PCE Working Group D. Dhody, Ed.
Internet-Draft Huawei Technologies
Intended status: Standards Track J. Hardwick
Expires: January 2, 2018 Metaswitch
V. Beeram
Juniper Networks
J. Tantsura
July 01, 2017

A YANG Data Model for Path Computation Element Communications Protocol (PCEP)
draft-ietf-pce-pcep-yang-05

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 data and state data (status information and counters for the collection of statistics).

Status of This Memo

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This Internet-Draft will expire on January 2, 2018.

Copyright Notice

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Table of Contents

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). [I-D.ietf-pce-stateful-pce] specifies extensions to PCEP to enable stateful control of MPLS TE LSPs.

This document defines a YANG [RFC6020] 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 (status information and counters for the collection of statistics).

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 [I-D.ietf-netmod-revised-datastores]. 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", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

3. Terminology and Notation

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

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

Further, this document also uses the following terms defined in [I-D.ietf-pce-stateful-pce] :

[I-D.ietf-pce-pce-initiated-lsp] :

[I-D.ietf-pce-lsp-setup-type] :

[I-D.ietf-pce-segment-routing] :

3.1. Tree Diagrams

      <status> <flags> <name> <opts> <type> <if-features>

      <status> is one of:
        +  for current
        x  for deprecated
        o  for obsolete

      <flags> is one of:
        rw  for configuration data
        ro  for non-configuration data
        -x  for rpcs and actions
        -n  for notifications

      <name> is the name of the node
        (<name>) means that the node is a choice node
       :(<name>) means that the node is a case node

      If the node is augmented into the tree from another module,
      its name is printed as <prefix>:<name>.

      <opts> is one of:
        ?  for an optional leaf, choice, anydata or anyxml
        !  for a presence container
        *  for a leaf-list or list
        [<keys>] for a list's keys

      <type> is the name of the type for leafs and leaf-lists

        If the type is a leafref, the type is printed as 
        "-> TARGET", where TARGET is either the leafref path, 
        with prefixed removed if possible.

      <if-features> is the list of features this node depends on,
        printed within curly brackets and a question mark "{...}?        
        

A graphical representation of the complete data tree is presented in Section 5. The meaning of the symbols in these diagrams is as follows and as per [I-D.ietf-netmod-rfc6087bis]. Each node is printed as:

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.

Prefixes and corresponding YANG modules
Prefix YANG module Reference
yang ietf-yang-types [RFC6991]
inet ietf-inet-types [RFC6991]
te ietf-te [I-D.ietf-teas-yang-te]
te-types ietf-te-types [I-D.ietf-teas-yang-te]
key-chain ietf-key-chain [RFC8177]
nacm ietf-netconf-acm [RFC6536]
tls-server ietf-tls-server [I-D.ietf-netconf-tls-client-server]
tls-client ietf-tls-client [I-D.ietf-netconf-tls-client-server]

4. Objectives

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

5. The Design of PCEP Data Model

module: ietf-pcep
    +--rw pcep!
       +--rw entity
          +--rw addr                          inet:ip-address
          +--rw enabled?                      boolean
          +--rw role                          pcep-role
          +--rw description?                  string
          +--rw speaker-entity-id?            string
          |       {stateful-sync-opt}?
          +--rw admin-status?                 pcep-admin-status
          +--ro index?                        uint32
          +--ro oper-status?                  pcep-oper-status
          +--rw domain
          |  +--rw domain* [domain-type domain]
          |     +--rw domain-type    domain-type
          |     +--rw domain         domain
          +--rw capability
          |  +--rw gmpls?                 boolean {gmpls}?
          |  +--rw bi-dir?                boolean
          |  +--rw diverse?               boolean
          |  +--rw load-balance?          boolean
          |  +--rw synchronize?           boolean {svec}?
          |  +--rw objective-function?    boolean
          |  |       {objective-function}?
          |  +--rw add-path-constraint?   boolean
          |  +--rw prioritization?        boolean
          |  +--rw multi-request?         boolean
          |  +--rw gco?                   boolean {gco}?
          |  +--rw p2mp?                  boolean {p2mp}?
          |  +--rw stateful {stateful}?
          |  |  +--rw enabled?                boolean
          |  |  +--rw active?                 boolean
          |  |  +--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 pce-info
          |  +--rw scope
          |  |  +--rw intra-area-scope?           boolean
          |  |  +--rw intra-area-pref?            uint8
          |  |  +--rw inter-area-scope?           boolean
          |  |  +--rw inter-area-scope-default?   boolean
          |  |  +--rw inter-area-pref?            uint8
          |  |  +--rw inter-as-scope?             boolean
          |  |  +--rw inter-as-scope-default?     boolean
          |  |  +--rw inter-as-pref?              uint8
          |  |  +--rw inter-layer-scope?          boolean
          |  |  +--rw inter-layer-pref?           uint8
          |  +--rw neigh-domains
          |  |  +--rw domain* [domain-type domain]
          |  |     +--rw domain-type    domain-type
          |  |     +--rw domain         domain
          |  +--rw path-key {path-key}?
          |     +--rw enabled?         boolean
          |     +--rw discard-timer?   uint32
          |     +--rw reuse-time?      uint32
          |     +--rw pce-id?          inet:ip-address
          +--rw connect-timer?                uint32
          +--rw connect-max-retry?            uint32
          +--rw init-backoff-timer?           uint32
          +--rw max-backoff-timer?            uint32
          +--rw open-wait-timer?              uint32
          +--rw keep-wait-timer?              uint32
          +--rw keep-alive-timer?             uint32
          +--rw dead-timer?                   uint32
          +--rw allow-negotiation?            boolean
          +--rw max-keep-alive-timer?         uint32
          +--rw max-dead-timer?               uint32
          +--rw min-keep-alive-timer?         uint32
          +--rw min-dead-timer?               uint32
          +--rw sync-timer?                   uint32 {svec}?
          +--rw request-timer?                uint32
          +--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    objective-function
          +--ro lsp-db {stateful}?
          |  +--ro db-ver?             uint64
          |  |       {stateful-sync-opt}?
          |  +--ro association-list*
          |  |       [id source global-source extended-id]
          |  |  +--ro type?            assoc-type
          |  |  +--ro id               uint16
          |  |  +--ro source           inet:ip-address
          |  |  +--ro global-source    uint32
          |  |  +--ro extended-id      string
          |  |  +--ro lsp* [plsp-id pcc-id]
          |  |     +--ro plsp-id
          |  |     |       -> /pcep/entity/lsp-db/lsp/plsp-id
          |  |     +--ro pcc-id
          |  |             -> /pcep/entity/lsp-db/lsp/pcc-id
          |  +--ro lsp* [plsp-id pcc-id]
          |     +--ro plsp-id               uint32
          |     +--ro pcc-id                inet:ip-address
          |     +--ro lsp-ref
          |     |  +--ro source?
          |     |  |       -> /te:te/lsps-state/lsp/source
          |     |  +--ro destination?
          |     |  |       -> /te:te/lsps-state/lsp/destination
          |     |  +--ro tunnel-id?
          |     |  |       -> /te:te/lsps-state/lsp/tunnel-id
