\
PCE Working Group                                          D. Dhody, Ed.
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                             J. Hardwick
Expires: 29 July 2022                                         Metaswitch
                                                               V. Beeram
                                                        Juniper Networks
                                                             J. Tantsura
                                                               Microsoft
                                                         25 January 2022


 A YANG Data Model for Path Computation Element Communications Protocol
                                 (PCEP)
                      draft-ietf-pce-pcep-yang-18

Abstract

   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.

Status of This Memo

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

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

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

   This Internet-Draft will expire on 29 July 2022.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.



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   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Terminology and Notation  . . . . . . . . . . . . . . . . . .   3
     3.1.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Prefixes in Data Node Names . . . . . . . . . . . . . . .   5
     3.3.  References in the Model . . . . . . . . . . . . . . . . .   6
   4.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  The Design of PCEP Data Model . . . . . . . . . . . . . . . .   9
     5.1.  The Overview of PCEP Data Model . . . . . . . . . . . . .   9
     5.2.  The Entity  . . . . . . . . . . . . . . . . . . . . . . .  10
     5.3.  The Peer Lists  . . . . . . . . . . . . . . . . . . . . .  14
     5.4.  The Session Lists . . . . . . . . . . . . . . . . . . . .  16
     5.5.  Notifications . . . . . . . . . . . . . . . . . . . . . .  18
     5.6.  RPC . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
   6.  The Design of PCEP Statistics Data Model  . . . . . . . . . .  19
   7.  Advanced PCE Features . . . . . . . . . . . . . . . . . . . .  22
     7.1.  Stateful PCE's LSP-DB . . . . . . . . . . . . . . . . . .  22
   8.  Other Considerations  . . . . . . . . . . . . . . . . . . . .  23
     8.1.  PCEP over TLS (PCEPS) . . . . . . . . . . . . . . . . . .  23
   9.  PCEP YANG Modules . . . . . . . . . . . . . . . . . . . . . .  23
     9.1.  ietf-pcep module  . . . . . . . . . . . . . . . . . . . .  23
     9.2.  ietf-pcep-stats module  . . . . . . . . . . . . . . . . .  79
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  97
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  99
   12. Implementation Status . . . . . . . . . . . . . . . . . . . . 100
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 100
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . . 101
     14.1.  Normative References . . . . . . . . . . . . . . . . . . 101
     14.2.  Informative References . . . . . . . . . . . . . . . . . 104
   Appendix A.  The Full PCEP Data Model . . . . . . . . . . . . . . 105
   Appendix B.  Example  . . . . . . . . . . . . . . . . . . . . . . 112
   Appendix C.  Contributor Addresses  . . . . . . . . . . . . . . . 115
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 116










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1.  Introduction

   The Path Computation Element (PCE) defined in [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.

   PCEP is the communication protocol between a PCC and PCE and is
   defined in [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).  [RFC8231] specifies extensions to PCEP to
   enable stateful control of MPLS TE LSPs.

   This document defines a YANG [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.

   This document contains a specification of the PCEP YANG module,
   "ietf-pcep" which provides the PCEP [RFC5440] data model.

   The PCEP operational state is included in the same tree as the PCEP
   configuration consistent with Network Management Datastore
   Architecture (NMDA) [RFC8342].  The origin of the data is indicated
   as per the origin metadata annotation.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Terminology and Notation

   This document uses the terminology defined in [RFC4655] and
   [RFC5440].  In particular, it uses the following acronyms.

   *  Path Computation Request message (PCReq).

   *  Path Computation Reply message (PCRep).

   *  Notification message (PCNtf).




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   *  Error message (PCErr).

   *  Request Parameters object (RP).

   *  Synchronization Vector object (SVEC).

   *  Explicit Route object (ERO).

   This document also uses the following terms defined in [RFC7420]:

   *  PCEP entity: a local PCEP speaker.

   *  PCEP peer: to refer to a remote PCEP speaker.

   *  PCEP speaker: where it is not necessary to distinguish between
      local and remote.

   Further, this document also uses the following terms defined in
   [RFC8231] :

   *  Stateful PCE, Passive Stateful PCE, Active Stateful PCE

   *  Delegation, Revocation, Redelegation

   *  LSP State Report, Path Computation Report message (PCRpt).

   *  LSP State Update, Path Computation Update message (PCUpd).

   *  PLSP-ID: a PCEP-specific identifier for the LSP.

   *  SRP: Stateful PCE Request Parameters

   [RFC8281] :

   *  PCE-initiated LSP, Path Computation LSP Initiate Message
      (PCInitiate).

   [RFC8408] :

   *  Path Setup Type (PST).

   [RFC8664] :

   *  Segment Routing (SR).

   [RFC5541] :

   *  Objective Function (OF).



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   [RFC8697] :

   *  Association.

   [RFC6241] :

   *  Configuration data.

   *  State data.

3.1.  Tree Diagrams

   A simplified graphical representation of the data model is used in
   this document.  The meaning of the symbols in these diagrams is
   defined in [RFC8340].

3.2.  Prefixes in Data Node Names

   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 Table 1.

   +=========+==================+======================================+
   |Prefix   | YANG module      | Reference                            |
   +=========+==================+======================================+
   |yang     | ietf-yang-types  | [RFC6991]                            |
   +---------+------------------+--------------------------------------+
   |inet     | ietf-inet-types  | [RFC6991]                            |
   +---------+------------------+--------------------------------------+
   |te-types | ietf-te-types    | [RFC8776]                            |
   +---------+------------------+--------------------------------------+
   |key-chain| ietf-key-chain   | [RFC8177]                            |
   +---------+------------------+--------------------------------------+
   |nacm     | ietf-netconf-acm | [RFC8341]                            |
   +---------+------------------+--------------------------------------+
   |tlss     | ietf-tls-server  | [I-D.ietf-netconf-tls-client-server] |
   +---------+------------------+--------------------------------------+
   |tlsc     | ietf-tls-client  | [I-D.ietf-netconf-tls-client-server] |
   +---------+------------------+--------------------------------------+
   |ospf     | ietf-ospf        | [I-D.ietf-ospf-yang]                 |
   +---------+------------------+--------------------------------------+
   |isis     | ietf-isis        | [I-D.ietf-isis-yang-isis-cfg]        |
   +---------+------------------+--------------------------------------+

              Table 1: Prefixes and corresponding YANG modules




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3.3.  References in the Model

