addr
       +--ro peer-overloaded?   boolean


                ]]></artwork>
      </figure>
    </t>
</section>    
    </section>
    <section title="The Design of PCEP Statistics Data Model" toc="default" anchor="sec.data-tree-stat">
    <t> The module, "ietf-pcep-stats", augments the ietf-pcep module to include statistics at the 
      PCEP peer and session level. 
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[


module: ietf-pcep-stats
  augment /pcep:pcep/pcep:entity/pcep:peers/pcep:peer:
    +--ro num-sess-setup-ok?     yang:counter32
    +--ro num-sess-setup-fail?   yang:counter32
    +--ro pcep-stats
       +--ro avg-rsp-time?               uint32
       +--ro lwm-rsp-time?               uint32
       +--ro hwm-rsp-time?               uint32
       +--ro num-pcreq-sent?             yang:counter32
       +--ro num-pcreq-rcvd?             yang:counter32
       +--ro num-pcrep-sent?             yang:counter32
       +--ro num-pcrep-rcvd?             yang:counter32
       +--ro num-pcerr-sent?             yang:counter32
       +--ro num-pcerr-rcvd?             yang:counter32
       +--ro num-pcntf-sent?             yang:counter32
       +--ro num-pcntf-rcvd?             yang:counter32
       +--ro num-keepalive-sent?         yang:counter32
       +--ro num-keepalive-rcvd?         yang:counter32
       +--ro num-unknown-rcvd?           yang:counter32
       +--ro num-corrupt-rcvd?           yang:counter32
       +--ro num-req-sent?               yang:counter32
       +--ro num-req-sent-pend-rep?      yang:counter32
       +--ro num-req-sent-ero-rcvd?      yang:counter32
       +--ro num-req-sent-nopath-rcvd?   yang:counter32
       +--ro num-req-sent-cancel-rcvd?   yang:counter32
       +--ro num-req-sent-error-rcvd?    yang:counter32
       +--ro num-req-sent-timeout?       yang:counter32
       +--ro num-req-sent-cancel-sent?   yang:counter32
       +--ro num-req-rcvd?               yang:counter32
       +--ro num-req-rcvd-pend-rep?      yang:counter32
       +--ro num-req-rcvd-ero-sent?      yang:counter32
       +--ro num-req-rcvd-nopath-sent?   yang:counter32
       +--ro num-req-rcvd-cancel-sent?   yang:counter32
       +--ro num-req-rcvd-error-sent?    yang:counter32
       +--ro num-req-rcvd-cancel-rcvd?   yang:counter32
       +--ro num-rep-rcvd-unknown?       yang:counter32
       +--ro num-req-rcvd-unknown?       yang:counter32
       +--ro svec {pcep:svec}?
       |  +--ro num-svec-sent?       yang:counter32
       |  +--ro num-svec-req-sent?   yang:counter32
       |  +--ro num-svec-rcvd?       yang:counter32
       |  +--ro num-svec-req-rcvd?   yang:counter32
       +--ro stateful {pcep:stateful}?
       |  +--ro num-pcrpt-sent?             yang:counter32
       |  +--ro num-pcrpt-rcvd?             yang:counter32
       |  +--ro num-pcupd-sent?             yang:counter32
       |  +--ro num-pcupd-rcvd?             yang:counter32
       |  +--ro num-rpt-sent?               yang:counter32
       |  +--ro num-rpt-rcvd?               yang:counter32
       |  +--ro num-rpt-rcvd-error-sent?    yang:counter32
       |  +--ro num-upd-sent?               yang:counter32
       |  +--ro num-upd-rcvd?               yang:counter32
       |  +--ro num-upd-rcvd-unknown?       yang:counter32
       |  +--ro num-upd-rcvd-undelegated?   yang:counter32
       |  +--ro num-upd-rcvd-error-sent?    yang:counter32
       |  +--ro initiation {pcep:pce-initiated}?
       |     +--ro num-pcinitiate-sent?            yang:counter32
       |     +--ro num-pcinitiate-rcvd?            yang:counter32
       |     +--ro num-initiate-sent?              yang:counter32
       |     +--ro num-initiate-rcvd?              yang:counter32
       |     +--ro num-initiate-rcvd-error-sent?   yang:counter32
       +--ro path-key {pcep:path-key}?
       |  +--ro num-unknown-path-key?      yang:counter32
       |  +--ro num-exp-path-key?          yang:counter32
       |  +--ro num-dup-path-key?          yang:counter32
       |  +--ro num-path-key-no-attempt?   yang:counter32
       +--ro num-req-sent-closed?        yang:counter32
       +--ro num-req-rcvd-closed?        yang:counter32
  augment /pcep:pcep/pcep:entity/pcep:peers/pcep:peer/pcep:sessions
            /pcep:session:
    +--ro pcep-stats
       +--ro avg-rsp-time?               uint32
       +--ro lwm-rsp-time?               uint32
       +--ro hwm-rsp-time?               uint32
       +--ro num-pcreq-sent?             yang:counter32
       +--ro num-pcreq-rcvd?             yang:counter32
       +--ro num-pcrep-sent?             yang:counter32
       +--ro num-pcrep-rcvd?             yang:counter32
       +--ro num-pcerr-sent?             yang:counter32
       +--ro num-pcerr-rcvd?             yang:counter32
       +--ro num-pcntf-sent?             yang:counter32
       +--ro num-pcntf-rcvd?             yang:counter32
       +--ro num-keepalive-sent?         yang:counter32
       +--ro num-keepalive-rcvd?         yang:counter32
       +--ro num-unknown-rcvd?           yang:counter32
       +--ro num-corrupt-rcvd?           yang:counter32
       +--ro num-req-sent?               yang:counter32
       +--ro num-req-sent-pend-rep?      yang:counter32
       +--ro num-req-sent-ero-rcvd?      yang:counter32
       +--ro num-req-sent-nopath-rcvd?   yang:counter32
       +--ro num-req-sent-cancel-rcvd?   yang:counter32
       +--ro num-req-sent-error-rcvd?    yang:counter32
       +--ro num-req-sent-timeout?       yang:counter32
       +--ro num-req-sent-cancel-sent?   yang:counter32
       +--ro num-req-rcvd?               yang:counter32
       +--ro num-req-rcvd-pend-rep?      yang:counter32
       +--ro num-req-rcvd-ero-sent?      yang:counter32
       +--ro num-req-rcvd-nopath-sent?   yang:counter32
       +--ro num-req-rcvd-cancel-sent?   yang:counter32
       +--ro num-req-rcvd-error-sent?    yang:counter32
       +--ro num-req-rcvd-cancel-rcvd?   yang:counter32
       +--ro num-rep-rcvd-unknown?       yang:counter32
       +--ro num-req-rcvd-unknown?       yang:counter32
       +--ro svec {pcep:svec}?
       |  +--ro num-svec-sent?       yang:counter32
       |  +--ro num-svec-req-sent?   yang:counter32
       |  +--ro num-svec-rcvd?       yang:counter32
       |  +--ro num-svec-req-rcvd?   yang:counter32
       +--ro stateful {pcep:stateful}?
       |  +--ro num-pcrpt-sent?             yang:counter32
       |  +--ro num-pcrpt-rcvd?             yang:counter32
       |  +--ro num-pcupd-sent?             yang:counter32
       |  +--ro num-pcupd-rcvd?             yang:counter32
       |  +--ro num-rpt-sent?               yang:counter32
       |  +--ro num-rpt-rcvd?               yang:counter32
       |  +--ro num-rpt-rcvd-error-sent?    yang:counter32
       |  +--ro num-upd-sent?               yang:counter32
       |  +--ro num-upd-rcvd?               yang:counter32
       |  +--ro num-upd-rcvd-unknown?       yang:counter32
       |  +--ro num-upd-rcvd-undelegated?   yang:counter32
       |  +--ro num-upd-rcvd-error-sent?    yang:counter32
       |  +--ro initiation {pcep:pce-initiated}?
       |     +--ro num-pcinitiate-sent?            yang:counter32
       |     +--ro num-pcinitiate-rcvd?            yang:counter32
       |     +--ro num-initiate-sent?              yang:counter32
       |     +--ro num-initiate-rcvd?              yang:counter32
       |     +--ro num-initiate-rcvd-error-sent?   yang:counter32
       +--ro path-key {pcep:path-key}?
          +--ro num-unknown-path-key?      yang:counter32
          +--ro num-exp-path-key?          yang:counter32
          +--ro num-dup-path-key?          yang:counter32
          +--ro num-path-key-no-attempt?   yang:counter32



            ]]></artwork></figure></t>
          </section>
    <section title="Advanced PCE Features" toc="default">
    <t>This document contains a specification of the base PCEP YANG module,
   "ietf-pcep" which provides the basic PCEP <xref target="RFC5440"/> data
   model.</t>
   <t>This document further handles advanced PCE features like -
   <list style="symbols">
   <t>Capability and Scope</t>
   <t>Domain information (local/neighbour) </t>
   <t>Path-Key</t>
   <t>OF</t>
   <t>GCO</t>
   <t>P2MP</t>
   <t>GMPLS</t>
   <t>Inter-Layer</t>
   <t>Stateful PCE</t>
   <t>Segement Routing</t>
   <t>Authentication including PCEPS (TLS)</t>
   </list>
   </t>
   
<section title="Stateful PCE's LSP-DB" toc="default">
   <t>In the operational state of PCEP which supports stateful PCE mode, the
   list of LSP state are maintained in LSP-DB. The key is the PLSP-ID and the
   PCC IP address.</t>
   <t>The PCEP data model contains the operational state
    of LSPs (/pcep/entity/lsp-db/lsp/) with PCEP specific
    attributes. The generic TE attributes of the LSP are defined
    in <xref target="I-D.ietf-teas-yang-te"/>. A reference to LSP
    state in TE model is maintained.</t>
    </section></section>
    <section title="Open Issues and Next Step" toc="default">
    <t>This section is added so that open issues can be tracked.
    This section would be removed when the document is ready for publication.</t>
    <section title="The PCE-Initiated LSP" toc="default">
    <t>The TE Model at <xref target="I-D.ietf-teas-yang-te"/> should
    support creating of tunnels at the controller (PCE) and marking
    them as PCE-Initiated. The LSP-DB in the PCEP Yang (/pcep/entity/lsp-db/lsp/initiation)
    also marks the LSPs which are PCE-initiated.</t>
    </section>
    
    </section>
    <section title="Other Considerations" toc="default">
    <section title="PCEP over TLS (PCEPS)" toc="default">
    <t><xref target="RFC8253"/> describe the use of TLS in PCEP. 
    The peer acting as the PCEP client MUST act as the TLS client.
    The TLS client actively opens the TLS connection and the TLS server
    passively listens for the incoming TLS connections.  The well-known
    TCP port number 4189 is used by PCEP servers to listen for TCP
    connections established by PCEP over TLS clients.  The TLS client
    MUST send the TLS ClientHello message to begin the TLS handshake.
    The TLS server MUST send a CertificateRequest in order to request a
    certificate from the TLS client.  Once the TLS handshake has
    finished, the client and the server MAY begin to exchange PCEP
    messages.  Client and server identity verification is done before the
    PCEP open message is sent.  This means that the identity
    verification is completed before the PCEP session is started..</t>
    </section>