          |     |  +--ro lsp-id?
          |     |  |       -> /te:te/lsps-state/lsp/lsp-id
          |     |  +--ro extended-tunnel-id?   leafref
          |     +--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?           lsp-error
          |     +--ro pst?                  pst
          |     +--ro association-list*
          |             [id source global-source extended-id]
          |        +--ro id               leafref
          |        +--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 explicit-route-usage?   identityref
          |     |     +--ro index                   uint32
          |     |     +--ro (type)?
          |     |        +--:(numbered)
          |     |        |  +--ro numbered-hop
          |     |        |     +--ro address?    te-types:te-tp-id
          |     |        |     +--ro hop-type?   te-hop-type
          |     |        +--:(as-number)
          |     |        |  +--ro as-number-hop
          |     |        |     +--ro as-number?   binary
          |     |        |     +--ro hop-type?    te-hop-type
          |     |        +--:(unnumbered)
          |     |        |  +--ro unnumbered-hop
          |     |        |     +--ro node-id?
          |     |        |     |       te-types:te-node-id
          |     |        |     +--ro link-tp-id?
          |     |        |     |       te-types:te-tp-id
          |     |        |     +--ro hop-type?     te-hop-type
          |     |        +--:(label)
          |     |        |  +--ro label-hop
          |     |        |     +--ro value?
          |     |        |             rt-types:generalized-label
          |     |        +--:(sid)
          |     |           +--ro sid-hop
          |     |              +--ro sid?
          |     |                      rt-types:generalized-label
          |     +--ro pcc-original?
          |     |       -> /pcep/entity/peers/peer/addr
          |     +--ro req-id?          uint32
          |     +--ro retrieved?       boolean
          |     +--ro pcc-retrieved?
          |     |       -> /pcep/entity/peers/peer/addr
          |     +--ro creation-time?   yang:timestamp
          |     +--ro discard-time?    uint32
          |     +--ro reuse-time?      uint32
          +--rw peers
             +--rw peer* [addr]
                +--rw addr                    inet:ip-address
                +--rw role                    pcep-role
                +--rw description?            string
                +--rw domain
                |  +--rw domain* [domain-type domain]
                |     +--rw domain-type    domain-type
                |     +--rw domain         domain
                +--rw capability
                |  +--rw gmpls?                 boolean
                |  |       {gmpls}?
                |  +--rw bi-dir?                boolean
                |  +--rw diverse?               boolean
                |  +--rw load-balance?          boolean
                |  +--rw synchronize?           boolean {svec}?
                |  +--rw objective-function?    boolean
                |  |       {objective-function}?
                |  +--rw add-path-constraint?   boolean
                |  +--rw prioritization?        boolean
                |  +--rw multi-request?         boolean
                |  +--rw gco?                   boolean {gco}?
                |  +--rw p2mp?                  boolean {p2mp}?
                |  +--rw stateful {stateful}?
                |  |  +--rw enabled?                boolean
                |  |  +--rw active?                 boolean
                |  |  +--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 pce-info
                |  +--rw scope
                |  |  +--rw intra-area-scope?           boolean
                |  |  +--rw intra-area-pref?            uint8
                |  |  +--rw inter-area-scope?           boolean
                |  |  +--rw inter-area-scope-default?   boolean
                |  |  +--rw inter-area-pref?            uint8
                |  |  +--rw inter-as-scope?             boolean
                |  |  +--rw inter-as-scope-default?     boolean
                |  |  +--rw inter-as-pref?              uint8
                |  |  +--rw inter-layer-scope?          boolean
                |  |  +--rw inter-layer-pref?           uint8
                |  +--rw neigh-domains
                |     +--rw domain* [domain-type domain]
                |        +--rw domain-type    domain-type
                |        +--rw domain         domain
                +--rw delegation-pref?        uint8 {stateful}?
                +--rw auth
                |  +--rw (auth-type-selection)?
                |     +--:(auth-key-chain)
                |     |  +--rw key-chain?
                |     |          key-chain:key-chain-ref
                |     +--:(auth-key)
                |     |  +--rw crypto-algorithm    identityref
                |     |  +--rw key-string
                |     |     +--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
                |           |     +--rw certificates
                |           |     |  +--rw certificate* [name]
                |           |     |     +--rw name    leafref
                |           |     +--rw client-auth
                |           |     |  +--rw trusted-ca-certs?       leafref
                |           |     |  +--rw trusted-client-certs?   leafref
                |           |     +--rw hello-params
                |           |             {tls-server-hello-params-config}?
                |           |        +--rw tls-versions
                |           |        |  +--rw tls-version*
                |           |        |          identityref
                |           |        +--rw cipher-suites
                |           |           +--rw cipher-suite*
                |           |                   identityref
                |           +--:(client)
                |              +--rw tls-client
                |                 +--rw server-auth
                |                 |  +--rw trusted-ca-certs?       leafref
                |                 |  +--rw trusted-server-certs?   leafref
                |                 +--rw client-auth
                |                 |  +--rw (auth-type)?
                |                 |     +--:(certificate)
                |                 |        +--rw certificate?   leafref
                |                 +--rw hello-params
                |                         {tls-client-hello-params-config}?
                |                    +--rw tls-versions
                |                    |  +--rw tls-version*
                |                    |          identityref
                |                    +--rw cipher-suites
                |                       +--rw cipher-suite*
                |                               identityref
                +--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?               uint32
                      +--ro remote-id?              uint32
                      +--ro keepalive-timer?        uint32
                      +--ro peer-keepalive-timer?   uint32
                      +--ro dead-timer?             uint32
                      +--ro peer-dead-timer?        uint32
                      +--ro ka-hold-time-rem?       uint32
                      +--ro overloaded?             boolean
                      +--ro overload-time?          uint32
                      +--ro peer-overloaded?        boolean
                      +--ro peer-overload-time?     uint32
                      +--ro lspdb-sync?             sync-state
                      |       {stateful}?
                      +--ro recv-db-ver?            uint64
                      |       {stateful,stateful-sync-opt}?
                      +--ro of-list {objective-function}?
                      |  +--ro objective-function* [of]
                      |     +--ro of    objective-function
                      +--ro speaker-entity-id?      string
                      |       {stateful-sync-opt}?
                      +--ro discontinuity-time?     yang:timestamp