   Following documents are referenced in the model defined in this
   document -

    +==========================+======================================+
    | Documents                | Reference                            |
    +==========================+======================================+
    | OSPF Protocol Extensions | [RFC5088]                            |
    | for Path Computation     |                                      |
    | Element (PCE) Discovery  |                                      |
    +--------------------------+--------------------------------------+
    | IS-IS Protocol           | [RFC5089]                            |
    | Extensions for Path      |                                      |
    | Computation Element      |                                      |
    | (PCE) Discovery          |                                      |
    +--------------------------+--------------------------------------+
    | Path Computation Element | [RFC5440]                            |
    | (PCE) Communication      |                                      |
    | Protocol (PCEP)          |                                      |
    +--------------------------+--------------------------------------+
    | Preserving Topology      | [RFC5520]                            |
    | Confidentiality in       |                                      |
    | Inter-Domain Path        |                                      |
    | Computation Using a      |                                      |
    | Path-Key-Based Mechanism |                                      |
    +--------------------------+--------------------------------------+
    | Encoding of Objective    | [RFC5541]                            |
    | Functions in the Path    |                                      |
    | Computation Element      |                                      |
    | Communication Protocol   |                                      |
    | (PCEP)                   |                                      |
    +--------------------------+--------------------------------------+
    | Path Computation Element | [RFC5557]                            |
    | Communication Protocol   |                                      |
    | (PCEP) Requirements and  |                                      |
    | Protocol Extensions in   |                                      |
    | Support of Global        |                                      |
    | Concurrent Optimization  |                                      |
    +--------------------------+--------------------------------------+
    | Common YANG Data Types   | [RFC6991]                            |
    +--------------------------+--------------------------------------+
    | YANG Data Model for Key  | [RFC8177]                            |
    | Chains                   |                                      |
    +--------------------------+--------------------------------------+
    | Path Computation Element | [RFC8231]                            |
    | Communication Protocol   |                                      |
    | (PCEP) Extensions for    |                                      |



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    | Stateful PCE             |                                      |
    +--------------------------+--------------------------------------+
    | Optimizations of Label   | [RFC8232]                            |
    | Switched Path State      |                                      |
    | Synchronization          |                                      |
    | Procedures for a         |                                      |
    | Stateful PCE             |                                      |
    +--------------------------+--------------------------------------+
    | PCEPS: Usage of TLS to   | [RFC8253]                            |
    | Provide a Secure         |                                      |
    | Transport for the Path   |                                      |
    | Computation Element      |                                      |
    | Communication Protocol   |                                      |
    | (PCEP)                   |                                      |
    +--------------------------+--------------------------------------+
    | Path Computation Element | [RFC8281]                            |
    | Communication Protocol   |                                      |
    | (PCEP) Extensions for    |                                      |
    | PCE-Initiated LSP Setup  |                                      |
    | in a Stateful PCE Model  |                                      |
    +--------------------------+--------------------------------------+
    | Extensions to the Path   | [RFC8306]                            |
    | Computation Element      |                                      |
    | Communication Protocol   |                                      |
    | (PCEP) for Point-to-     |                                      |
    | Multipoint Traffic       |                                      |
    | Engineering Label        |                                      |
    | Switched Paths           |                                      |
    +--------------------------+--------------------------------------+
    | Network Configuration    | [RFC8341]                            |
    | Access Control Model     |                                      |
    +--------------------------+--------------------------------------+
    | Conveying Path Setup     | [RFC8408]                            |
    | Type in PCE              |                                      |
    | Communication Protocol   |                                      |
    | (PCEP) Messages          |                                      |
    +--------------------------+--------------------------------------+
    | Traffic Engineering      | [RFC8776]                            |
    | Common YANG Types        |                                      |
    +--------------------------+--------------------------------------+
    | A YANG Data Model for    | [I-D.ietf-teas-yang-te]              |
    | Traffic Engineering      |                                      |
    | Tunnels and Interfaces   |                                      |
    +--------------------------+--------------------------------------+
    | YANG Groupings for TLS   | [I-D.ietf-netconf-tls-client-server] |
    | Clients and TLS Servers  |                                      |
    +--------------------------+--------------------------------------+
    | PCEP Extensions for      | [RFC8664]                            |



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    | Segment Routing          |                                      |
    +--------------------------+--------------------------------------+
    | PCEP Extensions for      | [RFC8697]                            |
    | Establishing             |                                      |
    | Relationships Between    |                                      |
    | Sets of LSPs             |                                      |
    +--------------------------+--------------------------------------+
    | YANG Data Model for OSPF | [I-D.ietf-ospf-yang]                 |
    | Protocol                 |                                      |
    +--------------------------+--------------------------------------+
    | YANG Data Model for IS-  | [I-D.ietf-isis-yang-isis-cfg]        |
    | IS Protocol              |                                      |
    +--------------------------+--------------------------------------+
    | PCEP extensions for      | [RFC8779]                            |
    | GMPLS                    |                                      |
    +--------------------------+--------------------------------------+
    | ASSOCIATION Type Field   | [IANA-PCEP]                          |
    | in Path Computation      |                                      |
    | Element Protocol (PCEP)  |                                      |
    | Numbers                  |                                      |
    +--------------------------+--------------------------------------+
    | Path Computation Element | [IANA-OSPF]                          |
    | (PCE) Capability Flags   |                                      |
    | in Open Shortest Path    |                                      |
    | First v2 (OSPFv2)        |                                      |
    | Parameters               |                                      |
    +--------------------------+--------------------------------------+

                  Table 2: References in the YANG modules

4.  Objectives

   This section describes some of the design objectives for the model:

   *  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.

   *  The data model should be suitable for new implementations to use
      as is.

   *  Mapping to the PCEP MIB Module should be clear.

   *  The data model should allow for static configurations of peers.






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   *  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.

   *  It should be fairly straightforward to augment the base data model
      for advanced PCE features.

5.  The Design of PCEP Data Model

5.1.  The Overview of PCEP Data Model

   The PCEP YANG module defined in this document has all the common
   building blocks for the PCEP protocol.

   module: ietf-pcep
     +--rw pcep!
        +--rw entity
           +--rw addr                          inet:ip-address-no-zone
           +--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 domains
           |  +--rw domains* [domain-type domain-info]
           |     +--...
           +--rw capability
           |  +--...
           +--rw pce-info
           |  +--rw scope
           |  |  +--...
           |  +--rw neighbour-domains
           |  |  +--...
           |  +--rw path-key {path-key}?
           |  |  +--...
           |  +--...
           +--...
           +--ro lsp-db {stateful}?
           |  +--ro db-ver?             uint64 {sync-opt}?
           |  +--ro association-list*
           |  |       [type id source global-source extended-id]
           |  |       {association}?
           |  |  +--...
           |  +--ro lsp* [plsp-id pcc-id lsp-id]



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           |     +--...
           +--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,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
          +--...