    </section>


    <section title="PCEP YANG Modules" toc="default">
      <section title="ietf-pcep module" toc="default">
    <t>RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
   actual RFC number and all occurrences of the revision date below with
   the date of RFC publication (and remove this note).</t>
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height="">
          <![CDATA[
<CODE BEGINS> file "ietf-pcep@2019-03-26.yang"
module ietf-pcep {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-pcep";
  prefix pcep;

  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-te {
    prefix te;
    reference
      "[I-D.ietf-teas-yang-te]: A YANG Data Model for Traffic
       Engineering Tunnels and Interfaces";
  }
  import ietf-te-types {
    prefix te-types;
    reference
      "[I-D.ietf-teas-yang-te-types]: Traffic Engineering Common YANG
       Types";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }
  import ietf-netconf-acm {
    prefix netconf-acm;
    reference
      "RFC 8341: Network Configuration Protocol (NETCONF) Access
       Control Model";
  }
  import ietf-tls-server {
    prefix tls-server;
    reference
      "[I-D.ietf-netconf-tls-client-server]: YANG Groupings for TLS
       Clients and TLS Servers";
  }
  import ietf-tls-client {
    prefix tls-client;
    reference
      "[I-D.ietf-netconf-tls-client-server]: YANG Groupings for TLS
       Clients and TLS Servers";
  }
  import ietf-ospf {
    prefix ospf;
    reference
      "[I-D.ietf-ospf-yang]: YANG Data Model for OSPF Protocol";
  }
  import ietf-isis {
    prefix isis;
    reference
      "[I-D.ietf-isis-yang-isis-cfg]: YANG Data Model for IS-IS
       Protocol";
  }

  organization
    "IETF PCE (Path Computation Element) Working Group";
  contact
    "WG Web:  <https://tools.ietf.org/wg/pce/>
     WG List:  <mailto:pce@ietf.org>
     Editor:   Dhruv Dhody
              <mailto:dhruv.ietf@gmail.com>";
  description
    "The YANG module defines a generic configuration and
     operational model for PCEP.

     Copyright (c) 2019 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (http://trustee.ietf.org/license-info).

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

  revision 2019-03-26 {
    description
      "Initial revision.";
    reference
      "RFC XXXX:  A YANG Data Model for Path Computation
       Element Communications Protocol (PCEP)";
  }

  /*
   * Typedefs
   */

  typedef pcep-role {
    type enumeration {
      enum unknown {
        value 0;
        description
          "An unknown role";
      }
      enum pcc {
        value 1;
        description
          "The role of a Path Computation Client";
      }
      enum pce {
        value 2;
        description
          "The role of Path Computation Element";
      }
      enum pcc-and-pce {
        value 3;
        description
          "The role of both Path Computation Client and
           Path Computation Element";
      }
    }
    description
      "The role of a PCEP speaker.
       Takes one of the following values
       - unknown(0): the role is not known.
       - pcc(1): the role is of a Path Computation
        Client (PCC).
       - pce(2): the role is of a Path Computation
        Server (PCE).
       - pccAndPce(3): the role is of both a PCC and
        a PCE.";
  }

  typedef pcep-oper-status {
    type enumeration {
      enum oper-status-up {
        value 1;
        description
          "The PCEP entity is active";
      }
      enum oper-status-down {
        value 2;
        description
          "The PCEP entity is inactive";
      }
      enum oper-status-going-up {
        value 3;
        description
          "The PCEP entity is activating";
      }
      enum oper-status-going-down {
        value 4;
        description
          "The PCEP entity is deactivating";
      }
      enum oper-status-failed {
        value 5;
        description
          "The PCEP entity has failed and will recover
           when possible.";
      }
      enum oper-status-failed-perm {
        value 6;
        description
          "The PCEP entity has failed and will not recover
           without operator intervention";
      }
    }
    description
      "The operational status of the PCEP entity.
       Takes one of the following values
       - oper-status-up(1): Active
       - oper-status-down(2): Inactive
       - oper-status-going-up(3): Activating
       - oper-status-going-down(4): Deactivating
       - oper-status-failed(5): Failed
       - oper-status-failed-perm(6): Failed Permanantly";
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  typedef pcep-initiator {
    type enumeration {
      enum local {
        value 1;
        description
          "The local PCEP entity initiated the session";
      }
      enum remote {
        value 2;
        description
          "The remote PCEP peer initiated the session";
      }
    }
    description
      "The initiator of the session, that is, whether the TCP
       connection was initiated by the local PCEP entity or
       the remote peer.
       Takes one of the following values
       - local(1): Initiated locally
       - remote(2): Initiated remotely";
  }

  typedef pcep-sess-state {
    type enumeration {
      enum tcp-pending {
        value 1;
        description
          "The tcp-pending state of PCEP session.";
      }
      enum open-wait {
        value 2;
        description
          "The open-wait state of PCEP session.";
      }
      enum keep-wait {
        value 3;
        description
          "The keep-wait state of PCEP session.";
      }
      enum session-up {
        value 4;
        description
          "The session-up state of PCEP session.";
      }
    }
    description
      "The current state of the session.
       The set of possible states excludes the idle state
       since entries do not exist in the idle state.
       Takes one of the following values
       - tcp-pending(1): PCEP TCP Pending state
       - open-wait(2): PCEP Open Wait state
       - keep-wait(3): PCEP Keep Wait state
       - session-up(4): PCEP Session Up state";
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  typedef domain-type {
    type enumeration {
      enum ospf-area {
        value 1;
        description
          "The OSPF area.";
      }
      enum isis-area {
        value 2;
        description
          "The IS-IS area.";
      }
      enum as {
        value 3;
        description
          "The Autonomous System (AS).";
      }
    }
    description
      "The PCE Domain Type";
  }

  typedef domain-ospf-area {
    type ospf:area-id-type;
    description
      "OSPF Area ID.";
    reference
      "[I-D.ietf-ospf-yang]: YANG Data Model for OSPF Protocol";
  }

  typedef domain-isis-area {
    type isis:area-address;
    description
      "IS-IS Area ID.";
    reference
      "[I-D.ietf-isis-yang-isis-cfg]: YANG Data Model for IS-IS
       Protocol";
  }

  typedef domain-as {
    type inet:as-number;
    description
      "Autonomous System number.";
  }

  typedef domain {
    type union {
      type domain-ospf-area;
      type domain-isis-area;
      type domain-as;
    }
    description
      "The Domain Information";
  }

  typedef operational-state {
    type enumeration {
      enum down {
        value 0;
        description
          "not active.";
      }
      enum up {
        value 1;
        description
          "signalled.";
      }
      enum active {
        value 2;
        description
          "up and carrying traffic.";
      }
      enum going-down {
        value 3;
        description
          "LSP is being torn down, resources are
           being released.";
      }
      enum going-up {
        value 4;
        description
          "LSP is being signalled.";
      }
    }
    description
      "The operational status of the LSP";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  typedef sync-state {
    type enumeration {
      enum pending {
        value 0;
        description
          "The state synchronization
           has not started.";
      }
      enum ongoing {
        value 1;
        description
          "The state synchronization
           is ongoing.";
      }
      enum finished {
        value 2;
        description
          "The state synchronization
           is finished.";
      }
    }
    description
      "The LSP-DB state synchronization operational
       status.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  /*
   * Features
   */

  feature svec {
    description
      "Support synchronized path computation.";
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  feature gmpls {
    description
      "Support GMPLS.";
    reference
      "[I-D.ietf-pce-gmpls-pcep-extensions]: PCEP extensions for
       GMPLS";
  }

  feature objective-function {
    description
      "Support OF as per RFC 5541.";
    reference
      "RFC 5541: Encoding of Objective Functions in the Path
       Computation Element Communication Protocol (PCEP)";
  }

  feature global-concurrent {
    description
      "Support GCO as per RFC 5557.";
    reference
      "RFC 5557: Path Computation Element Communication Protocol
       (PCEP) Requirements and Protocol Extensions in Support of
       Global Concurrent Optimization";
  }

  feature path-key {
    description
      "Support path-key as per RFC 5520.";
    reference
      "RFC 5520: Preserving Topology Confidentiality in Inter-
       Domain Path Computation Using a Path-Key-Based Mechanism";
  }

  feature p2mp {
    description
      "Support P2MP as per RFC 8306.";
    reference
      "RFC 8306: Extensions to the Path Computation Element
       Communication Protocol (PCEP) for Point-to-Multipoint
       Traffic Engineering Label Switched Paths";
  }

  feature stateful {
    description
      "Support stateful PCE as per RFC 8231.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  feature sync-opt {
    description
      "Support stateful sync optimization
       as per RFC 8232";
    reference
      "RFC 8232: Optimizations of Label Switched Path State
       Synchronization Procedures for a Stateful PCE";
  }

  feature pce-initiated {
    description
      "Support PCE-Initiated LSP as per
       RFC 8281.";
    reference
      "RFC 8281: Path Computation Element Communication Protocol
       (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful
       PCE Model";
  }

  feature tls {
    description
      "Support PCEP over TLS as per
       RFC 8253.";
    reference
      "RFC 8253: PCEPS: Usage of TLS to Provide a Secure Transport
       for the Path Computation Element Communication Protocol
       (PCEP)";
  }

  feature sr {
    description
      "Support Segment Routing for PCE.";
    reference
      "[I-D.ietf-pce-segment-routing]: PCEP Extensions for Segment
       Routing";
  }

  feature association {
    description
      "Support Association in PCEP.";
    reference
      "[I-D.ietf-pce-association-group]: PCEP Extensions for
       Establishing Relationships Between Sets of LSPs";
  }

  /*
   * Identities
   */

  identity lsp-error {
    if-feature "stateful";
    description
      "Base LSP error";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity no-error-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "No error, LSP is fine.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity unknown-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "Unknown reason.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity limit-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "Limit reached for PCE-controlled LSPs.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity pending-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "Too many pending LSP update requests.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity unacceptable-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "Unacceptable parameters.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity internal-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "Internal error.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity admin-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "LSP administratively brought down.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity preempted-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "LSP preempted.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  identity rsvp-lsp-error {
    base lsp-error;
    if-feature "stateful";
    description
      "RSVP signaling error.";
    reference
      "RFC 8231: Path Computation Element Communication Protocol
       (PCEP) Extensions for Stateful PCE";
  }

  /*
   * Groupings
   */

  grouping pce-scope {
    description
      "This grouping defines PCE path computation scope
       information which maybe relevant to PCE selection.
       This information corresponds to PCE auto-discovery
       information.";
    reference
      "RFC 5088: OSPF Protocol Extensions for Path
       Computation Element (PCE) Discovery
       RFC 5089: IS-IS Protocol Extensions for Path
       Computation Element (PCE) Discovery";
    leaf path-scope {
      type bits {
        bit intra-area-scope {
          description
            "PCE can compute intra-area paths.";
        }
        bit inter-area-scope {
          description
            "PCE can compute inter-area paths.";
        }
        bit inter-area-scope-default {
          description
            "PCE can act as a default PCE for inter-area
             path computation.";
        }
        bit inter-as-scope {
          description
            "PCE can compute inter-AS paths.";
        }
        bit inter-as-scope-default {
          description
            "PCE can act as a default PCE for inter-AS
             path computation.";
        }
        bit inter-layer-scope {
          description
            "PCE can compute inter-layer paths.";
        }
      }
      description
        "The field corresponding to the path scope bits";
    }
    leaf intra-area-pref {
      type uint8 {
        range "0..7";
      }
      description
        "The PCE's preference for intra-area TE LSP
         computation.";
    }
    leaf inter-area-pref {
      type uint8 {
        range "0..7";
      }
      description
        "The PCE's preference for inter-area TE LSP
         computation.";
    }
    leaf inter-as-pref {
      type uint8 {
        range "0..7";
      }
      description
        "The PCE's preference for inter-AS TE LSP
         computation.";
    }
    leaf inter-layer-pref {
      type uint8 {
        range "0..7";
      }
      description
        "The PCE's preference for inter-layer TE LSP
         computation.";
    }
  }