  rpcs:
    +---x trigger-resync {stateful,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?   leafref
    |  +--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?   leafref
    |  +--ro overloaded?          boolean
    |  +--ro overload-time?       uint32
    +---n pcep-session-local-overload-clear
    |  +--ro peer-addr?    -> /pcep/entity/peers/peer/addr
    |  +--ro overloaded?   boolean
    +---n pcep-session-peer-overload
    |  +--ro peer-addr?            -> /pcep/entity/peers/peer/addr
    |  +--ro session-initiator?    leafref
    |  +--ro peer-overloaded?      boolean
    |  +--ro peer-overload-time?   uint32
    +---n pcep-session-peer-overload-clear
       +--ro peer-addr?         -> /pcep/entity/peers/peer/addr
       +--ro peer-overloaded?   boolean
                  

The module, "ietf-pcep", defines the basic components of a PCE speaker.

5.1. 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.

5.2. 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 (addr-type, addr).

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.

5.3. The Session Lists

The session list contains PCEP session that the PCEP entity (PCE or PCC) is currently participating in. The statistics in session are semantically different from those in peer since the former applies to the current session only, whereas the latter is the aggregate for all sessions that have existed to that peer.

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. If either of these sessions reaches active state first, 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.

5.4. 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 notifications.

5.5. RPC

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

6. The Design of PCEP Statistics Data Model

module: ietf-pcep-stats
  augment /p:pcep/p:entity/p:peers/p:peer:
    +--ro num-sess-setup-ok?     yang:counter32
    +--ro num-sess-setup-fail?   yang:counter32
    +--ro pcep-stats
       +--ro avg-rsp-time?               uint32
       +--ro lwm-rsp-time?               uint32
       +--ro hwm-rsp-time?               uint32
       +--ro num-pcreq-sent?             yang:counter32
       +--ro num-pcreq-rcvd?             yang:counter32
       +--ro num-pcrep-sent?             yang:counter32
       +--ro num-pcrep-rcvd?             yang:counter32
       +--ro num-pcerr-sent?             yang:counter32
       +--ro num-pcerr-rcvd?             yang:counter32
       +--ro num-pcntf-sent?             yang:counter32
       +--ro num-pcntf-rcvd?             yang:counter32
       +--ro num-keepalive-sent?         yang:counter32
       +--ro num-keepalive-rcvd?         yang:counter32
       +--ro num-unknown-rcvd?           yang:counter32
       +--ro num-corrupt-rcvd?           yang:counter32
       +--ro num-req-sent?               yang:counter32
       +--ro num-req-sent-pend-rep?      yang:counter32
       +--ro num-req-sent-ero-rcvd?      yang:counter32
       +--ro num-req-sent-nopath-rcvd?   yang:counter32
       +--ro num-req-sent-cancel-rcvd?   yang:counter32
       +--ro num-req-sent-error-rcvd?    yang:counter32
       +--ro num-req-sent-timeout?       yang:counter32
       +--ro num-req-sent-cancel-sent?   yang:counter32
       +--ro num-req-rcvd?               yang:counter32
       +--ro num-req-rcvd-pend-rep?      yang:counter32
       +--ro num-req-rcvd-ero-sent?      yang:counter32
       +--ro num-req-rcvd-nopath-sent?   yang:counter32
       +--ro num-req-rcvd-cancel-sent?   yang:counter32
       +--ro num-req-rcvd-error-sent?    yang:counter32
       +--ro num-req-rcvd-cancel-rcvd?   yang:counter32
       +--ro num-rep-rcvd-unknown?       yang:counter32
       +--ro num-req-rcvd-unknown?       yang:counter32
       +--ro svec {p: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 {p: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 {p: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 {p: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 /p:pcep/p:entity/p:peers/p:peer/p:sessions/p:session:
    +--ro pcep-stats
       +--ro avg-rsp-time?               uint32
       +--ro lwm-rsp-time?               uint32
       +--ro hwm-rsp-time?               uint32
       +--ro num-pcreq-sent?             yang:counter32
       +--ro num-pcreq-rcvd?             yang:counter32
       +--ro num-pcrep-sent?             yang:counter32
       +--ro num-pcrep-rcvd?             yang:counter32
       +--ro num-pcerr-sent?             yang:counter32
       +--ro num-pcerr-rcvd?             yang:counter32
       +--ro num-pcntf-sent?             yang:counter32
       +--ro num-pcntf-rcvd?             yang:counter32
       +--ro num-keepalive-sent?         yang:counter32
       +--ro num-keepalive-rcvd?         yang:counter32
       +--ro num-unknown-rcvd?           yang:counter32
       +--ro num-corrupt-rcvd?           yang:counter32
       +--ro num-req-sent?               yang:counter32
       +--ro num-req-sent-pend-rep?      yang:counter32
       +--ro num-req-sent-ero-rcvd?      yang:counter32
       +--ro num-req-sent-nopath-rcvd?   yang:counter32
       +--ro num-req-sent-cancel-rcvd?   yang:counter32
       +--ro num-req-sent-error-rcvd?    yang:counter32
       +--ro num-req-sent-timeout?       yang:counter32
       +--ro num-req-sent-cancel-sent?   yang:counter32
       +--ro num-req-rcvd?               yang:counter32
       +--ro num-req-rcvd-pend-rep?      yang:counter32
       +--ro num-req-rcvd-ero-sent?      yang:counter32
       +--ro num-req-rcvd-nopath-sent?   yang:counter32
       +--ro num-req-rcvd-cancel-sent?   yang:counter32
       +--ro num-req-rcvd-error-sent?    yang:counter32
       +--ro num-req-rcvd-cancel-rcvd?   yang:counter32
       +--ro num-rep-rcvd-unknown?       yang:counter32
       +--ro num-req-rcvd-unknown?       yang:counter32
       +--ro svec {p: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 {p: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 {p: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 {p: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
            

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

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 -

7.1. Stateful PCE's LSP-DB

In the operational state of PCEP which supports stateful PCE mode, the list of LSP state are maintained in LSP-DB. The key is the PLSP-ID and the PCC IP address.

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. Open Issues and Next Step

This section is added so that open issues can be tracked. This section would be removed when the document is ready for publication.

8.1. The PCE-Initiated LSP

The TE Model at [I-D.ietf-teas-yang-te] should support creating of tunnels at the controller (PCE) and marking them as PCE-Initiated. The LSP-DB in the PCEP Yang (/pcep/entity/lsp-db/lsp/initiation) also marks the LSPs which are PCE-initiated.

9. Other Considerations

9.1. PCEP over TLS (PCEPS)

[I-D.ietf-pce-pceps] describe the use of TLS in PCEP. The peer acting as the PCEP client MUST act as the TLS client. The TLS client actively opens the TLS connection and the TLS server passively listens for the incoming TLS connections. The well-known TCP port number 4189 is used by PCEP servers to listen for TCP connections established by PCEP over TLS clients. The TLS client MUST send the TLS ClientHello message to begin the TLS handshake. The TLS server MUST send a CertificateRequest in order to request a certificate from the TLS client. Once the TLS handshake has finished, the client and the server MAY begin to exchange PCEP messages. Client and server identity verification is done before the PCEP open message is sent. This means that the identity verification is completed before the PCEP session is started..

10. PCEP YANG Modules

10.1. 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@2017-07-01.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";
    }

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

    import ietf-te {
        prefix "te";
    }

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

    import ietf-key-chain {
       prefix "key-chain";
    }

    import ietf-netconf-acm {
       prefix "nacm";
     }

    import ietf-tls-server {
       prefix "tls-server";
     }

    import ietf-tls-client {
       prefix "tls-client";
    }

    organization
        "IETF PCE (Path Computation Element) Working Group";

    contact
        "WG Web:   <http://tools.ietf.org/wg/pce/>
         WG List:  <mailto:pce@ietf.org>
         WG Chair: JP Vasseur
                   <mailto:jpv@cisco.com>
         WG Chair: Julien Meuric
                   <mailto:julien.meuric@orange.com>
         WG Chair: Jonathan Hardwick
                   <mailto:Jonathan.Hardwick@metaswitch.com>
         Editor:   Dhruv Dhody
                   <mailto:dhruv.ietf@gmail.com>";

    description
        "The YANG module defines a generic configuration and
         operational model for PCEP common across all of the
         vendor implementations.";


    revision 2017-07-01 {
        description "Initial revision.";
        reference
            "RFC XXXX:  A YANG Data Model for Path Computation
                        Element Communications Protocol
                        (PCEP)";
    }

    /*
     * Identities
     */

    identity pcep {
        description "Identity for the PCEP protocol.";
    }

    /*
     * Typedefs
     */
    typedef pcep-role {
        type enumeration {
            enum unknown {
                value "0";
                description
                "An unknown role";
            }
            enum pcc {
                value "1";
                description
                "The role of a Path Computation Client";
            }
            enum pce {
                value "2";
                description
                "The role of Path Computation Element";
            }
            enum pcc-and-pce {
                value "3";
                description
                "The role of both Path Computation Client and
                 Path Computation Element";
            }
        }

        description
            "The role of a PCEP speaker.
             Takes one of the following values
             - unknown(0): the role is not known.
             - pcc(1): the role is of a Path Computation
               Client (PCC).
             - pce(2): the role is of a Path Computation
               Server (PCE).
             - pccAndPce(3): the role is of both a PCC and
               a PCE.";

    }

    typedef pcep-admin-status {
        type enumeration {
                enum admin-status-up {
                value "1";
                description
                "Admin Status is Up";
            }
            enum admin-status-down {
                value "2";
                description
                "Admin Status is Down";
            }
        }

        description
        "The Admin Status of the PCEP entity.
         Takes one of the following values
             - admin-status-up(1): Admin Status is Up.
             - admin-status-down(2): Admin Status is Down";
    }

    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";
    }

    typedef pcep-initiator {
        type enumeration {
            enum local {
                value "1";
                description
                "The local PCEP entity initiated the session";
            }

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

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

            enum open-wait {
                value "2";
                description
                    "The open-wait state of PCEP session.";
            }

            enum keep-wait {
                value "3";
                description
                    "The keep-wait state of PCEP session.";
            }

            enum session-up {
                value "4";
                description
                    "The session-up state of PCEP session.";
            }
        }
        description
            "The current state of the session.
             The set of possible states excludes the idle state
             since entries do not exist in the idle state.
             Takes one of the following values
                - tcp-pending(1): PCEP TCP Pending state
                - open-wait(2): PCEP Open Wait state
                - keep-wait(3): PCEP Keep Wait state
                - session-up(4): PCEP Session Up state";
    }

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

    typedef domain-ospf-area {
        type union {
            type uint32;
            type yang:dotted-quad;
       }
       description
            "OSPF Area ID.";
    }

    typedef domain-isis-area {
        type string {
            pattern '[0-9A-Fa-f]{2}\.([0-9A-Fa-f]{4}\.){0,3}';
        }
        description
            "IS-IS Area ID.";
    }

    typedef domain-as {
        type uint32;
        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";
    }

    typedef lsp-error {
        type enumeration {
            enum no-error {
                value "0";
                description
                    "No error, LSP is fine.";
            }
            enum unknown {
                value "1";
                description
                    "Unknown reason.";
            }
            enum limit {
                value "2";
                description
                    "Limit reached for PCE-controlled LSPs.";
            }
            enum pending {
                value "3";
                description
                    "Too many pending LSP update requests.";
            }
            enum unacceptable {
                value "4";
                description
                    "Unacceptable parameters.";
            }
            enum internal {
                value "5";
                description
                    "Internal error.";
            }
            enum admin {
                value "6";
                description
                    "LSP administratively brought down.";
            }
            enum preempted {
                value "7";
                description
                    "LSP preempted.";
            }
            enum rsvp {
                value "8";
                description
                    "RSVP signaling error.";
            }
        }
        description
            "The LSP Error Codes.";
    }

