OPSAWG Working Group                                          B. Wu, Ed.
Internet-Draft                                                Q. Wu, Ed.
Intended status: Standards Track                                  Huawei
Expires: January 7, 23 July 2022                                  M. Boucadair, Ed.
                                                                  Orange
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                                  B. Wen
                                                                 Comcast
                                                                  C. Liu
                                                            China Unicom
                                                                   H. Xu
                                                           China Telecom
                                                            July 6, 2021
                                                         19 January 2022

    A YANG Model for Network and VPN Service Performance Monitoring
                draft-ietf-opsawg-yang-vpn-service-pm-01
                draft-ietf-opsawg-yang-vpn-service-pm-02

Abstract

   The data model for network topologies defined in RFC 8345 introduces
   vertical layering relationships between networks that can be
   augmented to cover network and service topologies.  This document
   defines a YANG module for both
   network performance monitoring (PM) of both
   networks and VPN service performance
   monitoring services that can be used to monitor and manage
   network performance on the topology at higher layer or the service
   topology between VPN sites.

   The YANG model defined in this document is designed as an
   augmentation to the network topology YANG model defined in RFC 8345
   and draws on relevant YANG types defined in RFC 6991, RFC 8345, and
   RFC 8532.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on January 7, 23 July 2022.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Network and VPN Service Performance Monitoring Model Usage  .   3
     3.1.  Collecting Data via Pub/Sub Mechanism . . . . . . . . . .   5
     3.2.  Collecting Data via Retrieval Methods . . . . . . . . . .   5
   4.  Description of The Data Model . . . . . . . . . . . . . . . .   5
     4.1.  Layering Relationship between Multiple Layers of
           Topology   5  . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Network Level . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Node Level  . . . . . . . . . . . . . . . . . . . . . . .   7   8
     4.4.  Link and Termination Point Level  . . . . . . . . . . . .   8   9
   5.  Network and VPN Service Performance Monitoring YANG Module  .  11  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  23  25
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  24  26
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  24  27
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  24  27
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  24  27
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  24  27
     10.2.  Informative References . . . . . . . . . . . . . . . . .  26  29
   Appendix A.  Illustrating Examples  . . . . . . . . . . . . . . .  27  30
     A.1.  Example of Pub/Sub Retrieval  . . . . . . . . . . . . . .  27  30
     A.2.  Example of RPC-based Retrieval  . . . . . . . . . . . . .  29  32
     A.3.  Example of Percentile Monitoring  . . . . . . . . . . . .  30  34
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  31  34

1.  Introduction

   [RFC8969] describes a framework for automating service and network
   management with YANG models, proposing models.  It proposes that the performance
   measurement telemetry model to be tied with the service, such as
   Layer 3 VPN and Layer 2 VPN, or network models to monitor the overall
   network performance or Service Level Agreements (SLA).

   This

   The performance of VPN services is associated with the performance
   changes of the underlay network that carries VPN services, such as
   the delay of the underlay tunnels and the packet loss status of the
   device interfaces.  Additionally, the integration of Layer 2/Layer 3
   VPN performance and network performance data enables the orchestrator
   to subscribe to VPN service performance in a unified manner.
   Therefore, this document defines a YANG module [RFC7950] for both network
   performance monitoring and
   VPN service performance monitoring.  This monitoring (PM).  The module can be used to
   monitor and manage network performance on the topology level or the
   service topology between VPN sites, in particular.

   This document does not introduce new metrics for network performance
   or mechanisms for measuring network performance, but uses the
   existing mechanisms and statistics to show display the performance
   monitoring statistics at the network and service layers.  All these
   metrics are defined as unidirectional metrics.

   The YANG module defined in this document is designed as an
   augmentation to the network topology YANG model defined in [RFC8345].

   This document uses the common VPN [RFC8345]
   and draws on relevant YANG module types defined in [RFC6991], [RFC8345],
   [RFC8532], and [I-D.ietf-opsawg-vpn-common].

   Appendix A provides a set of examples to illustrate the use of the
   module.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document following terms are to be interpreted as described defined in BCP
   14 [RFC2119][RFC8174] when, [RFC7950] and only when, they appear are used in all
   capitals, as shown here.

   Tree this
   specification:

   *  augment

   *  data model

   *  data node

   The terminology for describing YANG data models is found in
   [RFC7950].

   The tree diagrams used in this document follow the notation defined
   in [RFC8340].

3.  Network and VPN Service Performance Monitoring Model Usage

   Models are key for automating network management operations.
   According to [RFC8969], together with service and network models,
   performance measurement telemetry models are needed to monitor
   network performance to meet specific service requirements (typically
   captured in an SLA).  The YANG module defined in this document is
   designed to derive VPN or network level performance data based on
   lower-level data collected via monitoring counters of the involved
   devices.

                            +---------------+
                            |   Customer    |
                            +-------+-------+
                                    |
            Customer Service Models |
                                    |
                            +-------+---------+
                            |    Service      |
                            |  Orchestration  |
                            +------+-+--------+
                                   | |
            Network Service Models | | Network and VPN Service PM Models
                                   | |
                            +------+-+--------+
                            |     Network     |
                            |   Controller    |
                            +-------+---------+
                                    |
            +-----------------------+------------------------+
                                  Network

                   Figure 1: Reference Architecture

   As shown in Figure 1, in the context of layering model architecture
   described in [RFC8309], the network and VPN service performance
   monitoring (PM) model can be used to expose some a set of performance
   information to the above layer.  Such an information can be used by an
   orchestrator to subscribe to performance data.  The network
   controller will then notify the orchestrator about corresponding
   parameter changes.

   Before using the network and VPN service PM model, the mapping
   between the VPN service topology and the underlying physical network
   should be setup.  Also, set up.