  //pce-scope

  grouping domain {
    description
      "This grouping specifies a Domain where the
       PCEP speaker has topology visibility.";
    leaf domain-type {
      type domain-type;
      description
        "The domain type.";
    }
    leaf domain {
      type domain;
      description
        "The domain Information.";
    }
  }

  //domain

  grouping info {
    description
      "This grouping specifies all information which
       maybe relevant to both PCC and PCE.
       This information corresponds to PCE auto-discovery
       information.";
    container domain {
      description
        "The local domain for the PCEP entity";
      list domain {
        key "domain-type domain";
        description
          "The local domain.";
        uses domain {
          description
            "The local domain for the PCEP entity.";
        }
      }
    }
    container capability {
      description
        "The PCEP entity capability information of local
         PCEP entity. This maybe relevant to PCE selection
         as well. This information corresponds to PCE auto-
         discovery information.";
      reference
        "RFC 5088: OSPF Protocol Extensions for Path
         Computation Element (PCE) Discovery
         RFC 5089: IS-IS Protocol Extensions for Path
         Computation Element (PCE) Discovery";
      leaf capability {
        type bits {
          bit gmpls {
            if-feature "gmpls";
            description
              "Path computation with GMPLS link
               constraints.";
          }
          bit bi-dir {
            description
              "Bidirectional path computation.";
          }
          bit diverse {
            description
              "Diverse path computation.";
          }
          bit load-balance {
            description
              "Load-balanced path computation.";
          }
          bit synchronize {
            if-feature "svec";
            description
              "Synchronized paths computation.";
          }
          bit objective-function {
            if-feature "objective-function";
            description
              "Support for multiple objective functions.";
          }
          bit add-path-constraint {
            description
              "Support for additive path constraints (max
               hop count, etc.).";
          }
          bit prioritization {
            description
              "Support for request prioritization.";
          }
          bit multi-request {
            description
              "Support for multiple requests per message.";
          }
          bit global-concurrent {
            if-feature "global-concurrent";
            description
              "Support for Global Concurrent Optimization
               (GCO).";
          }
          bit p2mp {
            if-feature "p2mp";
            description
              "Support for P2MP path computation.";
          }
          bit active {
            if-feature "stateful";
            description
              "Support for active stateful PCE.";
          }
          bit passive {
            if-feature "stateful";
            description
              "Support for passive stateful PCE.";
          }
          bit p2mp-active {
            if-feature "stateful";
            if-feature "p2mp";
            description
              "Support for active stateful PCE for P2MP.";
          }
          bit p2mp-passive {
            if-feature "stateful";
            if-feature "p2mp";
            description
              "Support for passive stateful PCE for P2MP.";
          }
          bit p2mp-pce-initiated {
            if-feature "stateful";
            if-feature "pce-initiated";
            if-feature "p2mp";
            description
              "Support for PCE-initiated LSP for P2MP.";
          }
        }
        description
          "The bits string indicating the capabiliies";
        reference
          "RFC 5088: OSPF Protocol Extensions for Path
           Computation Element (PCE) Discovery
           RFC 5089: IS-IS Protocol Extensions for Path
           Computation Element (PCE) Discovery";
      }
      leaf pce-initiated {
        if-feature "pce-initiated";
        type boolean;
        description
          "Set to true if PCE-initiated LSP capability is
           enabled.";
        reference
          "RFC 8281: Path Computation Element Communication
           Protocol (PCEP) Extensions for PCE-Initiated LSP
           Setup in a Stateful PCE Model";
      }
      leaf include-db-ver {
        if-feature "stateful";
        if-feature "sync-opt";
        type boolean;
        description
          "Support inclusion of LSP-DB-VERSION
           in LSP object";
        reference
          "RFC 8232: Optimizations of Label Switched Path State
           Synchronization Procedures for a Stateful PCE";
      }
      leaf trigger-resync {
        if-feature "stateful";
        if-feature "sync-opt";
        type boolean;
        description
          "Support PCE triggered re-synchronization";
        reference
          "RFC 8232: Optimizations of Label Switched Path State
           Synchronization Procedures for a Stateful PCE";
      }
      leaf trigger-initial-sync {
        if-feature "stateful";
        if-feature "sync-opt";
        type boolean;
        description
          "PCE triggered initial synchronization";
        reference
          "RFC 8232: Optimizations of Label Switched Path State
           Synchronization Procedures for a Stateful PCE";
      }
      leaf incremental-sync {
        if-feature "stateful";
        if-feature "sync-opt";
        type boolean;
        description
          "Support incremental (delta) sync";
        reference
          "RFC 8232: Optimizations of Label Switched Path State
           Synchronization Procedures for a Stateful PCE";
      }
      container sr {
        if-feature "sr";
        description
          "If segment routing is supported";
        reference
          "[I-D.ietf-pce-segment-routing]: PCEP Extensions for Segment
           Routing";
        leaf enabled {
          type boolean;
          description
            "Set to true if SR is enabled";
        }
        leaf msd-limit {
          type boolean;
          default "false";
          description
            "True indicates no limit on MSD, the
             leaf msd is ignored";
        }
        leaf nai {
          type boolean;
          default "false";
          description
            "True indicates capability to resolve NAI
             to SID";
        }
      }
      //sr      
    }
    //capability  
    leaf msd {
      if-feature "sr";
      type uint8;
      description
        "Maximum SID Depth for SR";
      reference
        "[I-D.ietf-pce-segment-routing]: PCEP Extensions for Segment
         Routing";
    }
  }

  //info

  grouping pce-info {
    description
      "This grouping specifies all PCE information
       which maybe relevant to the PCE selection.
       This information corresponds to PCE auto-discovery
       information.";
    container scope {
      description
        "The path computation scope";
      uses pce-scope;
    }
    container neigh-domains {
      description
        "The list of neighbour PCE-Domain
         toward which a PCE can compute
         paths";
      list domain {
        key "domain-type domain";
        description
          "The neighbour domain.";
        uses domain {
          description
            "The PCE neighbour domain.";
        }
      }
    }
  }

  //pce-info

  grouping notification-instance-hdr {
    description
      "This group describes common instance specific data
       for notifications.";
    leaf peer-addr {
      type leafref {
        path "/pcep/entity/peers/peer/addr";
      }
      description
        "Reference to peer address";
    }
  }

  // notification-instance-hdr

  grouping notification-session-hdr {
    description
      "This group describes common session instance specific
       data for notifications.";
    leaf session-initiator {
      type leafref {
        path "/pcep/entity/peers/peer/sessions/"
           + "session/initiator";
      }
      description
        "Reference to pcep session initiator leaf";
    }
  }

  // notification-session-hdr

  grouping of-list {
    description
      "List of OF";
    reference
      "RFC 5541: Encoding of Objective Functions in the Path
       Computation Element Communication Protocol (PCEP)";
    list objective-function {
      key "of";
      description
        "The list of authorized OF";
      leaf of {
        type identityref {
          base te-types:objective-function-type;
        }
        description
          "The OF authorized";
      }
    }
  }

