Internet-Draft PCE-YANG January 2022
Dhody, et al. Expires 29 July 2022 [Page]
Workgroup:
PCE Working Group
Internet-Draft:
draft-ietf-pce-pcep-yang-18
Published:
Intended Status:
Standards Track
Expires:
Authors:
D. Dhody, Ed.
Huawei Technologies
J. Hardwick
Metaswitch
V. Beeram
Juniper Networks
J. Tantsura
Microsoft

A YANG Data Model for Path Computation Element Communications Protocol (PCEP)

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.

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).
  • 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).

[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.

Table 1: Prefixes and corresponding YANG modules
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]

3.3. References in the Model

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

Table 2: References in the YANG modules
Documents Reference
OSPF Protocol Extensions for Path Computation Element (PCE) Discovery [RFC5088]
IS-IS Protocol Extensions for Path Computation Element (PCE) Discovery [RFC5089]
Path Computation Element (PCE) Communication Protocol (PCEP) [RFC5440]
Preserving Topology Confidentiality in Inter-Domain Path Computation Using a Path-Key-Based Mechanism [RFC5520]
Encoding of Objective Functions in the Path Computation Element Communication Protocol (PCEP) [RFC5541]
Path Computation Element Communication Protocol (PCEP) Requirements and Protocol Extensions in Support of Global Concurrent Optimization [RFC5557]
Common YANG Data Types [RFC6991]
YANG Data Model for Key Chains [RFC8177]
Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE [RFC8231]
Optimizations of Label Switched Path State Synchronization Procedures for a Stateful PCE [RFC8232]
PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP) [RFC8253]
Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model [RFC8281]
Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths [RFC8306]
Network Configuration Access Control Model [RFC8341]
Conveying Path Setup Type in PCE Communication Protocol (PCEP) Messages [RFC8408]
Traffic Engineering Common YANG Types [RFC8776]
A YANG Data Model for Traffic Engineering Tunnels and Interfaces [I-D.ietf-teas-yang-te]
YANG Groupings for TLS Clients and TLS Servers [I-D.ietf-netconf-tls-client-server]
PCEP Extensions for Segment Routing [RFC8664]
PCEP Extensions for Establishing Relationships Between Sets of LSPs [RFC8697]
YANG Data Model for OSPF Protocol [I-D.ietf-ospf-yang]
YANG Data Model for IS-IS Protocol [I-D.ietf-isis-yang-isis-cfg]
PCEP extensions for GMPLS [RFC8779]
ASSOCIATION Type Field in Path Computation Element Protocol (PCEP) Numbers [IANA-PCEP]
Path Computation Element (PCE) Capability Flags in Open Shortest Path First v2 (OSPFv2) Parameters [IANA-OSPF]

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.
  • 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]
        |     +--...
        +--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.

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
        +--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
        |     |  +--ro srp-id?    uint32
        |     +--ro initiation {pce-initiated}?
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     +--ro symbolic-path-name?   string
        |     +--ro last-error?           identityref
        |     +--ro pst?                  identityref
        |     +--ro association-list*
        |             [type id source global-source extended-id]
        |             {association}?
        |        +--ro type
        |        |       -> /pcep/entity/lsp-db/association-list/type
        |        +--ro id
        |        |       -> /pcep/entity/lsp-db/association-list/id
        |        +--ro source           leafref
        |        +--ro global-source    leafref
        |        +--ro extended-id      leafref
        +--ro path-keys {path-key}?
        |  +--ro path-keys* [path-key]
        |     +--ro path-key         uint16
        |     +--ro cps
        |     |  +--ro explicit-route-objects* [index]
        |     |     +--ro index                        uint32
        |     |     +--ro (type)?
        |     |        +--:(numbered-node-hop)
        |     |        |  +--ro numbered-node-hop
        |     |        |     +--ro node-id     te-node-id
        |     |        |     +--ro hop-type?   te-hop-type
        |     |        +--:(numbered-link-hop)
        |     |        |  +--ro numbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(unnumbered-link-hop)
        |     |        |  +--ro unnumbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro node-id       te-node-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(as-number)
        |     |        |  +--ro as-number-hop
        |     |        |     +--ro as-number    inet:as-number
        |     |        |     +--ro hop-type?    te-hop-type
        |     |        +--:(label)
        |     |           +--ro label-hop
        |     |              +--ro te-label
        |     |                    ...
        |     +--ro pcc-original?    -> /pcep/entity/peers/peer/addr
        |     +--ro req-id?          uint32
        |     +--ro retrieved?       boolean
        |     +--ro pcc-retrieved?   -> /pcep/entity/peers/peer/addr
        |     +--ro creation-time?   yang:timestamp
        |     +--ro discard-time?    uint32
        |     +--ro reuse-time?      uint32
        +--rw peers
           +--rw peer* [addr]
              +--...