5.2.  The Entity

   The PCEP yang module may contain status information for the local
   PCEP entity.

   The entity has an IP address (using ietf-inet-types [RFC6991]) and a
   "role" leaf (the local entity PCEP role) as mandatory.

   Note that, the PCEP MIB module [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.

   The various information related to this entity such as its domain,
   capabilities etc.  When the entity is PCE it could also have path-key
   and the LSP-DB information.




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   module: ietf-pcep
     +--rw pcep!
        +--rw entity
           +--rw addr                          inet:ip-address-no-zone
           +--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 domains
           |  +--rw domains* [domain-type domain-info]
           |     +--rw domain-type    identityref
           |     +--rw domain-info    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 neighbour-domains
           |  |  +--rw domains* [domain-type domain-info]
           |  |     +--rw domain-type    identityref
           |  |     +--rw domain-info    domain
           |  +--rw path-key {path-key}?
           |     +--rw enabled?         boolean
           |     +--rw discard-timer?   uint32
           |     +--rw reuse-time?      uint32
           |     +--rw pce-id?          inet:ip-address-no-zone
           +--rw connect-timer?                uint16
           +--rw connect-max-retry?            uint32
           +--rw init-back-off-timer?          uint16
           +--rw max-back-off-timer?           uint32
           +--ro open-wait-timer?              uint16



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           +--ro keep-wait-timer?              uint16
           +--rw keepalive-timer?              uint8
           +--rw dead-timer?                   uint8
           +--rw allow-negotiation?            boolean
           +--rw max-keepalive-timer?          uint8
           +--rw max-dead-timer?               uint8
           +--rw min-keepalive-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-no-zone
           |  |  +--ro global-source    uint32
           |  |  +--ro extended-id      string
           |  |  +--ro lsp* [plsp-id pcc-id lsp-id]
           |  |     +--ro plsp-id    -> /pcep/entity/lsp-db/lsp/plsp-id
           |  |     +--ro pcc-id     -> /pcep/entity/lsp-db/lsp/pcc-id
           |  |     +--ro lsp-id     -> /pcep/entity/lsp-db/lsp/lsp-id
           |  +--ro lsp* [plsp-id pcc-id lsp-id]
           |     +--ro plsp-id               uint32
           |     +--ro pcc-id                inet:ip-address-no-zone
           |     +--ro source?               inet:ip-address-no-zone
           |     +--ro destination?          inet:ip-address-no-zone
           |     +--ro tunnel-id?            uint16
           |     +--ro lsp-id                uint16
           |     +--ro extended-tunnel-id?   inet:ip-address-no-zone
           |     +--ro admin-state?          boolean
           |     +--ro operational-state?    operational-state
           |     +--ro delegated
           |     |  +--ro enabled?   boolean
           |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr



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           |     |  +--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



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           |     +--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]
                 +--...


5.3.  The Peer Lists

   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.

   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.

   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.

   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.

   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.

   module: ietf-pcep
     +--rw pcep!
        +--rw entity
           +--...
           +--rw peers
              +--rw peer* [addr]
                 +--rw addr                    inet:ip-address-no-zone
                 +--rw role                    pcep-role
                 +--rw description?            string



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                 +--rw domains
                 |  +--rw domains* [domain-type domain-info]
                 |     +--rw domain-type    identityref
                 |     +--rw domain-info    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 neighbour-domains
                 |     +--rw domains* [domain-type domain-info]
                 |        +--rw domain-type    identityref
                 |        +--rw domain-info    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}?



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                 |        +--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]
                       +--...

5.4.  The Session Lists

   The session list contains PCEP sessions 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.

   Although [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.  When one
   of these sessions reaches the active state, then the other is
   discarded.

   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.














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   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 overloaded-timestamp?        yang:timestamp
                       +--ro overload-time?               uint32
                       +--ro peer-overloaded?             boolean
                       +--ro peer-overloaded-timestamp?   yang:timestamp
                       +--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}?






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5.5.  Notifications

   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 [RFC7420] notifications.

     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 overloaded-timestamp?   yang:timestamp
       |  +--ro overload-time?          uint32
       +---n pcep-session-local-overload-clear
       |  +--ro peer-addr?
       |  |       -> /pcep/entity/peers/peer/addr
       |  +--ro overloaded?                   boolean
       |  +--ro overloaded-clear-timestamp?   yang:timestamp
       +---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-overloaded-timestamp?   yang:timestamp
       |  +--ro peer-overload-time?          uint32
       +---n pcep-session-peer-overload-clear
          +--ro peer-addr?
          |       -> /pcep/entity/peers/peer/addr
          +--ro peer-overloaded?                   boolean
          +--ro peer-overloaded-clear-timestamp?   yang:timestamp

5.6.  RPC

   This YANG model defines a RPC to trigger state resynchronization to a
   particular PCEP peer.



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

6.  The Design of PCEP Statistics Data Model

   The module, "ietf-pcep-stats", augments the ietf-pcep module to
   include statistics at the PCEP peer and session level.  It includes a
   RPC to reset statistics.

   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 discontinuity-time?         yang:timestamp
          +--ro rsp-time-avg?               uint32
          +--ro rsp-time-lwm?               uint32
          +--ro rsp-time-hwm?               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



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          +--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 discontinuity-time?         yang:timestamp
          +--ro rsp-time-avg?               uint32
          +--ro rsp-time-lwm?               uint32
          +--ro rsp-time-hwm?               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



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          +--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



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             +--ro num-dup-path-key?          yang:counter32
             +--ro num-path-key-no-attempt?   yang:counter32

     rpcs:
       +---x statistics-reset
          +---w input
             +---w (peer-or-all)?
                +--:(peer)
                |  +---w peer-addr?
                |          -> /pcep:pcep/entity/peers/peer/addr
                +--:(all)

7.  Advanced PCE Features

   This document contains a specification of the base PCEP YANG module,
   "ietf-pcep" which provides the basic PCEP [RFC5440] data model.

   This document further handles advanced PCE features like -

   *  Capability and Scope

   *  Domain information (local/neighbour)

   *  Path-Key

   *  Objective Function (OF)

   *  Global Concurrent Optimization (GCO)

   *  P2MP

   *  GMPLS

   *  Inter-Layer

   *  Stateful PCE

   *  Segment Routing (SR)

   *  Authentication including PCEPS (TLS)

7.1.  Stateful PCE's LSP-DB

   In the operational datastore of stateful PCE, the list of LSP state
   are maintained in the LSP-DB.  The key is the PLSP-ID and the PCC's
   IP address.





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   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
   [I-D.ietf-teas-yang-te].  A reference to LSP state in TE model is
   maintained.