  /*
   * Configuration data nodes
   */

  container pcep {
    presence "The PCEP is enabled";
    description
      "Parameters for list of configured PCEP entities
       on the device.";
    container entity {
      description
        "The configured PCEP entity on the device.";
      leaf addr {
        type inet:ip-address;
        mandatory true;
        description
          "The local Internet address of this PCEP entity.
           If operating as a PCE server, the PCEP entity
           listens on this address. If operating as a PCC,
           the PCEP entity binds outgoing TCP connections
           to this address. It is possible for the PCEP entity
           to operate both as a PCC and a PCE Server, in which
           case it uses this address both to listen for incoming
           TCP connections and to bind outgoing TCP connections.";
      }
      leaf enabled {
        type boolean;
        default "true";
        description
          "The administrative status of this PCEP
           Entity.";
      }
      leaf role {
        type pcep-role;
        mandatory true;
        description
          "The role that this entity can play.
           Takes one of the following values.
           - unknown(0): this PCEP Entity role is not
           known.
           - pcc(1): this PCEP Entity is a PCC.
           - pce(2): this PCEP Entity is a PCE.
           - pcc-and-pce(3): this PCEP Entity is both
           a PCC and a PCE.";
      }
      leaf description {
        type string;
        description
          "Description of the PCEP entity configured
           by the user";
      }
      leaf speaker-entity-id {
        if-feature "sync-opt";
        type string;
        description
          "The Speaker Entity Identifier";
        reference
          "RFC 8232: Optimizations of Label Switched
           Path State  Synchronization Procedures for
           a Stateful PCE";
      }
      leaf admin-status {
        type boolean;
        default "true";
        description
          "The administrative status of this PCEP Entity.
           The value true represents admin status as up.
           This is the desired operational status as
           currently set by an operator or by default in
           the implementation. The value of oper-status
           represents the current status of an attempt to
           reach this desired status.";
      }
      leaf index {
        type uint32;
        config false;
        description
          "The index of the operational PECP entity";
      }
      leaf oper-status {
        type pcep-oper-status;
        config false;
        description
          "The operational status of the PCEP entity.
           Takes one of the following values.
           - oper-status-up(1): the PCEP entity is active.
           - oper-status-down(2): the PCEP entity is inactive.
           - oper-status-going-up(3): the PCEP entity is
           activating.
           - oper-status-going-down(4): the PCEP entity is
           deactivating.
           - oper-status-failed(5): the PCEP entity has
           failed and will recover when possible.
           - oper-status-failed-perm(6): the PCEP entity
           has failed and will not recover without
           operator intervention.";
      }
      uses info {
        description
          "Local PCEP entity information";
      }
      container pce-info {
        when "../role = 'pce'"
           + "or "
           + "../role = 'pcc-and-pce'" {
          description
            "These fields are applicable when the role is PCE.";
        }
        description
          "The Local PCE Entity PCE information";
        uses pce-info {
          description
            "Local PCE information";
        }
        container path-key {
          if-feature "path-key";
          description
            "Path-Key Configuration";
          reference
            "RFC 5520: Preserving Topology Confidentiality in Inter-
             Domain Path Computation Using a Path-Key-Based Mechanism";
          leaf enabled {
            type boolean;
            description
              "Enabled or Disabled";
          }
          leaf discard-timer {
            type uint32;
            units "minutes";
            default "10";
            description
              "A timer to discard unwanted path-keys";
          }
          leaf reuse-time {
            type uint32;
            units "minutes";
            default "30";
            description
              "A time after which the path-keys could be reused";
          }
          leaf pce-id {
            type inet:ip-address;
            description
              "PCE Address to be used in each Path-Key Subobject
               (PKS)";
          }
        }
      }
      leaf connect-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        default "60";
        description
          "The time in seconds that the PCEP entity will wait
           to establish a TCP connection with a peer.  If a
           TCP connection is not established within this time
           then PCEP aborts the session setup attempt.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf connect-max-retry {
        type uint32;
        default "5";
        description
          "The maximum number of times the system tries to
           establish a TCP connection to a peer before the
           session with the peer transitions to the idle
           state.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf init-backoff-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        description
          "The initial back-off time in seconds for retrying
           a failed session setup attempt to a peer.
           The back-off time increases for each failed
           session setup attempt, until a maximum back-off
           time is reached.  The maximum back-off time is
           max-backoff-timer.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf max-backoff-timer {
        type uint32;
        units "seconds";
        description
          "The maximum back-off time in seconds for retrying
           a failed session setup attempt to a peer.
           The back-off time increases for each failed session
           setup attempt, until this maximum value is reached.
           Session setup attempts then repeat periodically
           without any further increase in back-off time.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf open-wait-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        default "60";
        description
          "The time in seconds that the PCEP entity will wait
           to receive an Open message from a peer after the
           TCP connection has come up.
           If no Open message is received within this time then
           PCEP terminates the TCP connection and deletes the
           associated sessions.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf keep-wait-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        default "60";
        description
          "The time in seconds that the PCEP entity will wait
           to receive a Keepalive or PCErr message from a peer
           during session initialization after receiving an
           Open message.  If no Keepalive or PCErr message is
           received within this time then PCEP terminates the
           TCP connection and deletes the associated
           sessions.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf keep-alive-timer {
        type uint8;
        units "seconds";
        default "30";
        description
          "The keep alive transmission timer that this PCEP
           entity will propose in the initial OPEN message of
           each session it is involved in.  This is the
           maximum time between two consecutive messages sent
           to a peer. Zero means that the PCEP entity prefers
           not to send Keepalives at all.
           Note that the actual Keepalive transmission
           intervals, in either direction of an active PCEP
           session, are determined by negotiation between the
           peers as specified by RFC 5440, and so may differ
           from this configured value.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf dead-timer {
        type uint8;
        units "seconds";
        must '(. > ../keep-alive-timer)' {
          error-message "The dead timer must be "
                      + "larger than the keep alive timer";
        }
        default "120";
        description
          "The dead timer that this PCEP entity will propose
           in the initial OPEN message of each session it is
           involved in. This is the time after which a peer
           should declare a session down if it does not
           receive any PCEP messages. Zero suggests that the
           peer does not run a dead timer at all.";
        reference
          "RFC 5440: Path Computation Element (PCE) Communication
           Protocol (PCEP)";
      }
      leaf allow-negotiation {
        type boolean;
        description
          "Whether the PCEP entity will permit negotiation of
           session parameters.";
      }
      leaf max-keep-alive-timer {
        type uint8;
        units "seconds";
        description
          "In PCEP session parameter negotiation in seconds,
           the maximum value that this PCEP entity will
           accept from a peer for the interval between
           Keepalive transmissions. Zero means that the PCEP
           entity will allow no Keepalive transmission at
           all.";
      }
      leaf max-dead-timer {
        type uint8;
        units "seconds";
        description
          "In PCEP session parameter negotiation in seconds,
           the maximum value that this PCEP entity will accept
           from a peer for the Dead timer.  Zero means that
           the PCEP entity will allow not running a Dead
           timer.";
      }
      leaf min-keep-alive-timer {
        type uint8;
        units "seconds";
        description
          "In PCEP session parameter negotiation in seconds,
           the minimum value that this PCEP entity will
           accept for the interval between Keepalive
           transmissions. Zero means that the PCEP entity
           insists on no Keepalive transmission at all.";
      }
      leaf min-dead-timer {
        type uint8;
        units "seconds";
        description
          "In PCEP session parameter negotiation in
           seconds, the minimum value that this PCEP entity
           will accept for the Dead timer.  Zero means that
           the PCEP entity insists on not running a Dead
           timer.";
      }
      leaf sync-timer {
        if-feature "svec";
        type uint16;
        units "seconds";
        default "60";
        description
          "The value of SyncTimer in seconds is used in the
           case of synchronized path computation request
           using the SVEC object. Consider the case where a
           PCReq message is received by a PCE that contains
           the SVEC object referring to M synchronized path
           computation requests.  If after the expiration of
           the SyncTimer all the M path computation requests
           have not been, received a protocol error is
           triggered and the PCE MUST cancel the whole set
           of path computation requests.
           The aim of the SyncTimer is to avoid the storage
           of unused synchronized requests should one of
           them get lost for some reasons (for example, a
           misbehaving PCC).
           Zero means that the PCEP entity does not use the
           SyncTimer.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf request-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        description
          "The maximum time that the PCEP entity will wait
           for a response to a PCReq message.";
      }
      leaf max-sessions {
        type uint32;
        description
          "Maximum number of sessions involving this PCEP
           entity that can exist at any time.";
      }
      leaf max-unknown-reqs {
        type uint32;
        default "5";
        description
          "The maximum number of unrecognized requests and
           replies that any session on this PCEP entity is
           willing to accept per minute before terminating
           the session.
           A PCRep message contains an unrecognized reply
           if it contains an RP object whose request ID
           does not correspond to any in-progress request
           sent by this PCEP entity.
           A PCReq message contains an unrecognized request
           if it contains an RP object whose request ID is
           zero.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf max-unknown-msgs {
        type uint32;
        default "5";
        description
          "The maximum number of unknown messages that any
           session on this PCEP entity is willing to accept
           per minute before terminating the session.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf pcep-notification-max-rate {
        type uint32;
        mandatory true;
        description
          "This variable indicates the maximum number of
           notifications issued per second. If events
           occur more rapidly, the implementation may
           simply fail to emit these notifications during
           that period, or may queue them until an
           appropriate time. A value of 0 means no
           notifications are emitted and all should be
           discarded (that is, not queued).";
      }
      container stateful-parameter {
        if-feature "stateful";
        description
          "The configured stateful PCE parameters";
        leaf state-timeout {
          type uint32;
          units "seconds";
          description
            "When a PCEP session is terminated, a PCC
             waits for this time period before flushing
             LSP state associated with that PCEP session
             and reverting to operator-defined default
             parameters or behaviours.";
        }
        leaf redelegation-timeout {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          type uint32;
          units "seconds";
          description
            "When a PCEP session is terminated, a PCC
             waits for this time period before revoking
             LSP delegation to a PCE and attempting to
             redelegate LSPs associated with the
             terminated PCEP session to an alternate
             PCE.";
        }
        leaf rpt-non-pcep-lsp {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          type boolean;
          default "true";
          description
            "If set, a PCC reports LSPs that are not
             controlled by any PCE (for example, LSPs
             that are statically configured at the
             PCC). ";
        }
        reference
          "RFC 8231: Path Computation Element Communication Protocol
           (PCEP) Extensions for Stateful PCE";
      }
      container of-list {
        when "../role = 'pce'"
           + "or "
           + "../role = 'pcc-and-pce'" {
          description
            "These field are applicable when the role is
             PCE";
        }
        if-feature "objective-function";
        uses of-list;
        description
          "The authorized OF-List at PCE for all peers";
      }
      container lsp-db {
        if-feature "stateful";
        config false;
        description
          "The LSP-DB";
        leaf db-ver {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          if-feature "sync-opt";
          type uint64;
          description
            "The LSP State Database Version Number";
        }
        list association-list {
          if-feature "association";
          key "type id source global-source extended-id";
          description
            "List of all PCEP associations";
          reference
            "[I-D.ietf-pce-association-group]: PCEP
             Extensions for Establishing Relationships
             Between Sets of LSPs";
          leaf type {
            type identityref {
              base te-types:association-type;
            }
            description
              "The PCEP association type";
          }
          leaf id {
            type uint16;
            description
              "PCEP Association ID";
          }
          leaf source {
            type inet:ip-address;
            description
              "PCEP Association Source.";
          }
          leaf global-source {
            type uint32;
            description
              "PCEP Association Global Source.";
          }
          leaf extended-id {
            type string;
            description
              "Additional information to support unique
               identification.";
          }
          list lsp {
            key "plsp-id pcc-id";
            description
              "List of all LSP in this association";
            leaf plsp-id {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "lsp/plsp-id";
              }
              description
                "Reference to PLSP-ID in LSP-DB";
            }
            leaf pcc-id {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "lsp/pcc-id";
              }
              description
                "Reference to PCC-ID in LSP-DB";
            }
          }
        }
        list lsp {
          key "plsp-id pcc-id";
          description
            "List of all LSPs in LSP-DB";
          leaf plsp-id {
            type uint32 {
              range "1..1048575";
            }
            description
              "A PCEP-specific identifier for the LSP.  A PCC
               creates a unique PLSP-ID for each LSP that is
               constant for the lifetime of a PCEP session.
               PLSP-ID is 20 bits with 0 and 0xFFFFF are
               reserved";
          }
          leaf pcc-id {
            type inet:ip-address;
            description
              "The local internet address of the PCC, that
               generated the PLSP-ID.";
          }
          container lsp-ref {
            description
              "reference to ietf-te lsp state";
            leaf source {
              type leafref {
                path "/te:te/te:lsps-state/te:lsp/te:source";
              }
              description
                "Tunnel sender address extracted from
                 SENDER_TEMPLATE object";
              reference
                "RFC 3209: RSVP-TE: Extensions to RSVP for
                 LSP Tunnels";
            }
            leaf destination {
              type leafref {
                path "/te:te/te:lsps-state/te:lsp/te:"
                   + "destination";
              }
              description
                "Tunnel endpoint address extracted from
                 SESSION object";
              reference
                "RFC 3209: RSVP-TE: Extensions to RSVP for
                 LSP Tunnels";
            }
            leaf tunnel-id {
              type leafref {
                path "/te:te/te:lsps-state/te:lsp/te:tunnel-id";
              }
              description
                "Tunnel identifier used in the SESSION
                 that remains constant over the life
                 of the tunnel.";
              reference
                "RFC 3209: RSVP-TE: Extensions to RSVP for
                 LSP Tunnels";
            }
            leaf lsp-id {
              type leafref {
                path "/te:te/te:lsps-state/te:lsp/te:lsp-id";
              }
              description
                "Identifier used in the SENDER_TEMPLATE
                 and the FILTER_SPEC that can be changed
                 to allow a sender to share resources with
                 itself.";
              reference
                "RFC 3209: RSVP-TE: Extensions to RSVP for
                 LSP Tunnels";
            }
            leaf extended-tunnel-id {
              type leafref {
                path "/te:te/te:lsps-state/te:lsp/te:"
                   + "extended-tunnel-id";
              }
              description
                "Extended Tunnel ID of the LSP.";
              reference
                "RFC 3209: RSVP-TE: Extensions to RSVP for
                 LSP Tunnels";
            }
          }
          leaf admin-state {
            type boolean;
            description
              "The desired operational state";
          }
          leaf operational-state {
            type operational-state;
            description
              "The operational status of the LSP";
          }
          container delegated {
            description
              "The delegation related parameters";
            leaf enabled {
              type boolean;
              description
                "LSP is delegated or not";
            }
            leaf peer {
              type leafref {
                path "/pcep/entity/peers/peer/addr";
              }
              must '(../enabled = true())' {
                error-message "The LSP must be delegated";
              }
              description
                "At the PCC, the reference to the PCEP peer to
                 which LSP is delegated; At the PCE, the
                 reference to the PCEP peer which delegated this
                 LSP";
            }
            leaf srp-id {
              type uint32;
              description
                "The last SRP-ID-number associated with this
                 LSP.";
            }
          }
          container initiation {
            if-feature "pce-initiated";
            description
              "The PCE initiation related parameters";
            reference
              "RFC 8281: Path Computation Element Communication
               Protocol (PCEP) Extensions for PCE-Initiated LSP
               Setup in a Stateful PCE Model";
            leaf enabled {
              type boolean;
              description
                "Set to true if this LSP is initiated by a PCE";
            }
            leaf peer {
              type leafref {
                path "/pcep/entity/peers/peer/addr";
              }
              must '(../enabled = true())' {
                error-message "The LSP must be PCE-Initiated";
              }
              description
                "At the PCC, the reference to the PCEP peer
                 that initiated this LSP; At the PCE, the
                 reference to the PCEP peer where the LSP
                 is initiated";
            }
          }
          leaf symbolic-path-name {
            type string;
            description
              "The symbolic path name associated with the LSP.";
            reference
              "RFC 8231: Path Computation Element Communication
               Protocol (PCEP) Extensions for Stateful PCE";
          }
          leaf last-error {
            type identityref {
              base lsp-error;
            }
            description
              "The last error for the LSP.";
          }
          leaf pst {
            type identityref {
              base te-types:path-signaling-type;
            }
            default "te-types:path-setup-rsvp";
            description
              "The Path Setup Type";
            reference
              "RFC 8408: Conveying Path Setup Type in PCE
               Communication Protocol (PCEP) Messages";
          }
          list association-list {
            if-feature "association";
            key "type id source global-source extended-id";
            description
              "List of all PCEP associations";
            leaf type {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "association-list/type";
              }
              description
                "PCEP Association Type";
            }
            leaf id {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "association-list/id";
              }
              description