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
              +--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}?
              |        +--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.

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}?

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.

  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
       +--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
       +--ro num-keepalive-sent?         yang:counter32
       +--ro num-keepalive-rcvd?         yang:counter32
       +--ro num-unknown-rcvd?           yang:counter32
       +--ro num-corrupt-rcvd?           yang:counter32
       +--ro num-req-sent?               yang:counter32
       +--ro num-req-sent-pend-rep?      yang:counter32
       +--ro num-req-sent-ero-rcvd?      yang:counter32
       +--ro num-req-sent-nopath-rcvd?   yang:counter32
       +--ro num-req-sent-cancel-rcvd?   yang:counter32
       +--ro num-req-sent-error-rcvd?    yang:counter32
       +--ro num-req-sent-timeout?       yang:counter32
       +--ro num-req-sent-cancel-sent?   yang:counter32
       +--ro num-req-rcvd?               yang:counter32
       +--ro num-req-rcvd-pend-rep?      yang:counter32
       +--ro num-req-rcvd-ero-sent?      yang:counter32
       +--ro num-req-rcvd-nopath-sent?   yang:counter32
       +--ro num-req-rcvd-cancel-sent?   yang:counter32
       +--ro num-req-rcvd-error-sent?    yang:counter32
       +--ro num-req-rcvd-cancel-rcvd?   yang:counter32
       +--ro num-rep-rcvd-unknown?       yang:counter32
       +--ro num-req-rcvd-unknown?       yang:counter32
       +--ro svec {pcep:svec}?
       |  +--ro num-svec-sent?       yang:counter32
       |  +--ro num-svec-req-sent?   yang:counter32
       |  +--ro num-svec-rcvd?       yang:counter32
       |  +--ro num-svec-req-rcvd?   yang:counter32
       +--ro stateful {pcep:stateful}?
       |  +--ro num-pcrpt-sent?             yang:counter32
       |  +--ro num-pcrpt-rcvd?             yang:counter32
       |  +--ro num-pcupd-sent?             yang:counter32
       |  +--ro num-pcupd-rcvd?             yang:counter32
       |  +--ro num-rpt-sent?               yang:counter32
       |  +--ro num-rpt-rcvd?               yang:counter32
       |  +--ro num-rpt-rcvd-error-sent?    yang:counter32
       |  +--ro num-upd-sent?               yang:counter32
       |  +--ro num-upd-rcvd?               yang:counter32
       |  +--ro num-upd-rcvd-unknown?       yang:counter32
       |  +--ro num-upd-rcvd-undelegated?   yang:counter32
       |  +--ro num-upd-rcvd-error-sent?    yang:counter32
       |  +--ro initiation {pcep:pce-initiated}?
       |     +--ro num-pcinitiate-sent?            yang:counter32
       |     +--ro num-pcinitiate-rcvd?            yang:counter32
       |     +--ro num-initiate-sent?              yang:counter32
       |     +--ro num-initiate-rcvd?              yang:counter32
       |     +--ro num-initiate-rcvd-error-sent?   yang:counter32
       +--ro path-key {pcep:path-key}?
          +--ro num-unknown-path-key?      yang:counter32
          +--ro num-exp-path-key?          yang:counter32
          +--ro num-dup-path-key?          yang:counter32
          +--ro num-path-key-no-attempt?   yang:counter32

  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.