    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.";
    }

    typedef pst{
        type enumeration{
            enum rsvp-te{
                value "0";
                description
                    "RSVP-TE signaling protocol";
            }
            enum sr{
                value "1";
                description
                    "Segment Routing Traffic Engineering";
            }
        }
        description
            "The Path Setup Type";
    }

    typedef assoc-type{
        type enumeration{
            enum protection{
                value "1";
                description
                    "Path Protection Association Type";
            }
            enum policy{
                value "2";
                description
                    "Policy Association Type";
            }
            enum diversity{
                value "3";
                description
                    "Diversity Association Type";
            }
        }
        description
            "The PCEP Association Type";
    }

    typedef objective-function{
        type enumeration{
            enum mcp{
                value "1";
                description
                    "Minimum Cost Path (MCP)";
            }
            enum mlp{
                value "2";
                description
                    "Minimum Load Path (MLP)";
            }
            enum mbp{
                value "3";
                description
                    "Maximum residual Bandwidth Path (MBP)";
            }
            enum mbc{
                value "4";
                description
                    "Minimize aggregate Bandwidth Consumption
                     (MBC)";
            }
            enum mll{
                value "5";
                description
                    "Minimize the Load of the most loaded Link
                     (MLL)";
            }
            enum mcc{
                value "6";
                description
                    "Minimize the Cumulative Cost of a set of
                    paths (MCC)";
            }
            enum spt{
                value "7";
                description
                    "Shortest Path Tree (SPT)";
            }
            enum mct{
                value "8";
                description
                    "Minimum Cost Tree (MCT)";
            }
            enum mplp{
                value "9";
                description
                    "Minimum Packet Loss Path (MPLP)";
            }
            enum mup{
                value "10";
                description
                    "Maximum Under-Utilized Path (MUP)";
            }
            enum mrup{
                value "11";
                description
                    "Maximum Reserved Under-Utilized Path
                     (MRUP)";
            }
        }
        description
            "The PCEP Objective functions";
    }

    /*
     * Features
     */

    feature svec {
        description
            "Support synchronized path computation.";
    }

    feature gmpls {
        description
            "Support GMPLS.";
    }

    feature objective-function {
        description
            "Support OF as per RFC 5541.";
    }

    feature gco {
        description
            "Support GCO as per RFC 5557.";
    }

    feature path-key {
        description
            "Support path-key as per RFC 5520.";
    }

    feature p2mp {
        description
            "Support P2MP as per RFC 6006.";
    }

    feature stateful {
        description
            "Support stateful PCE.";
    }

    feature stateful-sync-opt {
        description
            "Support stateful sync optimization";
    }

    feature pce-initiated {
        description
            "Support PCE-Initiated LSP.";
    }

    feature tls {
        description
            "Support PCEP over TLS.";
    }

    feature sr {
        description
            "Support Segment Routing for PCE.";
    }

    /*
     * Groupings
     */
    grouping pcep-entity-info{
        description
            "This grouping defines the attributes for PCEP entity.";
        leaf connect-timer {
            type uint32 {
                range "1..65535";
            }
            units "seconds";
            default 60;
            description
                "The time in seconds that the PCEP entity will wait
                 to establish a TCP connection with a peer.  If a
                 TCP connection is not established within this time
                 then PCEP aborts the session setup attempt.";
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf connect-max-retry {
            type uint32;
            default 5;
            description
                "The maximum number of times the system tries to
                 establish a TCP connection to a peer before the
                 session with the peer transitions to the idle
                 state.";
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf init-backoff-timer {
            type uint32 {
                range "1..65535";
            }
            units "seconds";
            description
               "The initial back-off time in seconds for retrying
                a failed session setup attempt to a peer.
                The back-off time increases for each failed
                session setup attempt, until a maximum back-off
                time is reached.  The maximum back-off time is
                max-backoff-timer.";
        }

        leaf max-backoff-timer {
            type uint32;
            units "seconds";
            description
               "The maximum back-off time in seconds for retrying
                a failed session setup attempt to a peer.
                The back-off time increases for each failed session
                setup attempt, until this maximum value is reached.
                Session setup attempts then repeat periodically
                without any further increase in back-off time.";
        }

        leaf open-wait-timer {
            type uint32 {
                range "1..65535";
            }
            units "seconds";
            default 60;
            description
               "The time in seconds that the PCEP entity will wait
                to receive an Open message from a peer after the
                TCP connection has come up.
                If no Open message is received within this time then
                PCEP terminates the TCP connection and deletes the
                associated sessions.";
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf keep-wait-timer {
            type uint32 {
                range "1..65535";
            }
            units "seconds";
            default 60;
            description
                "The time in seconds that the PCEP entity will wait
                 to receive a Keepalive or PCErr message from a peer
                 during session initialization after receiving an
                 Open message.  If no Keepalive or PCErr message is
                 received within this time then PCEP terminates the
                 TCP connection and deletes the associated
                 sessions.";
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf keep-alive-timer {
            type uint32 {
                range "0..255";
            }
            units "seconds";
            default 30;
            description
                "The keep alive transmission timer that this PCEP
                 entity will propose in the initial OPEN message of
                 each session it is involved in.  This is the
                 maximum time between two consecutive messages sent
                 to a peer. Zero means that the PCEP entity prefers
                 not to send Keepalives at all.
                 Note that the actual Keepalive transmission
                 intervals, in either direction of an active PCEP
                 session, are determined by negotiation between the
                 peers as specified by RFC 5440, and so may differ
                 from this configured value.";
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf dead-timer {
            type uint32 {
                range "0..255";
            }
            units "seconds";
            must "(. > ../keep-alive-timer)" {
                error-message "The dead timer must be "
                       + "larger than the keep alive timer";
                description
                    "This value MUST be greater than
                     keep-alive-timer.";

            }
            default 120;
            description
                "The dead timer that this PCEP entity will propose
                 in the initial OPEN message of each session it is
                 involved in. This is the time after which a peer
                 should declare a session down if it does not
                 receive any PCEP messages. Zero suggests that the
                 peer does not run a dead timer at all." ;
            reference
                "RFC 5440: Path Computation Element (PCE)
                           Communication Protocol (PCEP)";
        }

        leaf allow-negotiation{
            type boolean;
            description
                "Whether the PCEP entity will permit negotiation of
                 session parameters.";
        }

        leaf max-keep-alive-timer{
            type uint32 {
                range "0..255";
            }
            units "seconds";
            description
                "In PCEP session parameter negotiation in seconds,
                 the maximum value that this PCEP entity will
                 accept from a peer for the interval between
                 Keepalive transmissions. Zero means that the PCEP
                 entity will allow no Keepalive transmission at
                 all." ;
        }

        leaf max-dead-timer{
            type uint32 {
                range "0..255";
            }
            units "seconds";
            description
                "In PCEP session parameter negotiation in seconds,
                 the maximum value that this PCEP entity will accept
                 from a peer for the Dead timer.  Zero means that
                 the PCEP entity will allow not running a Dead
                 timer.";
        }

        leaf min-keep-alive-timer{
            type uint32 {
                range "0..255";
            }
            units "seconds";
            description
                "In PCEP session parameter negotiation in seconds,
                 the minimum value that this PCEP entity will
                 accept for the interval between Keepalive
                 transmissions. Zero means that the PCEP entity
                 insists on no Keepalive transmission at all.";
        }

        leaf min-dead-timer{
            type uint32 {
                range "0..255";
            }
            units "seconds";
            description
                 "In PCEP session parameter negotiation in
                  seconds, the minimum value that this PCEP entity
                  will accept for the Dead timer.  Zero means that
                  the PCEP entity insists on not running a Dead
                  timer.";
        }

        leaf sync-timer{
            if-feature svec;
            type uint32 {
                range "0..65535";
            }
            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 uint32 {
                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)";
        }