   The YANG module defined in this document is designed to derive VPN or
   network level performance data based on lower-level data collected
   via monitoring counters of the involved devices.  The performance
   monitoring data per link in the underlying network can be collected
   using a network performance measurement method such as MPLS Loss and
   Delay Measurement [RFC6374].  The performance monitoring information
   reflecting the quality of the network or VPN service (e.g., end to end-to-
   end network performance data between source node and destination node
   in the network or between VPN sites) can be computed and aggregated,
   for example, using the information from the Traffic Engineering
   Database (TED), defined in
   [RFC7471], [RFC8570], or [RFC7471] [RFC8570] [RFC8571] or LMAP [RFC8194].

   The measurement and report intervals that are associated with these
   performance data usually depend on the configuration parameters. of the specific
   measurement method or collection method or various combinations.
   This document defines a network-wide measurement interval to align
   measurement requirements for networks or VPN services.

   In addition, the amount of performance data collected from the
   devices can be huge.  To avoid receiving a large amount of
   operational data of VPN instances, VPN interfaces, or tunnels, the
   network controller can specifically subscribe to metric-specific data
   using the tagging methods defined in [I-D.ietf-netmod-node-tags].

3.1.  Collecting Data via Pub/Sub Mechanism

   Some applications such as service-assurance applications, which must
   maintain a continuous view of operational data and state, can use the
   subscription model [RFC8641] specified in[RFC8641] to subscribe to the specific
   network performance data or VPN service performance data they are
   interested in, at the data source.

   The data source can, then, use the network and VPN service assurance
   model defined in this document and the YANG Push model [RFC8641] to
   distribute specific telemetry data to target recipients.

3.2.  Collecting Data via Retrieval Methods

   To obtain a snapshot of a large amount of performance data from a
   network element (including network controllers), service-assurance
   applications may use methods such as retrieving performance data or
   RPC commands defined as part of YANG models.

4.  Description of The Data Model

   This document defines the YANG module, "ietf-network-vpn-pm", which
   is an augmentation to the "ietf-network" and "ietf-network-topology".

   The performance monitoring data augments the service topology as
   shown in Figure 2.

   +----------------------+          +-----------------------+
   |ietf-network          |          |Network and VPN Service|
   |ietf-network-topology |<---------|Performance Monitoring |
   +----------------------+ augments |        Model          |
                                     +-----------------------+

                       Figure 2: Module Augmentation

4.1.  Layering Relationship between Multiple Layers of Topology

   [RFC8345] defines a YANG data model for network/service topologies
   and inventories.  The service topology described in [RFC8345]
   includes the virtual topology for a service layer above Layer 1 (L1),
   Layer 2 (L2), and Layer 3 (L3).  This service topology has the
   generic topology elements of node, link, and terminating point.  One
   typical example of a service topology is described in Figure 3 of
   [RFC8345]: two VPN service topologies instantiated over a common L3
   topology.  Each VPN service topology is mapped onto a subset of nodes
   from the common L3 topology.

   Figure 3 illustrates an example of a topology that maps between the
   VPN service topology and an underlying network:

                     VPN 1                       VPN 2
           +-----------------------+    +---------------------+
            /S1C-[VN3]...
          /                       /    /                     /
         /S1C_[VN3]:::           /    /S2A             S2B  /
        /      /         \   :::::     /    / -[VN1]______[VN3]-  / _[VN1]______[VN3]_  /
       /           \       :   /    /   :            :    /
         /    /Service Overlay
      /             \  S1A       :: : : : : :             :   /
        /S1B-[VN2]____[VN1]--
     /S1B_[VN2]____[VN1]_S1A /    /   : :            :  /
    +--------:-------:------+    +---:----:----------:-+
             :        :       :: : :       :         :
             :         :    :              :         :
   Site-1A   :  +-------:--: ----- -------- : -------:-----+ Site-1C
     [CE1]___: /__ ___ [N1]__________________ [N2]__ :___ /__[CE3]
             :/      /  / \             _____/ /    :    /
   [CE5]___  : ___  /  /    \     _____/      /   ::    /
 Site-2A    /:        /       \  /           /   :     /
           / :                [N5]          /   :     /  Underlay Network
          /   :     /       __/ \__        /   :     /
         /     :   /    ___/       \__    /   :     /
Site-1B /       : / ___/              \  /   :     /  Site-2B
    [CE2]-/------- [N4]_________________ [N3]:::-----/----[CE4]
[CE2]_ /________[N4]_________________ [N3]:::_____/____[CE4]
      +------------------------------------------+

    Legend:
    N:node   VN:VPN-Node  S:Site
    __  Link
    :   Mapping between networks

      Figure 3: Example of Topology Mapping Between VPN Service
                   Topology and Underlying Network

   As shown in Figure 3, two VPN services topologies are both built on
   top of one common underlying physical network:

   VPN 1:  This service topology supports hub-spoke communications for
      'customer 1' connecting the customer's access at three sites:
      'Site-1A', 'Site-1B', and 'Site-1C'.  These sites are connected to
      nodes that are mapped to node 1 (N1), node 2 (N2), and node 4 (N4)
      in the underlying physical network.  'Site-1A' plays the role of
      hub while 'Site-1B' and 'Site-1C' are configured as spoke.

   VPN 2:  This service supports any-to-any communications for 'customer
      2' connecting the customer's access at two sites: 'Site-
      2A' 'Site-2A' and
      'Site-2B'.  These sites are connected to nodes that are mapped to
      nodes 1 (N1) and node 3 (N3)5 in the underlying physical network.
      'Site-2A' and 'Site-2B' have 'any-to-any' role.

4.2.  Network Level

   For network performance monitoring, the container of "networks" in
   [RFC8345] do does not need to be extended.

   For VPN service performance monitoring, the container "service-type"
   is defined to indicate the VPN type, e.g., L3VPN or Virtual Private
   LAN Service (VPLS).  The values are taken from
   [I-D.ietf-opsawg-vpn-common].  When a network topology instance
   contains the L3VPN or other L2VPN network type, it represents a VPN
   instance that can perform performance monitoring.