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

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

  typedef pcep-sess-state {
    type enumeration {
      enum tcp-pending {
        value 1;
        description
          "The 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";
  }

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

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

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

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

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

  /*
   * Features
   */

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

  feature gmpls {
    description
      "Support GMPLS.";
    reference
      "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";
  }

  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
      "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.";
    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;
    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
      "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";
      }
      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

  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.";
          }
          bit load-balance {
            description
              "Load-balanced path computation.";
          }
          bit synchronize {
            if-feature "svec";
            description
              "Synchronized paths computation.";
          }
          bit objective-function {
            if-feature "objective-function";
            description
              "Support for multiple objective functions.";
          }
          bit add-path-constraint {
            description
              "Support for additive path constraints (max
               hop count, etc.).";
          }
          bit prioritization {
            description
              "Support for request prioritization.";
          }
          bit multi-request {
            description
              "Support for multiple requests per message.";
          }
          bit global-concurrent {
            if-feature "global-concurrent";
            description
              "Support for Global Concurrent Optimization
               (GCO).";
          }
          bit p2mp {
            if-feature "p2mp";
            description
              "Support for P2MP path computation.";
          }
          bit active {
            if-feature "stateful";
            description
              "Support for active stateful PCE.";
          }
          bit passive {
            if-feature "stateful";
            description
              "Support for passive stateful PCE.";
          }
          bit p2mp-active {
            if-feature "stateful";
            if-feature "p2mp";
            description
              "Support for active stateful PCE for P2MP.";
          }
          bit p2mp-passive {
            if-feature "stateful";
            if-feature "p2mp";
            description
              "Support for passive stateful PCE for P2MP.";
          }
          bit p2mp-pce-initiated {
            if-feature "stateful";
            if-feature "pce-initiated";
            if-feature "p2mp";
            description
              "Support for PCE-initiated LSP for P2MP.";
          }
        }
        description
          "The bits string indicating the capabiliies";
        reference
          "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
          "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";
        }
        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";
      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)";
    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.";
      }
      leaf role {
        type pcep-role;
        mandatory true;
        description
          "The role that this entity can play.
           Takes one of the following values.
           - unknown(0): this PCEP Entity role is not
           known.
           - pcc(1): this PCEP Entity is a PCC.
           - pce(2): this PCEP Entity is a PCE.
           - pcc-and-pce(3): this PCEP Entity is both
           a PCC and a PCE.";
      }
      leaf description {
        type string;
        description
          "Description of the PCEP entity configured
           by the user";
      }
      leaf speaker-entity-id {
        if-feature "sync-opt";
        type string;
        description
          "The Speaker Entity Identifier";
        reference
          "RFC 8232: Optimizations of Label Switched
           Path State  Synchronization Procedures for
           a Stateful PCE";
      }
      leaf admin-status {
        type boolean;
        default "true";
        description
          "The administrative status of this PCEP Entity.
           The value true represents admin status as up.
           This is the desired operational status as
           currently set by an operator or by default in
           the implementation. The value of oper-status
           represents the current status of an attempt to
           reach this desired status.";
      }
      leaf index {
        type uint32;
        config false;
        description
          "The index of the operational PECP entity";
      }
      leaf oper-status {
        type pcep-oper-status;
        config false;
        description
          "The operational status of the PCEP entity.
           Takes one of the following values.
           - oper-status-up(1): the PCEP entity is active.
           - oper-status-down(2): the PCEP entity is inactive.
           - oper-status-going-up(3): the PCEP entity is
           activating.
           - oper-status-going-down(4): the PCEP entity is
           deactivating.
           - oper-status-failed(5): the PCEP entity has
           failed and will recover when possible.
           - oper-status-failed-perm(6): the PCEP entity
           has failed and will not recover without
           operator intervention.";
      }
      uses info {
        description
          "Local PCEP entity information";
      }
      container pce-info {
        when "../role = 'pce'"
           + "or "
           + "../role = 'pcc-and-pce'" {
          description
            "These fields are applicable when the role is PCE.";
        }
        description
          "The Local PCE Entity PCE information";
        uses pce-info {
          description
            "Local PCE information";
        }
        container path-key {
          if-feature "path-key";
          description
            "Path-Key Configuration";
          reference
            "RFC 5520: Preserving Topology Confidentiality in Inter-
             Domain Path Computation Using a Path-Key-Based Mechanism";
          leaf enabled {
            type boolean;
            description
              "Enabled or Disabled; set to true when Enabled";
          }
          leaf discard-timer {
            type uint32;
            units "minutes";
            default "10";
            description
              "A timer to discard unwanted path-keys";
          }
          leaf reuse-time {
            type uint32;
            units "minutes";
            default "30";
            description
              "A time after which the path-keys could be reused";
          }
          leaf pce-id {
            type inet:ip-address-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)";
      }
      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";
        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.";