    }//pcep-entity-info

    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 intra-area-scope{
            type boolean;
            default true;
            description
                "PCE can compute intra-area paths.";
        }
        leaf intra-area-pref{
            type uint8{
                range "0..7";
            }
            description
              "The PCE's preference for intra-area TE LSP
              computation.";
        }
        leaf inter-area-scope{
            type boolean;
            default false;
            description
                "PCE can compute inter-area paths.";
        }
        leaf inter-area-scope-default{
            type boolean;
            default false;
            description
                "PCE can act as a default PCE for inter-area
                 path computation.";
        }
        leaf inter-area-pref{
            type uint8{
                range "0..7";
            }
            description
              "The PCE's preference for inter-area TE LSP
              computation.";
        }
        leaf inter-as-scope{
            type boolean;
            default false;
            description
                "PCE can compute inter-AS paths.";
        }
        leaf inter-as-scope-default{
            type boolean;
            default false;
            description
                "PCE can act as a default PCE for inter-AS
                 path computation.";
        }
        leaf inter-as-pref{
            type uint8{
                range "0..7";
            }
            description
              "The PCE's preference for inter-AS TE LSP
              computation.";
        }
        leaf inter-layer-scope{
            type boolean;
            default false;
            description
                "PCE can compute inter-layer paths.";
        }
        leaf inter-layer-pref{
            type uint8{
                range "0..7";
            }
            description
              "The PCE's preference for inter-layer TE LSP
              computation.";
        }
    }//pce-scope

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

    grouping capability{
        description
            "This grouping specifies a capability
             information of local PCEP entity. This maybe
             relevant to PCE selection as well. This
             information corresponds to PCE auto-discovery
             information.";
        reference
            "RFC 5088: OSPF Protocol Extensions for Path
                       Computation Element (PCE)
                       Discovery
             RFC 5089: IS-IS Protocol Extensions for Path
                       Computation Element (PCE)
                       Discovery";
        leaf gmpls{
            if-feature gmpls;
            type boolean;
            description
              "Path computation with GMPLS link
               constraints.";
        }
        leaf bi-dir{
            type boolean;
            description
              "Bidirectional path computation.";
        }
        leaf diverse{
            type boolean;
            description
              "Diverse path computation.";
        }
        leaf load-balance{
            type boolean;
            description
              "Load-balanced path computation.";
        }
        leaf synchronize{
            if-feature svec;
            type boolean;
            description
              "Synchronized paths computation.";
        }
        leaf objective-function{
            if-feature objective-function;
            type boolean;
            description
              "Support for multiple objective functions.";
        }
        leaf add-path-constraint{
            type boolean;
            description
              "Support for additive path constraints (max
               hop count, etc.).";
        }
        leaf prioritization{
            type boolean;
            description
              "Support for request prioritization.";
        }
        leaf multi-request{
            type boolean;
            description
              "Support for multiple requests per message.";
        }
        leaf gco{
            if-feature gco;
            type boolean;
            description
              "Support for Global Concurrent Optimization
               (GCO).";
        }
        leaf p2mp{
            if-feature p2mp;
            type boolean;
            description
              "Support for P2MP path computation.";
        }

        container stateful{
            if-feature stateful;
            description
                "If stateful PCE feature is present";
            leaf enabled{
                type boolean;
                description
                    "Enabled or Disabled";
            }
            leaf active{
                type boolean;
                description
                  "Support for active stateful PCE.";
            }
            leaf pce-initiated{
                if-feature pce-initiated;
                type boolean;
                description
                  "Support for PCE-initiated LSP.";
            }
            leaf include-db-ver{
                if-feature stateful-sync-opt;
                type boolean;
                description
                    "Support inclusion of LSP-DB-VERSION
                    in LSP object";
            }
            leaf trigger-resync{
                if-feature stateful-sync-opt;
                type boolean;
                description
                    "Support PCE triggered re-synchronization";
            }
            leaf trigger-initial-sync{
                if-feature stateful-sync-opt;
                type boolean;
                description
                    "PCE triggered initial synchronization";
            }
            leaf incremental-sync{
                if-feature stateful-sync-opt;
                type boolean;
                description
                    "Support incremental (delta) sync";
            }
        }
        container sr{
            if-feature sr;
            description
                "If segment routing is supported";
            leaf enabled{
                type boolean;
                description
                    "Enabled or Disabled";
            }

        }
    }//capability

    grouping info{
        description
            "This grouping specifies all information which
             maybe relevant to both PCC and PCE.
             This information corresponds to PCE auto-discovery
             information.";
        container domain{
            description
                "The local domain for the PCEP entity";
            list domain{
                key "domain-type domain";
                description
                    "The local domain.";
                uses domain{
                    description
                        "The local domain for the PCEP entity.";
                }
            }
        }
        container capability{
            description
                "The PCEP entity capability";
            uses capability{
                description
                    "The PCEP entity supported
                    capabilities.";
            }
        }


    }//info

    grouping pce-info{
        description
            "This grouping specifies all PCE information
             which maybe relevant to the PCE selection.
             This information corresponds to PCE auto-discovery
             information.";
        container scope{
            description
                "The path computation scope";
            uses pce-scope;
        }

        container neigh-domains{
            description
                "The list of neighbour PCE-Domain
                 toward which a PCE can compute
                 paths";
            list domain{
                key "domain-type domain";

                description
                    "The neighbour domain.";
                uses domain{
                    description
                        "The PCE neighbour domain.";
                }
            }
        }
    }//pce-info

    grouping lsp-state{
        description
            "This grouping defines the attributes for LSP in LSP-DB.
             These are the attributes specifically from the PCEP
             perspective";
        leaf plsp-id{
            type uint32{
                range "1..1048575";
            }
            description
                "A PCEP-specific identifier for the LSP.  A PCC
                 creates a unique PLSP-ID for each LSP that is
                 constant for the lifetime of a PCEP session.
                 PLSP-ID is 20 bits with 0 and 0xFFFFF are
                 reserved";
        }
        leaf pcc-id{
            type inet:ip-address;
            description
                "The local internet address of the PCC, that
                 generated the PLSP-ID.";
        }

        container lsp-ref{
            description
                "reference to ietf-te lsp state";

            leaf source {
                type leafref {
                    path "/te:te/te:lsps-state/te:lsp/te:source";
                }
                description
                  "Tunnel sender address extracted from
                  SENDER_TEMPLATE  object";
                reference "RFC3209";
            }
            leaf destination {
                type leafref {
                    path "/te:te/te:lsps-state/te:lsp/te:"
                         + "destination";
                }
                description
                    "Tunnel endpoint address extracted from
                    SESSION object";
                reference "RFC3209";
            }
            leaf tunnel-id {
                type leafref {
                    path "/te:te/te:lsps-state/te:lsp/te:tunnel-id";
                }
                description
                    "Tunnel identifier used in the SESSION
                    that remains constant over the life
                    of the tunnel.";
                reference "RFC3209";
            }
            leaf lsp-id {
                type leafref {
                    path "/te:te/te:lsps-state/te:lsp/te:lsp-id";
                }
                description
                    "Identifier used in the SENDER_TEMPLATE
                    and the FILTER_SPEC that can be changed
                    to allow a sender to share resources with
                    itself.";
                reference "RFC3209";
            }
            leaf extended-tunnel-id {
                type leafref {
                    path "/te:te/te:lsps-state/te:lsp/te:"
                    + "extended-tunnel-id";
                }
                description
                    "Extended Tunnel ID of the LSP.";
                reference "RFC3209";
            }
        }

        leaf admin-state{
            type boolean;
            description
                "The desired operational state";
        }
        leaf operational-state{
            type operational-state;
            description
                "The operational status of the LSP";
        }
        container delegated{
            description
                "The delegation related parameters";
            leaf enabled{
                type boolean;
                description
                    "LSP is delegated or not";
            }
            leaf peer{
                type leafref {
                    path "/pcep/entity/peers/peer/addr";
                }
                must "(../enabled = true())"
                {
                    error-message
                        "The LSP must be delegated";
                    description
                        "When LSP is a delegated LSP";
                }
                description
                    "At the PCC, the reference to the PCEP peer to
                    which LSP is delegated; At the PCE, the
                    reference to the PCEP peer which delegated this
                    LSP";
            }
            leaf srp-id{
                type uint32;
                description
                    "The last SRP-ID-number associated with this
                    LSP.";
            }
        }
        container initiation {
            if-feature pce-initiated;
            description
                "The PCE initiation related parameters";
            leaf enabled{
                type boolean;
                description
                    "LSP is PCE-initiated or not";
            }
            leaf peer{
                type leafref {
                    path "/pcep/entity/peers/peer/addr";
                }
                must "(../enabled = true())"
                {
                    error-message
                        "The LSP must be PCE-Initiated";
                    description
                        "When 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.";
        }
        leaf last-error{
            type lsp-error;
            description
                "The last error for the LSP.";
        }
        leaf pst{
            type pst;
            default "rsvp-te";
            description
                "The Path Setup Type";