   This model

   The tree in Figure 4 is a part of ietf-network-vpn-pm tree.  It
   defines the following set of network level attributes:

   "vpn-id":  Refers to an identifier of VPN service defined in
      [I-D.ietf-opsawg-vpn-common]).  This identifier is used to
      correlate the performance status with the network service
      configuration.

   "vpn-service-topology":  Indicates the type of the VPN topology.
      This model supports "any-to-any", "Hub and Spoke" (where Hubs can
      exchange traffic), and "Hub and Spoke disjoint" (where Hubs cannot
      exchange traffic) that are taken from
      [I-D.ietf-opsawg-vpn-common].  These VPN topology types can be
      used to describe how VPN sites communicate with each other.

   module: ietf-network-vpn-pm
     augment /nw:networks/nw:network/nw:network-types:
       +--rw service-type!
          +--rw service-type?   identityref
     augment /nw:networks/nw:network:
       +--rw vpn-pm-attributes
          +--rw vpn-id?                 vpn-common:vpn-id
          +--rw vpn-service-topology?   identityref

            Figure 4: Network Level View YANG Tree of the Hierarchies

4.3.  Node Level

   The tree in Figure 5 is the node part of ietf-network-vpn-pm tree.

   For network performance monitoring, a container of "pm-attributes" is
   augmented to the list of "node" that are defined in [RFC8345].  And
   the leaf of  The
   "node-type" indicates the device type of Provider Edge (PE), Provider
   (P) device, or Autonomous System Border Router (ASBR), so that the
   performance metric between any two nodes each with specific node type
   can be reported.

   For VPN service performance monitoring, this the model defines only the
   following minimal set of node level network topology attributes:

   "role":  Defines the role in a particular VPN service topology.  The
      roles are taken from [I-D.ietf-opsawg-vpn-common] (e.g., any-to-
      any-role, spoke-role, hub-role).

   "vpn-summary-statistics":  Lists a set of IPv4 statistics, IPv6
      statistics, and MAC statistics.  These statistics are specified
      separately.

     augment /nw:networks/nw:network/nw:node:
       +--rw pm-attributes
          +--rw node-type?                identityref
          +--rw role?                     identityref
          +--ro vpn-summary-statistics
             +--ro ipv4
             |  +--ro maximum-routes?        uint32
             |  +--ro total-active-routes?   uint32
             +--ro ipv6
             |  +--ro maximum-routes?        uint32
             |  +--ro total-active-routes?   uint32
             +--ro mac-num
                +--ro mac-num-limit?          uint32
                +--ro total-active-mac-num?   uint32

             Figure 5: Node Level View YANG Tree of the Hierarchies

4.4.  Link and Termination Point Level

   The tree in Figure 6 is the link and termination point (TP) part of
   ietf-network-vpn-pm tree.

   The 'links' are classified into two types: topology link defined in
   [RFC8345] and abstract link of a VPN between PEs.

   The performance data of a link is a collection of counters that
   report the performance status.

     augment /nw:networks/nw:network/nt:link:
       +--rw pm-attributes
          +--rw low-percentile?                percentile
          +--rw middle-percentile?             percentile
          +--rw high-percentile?               percentile
          +--ro pm-source?              string
          +--rw measurement-interval?          uint32
          +--ro reference-time?                yang:date-and-time
          +--ro measurement-interval?   uint32 pm-source?                     identityref
          +--ro pm-statistics one-way-pm-statistics
          |  +--ro loss-statistics
          |  |  +--ro packet-loss-count?   yang:counter64
          |  |  +--ro packet-reorder-count?       yang:counter64
          |  |  +--ro packets-out-of-seq-count?   yang:counter64
          |  |  +--ro packets-dup-count?          yang:counter64
          |  |  +--ro loss-ratio?          percentage
          |  +--ro delay-statistics
          |  |  +--ro direction?                 identityref
          |  |  +--ro unit-value?                identityref
          |  |  +--ro min-delay-value?           yang:gauge64
          |  |  +--ro max-delay-value?           yang:gauge64
          |  |  +--ro low-delay-percentile?      yang:gauge64
          |  |  +--ro middle-delay-percentile?   yang:gauge64
          |  |  +--ro high-delay-percentile?     yang:gauge64
          |  +--ro jitter-statistics
          |     +--ro unit-value?                 identityref
          |     +--ro min-jitter-value?           yang:gauge32
          |     +--ro max-jitter-value?           yang:gauge32
          |     +--ro low-jitter-percentile?      yang:gauge32
          |     +--ro middle-jitter-percentile?   yang:gauge32
          |     +--ro high-jitter-percentile?     yang:gauge32
          +--ro protocol-type? vpn-underlay-transport-type?   identityref
     augment /nw:networks/nw:network/nw:node/nt:termination-point:
          +--ro pm-statistics vpn-one-way-pm-statistics* [class-id]
             +--ro inbound-octets?             yang:counter64 class-id             string
             +--ro inbound-unicast?            yang:counter64 loss-statistics
             |  +--ro inbound-nunicast? packet-loss-count?   yang:counter64
             |  +--ro inbound-discards?           yang:counter32 loss-ratio?          percentage
             +--ro inbound-errors?             yang:counter64 delay-statistics
             |  +--ro inbound-unknown-protocol?   yang:counter64 unit-value?                identityref
             |  +--ro outbound-octets?            yang:counter64 min-delay-value?           yang:gauge64
             |  +--ro outbound-unicast?           yang:counter64 max-delay-value?           yang:gauge64
             |  +--ro outbound-nunicast?          yang:counter64 low-delay-percentile?      yang:gauge64
             |  +--ro outbound-discards?          yang:counter64 middle-delay-percentile?   yang:gauge64
             |  +--ro outbound-errors?            yang:counter64