        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.";
      }
      leaf sync-timer {
        if-feature "svec";
        type uint16;
        units "seconds";
        default "60";
        description
          "The value of SyncTimer in seconds is used in the
           case of synchronized path computation request
           using the SVEC object. Consider the case where a
           PCReq message is received by a PCE that contains
           the SVEC object referring to M synchronized path
           computation requests.  If after the expiration of
           the SyncTimer all the M path computation requests
           have not been, received a protocol error is
           triggered and the PCE must cancel the whole set
           of path computation requests.
           The aim of the SyncTimer is to avoid the storage
           of unused synchronized requests should one of
           them get lost for some reasons (for example, a
           misbehaving PCC).
           Zero means that the PCEP entity does not use the
           SyncTimer.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf request-timer {
        type uint16 {
          range "1..65535";
        }
        units "seconds";
        description
          "The maximum time that the PCEP entity will wait
           for a response to a PCReq message.";
      }
      leaf max-sessions {
        type uint32;
        description
          "Maximum number of sessions involving this PCEP
           entity that can exist at any time.";
      }
      leaf max-unknown-reqs {
        type uint32;
        default "5";
        description
          "The maximum number of unrecognized requests and
           replies that any session on this PCEP entity is
           willing to accept per minute before terminating
           the session.
           A PCRep message contains an unrecognized reply
           if it contains an RP object whose request ID
           does not correspond to any in-progress request
           sent by this PCEP entity.
           A PCReq message contains an unrecognized request
           if it contains an RP object whose request ID is
           zero.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf max-unknown-msgs {
        type uint32;
        default "5";
        description
          "The maximum number of unknown messages that any
           session on this PCEP entity is willing to accept
           per minute before terminating the session.";
        reference
          "RFC 5440: Path Computation Element (PCE)
           Communication Protocol (PCEP)";
      }
      leaf pcep-notification-max-rate {
        type uint32;
        mandatory true;
        description
          "This variable indicates the maximum number of
           notifications issued per second. If events
           occur more rapidly, the implementation may
           simply fail to emit these notifications during
           that period, or may queue them until an
           appropriate time. A value of 0 means no
           notifications are emitted and all should be
           discarded (that is, not queued).";
      }
      container stateful-parameter {
        if-feature "stateful";
        description
          "The configured stateful PCE parameters";
        leaf state-timeout {
          type uint32;
          units "seconds";
          description
            "When a PCEP session is terminated, a PCC
             waits for this time period before flushing
             LSP state associated with that PCEP session
             and reverting to operator-defined default
             parameters or behaviours.";
        }
        leaf redelegation-timeout {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          type uint32;
          units "seconds";
          description
            "When a PCEP session is terminated, a PCC
             waits for this time period before revoking
             LSP delegation to a PCE and attempting to
             redelegate LSPs associated with the
             terminated PCEP session to an alternate
             PCE.";
        }
        leaf rpt-non-pcep-lsp {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          type boolean;
          default "true";
          description
            "If set, a PCC reports LSPs that are not
             controlled by any PCE (for example, LSPs
             that are statically configured at the
             PCC). ";
        }
        reference
          "RFC 8231: Path Computation Element Communication Protocol
           (PCEP) Extensions for Stateful PCE";
      }
      container of-list {
        when "../role = 'pce'"
           + "or "
           + "../role = 'pcc-and-pce'" {
          description
            "These field are applicable when the role is
             PCE";
        }
        if-feature "objective-function";
        uses of-list;
        description
          "The authorized OF-List at PCE for all peers";
      }
      container lsp-db {
        if-feature "stateful";
        config false;
        description
          "The LSP-DB";
        leaf db-ver {
          when "../../role = 'pcc'"
             + "or "
             + "../../role = 'pcc-and-pce'" {
            description
              "This field is applicable when the role is
               PCC";
          }
          if-feature "sync-opt";
          type uint64;
          description
            "The LSP State Database Version Number";
        }
        list association-list {
          if-feature "association";
          key "type id source global-source extended-id";
          description
            "List of all PCEP associations";
          reference
            "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";
          }
          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 {
          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
               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";
              }
              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 {
            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 {
                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
            "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";
            }
            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";
            }
            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;
                  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 {
                    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;
            description
              "The timestamp value of the last time a
               session with this peer was successfully
               established.";
          }
          leaf session-fail-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp value of the last time a
               session with this peer failed to be
               established.";
          }
          leaf session-fail-up-time {
            type yang:timestamp;
            config false;
            description
              "The timestamp value of the last time a
               session with this peer failed from
               active.";
          }
          container sessions {
            config false;
            description
              "This entry represents a single PCEP
               session in which the local PCEP entity participates.
               This entry exists only if the corresponding PCEP
               session has been initialized by some event, such as
               manual user configuration, auto-discovery of a peer,