8.  Other Considerations

8.1.  PCEP over TLS (PCEPS)

   [RFC8253] describe the use of TLS v1.2 [RFC5246] or later 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
   sends the TLS ClientHello message to begin the TLS handshake.  The
   TLS server sends a CertificateRequest in order to request a
   certificate from the TLS client.  Once the TLS handshake has
   finished, the client and the server 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.

   Note that, a PCEP speaker could act as both a client (PCC) and a
   server (PCE).  The role within the context of a PCEP session is
   determined by the relationship it has with its peer (the same holds
   good for TLS as well).

9.  PCEP YANG Modules

9.1.  ietf-pcep module

   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).

   <CODE BEGINS> file "ietf-pcep@2022-01-25.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";
     }



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     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-te-types {
       prefix te-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering";
     }
     import ietf-key-chain {
       prefix key-chain;
       reference
         "RFC 8177: YANG Data Model for Key Chains";
     }
     import ietf-netconf-acm {
       prefix nacm;
       reference
         "RFC 8341: Network Configuration Protocol (NETCONF) Access
          Control Model";
     }
     import ietf-tls-server {
       prefix tlss;
       reference
         "I-D.ietf-netconf-tls-client-server: YANG Groupings for TLS
          Clients and TLS Servers";
     }
     import ietf-tls-client {
       prefix tlsc;
       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



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       "WG Web:  <https://datatracker.ietf.org/wg/pce/about/>
        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.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
        NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
        'MAY', and 'OPTIONAL' in this document are to be interpreted as
        described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.

        Copyright (c) 2022 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

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

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

     revision 2022-01-25 {
       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;



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           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).
          - pcc-and-pce(3): the role is of both a PCC and
           a PCE.";
       reference
         "RFC 5440: Path Computation Element (PCE) Communication
          Protocol (PCEP)";
     }

     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 {



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           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.



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          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 TCPPending state of PCEP session.";
         }
         enum open-wait {
           value 2;
           description
             "The OpenWait state of PCEP session.";
         }
         enum keep-wait {
           value 3;
           description
             "The KeepWait state of PCEP session.";
         }
         enum session-up {
           value 4;
           description
             "The SessionUP 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 TCPPending state
          - open-wait(2): PCEP OpenWait state
          - keep-wait(3): PCEP KeepWait state
          - session-up(4): PCEP SessionUP state";
       reference
         "RFC 5440: Path Computation Element (PCE) Communication
          Protocol (PCEP)";
     }

     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";



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     }

     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



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              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
      */




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

     feature gmpls {
       description
         "Support GMPLS.";
       reference
         "RFC 8779: 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 Global Concurrent Optimization (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 Point-to-Multipoint (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";



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     }

     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 state synchronization 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 (SR) for PCE.";
       reference
         "RFC 8664: Path Computation Element Communication Protocol
          (PCEP) Extensions for Segment Routing";
     }

     feature association {
       description



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         "Support Association in PCEP.";
       reference
         "RFC 8697: Path Computation Element Communication Protocol
          (PCEP) Extensions for Establishing Relationships between
          Sets of Label Switched Paths (LSPs)";
     }

     /*
      * Identities
      */

     identity domain-type {
       description
         "Base Domain Type for PCE";
     }

     identity ospf-area {
       base domain-type;
       description
         "The OSPF area.";
     }

     identity isis-area {
       base domain-type;
       description
         "The IS-IS area.";
     }

     identity autonomous-system {
       base domain-type;
       description
         "The Autonomous System (AS).";
     }

     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 {
       if-feature "stateful";
       base lsp-error;
       description
         "No error, LSP is fine.";



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       reference
         "RFC 8231: Path Computation Element Communication Protocol
          (PCEP) Extensions for Stateful PCE";
     }

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

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

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

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

     identity internal-lsp-error {
       if-feature "stateful";
       base lsp-error;



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       description
         "Internal error.";
       reference
         "RFC 8231: Path Computation Element Communication Protocol
          (PCEP) Extensions for Stateful PCE";
     }

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

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

     identity rsvp-lsp-error {
       if-feature "stateful";
       base lsp-error;
       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



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         "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 (L bit).";
           }
           bit inter-area-scope {
             description
               "PCE can compute inter-area paths (R bit).";
           }
           bit inter-area-scope-default {
             description
               "PCE can act as a default PCE for inter-area
                path computation. (Rd bit)";
           }
           bit inter-as-scope {
             description
               "PCE can compute inter-AS paths (S bit).";
           }
           bit inter-as-scope-default {
             description
               "PCE can act as a default PCE for inter-AS
                path computation (Sd bit).";
           }
           bit inter-layer-scope {
             description
               "PCE can compute inter-layer paths (Y bit).";
           }
         }
         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 (PrefL field). Where 7 reflects
            the highest preference.";
       }
       leaf inter-area-pref {
         type uint8 {
           range "0..7";



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         }
         description
           "The PCE's preference for inter-area TE LSP
            computation (PrefR field). Where 7 reflects
            the highest preference.";
       }
       leaf inter-as-pref {
         type uint8 {
           range "0..7";
         }
         description
           "The PCE's preference for inter-AS TE LSP
            computation (PrefS field). Where 7 reflects
            the highest preference.";
       }
       leaf inter-layer-pref {
         type uint8 {
           range "0..7";
         }
         description
           "The PCE's preference for inter-layer TE LSP
            computation (PrefY field). Where 7 reflects
            the highest preference.";
       }
     }

     //pce-scope

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

     //domain




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     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 domains {
         description
           "The local domain for the PCEP entity";
         list domains {
           key "domain-type domain-info";
           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
           "IANA OSPF: Path Computation Element (PCE) Capability
            Flags in Open Shortest Path First v2 (OSPFv2)
            Parameters
            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.";



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             }
             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.";



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             }
             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
             "IANA OSPF: Path Computation Element (PCE) Capability
              Flags in Open Shortest Path First v2 (OSPFv2)
              Parameters
              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



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             "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
             "RFC 8664: Path Computation Element Communication Protocol
              (PCEP) Extensions for Segment Routing";
           leaf enabled {
             type boolean;
             description
               "Set to true if SR is enabled";
           }



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           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 Node or
                Adjacency Identifier (NAI) to Segment
                Identifier (SID)";
           }
         }
         //sr
       }
       //capability
       leaf msd {
         if-feature "sr";
         type uint8;
         description
           "Maximum SID Depth for SR";
         reference
           "RFC 8664: Path Computation Element Communication Protocol
            (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 neighbour-domains {
         description
           "The list of neighbour PCE-Domain
            toward which a PCE can compute
            paths";



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         list domains {
           key "domain-type domain-info";
           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 Objective Functions (OF)";