        }

    }//lsp-state

    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 stateful-pce-parameter {
        description
        "This group describes stateful PCE specific
         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
                    "Valid at 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
                    "Valid at 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). ";
        }

    }

    grouping authentication {
        description "Authentication Information";
        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.";
                   }
                   container key-string {
                     description
                       "The key string.";
                     nacm:default-deny-all;
                     choice key-string-style {
                       description
                         "Key string styles";
                       case keystring {
                         leaf keystring {
                           type string;
                           description
                             "Key string in ASCII format.";
                         }
                       }
                       case hexadecimal {
                         if-feature "key-chain:hex-key-string";
                         leaf hexadecimal-string {
                           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
                              octets. Additionally, it discourages
                              usage of well-known words or
                              numbers.";
                         }
                       }
                     }
                   }
                }
                case auth-tls {
                    if-feature tls;
                    choice role{
                        description
                            "The role of the local entity";
                        case server {
                            container tls-server {
                                uses tls-server:tls-server-grouping {
                                description
                                    "Server TLS information.";
                                }
                                description
                                    "TLS related information";
                            }
                        }
                        case client{
                            container tls-client {
                                uses tls-client:tls-client-grouping {
                                description
                                    "Client TLS information.";
                                }
                                description
                                    "TLS related information";
                            }
                        }
                    }
                }
            }
        }
    }

    grouping path-key {
        description "Path-key related information";
        leaf enabled{
            type boolean;
            description
                "Enabled or Disabled";
        }
        leaf discard-timer {
            type uint32;
            units "minutes";
            default 10;
            description
                "A timer to discard unwanted path-keys";
        }
        leaf reuse-time {
            type uint32;
            units "minutes";
            default 30;
            description
                "A time after which the path-keys could be reused";
        }
        leaf pce-id {
            type inet:ip-address;
            description
                "PCE Address to be used in each Path-Key Subobject
                (PKS)";
        }
    }

    grouping path-key-state {
        description "Table to allow inspection of path-keys";
        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 explicit-route-usage {
                        type identityref {
                            base te-types:route-usage-type;
                        }
                        description
                            "An explicit-route hop action.";
                    }

                    uses te-types:explicit-route-hop_config;
                }
            }
            leaf pcc-original {
                type leafref {
                    path "/pcep/entity/peers/peer/addr";
                }
                description
                    "Reference to PCC peer address of
                    the original request";
            }
            leaf req-id {
                type uint32;
                description
                    "The request ID of the original PCReq.";
            }
            leaf retrieved  {
                type boolean;
                description
                    "If path-key has been retrieved yet";
            }
            leaf pcc-retrieved {
                type leafref {
                    path "/pcep/entity/peers/peer/addr";
                }
                must "(../retrieved = true())"
                {
                    error-message
                        "The Path-key should be retreived";
                    description
                        "When Path-Key has been retreived";
                }
                description
                    "Reference to PCC peer address which
                    retreived the path-key";
            }
            leaf creation-time {
                type yang:timestamp;
                description
                    "The timestamp value at the time this Path-Key
                    was created.";
            }
            leaf discard-time {
                type uint32;
                units "minutes";
                description
                    "A time after which this path-keys will be
                    discarded";
            }
            leaf reuse-time {
                type uint32;
                units "minutes";
                description
                    "A time after which this path-keys could be
                    reused";
            }
        }
    }

    grouping of-list {
        description "List of OF";
        list objective-function{
            key "of";

            description
                "The list of authorized OF";

            leaf of {
                type objective-function;
                description
                    "The OF authorized";
            }
        }
    }
    grouping association {
        description
            "Generic Association parameters";
        leaf type {
            type "assoc-type";
            description
                "The PCEP association type";
        }
        leaf id {
            type uint16;
            description
                "PCEP Association ID";
        }
        leaf source {
          type inet:ip-address;
          description
                "PCEP Association Source.";
        }
        leaf global-source {
          type uint32;
          description
                "PCEP Association Global
                Source.";
        }
        leaf extended-id{
            type string;
            description
                "Additional information to
                support unique identification.";
        }
    }
    grouping association-ref {
        description
            "Generic Association parameters";
        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.";
        }
    }

    grouping session-grouping {
        description
                "Session grouping";
        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 MIB 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 uint32 {
                        range "0..255";
                    }
                    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.";
                }

                leaf remote-id {
                    type uint32 {
                        range "0..255";
                    }
                    must "((../state != 'tcp-pending'" +
                         "and " +
                         "../state != 'open-wait' )" +
                         "or " +
                         "((../state = 'tcp-pending'" +
                         " or " +
                         "../state = 'open-wait' )" +
                         "and (. = 0)))" {
                           error-message
                               "Invalid remote-id";
                           description
                               "If state is tcp-
                                pending or open-wait
                                then this leaf is not
                                used and MUST be set
                                to zero.";
                         }
                    description
                        "The value of the PCEP session
                         ID used by the peer in its
                         Open message for this
                         session.";
                }

                leaf keepalive-timer {
                    type uint32 {
                        range "0..255";
                    }
                    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.";
                }

                leaf peer-keepalive-timer {
                   type uint32 {
                        range "0..255";
                   }
                   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.";
                }

                leaf dead-timer {
                    type uint32 {
                        range "0..255";
                    }
                    units "seconds";
                    description
                        "The dead timer interval for
                         this PCEP session.";
                }

                leaf peer-dead-timer {
                    type uint32 {
                         range "0..255";
                    }
                    units "seconds";
                    must "((../state != 'tcp-pending'" +
                         "and " +
                         "../state != 'open-wait' )" +
                         "or " +
                         "((../state = 'tcp-pending'" +
                         " or " +
                         "../state = 'open-wait' )" +
                         "and " +
                         "(. = 0)))" {
                            error-message
                               "Invalid Peer Dead
                                timer";
                            description
                                "If state is tcp-
                                 pending or open-wait
                                 then this leaf is not
                                 used and MUST be set to
                                 zero.";
                            }
                        description
                            "The peer's dead-timer interval
                             for this PCEP session.";
                }

                leaf ka-hold-time-rem {
                    type uint32 {
                        range "0..255";
                    }
                    units "seconds";
                    must "((../state != 'tcp-pending'" +
                         "and " +
                         "../state != 'open-wait' ) " +
                         "or " +
                         "((../state = 'tcp-pending'" +
                         "or " +
                         "../state = 'open-wait' )" +
                         "and " +
                         "(. = 0)))" {
                            error-message
                                "Invalid Keepalive hold
                                 time remaining";
                            description
                                "If state is tcp-pending
                                 or open-wait then this
                                 field is not used and
                                 MUST be set to zero.";
                           }
                    description
                        "The keep alive hold time
                         remaining for this session.";
                }
                leaf overloaded {
                   type boolean;
                   description
                        "If the local PCEP entity has
                         informed the peer that it is
                         currently overloaded, then
                         this is set to true.
                         Otherwise, it is set to
                         false.";
                }
                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.";
                }
                       
                leaf peer-overloaded {
                    type boolean;
                    description
                        "If the peer has informed the
                         local PCEP entity that it is
                         currently overloaded, then
                         this is set to true.
                         Otherwise, it is set to
                         false.";
                }

                leaf peer-overload-time {
                    type uint32;
                    units "seconds";
                    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.";
                }
                        
                leaf lspdb-sync {
                    if-feature stateful;
                    type sync-state;
                    description
                        "The LSP-DB state
                         synchronization status.";
                }
                        
                leaf recv-db-ver{
                    when "../role = 'pcc'" +
                         "or " +
                         "../role = 'pcc-and-pce'"
                    {
                        description
                            "Valid for PCEP Peer as
                             PCC";
                    }

                    if-feature stateful;
                    if-feature stateful-sync-opt;