               or an incoming TCP connection.";
            list session {
              key "initiator";
              description
                "The list of sessions, note that for a time being
                 two sessions may exist for a peer";
              leaf initiator {
                type pcep-initiator;
                description
                  "The initiator of the session,that is, whether
                   the TCP connection was initiated by the local
                   PCEP entity or the peer.
                   There is a window during session
                   initialization where two sessions can exist
                   between a pair of PCEP speakers, each
                   initiated by one of the speakers. One of
                   these sessions is always discarded before it
                   leaves OpenWait state. However, before it is
                   discarded, two sessions to the given peer
                   appear transiently in this YANG module. The
                   sessions are distinguished by who initiated
                   them, and so this field is the key.";
              }
              leaf role {
                type leafref {
                  path "/pcep/entity/role";
                }
                description
                  "The reference to peer role .";
              }
              leaf state-last-change {
                type yang:timestamp;
                description
                  "The timestamp value at the time this
                   session entered its current state as
                   denoted by the state leaf.";
              }
              leaf state {
                type pcep-sess-state;
                description
                  "The current state of the session.
                   The set of possible states excludes the
                   idle state since entries do not exist
                   in the idle state.";
              }
              leaf session-creation {
                type yang:timestamp;
                description
                  "The timestamp value at the time this
                   session was created.";
              }
              leaf connect-retry {
                type yang:counter32;
                description
                  "The number of times that the local PCEP
                   entity has attempted to establish a TCP
                   connection for this session without
                   success. The PCEP entity gives up when
                   this reaches connect-max-retry.";
              }
              leaf local-id {
                type uint8;
                description
                  "The value of the PCEP session ID used by
                   the local PCEP entity in the Open message
                   for this session. If state is tcp-pending
                   then this is the session ID that will be
                   used in the Open message. Otherwise, this
                   is the session ID that was sent in the
                   Open message.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf remote-id {
                type uint8;
                must "((../state != 'tcp-pending'"
                   + "and "
                   + "../state != 'open-wait' )"
                   + "or "
                   + "((../state = 'tcp-pending'"
                   + " or "
                   + "../state = 'open-wait' )"
                   + "and (. = 0)))" {
                  error-message "Invalid remote-id";
                  description
                    "If state is 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.";
                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)))" {
                  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";
                }
                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;
                units "seconds";
                must '((../peer-overloaded = '
                   + 'true()) or '
                   + '((../peer-overloaded !='
                   + 'true())'
                   + ' and '
                   + '(. = 0)))' {
                  error-message "Invalid peer overload time";
                  description
                    "This field is only used if peer-overloaded
                     is set to true. Otherwise, it is not used
                     and MUST be set to zero.";
                }
                description
                  "The interval of time that is remaining until
                   the peer will cease to be overloaded.  If it
                   is not known how long the peer will stay in
                   overloaded state, this leaf is set to zero.";
                reference
                  "RFC 5440: Path Computation Element (PCE)
                   Communication Protocol (PCEP)";
              }
              leaf lspdb-sync {
                if-feature "stateful";
                type sync-state;
                description
                  "The LSP-DB state synchronization status.";
                reference
                  "RFC 8231: Path Computation Element Communication
                   Protocol (PCEP) Extensions for Stateful PCE";
              }
              leaf recv-db-ver {
                when "../role = 'pcc'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "This field is applicable when the role is
                     PCC";
                }
                if-feature "stateful";
                if-feature "sync-opt";
                type uint64;
                description
                  "The last received LSP State Database Version
                   Number";
                reference
                  "RFC 8231: Path Computation Element Communication
                   Protocol (PCEP) Extensions for Stateful PCE";
              }
              container of-list {
                when "../role = 'pce'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "These fields are applicable when the role is
                     PCE";
                }
                if-feature "objective-function";
                uses of-list;
                description
                  "Indicate the list of supported OF on this
                   session";
                reference
                  "RFC 5541: Encoding of Objective Functions in
                   the Path  Computation Element Communication
                   Protocol (PCEP)";
              }
              container pst-list {
                when "../role = 'pce'"
                   + "or "
                   + "../role = 'pcc-and-pce'" {
                  description
                    "These fields are applicable when the role is
                     PCE";
                }
                description
                  "Indicate the list of supported
                   PST on this session";
                reference
                  "RFC 8408: Conveying Path Setup Type in PCE
                   Communication Protocol (PCEP) Messages";
                list path-setup-type {
                  key "pst";
                  description
                    "The list of PST";
                  leaf pst {
                    type identityref {
                      base te-types:path-signaling-type;
                    }
                    description
                      "The PST supported";
                  }
                }
              }
              container assoc-type-list {
                if-feature "association";
                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
   */