    Figure 6: Link and Termination point Level View of the high-delay-percentile?     yang:gauge64
             +--ro jitter-statistics
                +--ro unit-value?                 identityref
                +--ro min-jitter-value?           yang:gauge32
                +--ro max-jitter-value?           yang:gauge32
                +--ro low-jitter-percentile?      yang:gauge32
                +--ro middle-jitter-percentile?   yang:gauge32
                +--ro high-jitter-percentile?     yang:gauge32
     augment /nw:networks/nw:network/nw:node/nt:termination-point:
       +--ro pm-statistics
          +--ro reference-time?             yang:date-and-time
          +--ro inbound-octets?             yang:counter64
          +--ro inbound-unicast?            yang:counter64
          +--ro inbound-nunicast?           yang:counter64
          +--ro inbound-discards?           yang:counter32
          +--ro inbound-errors?             yang:counter64
          +--ro inbound-unknown-protocol?   yang:counter64
          +--ro outbound-octets?            yang:counter64
          +--ro outbound-unicast?           yang:counter64
          +--ro outbound-nunicast?          yang:counter64
          +--ro outbound-discards?          yang:counter64
          +--ro outbound-errors?            yang:counter64
          +--ro vpn-network-access* [network-access-id]
             +--ro network-access-id           vpn-common:vpn-id
             +--ro reference-time?             yang:date-and-time
             +--ro inbound-octets?             yang:counter64
             +--ro inbound-unicast?            yang:counter64
             +--ro inbound-nunicast?           yang:counter64
             +--ro inbound-discards?           yang:counter32
             +--ro inbound-errors?             yang:counter64
             +--ro inbound-unknown-protocol?   yang:counter64
             +--ro outbound-octets?            yang:counter64
             +--ro outbound-unicast?           yang:counter64
             +--ro outbound-nunicast?          yang:counter64
             +--ro outbound-discards?          yang:counter64
             +--ro outbound-errors?            yang:counter64

        Figure 6: Link and Termination point Level YANG Tree of the
                                hierarchies

   For the data nodes of 'link' depicted in Figure 6, the YANG module
   defines the following minimal set of link-level performance
   attributes:

   Percentile parameters:  The module supports reporting delay and
      jitter metric by percentile values.  By default, low percentile
      (10th percentile), mid percentile (50th percentile), high
      percentile (90th percentile) are used.  Setting a percentile into to
      0.00 indicates the client is not interested in receiving
      particular percentile.  If all percentile nodes are set to 0.00,
      this represents that no percentile related nodes will be reported
      for a given performance metric (e.g. (e.g., one-way delay, one-way delay
      variation) and only peak/min values will be reported.  For
      example, a client can inform the server that it is interested in
      receiving only high percentiles.  Then for a given link, at a
      given "reference-time" and "measurement-interval", the 'high-delay-
      percentile' 'high-
      delay-percentile' and 'high-jitter-percentile' will be reported.
      An example to illustrate the use of percentiles is provided in
      Appendix A.3.

   "pm-source":

   PM source ("pm-source"):  Indicates the performance monitoring
      source.  The data for the topology link can be based, e.g., on
      BGP-LS [RFC8571].  The statistics of the VPN abstract links can be
      collected based upon VPN OAM mechanisms, e.g., OAM mechanisms
      specified in [I-D.ietf-opsawg-l3sm-l3nm], or Ethernet service OAM
      specified in [I-D.ietf-opsawg-l2nm].  Alternatively, the data can
      be based upon the underlay technology OAM mechanisms, for example,
      GRE tunnel OAM.

   Measurement interval ("measurement-interval"):  Specifies the
      performance measurement interval, in seconds.

   Reference time ("reference-time"):  Indicates the start time of the
      performance measurement for link statistics.  For termination
      point metrics, this parameter indicates the timestamp when the
      counters are obtained.

   Loss Statistics: statistics:  A set of one-way loss statistics attributes that
      are used to measure end to end loss between VPN sites or between
      any two network nodes.  The exact loss value or the loss
      percentage can be reported.

   Delay Statistics: statistics:  A set of one-way delay statistics attributes that
      are used to measure end to end latency between VPN sites or
      between any two network nodes.  The peak/min values or percentile
      values can be reported.

   Jitter Statistics: statistics:  A set of one-way IP Packet Delay Variation
      [RFC3393] statistics attributes that are used to measure end to
      end jitter between VPN sites or between any two network nodes.
      The peak/min values or percentile values can be reported.

   "protocol-type":  Indicates

   VPN underlay transport type ("vpn-underlay-transport-type"):  Indicat
      es the abstract link protocol-type of a VPN, such as GRE or IP-in-IP. IP-in-
      IP.  The leaf refers to an identifier of the "underlay-transport"
      defined in [I-D.ietf-opsawg-vpn-common], which describes the
      transport technology to carry the traffic of the VPN service.

   VPN PM statistics ("vpn-unidirectional-pm-statistics"):  Lists
      performance measurement statistics for the abstract underlay link
      between VPN PEs with given "class-id" names.  The list is defined
      separately from "one-way-pm-statistics", which is used to collect
      generic metrics for unspecified "class-id" names.

   For the data nodes of 'termination-point' depicted in Figure 6, the
   module defines the following minimal set of statistics:

   Inbound statistics:  A set of inbound statistics attributes that are
      used to measure the inbound statistics of the termination point,
      such as received packets, received packets with errors, etc.

   Outbound statistics:  A set of outbound statistics attributes that
      are used to measure the outbound statistics of the termination
      point, such as sent packets, packets that could not be sent due to
      errors, etc.

   VPN network access ("vpn-network-access"):  Lists counters of the VPN
      network access defined in [I-D.ietf-opsawg-l3sm-l3nm] or
      [I-D.ietf-opsawg-l2nm].  When multiple VPN network accesses are
      created using the same physical port, finer-grained metrics can be
      monitored.

5.  Network and VPN Service Performance Monitoring YANG Module

   The "ietf-network-vpn-pm" module uses types defined in [RFC8345],
   [RFC6991], [RFC8532], and [RFC8532]. [I-D.ietf-opsawg-vpn-common].