                    type uint64;

                    description
                        "The last received LSP State
                         Database Version Number";
                }
                        
                container of-list{
                    when "../role = 'pce'" +
                         "or " +
                         "../role = 'pcc-and-pce'"
                    {
                        description
                            "Valid for PCEP Peer as
                             PCE";
                    }
                    if-feature objective-function;

                    uses of-list;

                    description
                        "Indicate the list of supported
                         OF on this session";
                }


                leaf speaker-entity-id{
                    if-feature stateful-sync-opt;
                    type string;
                    description
                        "The Speaker Entity Identifier";
                }

                leaf discontinuity-time {
                    type yang:timestamp;
                    description
                         "The timestamp value of the
                          time when the statistics were
                          last reset.";
                }
            } // session
        } // sessions
    }
    /*
     * Configuration data nodes
     */
    container pcep{

        presence
            "The PCEP is enabled";

            description
            "Parameters for list of configured PCEP entities
             on the device.";

        container entity {

            description
                "The configured PCEP entity on the device.";

            leaf addr {
                type inet:ip-address;
                mandatory true;
                description
                    "The local Internet address of this PCEP
                    entity.
                    If operating as a PCE server, the PCEP
                    entity listens on this address.
                    If operating as a PCC, the PCEP entity
                    binds outgoing TCP connections to this
                    address.
                    It is possible for the PCEP entity to
                    operate both as a PCC and a PCE Server, in
                    which case it uses this address both to
                    listen for incoming TCP connections and to
                    bind outgoing TCP connections.";
            }

            leaf enabled {
                type boolean;
                default true;
                description
                    "The administrative status of this PCEP
                     Entity.";
            }

            leaf role {
                type pcep-role;
                mandatory true;
                description
                    "The role that this entity can play.
                     Takes one of the following values.
                     - unknown(0): this PCEP Entity role is not
                       known.
                     - pcc(1): this PCEP Entity is a PCC.
                     - pce(2): this PCEP Entity is a PCE.
                     - pcc-and-pce(3): this PCEP Entity is both
                       a PCC and a PCE.";
            }

            leaf description {
                type string;
                description
                    "Description of the PCEP entity configured
                     by the user";
            }

            leaf speaker-entity-id{
                if-feature stateful-sync-opt;
                type string;
                description
                    "The Speaker Entity Identifier";
            }

            leaf admin-status {
                type pcep-admin-status;
                description
                    "The administrative status of this PCEP Entity.
                     This is the desired operational status as
                     currently set by an operator or by default in
                     the implementation.  The value of enabled
                     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
                        "Valid at PCE";
                }
                uses pce-info {
                    description
                        "Local PCE information";
                }
                container path-key {
                    if-feature path-key;
                    uses path-key {
                        description
                            "Path-Key Configuration";
                    }
                    description
                        "Path-Key Configuration";
                }

                description
                    "The Local PCE Entity PCE information";
            }

            uses pcep-entity-info {
                description
                    "The configuration related to the PCEP
                     entity.";
            }

            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;
                must "(/pcep/entity/capability/stateful/enabled" +
                     " = true())"
                {
                    error-message
                        "The Stateful PCE must be enabled";
                    description
                        "When PCEP entity is stateful
                         enabled";
                }
                uses stateful-pce-parameter;

                description
                    "The configured stateful parameters";
            }

            container of-list{
                when "../role = 'pce'" +
                         "or " +
                         "../role = 'pcc-and-pce'"
                    {
                        description
                            "Valid at 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
                            "Valid at PCC";
                    }
                    if-feature stateful-sync-opt;
                    type uint64;
                    description
                        "The LSP State Database Version Number";
                }
                list association-list {
                    key "id source global-source extended-id";
                    description
                        "List of all PCEP associations";
                    uses association {
                        description
                            "The Association attributes";
                    }
                    list lsp {
                        key "plsp-id pcc-id";
                        description
                            "List of all LSP in this association";
                        leaf plsp-id {
                            type leafref {
                                path "/pcep/entity/lsp-db/"
                                + "lsp/plsp-id";
                            }
                            description
                                "Reference to PLSP-ID in LSP-DB";
                        }
                        leaf pcc-id {
                            type leafref {
                                path "/pcep/entity/lsp-db/"
                                + "lsp/pcc-id";
                            }
                            description
                                "Reference to PCC-ID in LSP-DB";
                        }
                    }
                }
                list lsp {
                    key "plsp-id pcc-id";
                    description
                        "List of all LSPs in LSP-DB";
                    uses lsp-state {
                        description
                            "The PCEP specific attributes for
                             LSP-DB.";
                    }
                    list association-list {
                        key "id source global-source extended-id";
                        description
                            "List of all PCEP associations";
                        uses association-ref {
                            description
                                "Reference to the Association
                                 attributes";
                        }
                    }

                }
            }

            container path-keys {
                 when "../role = 'pce' or ../role = 'pcc-and-pce'" {
                     description
                         "Valid at PCE";
                 }
                 if-feature path-key;
                 config false;
                 uses path-key-state;
                 description
                    "The path-keys generated by the PCE";
            }

            container peers{
                description
                    "The list of configured peers for the
                     entity (remote PCE)";
                list peer{
                    key "addr";

                    description
                        "The peer configured for the entity.
                         (remote PCE)";

                    leaf addr {
                        type inet:ip-address;
                        description
                            "The local Internet address of this
                             PCEP peer.";
                    }

                    leaf role {
                        type pcep-role;
                        mandatory true;
                        description
                            "The role of the PCEP Peer.
                             Takes one of the following values.
                               - unknown(0): this PCEP peer role is not
                                 known.
                               - pcc(1): this PCEP peer is a PCC.
                               - pce(2): this PCEP peer is a PCE.
                               - pcc-and-pce(3): this PCEP peer
                                 is both a PCC and a PCE.";
                    }

                    leaf description {
                        type string;
                        description
                            "Description of the PCEP peer
                             configured by the user";
                    }
                    uses info {
                        description
                            "PCE Peer information";
                    }

                    container pce-info {
                        uses pce-info {
                            description
                                "PCE Peer information";
                        }
                        description
                            "The PCE Peer information";
                    }

                    leaf delegation-pref{
                        if-feature stateful;
                        type uint8{
                            range "0..7";
                        }
                        must "(/pcep/entity/capability/stateful" +
                             "/active = true())"
                        {
                            error-message
                                "The Active Stateful PCE must be
                                 enabled";
                            description
                                "When PCEP entity is active stateful
                                 enabled";
                        }
                        description
                            "The PCE peer delegation preference.";
                    }
                    uses authentication {
                        description
                            "PCE Peer authentication";
                    }
                    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.";
                    }

                    uses session-grouping {
                        description
                            "session information";
                    }
                }//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.";
        }
    } //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.";
        }
    } //notification

    notification pcep-session-local-overload {
        description
            "This notification is sent when the local PCEP entity
            enters overload state for a peer.";

        uses notification-instance-hdr;

        uses notification-session-hdr;

        leaf overloaded {
            type boolean;
            description
                 "If the local PCEP entity has informed the peer
                 that it is currently overloaded, then this is set
                 to true. Otherwise, it is set to false.";
        }

        leaf overload-time {
            type uint32;
            units "seconds";
            description
                 "The interval of time that is remaining until the
                 local PCEP entity will cease to be overloaded on
                 this session.";
        }
    } //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.";
        }
    } //notification

    notification pcep-session-peer-overload {
        description
            "This notification is sent when a peer enters overload
            state.";

        uses notification-instance-hdr;

        uses notification-session-hdr;

        leaf peer-overloaded {
            type boolean;
            description
                "If the peer has informed the local PCEP entity that
                it is currently overloaded, then this is set to
                true. Otherwise, it is set to false.";
        }

        leaf peer-overload-time {
            type uint32;
            units "seconds";
            description
                "The interval of time that is remaining until the
                peer will cease to be overloaded.  If it is not
                known how long the peer will stay in overloaded
                state, this leaf is set to zero.";
        }
    } //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.";
        }
    } //notification

    /*
     * RPC
     */

    rpc trigger-resync {
        if-feature stateful;
        if-feature stateful-sync-opt;
        description
            "Trigger the resyncrinization at the 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.";
            }
        }
    }//rpc