                "PCEP Association ID";
            }
            leaf source {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "association-list/source";
              }
              description
                "PCEP Association Source.";
            }
            leaf global-source {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "association-list/global-source";
              }
              description
                "PCEP Association Global Source.";
            }
            leaf extended-id {
              type leafref {
                path "/pcep/entity/lsp-db/"
                   + "association-list/extended-id";
              }
              description
                "Additional information to
                 support unique identification.";
            }
            reference
              "[I-D.ietf-pce-association-group]: PCEP
               Extensions for Establishing Relationships
               Between Sets of LSPs";
          }
        }
      }
      container path-keys {
        when "../role = 'pce' or ../role = 'pcc-and-pce'" {
          description
            "These fields are applicable when the role is
             PCE";
        }
        if-feature "path-key";
        config false;
        description
          "The path-keys generated by the PCE";
        reference
          "RFC 5520: Preserving Topology Confidentiality
           in Inter-Domain Path Computation Using a Path-
           Key-Based Mechanism";
        list path-keys {
          key "path-key";
          description
            "The list of path-keys generated by the PCE";
          leaf path-key {
            type uint16;
            description
              "The identifier, or token used to represent
               the Confidential Path Segment (CPS) within
               the context of the PCE";
          }
          container cps {
            description
              "The Confidential Path Segment (CPS)";
            list explicit-route-objects {
              key "index";
              description
                "List of explicit route objects";
              leaf index {
                type uint32;
                description
                  "ERO subobject index";
              }
              uses te-types:explicit-route-hop;
            }
          }
          leaf pcc-original {
            type leafref {
              path "/pcep/entity/peers/peer/addr";
            }
            description
              "Reference to PCC peer address of
               the original request";
          }
          leaf req-id {
            type uint32;
            description
              "The request ID of the original PCReq.";
          }
          leaf retrieved {
            type boolean;
            description
              "If path-key has been retrieved yet";
          }
          leaf pcc-retrieved {
            type leafref {
              path "/pcep/entity/peers/peer/addr";
            }
            must '(../retrieved = true())' {
              error-message "The Path-key should be retreived";
            }
            description
              "Reference to PCC peer address which
               retreived the path-key";
          }
          leaf creation-time {
            type yang:timestamp;
            description
              "The timestamp value at the time this Path-Key
               was created.";
          }
          leaf discard-time {
            type uint32;
            units "minutes";
            description
              "A time after which this path-keys will be
               discarded";
          }
          leaf reuse-time {
            type uint32;
            units "minutes";
            description
              "A time after which this path-keys could be
               reused";
          }
        }
      }
      container peers {
        description
          "The list of configured peers for the
           entity (remote PCE)";
        list peer {
          key "addr";
          description
            "The peer configured for the entity.
             (remote PCE)";
          leaf addr {
            type inet:ip-address;
            description
              "The local Internet address of this
               PCEP peer.";
          }
          leaf role {
            type pcep-role;
            mandatory true;
            description
              "The role of the PCEP Peer.
               Takes one of the following values.
               - unknown(0): this PCEP peer role is not
               known.
               - pcc(1): this PCEP peer is a PCC.
               - pce(2): this PCEP peer is a PCE.
               - pcc-and-pce(3): this PCEP peer
               is both a PCC and a PCE.";
          }
          leaf description {
            type string;
            description
              "Description of the PCEP peer
               configured by the user";
          }
          uses info {
            description
              "PCE Peer information";
          }
          container pce-info {
            uses pce-info {
              description
                "PCE Peer information";
            }
            description
              "The PCE Peer information";
          }
          leaf delegation-pref {
            if-feature "stateful";
            type uint8 {
              range "0..7";
            }
            description
              "The PCE peer delegation preference.";
          }
          container auth {
            description
              "The Authentication options";
            choice auth-type-selection {
              description
                "Options for expressing authentication
                 setting.";
              case auth-key-chain {
                leaf key-chain {
                  type key-chain:key-chain-ref;
                  description
                    "key-chain name.";
                }
              }
              case auth-key {
                leaf crypto-algorithm {
                  type identityref {
                    base key-chain:crypto-algorithm;
                  }
                  mandatory true;
                  description
                    "Cryptographic algorithm associated
                     with key.";
                }
                choice key-string-style {
                  description
                    "Key string styles";
                  case keystring {
                    leaf keystring {
                      netconf-acm:default-deny-all;
                      type string;
                      description
                        "Key string in ASCII format.";
                    }
                  }
                  case hexadecimal {
                    if-feature "key-chain:hex-key-string";
                    leaf hexadecimal-string {
                      netconf-acm:default-deny-all;
                      type yang:hex-string;
                      description
                        "Key in hexadecimal string format. When
                         compared to ASCII, specification in
                         hexadecimal affords greater key entropy
                         with the same number of internal
                         key-string octets.  Additionally, it
                         discourages usage of well-known words or
                         numbers.";
                    }
                  }
                }
              }
              case auth-tls {
                if-feature "tls";
                choice role {
                  description
                    "The role of the local entity";
                  case server {
                    container tls-server {
                      uses tls-server:tls-server-grouping {
                        description
                          "Server TLS information.";
                      }
                      description
                        "TLS related information";
                    }
                  }
                  case client {
                    container tls-client {
                      uses tls-client:tls-client-grouping {
                        description
                          "Client TLS information.";
                      }
                      description
                        "TLS related information";
                    }
                  }
                }
              }
            }
          }
          leaf discontinuity-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp of the time when the information and
               statistics were last reset.";
          }
          leaf initiate-session {
            type boolean;
            config false;
            description
              "Indicates whether the local PCEP entity initiates
               sessions to this peer, or waits for the peer to
               initiate a session.";
          }
          leaf session-exists {
            type boolean;
            config false;
            description
              "Indicates whether a session with
               this peer currently exists.";
          }
          leaf session-up-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp value of the last time a
               session with this peer was successfully
               established.";
          }
          leaf session-fail-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp value of the last time a
               session with this peer failed to be
               established.";
          }
          leaf session-fail-up-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp value of the last time a
               session with this peer failed from
               active.";
          }
          container sessions {
            config false;
            description
              "This entry represents a single PCEP
               session in which the local PCEP entity participates.
               This entry exists only if the corresponding PCEP
               session has been initialized by some event, such as
               manual user configuration, auto-discovery of a peer,
               or an incoming TCP connection.";
            list session {
              key "initiator";
              description
                "The list of sessions, note that for a time being
                 two sessions may exist for a peer";
              leaf initiator {
                type pcep-initiator;
                description
                  "The initiator of the session,that is, whether
                   the TCP connection was initiated by the local
                   PCEP entity or the peer.
                   There is a window during session
                   initialization where two sessions can exist
                   between a pair of PCEP speakers, each
                   initiated by one of the speakers. One of
                   these sessions is always discarded before it
                   leaves OpenWait state. However, before it is
                   discarded, two sessions to the given peer
                   appear transiently in this yang module. The
                   sessions are distinguished by who initiated
                   them, and so this field is the key.";
              }
              leaf role {
                type leafref {
                  path "/pcep/entity/role";
                }
                description
                  "The reference to peer role .";
              }
              leaf state-last-change {
                type yang:timestamp;
                description
                  "The timestamp value at the time this
                   session entered its current state as
                   denoted by the state leaf.";
              }
              leaf state {
                type pcep-sess-state;
                description
                  "The current state of the session.
                   The set of possible states excludes the
                   idle state since entries do not exist
                   in the idle state.";
              }
              leaf session-creation {
                type yang:timestamp;
                description
                  "The timestamp value at the time this
                   session was created.";
              }
              leaf connect-retry {
                type yang:counter32;
                description
                  "The number of times that the local PCEP
                   entity has attempted to establish a TCP
                   connection for this session without
                   success. The PCEP entity gives up when
                   this reaches connect-max-retry.";
              }
              leaf local-id {
                type uint8;
                description
                  "The value of the PCEP session ID used by
                   the local PCEP entity in the Open message
                   for this session. If state is tcp-pending
                   then this is the session ID that will be
                   used in the Open message. Otherwise, this
                   is the session ID that was sent in the
                   Open message.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf remote-id {
                type uint8;
                must "((../state != 'tcp-pending'"
                   + "and "
                   + "../state != 'open-wait' )"
                   + "or "
                   + "((../state = 'tcp-pending'"
                   + " or "
                   + "../state = 'open-wait' )"
                   + "and (. = 0)))" {
                  error-message "Invalid remote-id";
                  description
                    "If state is tcp-pending or open-wait then
                     this leaf is not used and MUST be set to
                     zero.";
                }
                description
                  "The value of the PCEP session ID used by the
                   peer in its Open message for this session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf keepalive-timer {
                type uint8;
                units "seconds";
                must "(../state = 'session-up'"
                   + "or "
                   + "(../state != 'session-up'"
                   + "and (. = 0)))" {
                  error-message "Invalid keepalive timer";
                  description
                    "This field is used if and only if state is
                     session-up. Otherwise, it is not used and
                     MUST be set to zero.";
                }
                description
                  "The agreed maximum interval at which the local
                   PCEP entity transmits PCEP messages on this PCEP
                   session.  Zero means that the local PCEP entity
                   never sends Keepalives on this session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf peer-keepalive-timer {
                type uint8;
                units "seconds";
                must "(../state = 'session-up'"
                   + "or "
                   + "(../state != 'session-up'"
                   + "and "
                   + "(. = 0)))" {
                  error-message "Invalid Peer keepalive timer";
                  description
                    "This field is used if and only if state is
                     session-up. Otherwise, it is not used and MUST
                     be set to zero.";
                }
                description
                  "The agreed maximum interval at which the peer
                   transmits PCEP messages on this PCEP session.
                   Zero means that the peer never sends Keepalives
                   on this session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf dead-timer {
                type uint8;
                units "seconds";
                description
                  "The dead timer interval for this PCEP session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf peer-dead-timer {
                type uint8;
                units "seconds";
                must "((../state != 'tcp-pending'"
                   + "and "
                   + "../state != 'open-wait' )"
                   + "or "
                   + "((../state = 'tcp-pending'"
                   + " or "
                   + "../state = 'open-wait' )"
                   + "and "
                   + "(. = 0)))" {
                  error-message "Invalid Peer Dead timer";
                  description
                    "If state is tcp-pending or open-wait then this
                     leaf is not used and MUST be set to zero.";
                }
                description
                  "The peer's dead-timer interval
                   for this PCEP session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf ka-hold-time-rem {
                type uint8;
                units "seconds";
                must "((../state != 'tcp-pending'"
                   + "and "
                   + "../state != 'open-wait' ) "
                   + "or "
                   + "((../state = 'tcp-pending'"
                   + "or "
                   + "../state = 'open-wait' )"
                   + "and "
                   + "(. = 0)))" {
                  error-message
                    "Invalid Keepalive hold time remaining";
                  description
                    "If state is tcp-pending or open-wait then this
                     field is not used and MUST be set to zero.";
                }
                description
                  "The keep alive hold time remaining for this
                   session.";
              }
              leaf overloaded {
                type boolean;
                description
                  "If the local PCEP entity has informed the peer that
                   it is currently overloaded, then this is set to true.
                   Otherwise, it is set to false.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf overload-time {
                type uint32;
                units "seconds";
                must '((../overloaded = true()) '
                   + 'or ((../overloaded != true()) '
                   + 'and (. = 0)))' {
                  error-message "Invalid overload-time";
                  description
                    "This field is only used if overloaded is set to
                     true. Otherwise, it is not used and MUST be set
                     to zero.";
                }
                description
                  "The interval of time that is remaining until the
                   local PCEP entity will cease to be overloaded on
                   this session.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf peer-overloaded {
                type boolean;
                description
                  "If the peer has informed the local PCEP entity
                   that it is currently overloaded, then this is
                   set to true. Otherwise, it is set to false.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf peer-overload-time {
                type uint32;
                units "seconds";
                must '((../peer-overloaded = '
                   + 'true()) or '
                   + '((../peer-overloaded !='
                   + 'true())'
                   + ' and '
                   + '(. = 0)))' {
                  error-message "Invalid peer overload time";
                  description
                    "This field is only used if peer-overloaded
                     is set to true. Otherwise, it is not used
                     and MUST be set to zero.";
                }
                description
                  "The interval of time that is remaining until
                   the peer will cease to be overloaded.  If it
                   is not known how long the peer will stay in
                   overloaded state, this leaf is set to zero.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf lspdb-sync {
                if-feature "stateful";
                type sync-state;
                description
                  "The LSP-DB state synchronization status.";
                reference
                  "RFC 8231: Path Computation Element Communication
                   Protocol (PCEP) Extensions for Stateful PCE";
              }
              leaf recv-db-ver {
                when "../role = 'pcc'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "This field is applicable when the role is
                     PCC";
                }
                if-feature "stateful";
                if-feature "sync-opt";
                type uint64;
                description
                  "The last received LSP State Database Version
                   Number";
                reference
                  "RFC 8231: Path Computation Element Communication
                   Protocol (PCEP) Extensions for Stateful PCE";
              }
              container of-list {
                when "../role = 'pce'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "These fields are applicable when the role is
                     PCE";
                }
                if-feature "objective-function";
                uses of-list;
                description
                  "Indicate the list of supported OF on this
                   session";
                reference
                  "RFC 5541: Encoding of Objective Functions in
                   the Path  Computation Element Communication
                   Protocol (PCEP)";
              }
              container pst-list {
                when "../role = 'pce'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "These fields are applicable when the role is
                     PCE";
                }
                description
                  "Indicate the list of supported
                   PST on this session";
                reference
                  "RFC 8408: Conveying Path Setup Type in PCE
                   Communication Protocol (PCEP) Messages";
                list path-setup-type {
                  key "pst";
                  description
                    "The list of authorized PST";
                  leaf pst {
                    type identityref {
                      base te-types:path-signaling-type;
                    }
                    description
                      "The PST authorized";
                  }
                }
              }
              container assoc-type-list {
                if-feature "association";
                description
                  "Indicate the list of supported association types
                   on this session";
                reference
                  "[I-D.ietf-pce-association-group]: PCEP
                   Extensions for Establishing Relationships
                   Between Sets of LSPs";
                list assoc-type {
                  key "at";
                  description
                    "The list of authorized association types";
                  leaf at {
                    type identityref {
                      base te-types:association-type;
                    }
                    description
                      "The association type authorized";
                  }
                }
              }
              leaf speaker-entity-id {
                if-feature "sync-opt";
                type string;
                description
                  "The Speaker Entity Identifier";
                reference
                  "RFC 8232: Optimizations of Label Switched
                   Path State  Synchronization Procedures for
                   a Stateful PCE";
              }
              leaf discontinuity-time {
                type yang:timestamp;
                description
                  "The timestamp value of the time when the
                   statistics were last reset.";
              }
            }
            // session
          }
          // sessions
        }
        //peer
      }
      //peers
    }
    //entity
  }