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       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-no-zone;
           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; set to true when UP.";



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         }
         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";
         }



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         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; set to true when Enabled";
             }
             leaf discard-timer {



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               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-no-zone;
               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)";
         }



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         leaf init-back-off-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 the
              max-back-off-timer leaf.";
           reference
             "RFC 5440: Path Computation Element (PCE) Communication
              Protocol (PCEP)";
         }
         leaf max-back-off-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;
           units "seconds";
           config false;
           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;
           units "seconds";



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           config false;
           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 keepalive-timer {
           type uint8;
           units "seconds";
           default "30";
           description
             "The Keepalive 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 '(. > ../keepalive-timer)' {
             error-message "The DeadTimer must be "
                         + "larger than the Keepalive timer";
           }
           default "120";
           description
             "The DeadTimer 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 DeadTimer at all.";



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           reference
             "RFC 5440: Path Computation Element (PCE) Communication
              Protocol (PCEP)";
         }
         leaf allow-negotiation {
           type boolean;
           default "true";
           description
             "Whether the PCEP entity will permit negotiation of
              session parameters.";
         }
         leaf max-keepalive-timer {
           type uint8;
           units "seconds";
           description
             "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
             "The maximum value in seconds, that this PCEP
              entity will accept from a peer for the DeadTimer.
              Zero means that the PCEP entity will allow not
              running a DeadTimer.";
         }
         leaf min-keepalive-timer {
           type uint8;
           units "seconds";
           description
             "The minimum value in seconds, 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
             "The minimum value in seconds, that this PCEP
              entity will accept for the DeadTimer. Zero
              means that the PCEP entity insists on not
              running a DeadTimer.";



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         }
         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



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              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



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                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";



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           }
           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
               "RFC 8697: Path Computation Element Communication
                Protocol (PCEP) Extensions for Establishing
                Relationships between Sets of Label Switched
                Paths (LSPs)";
             leaf type {
               type identityref {
                 base te-types:association-type;
               }
               description
                 "The PCEP Association Type";
               reference
                 "IANA PCEP: ASSOCIATION Type Field in Path
                  Computation Element Protocol (PCEP) Numbers";
             }
             leaf id {
               type uint16;
               description
                 "PCEP Association ID";



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             }
             leaf source {
               type inet:ip-address-no-zone;
               description
                 "PCEP Association Source.";
             }
             leaf global-source {
               type uint32;
               description
                 "PCEP Global Association Source.";
             }
             leaf extended-id {
               type string;
               description
                 "Additional information to support unique
                  identification (Extended Association ID).";
             }
             list lsp {
               key "plsp-id pcc-id lsp-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";
               }
               leaf lsp-id {
                 type leafref {
                   path "/pcep/entity/lsp-db/"
                      + "lsp/lsp-id";
                 }
                 description
                   "Reference to LSP ID in LSP-DB";
               }
             }
           }
           list lsp {



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             key "plsp-id pcc-id lsp-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-no-zone;
               description
                 "The local internet address of the PCC, that
                  generated the PLSP-ID.";
             }
             leaf source {
               type inet:ip-address-no-zone;
               description
                 "Tunnel sender address extracted from
                  LSP-IDENTIFIERS TLV";
               reference
                 "RFC 8231: Path Computation Element
                  Communication Protocol (PCEP) Extensions
                  for Stateful PCE";
             }
             leaf destination {
               type inet:ip-address-no-zone;
               description
                 "Tunnel endpoint address extracted from
                  LSP-IDENTIFIERS TLV";
               reference
                 "RFC 8231: Path Computation Element
                  Communication Protocol (PCEP) Extensions
                  for Stateful PCE";
             }
             leaf tunnel-id {
               type uint16;
               description
                 "Tunnel identifier used in the LSP-IDENTIFIERS
                  TLV that remains constant over the life
                  of the tunnel.";
               reference
                 "RFC 8231: Path Computation Element



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                  Communication Protocol (PCEP) Extensions
                  for Stateful PCE";
             }
             leaf lsp-id {
               type uint16;
               description
                 "Identifier used in the LSP-IDENTIFIERS TLV
                  that can be changed to allow a sender to share
                  resources with itself.";
               reference
                 "RFC 8231: Path Computation Element
                  Communication Protocol (PCEP) Extensions
                  for Stateful PCE";
             }
             leaf extended-tunnel-id {
               type inet:ip-address-no-zone;
               description
                 "Extended Tunnel ID of the LSP in LSP-IDENTIFIERS
                  TLV.";
               reference
                 "RFC 8231: Path Computation Element
                  Communication Protocol (PCEP) Extensions
                  for Stateful PCE";
             }
             leaf admin-state {
               type boolean;
               default "true";
               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;
                 default "false";
                 description
                   "LSP is delegated or not; set to true when
                    delegated";
               }
               leaf peer {
                 type leafref {
                   path "/pcep/entity/peers/peer/addr";



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                 }
                 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 {
                   range "1..4294967294";
                 }
                 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;
                 default "false";
                 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 {



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               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 (PST)";
               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 {



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                   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
                 "RFC 8697: Path Computation Element Communication
                  Protocol (PCEP) Extensions for Establishing
                  Relationships between Sets of Label Switched
                  Paths (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



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               "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 retrieved";
               }



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               description
                 "Reference to PCC peer address which
                  retrieved 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-no-zone;
               description
                 "The local Internet address of this
                  PCEP peer.";
             }
             leaf role {
               type pcep-role;
               must '(. != "pcc-and-pce")' {
                 error-message
                   "The PCEP peer cannot be both
                    PCE and PCC at the same time";
               }



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               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): is not allowed as PCEP
                  peer cannot be acting as both a PCC and a
                  PCE at the sametime.";
             }
             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;



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                     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 {
                         nacm:default-deny-all;
                         type string;
                         description
                           "Key string in ASCII format.";
                       }
                     }
                     case hexadecimal {
                       if-feature "key-chain:hex-key-string";
                       leaf hexadecimal-string {
                         nacm: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 {



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                       container tls-server {
                         uses tlss:tls-server-grouping {
                           description
                             "Server TLS information.";
                         }
                         description
                           "TLS related information";
                       }
                     }
                     case client {
                       container tls-client {
                         uses tlsc: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;



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               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



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                      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



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                      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 TCPPending or OpenWait 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.";



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                   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 DeadTimer 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)))" {



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                     error-message "Invalid Peer DeadTimer";
                     description
                       "If state is TCPPending or OpenWait then this
                        leaf is not used and MUST be set to zero.";
                   }
                   description
                     "The peer's DeadTimer 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 TCPPending or OpenWait then this
                        field is not used and MUST be set to zero.";
                   }
                   description
                     "The Keepalive 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 overloaded-timestamp {
                   when '(../overloaded = true())' {
                     description
                       "Valid when overloaded";