   <CODE BEGINS> file "ietf-network-vpn-pm@2021-07-06.yang" "ietf-network-vpn-pm@2021-01-18.yang"
   module ietf-network-vpn-pm {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm";
     prefix nvp;

     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Types";
     }
     import ietf-vpn-common {
       prefix vpn-common;
       reference
         "RFC CCCC: XXXX: A Layer 2/3 VPN Common YANG Model"; Model.";
       // RFC Ed.: replace XXXX with actual RFC number and remove
       // this note.
     }
     import ietf-network {
       prefix nw;
       reference
         "RFC 8345: A YANG Data Model for Network
                    Topologies, Section 6.1";
     }
     import ietf-network-topology {
       prefix nt;
       reference
         "RFC 8345: A YANG Data Model for Network
                    Topologies, Section 6.2";
     }
     import ietf-lime-time-types {
       prefix lime;
       reference
         "RFC 8532: Generic YANG Data Model for the Management of
                    Operations, Administration, and Maintenance
                    (OAM) Protocols That Use Connectionless Communications";
     }

     organization
       "IETF OPSAWG Working Group";
     contact
       "Editor: Qin Wu
                <bill.wu@huawei.com>
        Editor: Bo Wu
                <lana.wubo@huawei.com>
        Editor: Mohamed Boucadair
                <mohamed.boucadair@orange.com>";
     description
       "This module defines a model for Network and VPN Service Performance
        monitoring.

        Copyright (c) 2021 2022 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject
        to the license terms contained in, the Simplified BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info).
        This version of this YANG module is part of RFC XXXX; see
        the RFC itself for full legal notices.";

     // RFC Ed.: update the date below with the date of RFC
     // publication and remove this note.
     // RFC Ed.: replace XXXX with actual RFC number and remove
     // this note.

     revision 2021-07-06 2022-01-18 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Model for Network and VPN Service Performance
                    Monitoring";
     }

     identity node-type {
       description
         "Base identity for node type";
     }

     identity pe {
       base node-type;
       description
      "Identity for Provider
         "Provider Edge (PE) node type.";
     }

     identity asbr {
       base node-type;
       description
      "Identity for Autonomous
         "Autonomous System Border Router (ASBR) node type.";
     }

     identity p {
       base node-type;
       description
      "Identity for P
         "P node type.";
     }

     identity direction pm-source-type {
       description
         "Base identity for measurement direction including
       one-way measurement and two-way measurement."; from which specific performance monitoring
          mechanism types are derived.";
     }

     identity one-way pm-source-bgpls {
       base direction; pm-source-type;
       description
      "Identity for one-way measurement.";
         "Indicates BGP-LS as the performance monitoring metric source";
       reference
         "RFC8571: BGP - Link State (BGP-LS) Advertisement of
           IGP Traffic Engineering Performance Metric Extensions";
     }

     identity two-way pm-source-twamp {
       base direction; pm-source-type;
       description
      "Identity for two-way measurement.";
         "Indicates Two-Way Active Measurement Protocol(TWAMP)
          as the performance monitoring metric source.";
       reference
         "RFC5357: : A Two-Way Active Measurement Protocol (TWAMP)";
     }

     identity pm-source-y-1731 {
       base pm-source-type;
       description
         "Indicates Ethernet OAM Y.1731 as the performance monitoring
          metric source.";
       reference
         "ITU-T Y.1731";
     }

     typedef percentage {
       type decimal64 {
         fraction-digits 5;
         range "0..100";
       }
       description
         "Percentage.";
     }

     typedef percentile {
       type decimal64 {
         fraction-digits 5;
         range "1..100";
       }
       description
         "The percentile is a statistical value that indicates that a
          certain percentage of a set of data falls below it.";
     }

     grouping vpn-summary-statistics {
       description
         "VPN Statistics grouping used for network topology
          augmentation.";
       container vpn-summary-statistics {
         config false;
         description
           "Container for VPN summary statistics.";
         container ipv4 {
           leaf maximum-routes {
             type uint32;
             description
            "Total
               "Indicates the maximum number of IPv4 routes for the VPN.";
           }
           leaf total-active-routes {
             type uint32;
             description
            "Total
               "Indicates total active IPv4 routes for the VPN.";
           }
           description
             "IPv4-specific parameters.";
         }
         container ipv6 {
           leaf maximum-routes {
             type uint32;
             description
            "Total
               "Indicates the maximum number of IPv6 routes for the VPN.";
           }
           leaf total-active-routes {
             type uint32;
             description
            "Total
               "Indicates total active IPv6 routes for the VPN.";
           }
           description
             "IPv6-specific parameters.";
         }
         container mac-num {
           leaf mac-num-limit {
             type uint32;
             description
               "Maximum number of MAC addresses.";
           }
           leaf total-active-mac-num {
             type uint32;
             description
               "Total active MAC entries for the VPN.";
           }
           description
             "MAC statistics.";
         }
       }
     }
     grouping link-error-statistics link-loss-statistics {
       description
         "Grouping for per link error statistics.";
       container loss-statistics {
         description
           "Per link loss statistics.";
         leaf packet-loss-count {
           type yang:counter64;
           description
             "Total received packet drops count.";
         }
         leaf packet-reorder-count {
        type yang:counter64;
        description
          "Total received packet reordered count.";
      }
      leaf packets-out-of-seq-count {
        type yang:counter64;
        description
          "Total received out of sequence count.";
      }
      leaf packets-dup-count {
        type yang:counter64;
        description
          "Total received packet duplicates count.";
      }
      leaf loss-ratio {
           type percentage;
           description
             "Loss ratio of the packets. Express as percentage
              of packets lost with respect to packets sent.";
         }
       }
     }