  //pcep
  /*
   * Notifications
   */

  notification pcep-session-up {
    description
      "This notification is sent when the value of
       '/pcep/peers/peer/sessions/session/state'
       enters the 'session-up' state.";
    uses notification-instance-hdr;
    uses notification-session-hdr;
    leaf state-last-change {
      type yang:timestamp;
      description
        "The timestamp value at the time this session
         entered its current state as denoted by the state
         leaf.";
    }
    leaf state {
      type pcep-sess-state;
      description
        "The current state of the session.
         The set of possible states excludes the idle state
         since entries do not exist in the idle state.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification

  notification pcep-session-down {
    description
      "This notification is sent when the value of
       '/pcep/peers/peer/sessions/session/state'
       leaves the 'session-up' state.";
    uses notification-instance-hdr;
    leaf session-initiator {
      type pcep-initiator;
      description
        "The initiator of the session.";
    }
    leaf state-last-change {
      type yang:timestamp;
      description
        "The timestamp value at the time this session
         entered its current state as denoted by the state
         leaf.";
    }
    leaf state {
      type pcep-sess-state;
      description
        "The current state of the session.
         The set of possible states excludes the idle state
         since entries do not exist in the idle state.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification

  notification pcep-session-local-overload {
    description
      "This notification is sent when the local PCEP entity
       enters overload state for a peer.";
    uses notification-instance-hdr;
    uses notification-session-hdr;
    leaf overloaded {
      type boolean;
      description
        "If the local PCEP entity has informed the peer
         that it is currently overloaded, then this is set
         to true. Otherwise, it is set to false.";
    }
    leaf overload-time {
      type uint32;
      units "seconds";
      description
        "The interval of time that is remaining until the
         local PCEP entity will cease to be overloaded on
         this session.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification

  notification pcep-session-local-overload-clear {
    description
      "This notification is sent when the local PCEP entity
       leaves overload state for a peer.";
    uses notification-instance-hdr;
    leaf overloaded {
      type boolean;
      description
        "If the local PCEP entity has informed the peer
         that it is currently overloaded, then this is set
         to true.  Otherwise, it is set to false.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification

  notification pcep-session-peer-overload {
    description
      "This notification is sent when a peer enters overload
       state.";
    uses notification-instance-hdr;
    uses notification-session-hdr;
    leaf peer-overloaded {
      type boolean;
      description
        "If the peer has informed the local PCEP entity that
         it is currently overloaded, then this is set to
         true. Otherwise, it is set to false.";
    }
    leaf peer-overload-time {
      type uint32;
      units "seconds";
      description
        "The interval of time that is remaining until the
         peer will cease to be overloaded.  If it is not
         known how long the peer will stay in overloaded
         state, this leaf is set to zero.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification

  notification pcep-session-peer-overload-clear {
    description
      "This notification is sent when a peer leaves overload
       state.";
    uses notification-instance-hdr;
    leaf peer-overloaded {
      type boolean;
      description
        "If the peer has informed the local PCEP entity that
         it is currently overloaded, then this is set to
         true. Otherwise, it is set to false.";
    }
    reference
      "RFC 5440: Path Computation Element (PCE) Communication
       Protocol (PCEP)";
  }

  //notification
  /*
   * RPC
   */

  rpc trigger-resync {
    if-feature "stateful";
    if-feature "sync-opt";
    description
      "Trigger the resyncrinization at the PCE";
    reference
      "RFC 8232: Optimizations of Label Switched Path State
       Synchronization Procedures for a Stateful PCE";
    input {
      leaf pcc {
        type leafref {
          path "/pcep/entity/peers/peer/addr";
        }
        description
          "The IP address to identify the PCC. The state
           syncronization is re-triggered for all LSPs from
           the PCC. The rpc on the PCC will be ignored.";
      }
    }
    //input
  }

  //rpc
}

<CODE ENDS>
                     ]]></artwork>
        </figure>
</section>
<section title="ietf-pcep-stats module" toc="default">
      <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height="">
          <![CDATA[
<CODE BEGINS> file "ietf-pcep-stats@2019-03-26.yang"
module ietf-pcep-stats {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-pcep-stats";
  prefix pcep-stats;

  import ietf-pcep {
    prefix pcep;
    reference
      "RFC XXXX: A YANG Data Model for Path Computation
       Element Communications Protocol (PCEP)";
  }
  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }

  organization
    "IETF PCE (Path Computation Element) Working Group";
  contact
    "WG Web:  <https://tools.ietf.org/wg/pce/>
     WG List:  <mailto:pce@ietf.org>
     Editor:   Dhruv Dhody
              <mailto:dhruv.ietf@gmail.com>";
  description
    "The YANG module augments the PCEP yang operational
     model with statistics, counters and telemetry data.

     Copyright (c) 2019 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (httpcep://trustee.ietf.org/license-info).