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

  //notification

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

  //notification

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

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

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

  //augment

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

  //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]

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.

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 -

    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.

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, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <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, , <https://www.rfc-editor.org/info/rfc5088>.
[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, , <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, , <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, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <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, , <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, , <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, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8306>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <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, , <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, , <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, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8779>.

14.2. Informative References

[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, , <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, , <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, , <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, , <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, , <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.

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
        +--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
        |     |  +--ro srp-id?    uint32
        |     +--ro initiation {pce-initiated}?
        |     |  +--ro enabled?   boolean
        |     |  +--ro peer?      -> /pcep/entity/peers/peer/addr
        |     +--ro symbolic-path-name?   string
        |     +--ro last-error?           identityref
        |     +--ro pst?                  identityref
        |     +--ro association-list*
        |             [type id source global-source extended-id]
        |             {association}?
        |        +--ro type
        |        |       -> /pcep/entity/lsp-db/association-list/type
        |        +--ro id
        |        |       -> /pcep/entity/lsp-db/association-list/id
        |        +--ro source           leafref
        |        +--ro global-source    leafref
        |        +--ro extended-id      leafref
        +--ro path-keys {path-key}?
        |  +--ro path-keys* [path-key]
        |     +--ro path-key         uint16
        |     +--ro cps
        |     |  +--ro explicit-route-objects* [index]
        |     |     +--ro index                        uint32
        |     |     +--ro (type)?
        |     |        +--:(numbered-node-hop)
        |     |        |  +--ro numbered-node-hop
        |     |        |     +--ro node-id     te-node-id
        |     |        |     +--ro hop-type?   te-hop-type
        |     |        +--:(numbered-link-hop)
        |     |        |  +--ro numbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(unnumbered-link-hop)
        |     |        |  +--ro unnumbered-link-hop
        |     |        |     +--ro link-tp-id    te-tp-id
        |     |        |     +--ro node-id       te-node-id
        |     |        |     +--ro hop-type?     te-hop-type
        |     |        |     +--ro direction?    te-link-direction
        |     |        +--:(as-number)
        |     |        |  +--ro as-number-hop
        |     |        |     +--ro as-number    inet:as-number
        |     |        |     +--ro hop-type?    te-hop-type
        |     |        +--:(label)
        |     |           +--ro label-hop
        |     |              +--ro te-label
        |     |                    ...
        |     +--ro pcc-original?    -> /pcep/entity/peers/peer/addr
        |     +--ro req-id?          uint32
        |     +--ro retrieved?       boolean
        |     +--ro pcc-retrieved?   -> /pcep/entity/peers/peer/addr
        |     +--ro creation-time?   yang:timestamp
        |     +--ro discard-time?    uint32
        |     +--ro reuse-time?      uint32
        +--rw peers
           +--rw peer* [addr]
              +--rw addr                    inet:ip-address-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?
              |     |          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
                    |       {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?
    |  |       -> /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",
        "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": [
                         {
                             "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",
                             }
                         }
                     ]
                 }
            }
        ]
    }
}

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
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
Jonathan Hardwick
Metaswitch
100 Church Street
Enfield
EN2 6BQ
United Kingdom
Vishnu Pavan Beeram
Juniper Networks
India
Jeff Tantsura
Microsoft
United States of America