     grouping link-delay-statistics {
       description
         "Grouping for per link delay statistics"; statistics.";
       container delay-statistics {
         description
           "Link delay summarised information. By default,
         one way measurement protocol (e.g., OWAMP) is used
         to measure delay.";
      leaf direction {
        type identityref {
          base direction;
        }
        default "one-way";
        description
          "Define measurement direction including delay summarized information. By default,
            one way measurement and two way measurement.";
      } protocol (e.g., OWAMP) is used
            to measure delay.";
         leaf unit-value {
           type identityref {
             base lime:time-unit-type;
           }
           default "lime:milliseconds";
           description
             "Time units, where the options are s, ms, ns, etc.";
         }
         leaf min-delay-value {
           type yang:gauge64;
           description
             "Minimum delay value observed."; observed one-way delay.";
         }
         leaf max-delay-value {
           type yang:gauge64;
           description
             "Maximum delay value observed."; observed one-way delay.";
         }
         leaf low-delay-percentile {
           type yang:gauge64;
           description
             "Low percentile of the delay observed one-way delay with
              specific measurement method.";
         }
         leaf middle-delay-percentile {
           type yang:gauge64;
           description
             "Middle percentile of the delay observed one-way delay with
              specific measurement method.";
         }
         leaf high-delay-percentile {
           type yang:gauge64;
           description
             "High percentile of the delay observed one-way delay with
              specific measurement method.";
         }
       }
     }

     grouping link-jitter-statistics {
       description
         "Grouping for per link jitter statistics"; statistics.";
       container jitter-statistics {
         description
           "Link jitter summarised summarized information. By default,
            jitter is measured using one-way IP Packet Delay Variation
            (IPDV).";
         leaf unit-value {
           type identityref {
             base lime:time-unit-type;
           }
           default "lime:milliseconds";
           description
             "Time units, where the options are s, ms, ns, etc.";
         }
         leaf min-jitter-value {
           type yang:gauge32;
           description
             "Minimum jitter value observed."; observed one-way jitter.";
         }
         leaf max-jitter-value {
           type yang:gauge32;
           description
             "Maximum jitter value observed."; observed one-way jitter.";
         }
         leaf low-jitter-percentile {
           type yang:gauge32;
           description
             "Low percentile of the jitter observed."; observed one-way jitter.";
         }
         leaf middle-jitter-percentile {
           type yang:gauge32;
           description
             "Middle percentile of the jitter observed."; observed one-way jitter.";
         }
         leaf high-jitter-percentile {
           type yang:gauge32;
           description
             "High percentile of the jitter observed."; observed one-way jitter.";
         }
       }
     }

     grouping tp-svc-telemetry {
       leaf reference-time {
         type yang:date-and-time;
         config false;
         description
           "Indicates the time when the statistics are collected.";
       }
       leaf inbound-octets {
         type yang:counter64;
         description
           "The total number of octets received on the
            interface, including framing characters.";
       }
       leaf inbound-unicast {
         type yang:counter64;
         description
           "Inbound unicast packets were received, and delivered
            to a higher layer during the last period.";
       }
       leaf inbound-nunicast {
         type yang:counter64;
         description
           "The number of non-unicast (i.e., subnetwork-
            broadcast or subnetwork-multicast) packets
            delivered to a higher-layer protocol.";
       }
       leaf inbound-discards {
         type yang:counter32;
         description
           "The number of inbound packets which were chosen
            to be discarded even though no errors had been
            detected to prevent their being deliverable to a
            higher-layer protocol.";

       }
       leaf inbound-errors {
         type yang:counter64;
         description
           "The number of inbound packets that contained
            errors preventing them from being deliverable to a
            higher-layer protocol.";
       }
       leaf inbound-unknown-protocol {
         type yang:counter64;
         description
           "The number of packets received via the interface
            which were discarded because of an unknown or
            unsupported protocol.";
       }
       leaf outbound-octets {
         type yang:counter64;
         description
           "The total number of octets transmitted out of the
            interface, including framing characters.";
       }
       leaf outbound-unicast {
         type yang:counter64;
         description
           "The total number of packets that higher-level
            protocols requested be transmitted to a
            subnetwork-unicast address, including those that
            were discarded or not sent.";
       }
       leaf outbound-nunicast {
         type yang:counter64;
         description
           "The total number of packets that higher-level
            protocols requested be transmitted to a non-
            unicast (i.e., a subnetwork-broadcast or
            subnetwork-multicast) address, including those
            that were discarded or not sent.";
       }
       leaf outbound-discards {
         type yang:counter64;
         description
           "The number of outbound packets which were chosen
            to be discarded even though no errors had been
            detected to prevent their being transmitted. One
            possible reason for discarding such a packet could
            be to free up buffer space.";
       }
       leaf outbound-errors {
         type yang:counter64;
         description
           "The number of outbound packets that contained
            errors preventing them from being deliverable to a
            higher-layer protocol.";
       }
       description
         "Grouping for interface service telemetry.";
     }

     augment "/nw:networks/nw:network/nw:network-types" {
       description
         "Defines the service topologies types"; types.";
       container service-type {
         presence "Indicates Network network service topology"; topology.";
         leaf service-type {
           type identityref {
             base vpn-common:service-type;
           }
           description
             "The presence identifies the network service type,
              e.g., L3VPN, VPLS, etc.";
         }
         description
           "Container for VPN service type.";
       }
     }

     augment "/nw:networks/nw:network" {
       when 'nw:network-types/nvp:service-type' {
         description
        "Augment
           "Augments only for VPN Network topology.";
       }
       description
      "Augment
         "Augments the network with service topology attributes";
       container vpn-pm-attributes {
         leaf vpn-id {
           type vpn-common:vpn-id;
           description
             "VPN identifier.";
         }
         leaf vpn-service-topology {
           type identityref {
             base vpn-common:vpn-topology;
           }
           description
             "VPN service topology, e.g., hub-spoke, any-to-any,
           hub-spoke-disjoint";
              hub-spoke-disjoint.";