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

  revision 2019-03-26 {
    description
      "Initial revision.";
    reference
      "RFC XXXX:  A YANG Data Model for Path Computation
       Element Communications Protocol (PCEP)";
  }

  /*
   * Groupings
   */

  grouping pcep-stats {
    description
      "This grouping defines statistics for PCEP. It is used
       for both peer and current session.";
    leaf avg-rsp-time {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type uint32;
      units "milliseconds";
      description
        "The average response time. If an average response time
         has not been calculated then this leaf has the value
         zero.";
    }
    leaf lwm-rsp-time {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type uint32;
      units "milliseconds";
      description
        "The smallest (low-water mark) response time seen.
         If no responses have been received then this leaf has
         the value zero.";
    }
    leaf hwm-rsp-time {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type uint32;
      units "milliseconds";
      description
        "The greatest (high-water mark) response time seen.
         If no responses have been received then this object
         has the value zero.";
    }
    leaf num-pcreq-sent {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of PCReq messages sent.";
    }
    leaf num-pcreq-rcvd {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of PCReq messages received.";
    }
    leaf num-pcrep-sent {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of PCRep messages sent.";
    }
    leaf num-pcrep-rcvd {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of PCRep messages received.";
    }
    leaf num-pcerr-sent {
      type yang:counter32;
      description
        "The number of PCErr messages sent.";
    }
    leaf num-pcerr-rcvd {
      type yang:counter32;
      description
        "The number of PCErr messages received.";
    }
    leaf num-pcntf-sent {
      type yang:counter32;
      description
        "The number of PCNtf messages sent.";
    }
    leaf num-pcntf-rcvd {
      type yang:counter32;
      description
        "The number of PCNtf messages received.";
    }
    leaf num-keepalive-sent {
      type yang:counter32;
      description
        "The number of Keepalive messages sent.";
    }
    leaf num-keepalive-rcvd {
      type yang:counter32;
      description
        "The number of Keepalive messages received.";
    }
    leaf num-unknown-rcvd {
      type yang:counter32;
      description
        "The number of unknown messages received.";
    }
    leaf num-corrupt-rcvd {
      type yang:counter32;
      description
        "The number of corrupted PCEP message received.";
    }
    leaf num-req-sent {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests sent.  A request corresponds
         1:1 with an RP object in a PCReq message. This might
         be greater than num-pcreq-sent because multiple
         requests can be batched into a single PCReq
         message.";
    }
    leaf num-req-sent-pend-rep {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that have been sent for
         which a response is still pending.";
    }
    leaf num-req-sent-ero-rcvd {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that have been sent for
         which a response with an ERO object was received.
         Such responses indicate that a path was
         successfully computed by the peer.";
    }
    leaf num-req-sent-nopath-rcvd {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that have been sent for
         which a response with a NO-PATH object was
         received. Such responses indicate that the peer
         could not find a path to satisfy the
         request.";
    }
    leaf num-req-sent-cancel-rcvd {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that were cancelled with
         a PCNtf message. This might be different than
         num-pcntf-rcvd because not all PCNtf messages are
         used to cancel requests, and a single PCNtf message
         can cancel multiple requests.";
    }
    leaf num-req-sent-error-rcvd {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that were rejected with a
         PCErr message. This might be different than
         num-pcerr-rcvd because not all PCErr messages are
         used to reject requests, and a single PCErr message
         can reject multiple requests.";
    }
    leaf num-req-sent-timeout {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that have been sent to a peer
         and have been abandoned because the peer has taken too
         long to respond to them.";
    }
    leaf num-req-sent-cancel-sent {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of requests that were sent to the peer and
         explicitly cancelled by the local PCEP entity sending
         a PCNtf.";
    }
    leaf num-req-rcvd {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests received.  A request
         corresponds 1:1 with an RP object in a PCReq
         message.
         This might be greater than num-pcreq-rcvd because
         multiple requests can be batched into a single
         PCReq message.";
    }
    leaf num-req-rcvd-pend-rep {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests that have been received for
         which a response is still pending.";
    }
    leaf num-req-rcvd-ero-sent {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests that have been received for
         which a response with an ERO object was sent.  Such
         responses indicate that a path was successfully
         computed by the local PCEP entity.";
    }
    leaf num-req-rcvd-nopath-sent {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests that have been received for
         which a response with a NO-PATH object was sent. Such
         responses indicate that the local PCEP entity could
         not find a path to satisfy the request.";
    }
    leaf num-req-rcvd-cancel-sent {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests received that were cancelled
         by the local PCEP entity sending a PCNtf message.
         This might be different than num-pcntf-sent because
         not all PCNtf messages are used to cancel requests,
         and a single PCNtf message can cancel multiple
         requests.";
    }
    leaf num-req-rcvd-error-sent {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests received that were cancelled
         by the local PCEP entity sending a PCErr message.
         This might be different than num-pcerr-sent because
         not all PCErr messages are used to cancel requests,
         and a single PCErr message can cancel multiple
         requests.";
    }
    leaf num-req-rcvd-cancel-rcvd {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of requests that were received from the
         peer and explicitly cancelled by the peer sending
         a PCNtf.";
    }
    leaf num-rep-rcvd-unknown {
      when "../../pcep:role = 'pce'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCE";
      }
      type yang:counter32;
      description
        "The number of responses to unknown requests
         received. A response to an unknown request is a
         response whose RP object does not contain the
         request ID of any request that is currently
         outstanding on the session.";
    }
    leaf num-req-rcvd-unknown {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      type yang:counter32;
      description
        "The number of unknown requests that have been
         received. An unknown request is a request
         whose RP object contains a request ID of zero.";
    }
    container svec {
      if-feature "pcep:svec";
      description
        "If synchronized path computation is supported";
      leaf num-svec-sent {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of SVEC objects sent in PCReq messages.
           An SVEC object represents a set of synchronized
           requests.";
      }
      leaf num-svec-req-sent {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of requests sent that appeared in one
           or more SVEC objects.";
      }
      leaf num-svec-rcvd {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of SVEC objects received in PCReq
           messages. An SVEC object represents a set of
           synchronized requests.";
      }
      leaf num-svec-req-rcvd {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of requests received that appeared
           in one or more SVEC objects.";
      }
    }
    //svec
    container stateful {
      if-feature "pcep:stateful";
      description
        "Stateful PCE related statistics";
      leaf num-pcrpt-sent {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of PCRpt messages sent.";
      }
      leaf num-pcrpt-rcvd {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of PCRpt messages received.";
      }
      leaf num-pcupd-sent {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of PCUpd messages sent.";
      }
      leaf num-pcupd-rcvd {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of PCUpd messages received.";
      }
      leaf num-rpt-sent {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of LSP Reports sent.  A LSP report
           corresponds 1:1 with an LSP object in a PCRpt
           message. This might be greater than
           num-pcrpt-sent because multiple reports can
           be batched into a single PCRpt message.";
      }
      leaf num-rpt-rcvd {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of LSP Reports received.  A LSP report
           corresponds 1:1 with an LSP object in a PCRpt
           message.
           This might be greater than num-pcrpt-rcvd because
           multiple reports can be batched into a single
           PCRpt message.";
      }
      leaf num-rpt-rcvd-error-sent {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of reports of LSPs received that were
           responded by the local PCEP entity by sending a
           PCErr message.";
      }
      leaf num-upd-sent {
        when "../../../pcep:role = 'pcc'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of LSP updates sent.  A LSP update
           corresponds 1:1 with an LSP object in a PCUpd
           message. This might be greater than
           num-pcupd-sent because multiple updates can
           be batched into a single PCUpd message.";
      }
      leaf num-upd-rcvd {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of LSP Updates received.  A LSP update
           corresponds 1:1 with an LSP object in a PCUpd
           message.
           This might be greater than num-pcupd-rcvd because
           multiple updates can be batched into a single
           PCUpd message.";
      }
      leaf num-upd-rcvd-unknown {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of updates to unknown LSPs
           received. An update to an unknown LSP is a
           update whose LSP object does not contain the
           PLSP-ID of any LSP that is currently
           present.";
      }
      leaf num-upd-rcvd-undelegated {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of updates to not delegated LSPs
           received. An update to an undelegated LSP is a
           update whose LSP object does not contain the
           PLSP-ID of any LSP that is currently
           delegated to current PCEP session.";
      }
      leaf num-upd-rcvd-error-sent {
        when "../../../pcep:role = 'pce'"
           + "or "
           + "../../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of updates to LSPs received that were
           responded by the local PCEP entity by sending a
           PCErr message.";
      }
      container initiation {
        if-feature "pcep:pce-initiated";
        description
          "PCE-Initiated related statistics";
        leaf num-pcinitiate-sent {
          when "../../../../pcep:role = 'pcc'"
             + "or "
             + "../../../../pcep:role = 'pcc-and-pce'" {
            description
              "Valid for PCEP Peer as PCC";
          }
          type yang:counter32;
          description
            "The number of PCInitiate messages sent.";
        }
        leaf num-pcinitiate-rcvd {
          when "../../../../pcep:role = 'pce'"
             + "or "
             + "../../../../pcep:role = 'pcc-and-pce'" {
            description
              "Valid for PCEP Peer as PCE";
          }
          type yang:counter32;
          description
            "The number of PCInitiate messages received.";
        }
        leaf num-initiate-sent {
          when "../../../../pcep:role = 'pcc'"
             + "or "
             + "../../../../pcep:role = 'pcc-and-pce'" {
            description
              "Valid for PCEP Peer as PCC";
          }
          type yang:counter32;
          description
            "The number of LSP Initiation sent via PCE.
             A LSP initiation corresponds 1:1 with an LSP
             object in a PCInitiate message. This might be
             greater than num-pcinitiate-sent because
             multiple initiations can be batched into a
             single PCInitiate message.";
        }
        leaf num-initiate-rcvd {
          when "../../../../pcep:role = 'pce'"
             + "or "
             + "../../../../pcep:role = 'pcc-and-pce'" {
            description
              "Valid for PCEP Peer as PCE";
          }
          type yang:counter32;
          description
            "The number of LSP Initiation received from
             PCE.  A LSP initiation corresponds 1:1 with
             an LSP object in a PCInitiate message. This
             might be greater than num-pcinitiate-rcvd
             because multiple initiations can be batched
             into a single PCInitiate message.";
        }
        leaf num-initiate-rcvd-error-sent {
          when "../../../../pcep:role = 'pce'"
             + "or "
             + "../../../../pcep:role = 'pcc-and-pce'" {
            description
              "Valid for PCEP Peer as PCE";
          }
          type yang:counter32;
          description
            "The number of initiations of LSPs received
             that were responded by the local PCEP entity
             by sending a PCErr message.";
        }
      }
      //initiation
    }
    //stateful
    container path-key {
      when "../../pcep:role = 'pcc'"
         + "or "
         + "../../pcep:role = 'pcc-and-pce'" {
        description
          "Valid for PCEP Peer as PCC";
      }
      if-feature "pcep:path-key";
      description
        "If Path-Key is supported";
      leaf num-unknown-path-key {
        type yang:counter32;
        description
          "The number of attempts to expand an unknown
           path-key.";
      }
      leaf num-exp-path-key {
        type yang:counter32;
        description
          "The number of attempts to expand an expired
           path-key.";
      }
      leaf num-dup-path-key {
        type yang:counter32;
        description
          "The number of duplicate attempts to expand same
           path-key.";
      }
      leaf num-path-key-no-attempt {
        type yang:counter32;
        description
          "The number of expired path-keys with no attempt to
           expand it.";
      }
    }
    //path-key 
  }

  //pcep-stats
  /*
   * Augment modules to add statistics
   */

  augment "/pcep:pcep/pcep:entity/pcep:peers/pcep:peer" {
    description
      "Augmenting the statistics";
    leaf num-sess-setup-ok {
      type yang:counter32;
      config false;
      description
        "The number of PCEP sessions successfully established with
         the peer, including any current session.  This counter is
         incremented each time a session with this peer is
         successfully established.";
    }
    leaf num-sess-setup-fail {
      type yang:counter32;
      config false;
      description
        "The number of PCEP sessions with the peer
         that have been attempted but failed
         before being fully established. This
         counter is incremented each time a
         session retry to this peer fails.";
    }
    container pcep-stats {
      config false;
      description
        "The container for all statistics at peer level.";
      uses pcep-stats {
        description
          "Since PCEP sessions can be ephemeral, the peer statistics
           tracks a peer even when no PCEP session currently exists
           to that peer. The statistics contained are an aggregate of
           the statistics for all successive sessions to that peer.";
      }
      leaf num-req-sent-closed {
        when "../../pcep:role = 'pce'"
           + "or "
           + "../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCE";
        }
        type yang:counter32;
        description
          "The number of requests that were sent to the peer and
           implicitly cancelled when the session they were sent
           over was closed.";
      }
      leaf num-req-rcvd-closed {
        when "../../pcep:role = 'pcc'"
           + "or "
           + "../../pcep:role = 'pcc-and-pce'" {
          description
            "Valid for PCEP Peer as PCC";
        }
        type yang:counter32;
        description
          "The number of requests that were received from the peer
           and implicitly cancelled when the session they were
           received over was closed.";
      }
    }
    //pcep-stats
  }