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                   }
                   type yang:timestamp;
                   description
                     "The timestamp value of the time when the
                      overloaded field was set to true.";
                 }
                 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-overloaded-timestamp {
                   when '(../peer-overloaded = true())' {
                     description
                       "Valid when Peer is overloaded";
                   }
                   type yang:timestamp;
                   description
                     "The timestamp value of the time when the
                      peer-overloaded field was set to true.";
                 }
                 leaf peer-overload-time {
                   type uint32;



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                   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";



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                 }
                 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 PST";
                     leaf pst {
                       type identityref {
                         base te-types:path-signaling-type;
                       }
                       description
                         "The PST supported";
                     }
                   }
                 }
                 container assoc-type-list {
                   if-feature "association";



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                   description
                     "Indicate the list of supported association types
                      on this session";
                   reference
                     "RFC 8697: Path Computation Element Communication
                      Protocol (PCEP) Extensions for Establishing
                      Relationships between Sets of Label Switched
                      Paths (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";
                 }
               }
               // session
             }
             // sessions
           }
           //peer
         }
         //peers
       }
       //entity
     }

     //pcep
     /*
      * Notifications
      */




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     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;



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         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 overloaded-timestamp {
         type yang:timestamp;
         description
           "The timestamp value of the time when the
            overloaded field was set to true.";
       }
       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



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         "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.";
       }
       leaf overloaded-clear-timestamp {
         type yang:timestamp;
         description
           "The timestamp value of the time when the
            overloaded field was 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-overloaded-timestamp {
         type yang:timestamp;
         description
           "The timestamp value of the time when the
            peer-overloaded field was set to true.";
       }
       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



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            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.";
       }
       leaf peer-overloaded-clear-timestamp {
         type yang:timestamp;
         description
           "The timestamp value of the time when the
            peer-overloaded field was 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 resynchronization at the PCE";
       reference
         "RFC 8232: Optimizations of Label Switched Path State
          Synchronization Procedures for a Stateful PCE";
       input {
         leaf pcc {



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           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>

9.2.  ietf-pcep-stats module

   <CODE BEGINS> file "ietf-pcep-stats@2022-01-25.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://datatracker.ietf.org/wg/pce/about/>
        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) 2022 IETF Trust and the persons identified as



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        authors of the code.  All rights reserved.

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

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

     revision 2022-01-25 {
       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 discontinuity-time {
         type yang:timestamp;
         description
           "The timestamp value of the time when the
            statistics were last reset.";
       }
       leaf rsp-time-avg {
         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.";
       }



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       leaf rsp-time-lwm {
         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 rsp-time-hwm {
         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



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           "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.";



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       }
       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



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             "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



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           "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.";
       }



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       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;



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         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



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            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'"



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              + "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;



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           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;



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           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.



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              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 {



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           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";
             }



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             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.";
         }



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         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 {



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           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



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              that peer. These are lost when the session goes down.";
         }
       }
     }

     //augment

     rpc statistics-reset {
       description
         "Reset statistics collected.";
       input {
         choice peer-or-all {
           description
             "Resets statistics for a particular peer or
              all";
           case peer {
             leaf peer-addr {
               type leafref {
                 path "/pcep:pcep/pcep:entity/pcep:peers"
                    + "/pcep:peer/pcep:addr";
               }
               description
                 "Reference to peer address";
             }
             description
               "This resets all the statistics collected for
                the peer.";
           }
           case all {
             description
               "This resets all the statistics collected.";
           }
         }
       }
     }
   }
   <CODE ENDS>

10.  Security Considerations

   The YANG modules defined in this document is designed to be accessed
   via network management protocol such as NETCONF [RFC6241] or RESTCONF
   [RFC8040].  The lowest NETCONF layer is the secure transport layer
   and the mandatory-to-implement secure transport is SSH [RFC6242].
   The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement
   secure transport is TLS [RFC8446]





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   The NETCONF access control model [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.

   There are a number of data nodes defined in the ietf-pcep 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.,
   <edit-config>) to these data nodes without proper protection can have
   a negative effect on network operations.  These are the subtrees and
   data nodes and their sensitivity/vulnerability:

      /pcep/entity/ - configure local parameters, capabilities etc.

      /pcep/entity/peers - configure remote peers to setup PCEP session.

   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.

   Some of the readable data nodes in the ietf-pcep 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:

      /pcep/lsp-db - All the LSPs in the network.  Unauthorized access
      to this could provide the all path and network usage information.

      /pcep/path-keys/ - The Confidential Path Segments (CPS) are hidden
      using path-keys.  Unauthorized access to this could leak
      confidential path information.

   Some of the RPC operations in the ietf-pcep 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:

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








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   The actual authentication key data (whether locally specified or part
   of a key-chain) is sensitive and needs to be kept secret from
   unauthorized parties; compromise of the key data would allow an
   attacker to forge PCEP traffic that would be accepted as authentic,
   potentially compromising the TE domain.

   The model describes several notifications, implementations must rate-
   limit the generation of these notifications to avoid creating
   significant notification load.  Otherwise, this notification load may
   have some side effects on the system stability and may be exploited
   as an attack vector.

   Further, this document also include another YANG module (called ietf-
   pcep-stats) for maintaining the statistics by augmenting the ietf-
   pcep YANG module.  There are no data nodes defined in this module
   which are writable/creatable/deletable (i.e., config true).  The
   readable data nodes in this YANG module may be considered sensitive
   or vulnerable in some network environments.  The statistics could
   provide information related to the current usage patterns of the
   network.  It is thus important to control read access (e.g., via get,
   get-config, or notification).

   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:

      statistics-reset - The RPC is used to reset statistics.
      Unauthorized reset could impact monitoring.

11.  IANA Considerations

   This document request the IANA to register two URIs in the "IETF XML
   Registry" [RFC3688].  Following the format in RFC 3688, the following
   registrations are requested -

         URI:                urn:ietf:params:xml:ns:yang:ietf-pcep
         Registrant Contact: The IESG
         XML:                N/A; the requested URI is an XML namespace.

         URI:                urn:ietf:params:xml:ns:yang:ietf-pcep-stats
         Registrant Contact: The IESG
         XML:                N/A; the requested URI is an XML namespace.

   This document request the IANA to register two YANG modules in the
   "YANG Module Names" registry [RFC6020], as follows -





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       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]


12.  Implementation Status

   [Note to the RFC Editor - remove this section before publication, as
   well as remove the reference to RFC 7942.]