         }
         description
           "Container for vpn VPN topology attributes.";
       }
     }

     augment "/nw:networks/nw:network/nw:node" {
       description
      "Augment
         "Augments the network node with other general attributes"; attributes.";
       container pm-attributes {
         leaf node-type {
           type identityref {
             base node-type;
           }
           description
             "Node type, e.g., PE, P, ASBR.";
         }
         description
           "Container for node attributes.";
       }
     }

     augment "/nw:networks/nw:network/nw:node/pm-attributes" {
       when '../../nw:network-types/nvp:service-type' {
         description
        "Augment
           "Augments only for VPN node attributes.";
       }
       description
      "Augment
         "Augments the network node with VPN specific attributes"; attributes.";
       leaf role {
         type identityref {
           base vpn-common:role;
         }
         default "vpn-common:any-to-any-role";
         description
           "Role of the node in the VPN.";
       }
       uses vpn-summary-statistics;
     }

     augment "/nw:networks/nw:network/nt:link" {
       description
      "Augment
         "Augments the network topology link with performance monitoring
       attributes";
          attributes.";
       container pm-attributes {
         description
           "Container for PM attributes.";
         leaf low-percentile {
           type percentile;
           default "10.00";
           description
             "Low percentile to report. Setting low-percentile
              into 0.00 indicates the client is not interested in receiving
              low percentile.";
         }
         leaf middle-percentile {
           type percentile;
           default "50.00";
           description
             "Middle percentile to report. Setting middle-percentile
              into 0.00 indicates the client is not interested in receiving
              middle percentile.";
         }
         leaf high-percentile {
           type percentile;
           default "90.00"; "95.00";
           description
             "High percentile to report. Setting high-percentile
              into 0.00 indicates the client is not interested in receiving
              high percentile"; percentile.";
         }
         leaf pm-source measurement-interval {
           type string;
        config false; uint32;
           units "seconds";
           default "60";
           description
          "The OAM tool used to collect
             "Indicates the time interval to perform PM data."; measurement.";
         }
         leaf reference-time {
           type yang:date-and-time;
           config false;
           description
             "The time that the current Measurement Interval measurement-interval started.";
         }
         leaf measurement-interval pm-source {
           type uint32;
        units "seconds";
        default "60"; identityref {
             base pm-source-type;
           }
           config false;
           description
          "Interval
             "The OAM tool used to calculate performance metric."; collect the PM data.";
         }
         container pm-statistics one-way-pm-statistics {
           config false;
           description
             "Container for link telemetry attributes.";

           uses link-error-statistics; link-loss-statistics;
           uses link-delay-statistics;
           uses link-jitter-statistics;
         }
       }
     }

     augment "/nw:networks/nw:network/nt:link/pm-attributes" {
       when '../../nw:network-types/nvp:service-type' {
         description
          "Container
           "Augments only for VPN Network topology.";
       }
       description
         "Augments the network topology link with VPN service telemetry
          performance monitoring attributes.";
       leaf vpn-underlay-transport-type {
         type identityref {
           base vpn-common:protocol-type;
         }
         config false;
         description
           "The leaf indicates the underlay transport type of
            a VPN service, e.g., GRE, LDP, etc.";
       }
       list vpn-one-way-pm-statistics {
         key "class-id";
         config false;
         description
           "The list of PM data based on class of service.";
         leaf class-id {
           type string;
           description
             "The class-id is used to identify the class of service.
              This identifier is internal to the administration.";
         }
         uses link-loss-statistics;
         uses link-delay-statistics;
         uses link-jitter-statistics;
       }
     }

     augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
       description
         "Augments the network topology termination point with
          performance monitoring attributes.";
       container pm-statistics {
         config false;
         description
           "Container for termination point PM attributes.";
         uses tp-svc-telemetry;
       }
     }

     augment "/nw:networks/nw:network/nt:link/pm-attributes" "/nw:networks/nw:network/nw:node/nt:termination-point/pm-statistics" {
       when '../../nw:network-types/nvp:service-type' '../../../nw:network-types/nvp:service-type' {
         description
        "Augment
           "Augments only for VPN Network topology.";
       }
       description
      "Augment
         "Augments the network topology link termination-point with
          VPN service performance monitoring attributes";
    leaf protocol-type {
      type identityref
       list vpn-network-access {
        base vpn-common:protocol-type;
      }
      config false;
         key "network-access-id";
         description
        "Underlay-transport type, e.g., GRE, LDP, etc.";
    }

  }

  augment "/nw:networks/nw:network/nw:node/nt:termination-point"
           "The list of PM based on VPN network accesses.";
         leaf network-access-id {
           type vpn-common:vpn-id;
           description
      "Augment
             "References to an identifier for the VPN network topology termination point with
       performance monitoring attributes";
    container pm-statistics {
      config false;
              access, e.g. L3VPN or VPLS.";
         }
         uses tp-svc-telemetry;
      description
        "Container for termination point PM attributes.";
       }
     }
   }
   <CODE ENDS>

6.  Security Considerations

   The YANG modules defined in this document MAY be accessed via the
   RESTCONF protocol [RFC8040] or NETCONF protocol [RFC6241].  The
   lowest RESTCONF or NETCONF layer requires that the transport-layer
   protocol provides both data integrity and confidentiality, see
   Section 2 in [RFC8040] and [RFC6241].  The lowest NETCONF layer is
   the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH)[RFC6242] . (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in this YANG module that 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 with the write
   operation that can be exploited to impact the network monitoring:

   *  "/nw:networks/nw:network/nw:network-types"

   *  "/nw:networks/nw:network/nvp:vpn-pm-attributes"

   *  "/nw:networks/nw:network/nw:node/nvp:pm-attributes"

   *  /nw:networks/nw:network/nt:link/nvp:pm-attributes"

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  The nodes
   reveals the quality of a service that is operated by an operator.  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:

   o  /nw:networks/nw:network/svc-topo:svc-telemetry-attributes

   o  /nw:networks/nw:network/nw:node/svc-topo:node-attributes

   *  "/nw:networks/nw:network/nw:node/nvp:pm-attributes/nvp:vpn-
      summary-statistics": Unauthorized access to this subtree can
      disclose the operational state information of VPN instances.

   *  "/nw:networks/nw:network/nt:link/nvp:pm-attributes/nvp:one-way-pm-
      statistics": Unauthorized access to this subtree can disclose the
      operational state information of network links or VPN underlay
      tunnels.