  //augment

  augment "/pcep:pcep/pcep:entity/pcep:peers/pcep:peer/"
        + "pcep:sessions/pcep:session" {
    description
      "Augmenting the statistics";
    container pcep-stats {
      description
        "The container for all statistics at session level.";
      uses pcep-stats {
        description
          "The statistics contained are for the current sessions to
           that peer. These are lost when the session goes down.";
      }
    }
    //pcep-stats
  }

  //augment
}


<CODE ENDS>
                     ]]></artwork>
        </figure>  
  </section>
  </section>



    <section title="Security Considerations" toc="default">
      <t>The YANG module defined in this document is designed to be accessed via
   network management protocol such as NETCONF <xref target="RFC6241"/>
   or RESTCONF <xref target="RFC8040"/>.  The lowest NETCONF layer is the secure
   transport layer and the mandatory-to-implement secure transport is
   SSH <xref target="RFC6242"/>. The lowest RESTCONF layer is HTTPS, and the
   mandatory-to-implement secure transport is TLS <xref target="RFC8446"/></t>

        <t>The NETCONF access control model <xref target="RFC8341"/> provides
   the means to restrict access for particular NETCONF or RESTCONF users to a
   pre-configured subset of all available NETCONF or RESTCONF protocol
   operations and content.</t>

        <t>There are a number of data nodes defined in the YANG module which are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g.,  &lt;edit-config&gt;)
   to these data nodes without proper protection can have a negative
   effect on network operations. These are the subtrees and data nodes and 
   their sensitivity/vulnerability:
   <list>
   <t>/pcep/entity/ - configure local parameters, capabilities etc.</t>
   <t>/pcep/entity/peers - configure remote peers to setup PCEP session.</t>
   </list></t>

   <t>Unauthorized access to above list can adversely affect the
   PCEP session between the local entity and the peers.  This may
   lead to inability to compute new paths, stateful operations on 
   the delegated as well as PCE-initiated LSPs.</t>

   <t>Some of the readable data nodes in this YANG module may be considered 
    sensitive or vulnerable in some network environments. It is thus important 
    to control read access (e.g., via get, get-config, or notification) to 
    these data nodes. These are the subtrees and data nodes and their 
    sensitivity/vulnerability:

   <list>
    <t>/pcep/lsp-db - All the LSPs in the network. Unauthorized access to
      this could provide the all path and network usage information.</t>
    <t>/pcep/path-keys/ - The Confidential Path Segments (CPS) are hidden
      using path-keys. Unauthorized access to this could leak confidential
      path information.
    </t>
  </list></t>

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

  <t>trigger-resync - trigger resynchronization with the PCE. Unauthorized access to 
      this could force a PCEP session into continuous state synchronization. </t>
  </list></t>

    </section>

    
    <section title="IANA Considerations" toc="default">
    <t>This document registers a URI in the "IETF XML Registry"
    <xref target="RFC3688"/>.
   Following the format in RFC 3688, the following registration has been
   made.
   <list style="hanging">

       <t hangText="URI:">urn:ietf:params:xml:ns:yang:ietf-pcep</t>

       <t hangText="Registrant Contact:">The PCE WG of the IETF.</t>

       <t hangText="XML:">N/A; the requested URI is an XML namespace.</t>
       </list>
   </t>
   <t>This document registers a YANG module in the "YANG Module Names"
   registry <xref target="RFC6020"/>.
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
    Name:         ietf-pcep
    Namespace:    urn:ietf:params:xml:ns:yang:ietf-pcep
    Prefix:       pcep
    Reference:    [This.I-D]

    Name:         ietf-pcep-stats
    Namespace:    urn:ietf:params:xml:ns:yang:ietf-pcep-stats
    Prefix:       pcep-stats
    Reference:    [This.I-D]

        ]]></artwork>
        </figure>
    </t>
    </section>

    <section title="Acknowledgements" toc="default">
      <t>The initial document is based on the PCEP MIB
      <xref target="RFC7420"/>. We would
      like to thank the authors of aforementioned documents.</t>
      <t>Thanks to Mahesh Jethmalani for the Yang Doctor review.</t>
      <t>Thanks to Martin Bjorklund and Tom Petch for providing guidance regarding the Yang guidelines.</t>
    </section>
  </middle>
  <back>
    <references title="Normative References">
    <?rfc include="reference.RFC.2119.xml" ?>
    <?rfc include="reference.RFC.3209.xml" ?>
    <?rfc include="reference.RFC.3688.xml" ?>
    <?rfc include="reference.RFC.5088.xml" ?>
    <?rfc include="reference.RFC.5089.xml" ?>
    <?rfc include="reference.RFC.5440.xml" ?>
    <?rfc include="reference.RFC.5520.xml" ?>
    <?rfc include="reference.RFC.5541.xml" ?>
    <?rfc include="reference.RFC.5557.xml" ?>
    
    <?rfc include="reference.RFC.6020.xml" ?>
    <?rfc include="reference.RFC.6241.xml" ?>
    <?rfc include="reference.RFC.6242.xml" ?>
    
    <?rfc include="reference.RFC.6991.xml" ?>
    <?rfc include="reference.RFC.7950.xml" ?>
    <?rfc include="reference.RFC.8177.xml" ?>
    <?rfc include="reference.RFC.8040.xml" ?>
    <?rfc include="reference.RFC.8174.xml"?>
    <?rfc include="reference.RFC.8231.xml"?>
    <?rfc include="reference.RFC.8232.xml"?>
    <?rfc include="reference.RFC.8253.xml"?>
    <?rfc include="reference.RFC.8281.xml"?>
    <?rfc include="reference.RFC.8306.xml"?>
    <?rfc include="reference.RFC.8340.xml"?>
    <?rfc include="reference.RFC.8341.xml" ?>
    <?rfc include="reference.RFC.8408.xml" ?>
    <?rfc include="reference.RFC.8446.xml" ?>
    
    
    <?rfc include="reference.I-D.ietf-teas-yang-te"?>
    <?rfc include="reference.I-D.ietf-teas-yang-te-types"?>

    <?rfc include="reference.I-D.ietf-netconf-tls-client-server"?>
    <?rfc include="reference.I-D.ietf-pce-association-group"?>
    <?rfc include="reference.I-D.ietf-pce-segment-routing"?>
    <?rfc include="reference.I-D.ietf-isis-yang-isis-cfg"?>
    <?rfc include="reference.I-D.ietf-ospf-yang"?>
    <?rfc include="reference.I-D.ietf-pce-gmpls-pcep-extensions"?>

    </references>
    <references title="Informative References">
      
      <?rfc include="reference.RFC.4655.xml" ?>
      
      
      
      
      <?rfc include="reference.RFC.7420.xml" ?>      
      
      
      <?rfc include="reference.RFC.8342.xml"?>

          
      
      

    </references>

    <section title="Example" toc="default">
    <t>The example below provide an overview of PCEP peer session informations and LSP-DB in the Yang Module. 
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
   

       +-------+                  +-------+ 
       |       |                  |       |  
       | PCC1  |<---------------->|       |
       |       |                  |       |
       +-------+                  |       |  
      IP:192.0.2.1                |       |  
                                  |  PCE  |  
                                  |       |  
       +-------+                  |       |  
       |       |                  |       |  
       | PCC2  |<---------------->|       |
       |       |                  |       |       
       +-------+                  |       |
      IP:192.0.2.2                |       |
                                  |       |  
                                  |       |  
       +-------+                  |       |  
       |       |                  |       |  
       | PCC4  |<---------------->|       |
       |       |                  |       |       
       +-------+                  |       |
      IP:2001:DB8::4              |       |                                                      
                                  +-------+
                                IP:192.0.2.3
                                   2001:DB8::3   

at PCE: 
{
   "entity": [
   {
        "addr": "192.0.2.3",
        "oper-status": "oper-status-up",
        "role":"pce",
        "capability" : {
            "stateful": {
                 "enabled": true
            }
        }
        "lsp-db" : [
           "lsp" : {
                "plsp-id": 3,
                "pcc-id" :"192.0.2.1",
                "lsp-ref" : {
                  "source": "192.0.2.1",
                  "destination": "192.0.2.4"
                  "tunnel-id": 16,
                  "lsp-id": 3,
                  "extended-tunnel-id": 0
                },
                "oper-status": "oper-status-up",
                "delegated": true,
                "symbolic-path-name": "iewauh",
                },
           "lsp" : {
                "plsp-id": 4,
                "pcc-id" :"192.0.2.2",
                "lsp-ref" : {
                  "source": "192.0.2.2",
                  "destination": "192.0.2.5"
                  "tunnel-id": 17,
                  "lsp-id": 4
                  "extended-tunnel-id": 0
                },
                "oper-status": "oper-status-up",
                "delegated": true,
                "symbolic-path-name": "iewauhiewauh",
                "extended-tunnel-id": 0
                }
        ]
        "peers":[
            {
                "peer": {
                     "addr":"192.0.2.1",
                     "role": "pcc",
                     
                     "capability": {
                         "stateful" : {
                              "enabled": true,
                              "active": yes,
                         } 
                     }
                     "sessions": [
                         {
                             "session": {
                                 "initiator": "remote",
                                 "role": "pcc",  
                             }
                         }
                     ]
                 }
            }, 
            {
                "peer": {
                     "addr":"192.0.2.2",
                     "role": "pcc",
                     
                     "capability": {
                         "stateful" : {
                              "enabled": true,
                              "active": true,
                         } 
                     }
                     "sessions": [
                         {
                             "session": {
                                 "initiator": "remote",
                                 "role": "pcc",  
                             }
                         }
                     ]
                 }
            }
        ]        
    },

   {
        "addr": "2001:DB8::3",
        "oper-status": "oper-status-up",
        "role":"pce",
        "peers":[
            {
                "peer": {
                     "addr":"2001:DB8::4",
                     "role": "pcc",
                     "sessions": [
                         {
                             "session": {
                                 "initiator": "remote",
                                 "role": "pcc",  
                             }
                         }
                     ]
                 }
            }
        ]        
    }
}

        ]]></artwork>
        </figure>
      </t>
    </section>

<section title="Contributor Addresses" toc="default">
    <t>
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
Rohit Pobbathi
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: rohit.pobbathi@huawei.com

Vinod KumarS
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: vinods.kumar@huawei.com

Zafar Ali
Cisco Systems
Canada

EMail: zali@cisco.com

Xufeng Liu
Jabil
8281 Greensboro Drive, Suite 200
McLean  VA 22102
USA

EMail: Xufeng_Liu@jabil.com

Young Lee
Huawei Technologies
5340 Legacy Drive, Building 3
Plano, TX 75023, USA

Phone: (469) 277-5838
EMail: leeyoung@huawei.com

Udayasree Palle
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: udayasreereddy@gmail.com

Xian Zhang
Huawei Technologies
Bantian, Longgang District
Shenzhen  518129
P.R.China

EMail: zhang.xian@huawei.com

Avantika
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: s.avantika.avantika@gmail.com

Shashikanth
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: shashikanth.vh@huawei.com

        ]]></artwork>
        </figure>
      </t>
    </section>

  </back>
</rfc>