}//module

<CODE ENDS>
                     

10.2. ietf-pcep-stats module

          
<CODE BEGINS> file "ietf-pcep-stats@2017-07-01.yang"
module ietf-pcep-stats {

    yang-version 1.1;

    namespace "urn:ietf:params:xml:ns:yang:ietf-pcep-stats";
    prefix ps;


    import ietf-pcep {
       prefix p;
    }

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



    organization
        "IETF PCE (Path Computation Element) Working Group";

    contact
        "WG Web:   <http://tools.ietf.org/wg/pce/>
         WG List:  <mailto:pce@ietf.org>
         WG Chair: JP Vasseur
                   <mailto:jpv@cisco.com>
         WG Chair: Julien Meuric
                   <mailto:julien.meuric@orange.com>
         WG Chair: Jonathan Hardwick
                   <mailto:Jonathan.Hardwick@metaswitch.com>
         Editor:   Dhruv Dhody
                   <mailto:dhruv.ietf@gmail.com>";

    description
        "The YANG module augments the PCEP yang operational
        model with statistics, counters and telemetry data";


    revision 2017-07-01 {
        description "Initial revision.";
        reference
            "RFC XXXX:  A YANG Data Model for Path Computation
                        Element Communications Protocol
                        (PCEP)";
    }




    /*
     * Groupings
     */

    grouping pcep-stats{
        description
            "This grouping defines statistics for PCEP. It is used
             for both peer and current session.";
        leaf avg-rsp-time{
            when "../../p:role = 'pce'" +
                 "or " +
                 "../../p:role = 'pcc-and-pce'"
            {
                description
                    "Valid for PCEP Peer as PCE";
            }
            type uint32;
            units "milliseconds";

            description
              "The average response time.
               If an average response time has not been
               calculated then this leaf has the value zero.";
        }

        leaf lwm-rsp-time{
            when "../../p:role = 'pce'" +
                 "or " +
                 "../../p:role = 'pcc-and-pce'"
            {
                description
                    "Valid for PCEP Peer as PCE";
            }
            type uint32;
            units "milliseconds";

            description
             "The smallest (low-water mark) response time seen.
              If no responses have been received then this
              leaf has the value zero.";
        }

        leaf hwm-rsp-time{
            when "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pce'" +
                 "or " +
                 "../../p: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 "../../p:role = 'pcc'" +
                 "or " +
                 "../../p: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 p:svec;
            description
                "If synchronized path computation is supported";
            leaf num-svec-sent{
                when "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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.";
            }
        }
        container stateful{
            if-feature p:stateful;
            description
                "Stateful PCE related statistics";
            leaf num-pcrpt-sent{
                when "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pcc'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 "../../../p:role = 'pce'" +
                     "or " +
                     "../../../p: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 p:pce-initiated;
                description
                    "PCE-Initiated related statistics";
                leaf num-pcinitiate-sent{
                    when "../../../../p:role = 'pcc'" +
                         "or " +
                         "../../../../p: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 "../../../../p:role = 'pce'" +
                         "or " +
                         "../../../../p: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 "../../../../p:role = 'pcc'" +
                         "or " +
                         "../../../../p: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 "../../../../p:role = 'pce'" +
                         "or " +
                         "../../../../p: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 "../../../../p:role = 'pce'" +
                         "or " +
                         "../../../../p: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.";
                }
            }
        }
        container path-key {
            when "../../p:role = 'pcc'" +
                 "or " +
                 "../../p:role = 'pcc-and-pce'"
            {
                description
                    "Valid for PCEP Peer as PCC";
            }
            if-feature p: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.";
            }
        }
    }//pcep-stats

    /*
     * Augment modules to add statistics
     */

    augment "/p:pcep/p:entity/p:peers/p:peer" {
        description
            "Augmenting the statistics";
        leaf num-sess-setup-ok{
            type yang:counter32;
            config false;
            description
                "The number of PCEP sessions successfully
                 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 "../../p:role = 'pce'" +
                     "or " +
                     "../../p: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 "../../p:role = 'pcc'" +
                     "or " +
                     "../../p: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 "/p:pcep/p:entity/p:peers/p:peer/" +
            "p:sessions/p:session" {
        description
            "Augmenting the statistics";
        container pcep-stats {
            description
                "The container for all statistics
                 at session level.";
            uses pcep-stats{
                description
                    "The statistics contained are
                     for the current sessions to
                     that peer. These are lost
                     when the session goes down.
                     ";
            }
        }//pcep-stats
    }//augment

}//module

<CODE ENDS>
                     

11. Security Considerations

The YANG module 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 [RFC5246]

The NETCONF access control model [RFC6536] 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 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:

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

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:

12. IANA Considerations

This document registers a URI in the "IETF XML Registry" [RFC3688]. Following the format in RFC 3688, the following registration has been made.

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

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

This document registers a YANG module in the "YANG Module Names" registry [RFC6020].

13. Acknowledgements

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

14. References

14.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012.
[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013.
[RFC8177] Lindem, A., Qu, Y., Yeung, D., Chen, I. and J. Zhang, "YANG Data Model for Key Chains", RFC 8177, DOI 10.17487/RFC8177, June 2017.
[RFC8040] Bierman, A., Bjorklund, M. and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017.
[I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J. and R. Varga, "PCEP Extensions for Stateful PCE", Internet-Draft draft-ietf-pce-stateful-pce-21, June 2017.
[I-D.ietf-pce-pce-initiated-lsp] Crabbe, E., Minei, I., Sivabalan, S. and R. Varga, "PCEP Extensions for PCE-initiated LSP Setup in a Stateful PCE Model", Internet-Draft draft-ietf-pce-pce-initiated-lsp-10, June 2017.
[I-D.ietf-pce-lsp-setup-type] Sivabalan, S., Tantsura, J., Minei, I., Varga, R. and J. Hardwick, "Conveying path setup type in PCEP messages", Internet-Draft draft-ietf-pce-lsp-setup-type-04, April 2017.
[I-D.ietf-pce-segment-routing] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W. and J. Hardwick, "PCEP Extensions for Segment Routing", Internet-Draft draft-ietf-pce-segment-routing-09, April 2017.
[I-D.ietf-teas-yang-te] Saad, T., Gandhi, R., Liu, X., Beeram, V., Shah, H. and I. Bryskin, "A YANG Data Model for Traffic Engineering Tunnels and Interfaces", Internet-Draft draft-ietf-teas-yang-te-07, June 2017.
[I-D.ietf-netconf-tls-client-server] Watsen, K. and G. Wu, "TLS Client and Server Models", Internet-Draft draft-ietf-netconf-tls-client-server-03, June 2017.

14.2. Informative References

[RFC4655] Farrel, A., Vasseur, J. and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D. and J. Hardwick, "Path Computation Element Communication Protocol (PCEP) Management Information Base (MIB) Module", RFC 7420, DOI 10.17487/RFC7420, December 2014.
[I-D.ietf-netmod-rfc6087bis] Bierman, A., "Guidelines for Authors and Reviewers of YANG Data Model Documents", Internet-Draft draft-ietf-netmod-rfc6087bis-13, June 2017.
[I-D.ietf-netmod-revised-datastores] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K. and R. Wilton, "Network Management Datastore Architecture", Internet-Draft draft-ietf-netmod-revised-datastores-02, May 2017.
[I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, Q. and D. Dhody, "Secure Transport for PCEP", Internet-Draft draft-ietf-pce-pceps-14, May 2017.

Appendix A. Contributor Addresses

Rohit Pobbathi
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka  560066
India

EMail: rohit.pobbathi@huawei.com

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

EMail: vinods.kumar@huawei.com

Zafar Ali
Cisco Systems
Canada

EMail: zali@cisco.com

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

EMail: Xufeng_Liu@jabil.com

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

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

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

EMail: udayasreereddy@gmail.com

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

EMail: zhang.xian@huawei.com

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

EMail: s.avantika.avantika@gmail.com

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

EMail: shashikanth.vh@huawei.com

        

Authors' Addresses

Dhruv Dhody (editor) Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560066 India EMail: dhruv.ietf@gmail.com
Jonathan Hardwick Metaswitch 100 Church Street Enfield, EN2 6BQ UK EMail: jonathan.hardwick@metaswitch.com
Vishnu Pavan Beeram Juniper Networks USA EMail: vbeeram@juniper.net
Jeff Tantsura USA EMail: jefftant@gmail.com