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in [RFC7942].
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   According to [RFC7942], "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.
   It is up to the individual working groups to use this information as
   they see fit".

   Currently, there are no known implementations of the YANG Module as
   specified.

13.  Acknowledgements

   The initial document is based on the PCEP MIB [RFC7420].  We would
   like to thank the authors of aforementioned documents.

   Thanks to Mahesh Jethmalani for the Yang Doctor review.

   Thanks to Martin Bjorklund and Tom Petch for providing guidance
   regarding the Yang guidelines.



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14.  References

14.1.  Normative References

   [I-D.ietf-isis-yang-isis-cfg]
              Litkowski, S., Yeung, D., Lindem, A., Zhang, J., and L.
              Lhotka, "YANG Data Model for IS-IS Protocol", Work in
              Progress, Internet-Draft, draft-ietf-isis-yang-isis-cfg-
              42, 15 October 2019, <https://www.ietf.org/archive/id/
              draft-ietf-isis-yang-isis-cfg-42.txt>.

   [I-D.ietf-netconf-tls-client-server]
              Watsen, K., "YANG Groupings for TLS Clients and TLS
              Servers", Work in Progress, Internet-Draft, draft-ietf-
              netconf-tls-client-server-26, 14 December 2021,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-tls-
              client-server-26.txt>.

   [I-D.ietf-ospf-yang]
              Yeung, D., Qu, Y., Zhang, J., Chen, I., and A. Lindem,
              "YANG Data Model for OSPF Protocol", Work in Progress,
              Internet-Draft, draft-ietf-ospf-yang-29, 17 October 2019,
              <https://www.ietf.org/archive/id/draft-ietf-ospf-yang-
              29.txt>.

   [I-D.ietf-teas-yang-te]
              Saad, T., Gandhi, R., Liu, X., Beeram, V. P., Bryskin, I.,
              and O. G. D. Dios, "A YANG Data Model for Traffic
              Engineering Tunnels, Label Switched Paths and Interfaces",
              Work in Progress, Internet-Draft, draft-ietf-teas-yang-te-
              28, 25 October 2021, <https://www.ietf.org/archive/id/
              draft-ietf-teas-yang-te-28.txt>.

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

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

   [RFC5088]  Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
              Zhang, "OSPF Protocol Extensions for Path Computation
              Element (PCE) Discovery", RFC 5088, DOI 10.17487/RFC5088,
              January 2008, <https://www.rfc-editor.org/info/rfc5088>.





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   [RFC5089]  Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
              Zhang, "IS-IS Protocol Extensions for Path Computation
              Element (PCE) Discovery", RFC 5089, DOI 10.17487/RFC5089,
              January 2008, <https://www.rfc-editor.org/info/rfc5089>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC5520]  Bradford, R., Ed., Vasseur, JP., and A. Farrel,
              "Preserving Topology Confidentiality in Inter-Domain Path
              Computation Using a Path-Key-Based Mechanism", RFC 5520,
              DOI 10.17487/RFC5520, April 2009,
              <https://www.rfc-editor.org/info/rfc5520>.

   [RFC5541]  Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of
              Objective Functions in the Path Computation Element
              Communication Protocol (PCEP)", RFC 5541,
              DOI 10.17487/RFC5541, June 2009,
              <https://www.rfc-editor.org/info/rfc5541>.

   [RFC5557]  Lee, Y., Le Roux, JL., King, D., and E. Oki, "Path
              Computation Element Communication Protocol (PCEP)
              Requirements and Protocol Extensions in Support of Global
              Concurrent Optimization", RFC 5557, DOI 10.17487/RFC5557,
              July 2009, <https://www.rfc-editor.org/info/rfc5557>.

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

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

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

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






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

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

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

   [RFC8177]  Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J.
              Zhang, "YANG Data Model for Key Chains", RFC 8177,
              DOI 10.17487/RFC8177, June 2017,
              <https://www.rfc-editor.org/info/rfc8177>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

   [RFC8232]  Crabbe, E., Minei, I., Medved, J., Varga, R., Zhang, X.,
              and D. Dhody, "Optimizations of Label Switched Path State
              Synchronization Procedures for a Stateful PCE", RFC 8232,
              DOI 10.17487/RFC8232, September 2017,
              <https://www.rfc-editor.org/info/rfc8232>.

   [RFC8253]  Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
              "PCEPS: Usage of TLS to Provide a Secure Transport for the
              Path Computation Element Communication Protocol (PCEP)",
              RFC 8253, DOI 10.17487/RFC8253, October 2017,
              <https://www.rfc-editor.org/info/rfc8253>.

   [RFC8281]  Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for PCE-Initiated LSP Setup in a Stateful PCE
              Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
              <https://www.rfc-editor.org/info/rfc8281>.

   [RFC8306]  Zhao, Q., Dhody, D., Ed., Palleti, R., and D. King,
              "Extensions to the Path Computation Element Communication
              Protocol (PCEP) for Point-to-Multipoint Traffic
              Engineering Label Switched Paths", RFC 8306,
              DOI 10.17487/RFC8306, November 2017,
              <https://www.rfc-editor.org/info/rfc8306>.




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

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

   [RFC8408]  Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J.
              Hardwick, "Conveying Path Setup Type in PCE Communication
              Protocol (PCEP) Messages", RFC 8408, DOI 10.17487/RFC8408,
              July 2018, <https://www.rfc-editor.org/info/rfc8408>.

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

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC8697]  Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
              Dhody, D., and Y. Tanaka, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Establishing
              Relationships between Sets of Label Switched Paths
              (LSPs)", RFC 8697, DOI 10.17487/RFC8697, January 2020,
              <https://www.rfc-editor.org/info/rfc8697>.

   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

   [RFC8779]  Margaria, C., Ed., Gonzalez de Dios, O., Ed., and F.
              Zhang, Ed., "Path Computation Element Communication
              Protocol (PCEP) Extensions for GMPLS", RFC 8779,
              DOI 10.17487/RFC8779, July 2020,
              <https://www.rfc-editor.org/info/rfc8779>.

14.2.  Informative References








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   [IANA-OSPF]
              "Path Computation Element (PCE) Capability Flags in Open
              Shortest Path First v2 (OSPFv2) Parameters",
              <https://www.iana.org/assignments/ospfv2-parameters/
              ospfv2-parameters.xhtml#ospfv2-parameters-14>.

   [IANA-PCEP]
              "ASSOCIATION Type Field in Path Computation Element
              Protocol (PCEP) Numbers",
              <https://www.iana.org/assignments/pcep/
              pcep.xhtml#association-type-field>.

   [RFC4655]  Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
              Computation Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <https://www.rfc-editor.org/info/rfc4655>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC7420]  Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
              Hardwick, "Path Computation Element Communication Protocol
              (PCEP) Management Information Base (MIB) Module",
              RFC 7420, DOI 10.17487/RFC7420, December 2014,
              <https://www.rfc-editor.org/info/rfc7420>.

   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,
              <https://www.rfc-editor.org/info/rfc7942>.

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

Appendix A.  The Full PCEP Data Model

   The module, "ietf-pcep", defines the basic components of a PCE
   speaker.  The tree depth in the tree is set to 10.









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   module: ietf-pcep
     +--rw pcep!
        +--rw entity
           +--rw addr                          inet:ip-address-no-zone
           +--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 domains
           |  +--rw domains* [domain-type domain-info]
           |     +--rw domain-type    identityref
           |     +--rw domain-info    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 neighbour-domains
           |  |  +--rw domains* [domain-type domain-info]
           |  |     +--rw domain-type    identityref
           |  |     +--rw domain-info    domain
           |  +--rw path-key {path-key}?
           |     +--rw enabled?         boolean
           |     +--rw discard-timer?   uint32
           |     +--rw reuse-time?      uint32
           |     +--rw pce-id?          inet:ip-address-no-zone
           +--rw connect-timer?                uint16
           +--rw connect-max-retry?            uint32
           +--rw init-back-off-timer?          uint16
           +--rw max-back-off-timer?           uint32
           +--ro open-wait-timer?              uint16



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           +--ro keep-wait-timer?              uint16
           +--rw keepalive-timer?              uint8
           +--rw dead-timer?                   uint8
           +--rw allow-negotiation?            boolean
           +--rw max-keepalive-timer?          uint8
           +--rw max-dead-timer?               uint8
           +--rw min-keepalive-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-no-zone
           |  |  +--ro global-source    uint32
           |  |  +--ro extended-id      string
           |  |  +--ro lsp* [plsp-id pcc-id lsp-id]
           |  |     +--ro plsp-id    -> /pcep/entity/lsp-db/lsp/plsp-id
           |  |     +--ro pcc-id     -> /pcep/entity/lsp-db/lsp/pcc-id
           |  |     +--ro lsp-id     -> /pcep/entity/lsp-db/lsp/lsp-id
           |  +--ro lsp* [plsp-id pcc-id lsp-id]
           |     +--ro plsp-id               uint32
           |     +--ro pcc-id                inet:ip-address-no-zone
           |     +--ro source?               inet:ip-address-no-zone
           |     +--ro destination?          inet:ip-address-no-zone
           |     +--ro tunnel-id?            uint16
           |     +--ro lsp-id                uint16
           |     +--ro extended-tunnel-id?   inet:ip-address-no-zone
           |     +--ro admin-state?          boolean
           |     +--ro operational-state?    operational-state
           |     +--ro delegated
           |     |  +--ro enabled?   boolean
           |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr



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           |     |  +--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



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           |     +--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-no-zone
                 +--rw role                    pcep-role
                 +--rw description?            string
                 +--rw domains
                 |  +--rw domains* [domain-type domain-info]
                 |     +--rw domain-type    identityref
                 |     +--rw domain-info    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 neighbour-domains
                 |     +--rw domains* [domain-type domain-info]
                 |        +--rw domain-type    identityref
                 |        +--rw domain-info    domain
                 +--rw delegation-pref?        uint8 {stateful}?
                 +--rw auth
                 |  +--rw (auth-type-selection)?
                 |     +--:(auth-key-chain)
                 |     |  +--rw key-chain?



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                 |     |          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 overloaded-timestamp?        yang:timestamp
                       +--ro overload-time?               uint32
                       +--ro peer-overloaded?             boolean
                       +--ro peer-overloaded-timestamp?   yang:timestamp
                       +--ro peer-overload-time?          uint32
                       +--ro lspdb-sync?                  sync-state



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                       |       {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}?

     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 overloaded-timestamp?   yang:timestamp
       |  +--ro overload-time?          uint32
       +---n pcep-session-local-overload-clear
       |  +--ro peer-addr?
       |  |       -> /pcep/entity/peers/peer/addr
       |  +--ro overloaded?                   boolean
       |  +--ro overloaded-clear-timestamp?   yang:timestamp
       +---n pcep-session-peer-overload
       |  +--ro peer-addr?
       |  |       -> /pcep/entity/peers/peer/addr
       |  +--ro session-initiator?



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       |  |       -> /pcep/entity/peers/peer/sessions/session/initiator
       |  +--ro peer-overloaded?             boolean
       |  +--ro peer-overloaded-timestamp?   yang:timestamp
       |  +--ro peer-overload-time?          uint32
       +---n pcep-session-peer-overload-clear
          +--ro peer-addr?
          |       -> /pcep/entity/peers/peer/addr
          +--ro peer-overloaded?                   boolean
          +--ro peer-overloaded-clear-timestamp?   yang:timestamp

Appendix B.  Example

   The example below provide an overview of PCEP peer session
   informations and LSP-DB in the Yang Module.



          +-------+                  +-------+
          |       |                  |       |
          | 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",



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           "oper-status": "oper-status-up",
           "role":"pce",
           "capability" : {
               "stateful": {
                    "enabled": true
               }
           }
           "lsp-db" : [
              "lsp" : {
                   "plsp-id": 3,
                   "pcc-id" :"192.0.2.1",
                   "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",
                   "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": [
                            {



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                                "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",
                                }
                            }



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                        ]
                    }
               }
           ]
       }
   }


Appendix C.  Contributor Addresses

   Rohit Pobbathi
   Nokia Networks
   India

   EMail: rohit.pobbathi_ashok@nokia.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
   Volta Networks

   EMail: xufeng.liu.ietf@gmail.com

   Young Lee
   Samsung

   EMail: younglee.tx@gmail.com

   Udayasree Palle

   EMail: udayasreereddy@gmail.com

   Xian Zhang
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129



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   P.R.China

   EMail: zhang.xian@huawei.com

   Avantika
   ECI Telecom
   India

   EMail: avantika.srm@gmail.com

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

   EMail: shashikanth.vh@huawei.com


Authors' Addresses

   Dhruv Dhody (editor)
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore 560066
   Karnataka
   India

   Email: dhruv.ietf@gmail.com


   Jonathan Hardwick
   Metaswitch
   100 Church Street
   Enfield
   EN2 6BQ
   United Kingdom

   Email: jonathan.hardwick@metaswitch.com


   Vishnu Pavan Beeram
   Juniper Networks
   India

   Email: vbeeram@juniper.net





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   Jeff Tantsura
   Microsoft
   United States of America

   Email: jefftant.ietf@gmail.com














































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