   *  "/nw:networks/nw:network/nw:node/nt:termination-point/nvp:pm-
      statistics": Unauthorized access to this subtree can disclose the
      operational state information of network termination points or VPN
      network accesses.

7.  IANA Considerations

   This document requests IANA to register the following URI in the "ns"
   subregistry within the "IETF XML Registry" [RFC3688]:

      URI: urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm
      Registrant Contact: The IESG.
      XML: N/A, the requested URI is an XML namespace.

   This document requests IANA to register the following YANG module in
   the "YANG Module Names" subregistry [RFC6020] within the "YANG
   Parameters" registry.

      Name:         ietf-network-vpn-pm
      Namespace:    urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm
      Maintained by IANA: N
      Prefix:       nvp
      Reference:    RFC XXXX (RFC Ed.: replace XXXX with actual
           RFC number and remove this note.)

8.  Acknowledgements

   Thanks to Joe Clarke, Adrian Farrel, Greg Mirsky, Roque Gagliano,
   Erez Segev, and Dhruv Dhody for reviewing and providing important
   input to this document.

9.  Contributors

   The following authors contributed significantly to this document:

      Michale Wang
      Huawei
      Email:wangzitao@huawei.com

      Roni Even
      Huawei
      Email: ron.even.tlv@gmail.com

      Change Liu
      China Unicom
      Email: liuc131@chinaunicom.cn

      Honglei Xu
      China Telecom
      Email: xuhl.bri@chinatelecom.cn

10.  References

10.1.  Normative References

   [I-D.ietf-opsawg-vpn-common]
              Barguil, S., Dios, O. G. D., Boucadair, M., and Q. Wu, "A
              Layer 2/3 VPN Common YANG Model", draft-ietf-opsawg-vpn-
              common-07 (work Work in progress), April 2021. Progress,
              Internet-Draft, draft-ietf-opsawg-vpn-common-12, 29
              September 2021, <https://www.ietf.org/archive/id/draft-
              ietf-opsawg-vpn-common-12.txt>.

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

   [RFC3393]  Demichelis, C. and P. Chimento, "IP Packet Delay Variation
              Metric for IP Performance Metrics (IPPM)", RFC 3393,
              DOI 10.17487/RFC3393, November 2002,
              <https://www.rfc-editor.org/info/rfc3393>.

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

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

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

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

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374,
              DOI 10.17487/RFC6374, September 2011,
              <https://www.rfc-editor.org/info/rfc6374>.

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

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

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

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

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

   [RFC8345]  Clemm, A., Medved, J., Varga, R., Bahadur, N.,
              Ananthakrishnan, H., and X. Liu, "A YANG Data Model for
              Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March
              2018, <https://www.rfc-editor.org/info/rfc8345>.

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

   [RFC8532]  Kumar, D., Wang, Z., Wu, Q., Ed., Rahman, R., and S.
              Raghavan, "Generic YANG Data Model for the Management of
              Operations, Administration, and Maintenance (OAM)
              Protocols That Use Connectionless Communications",
              RFC 8532, DOI 10.17487/RFC8532, April 2019,
              <https://www.rfc-editor.org/info/rfc8532>.

   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

10.2.  Informative References

   [I-D.ietf-netmod-node-tags]
              Wu, Q., Claise, B., Liu, P., Du, Z., and M. Boucadair,
              "Self Describing Data Object Tags", Work in Progress,
              Internet-Draft, draft-ietf-netmod-node-tags-04, 11
              November 2021, <https://www.ietf.org/archive/id/draft-
              ietf-netmod-node-tags-04.txt>.

   [I-D.ietf-opsawg-l2nm]
              Barguil, S., Dios, O. G. D., Boucadair, M., and L. A.
              Munoz, "A Layer 2 VPN Network YANG Model", draft-ietf-
              opsawg-l2nm-02 (work Work in progress), April 2021.
              Progress, Internet-Draft, draft-ietf-opsawg-l2nm-12, 22
              November 2021, <https://www.ietf.org/archive/id/draft-
              ietf-opsawg-l2nm-12.txt>.

   [I-D.ietf-opsawg-l3sm-l3nm]
              Barguil, S., Dios, O. G. D., Boucadair, M., Munoz, L. A.,
              and A. Aguado, "A Layer 3 VPN Network YANG Model", draft-
              ietf-opsawg-l3sm-l3nm-08 (work Work in progress), April 2021.
              Progress, Internet-Draft, draft-ietf-opsawg-l3sm-l3nm-18,
              8 October 2021, <https://www.ietf.org/archive/id/draft-
              ietf-opsawg-l3sm-l3nm-18.txt>.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, DOI 10.17487/RFC5357, October 2008,
              <https://www.rfc-editor.org/info/rfc5357>.

   [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
              Previdi, "OSPF Traffic Engineering (TE) Metric
              Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
              <https://www.rfc-editor.org/info/rfc7471>.

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

   [RFC8194]  Schoenwaelder, J. and V. Bajpai, "A YANG Data Model for
              LMAP Measurement Agents", RFC 8194, DOI 10.17487/RFC8194,
              August 2017, <https://www.rfc-editor.org/info/rfc8194>.

   [RFC8309]  Wu, Q., Liu, W., and A. Farrel, "Service Models
              Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
              <https://www.rfc-editor.org/info/rfc8309>.

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

   [RFC8570]  Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
              D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
              Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
              2019, <https://www.rfc-editor.org/info/rfc8570>.

   [RFC8571]  Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and
              C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of
              IGP Traffic Engineering Performance Metric Extensions",
              RFC 8571, DOI 10.17487/RFC8571, March 2019,
              <https://www.rfc-editor.org/info/rfc8571>.

   [RFC8969]  Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and
              L. Geng, "A Framework for Automating Service and Network
              Management with YANG", RFC 8969, DOI 10.17487/RFC8969,
              January 2021, <https://www.rfc-editor.org/info/rfc8969>.

Appendix A.  Illustrating Examples

A.1.  Example of Pub/Sub Retrieval

   The example shown in Figure 7 illustrates how a client subscribes to
   the performance monitoring information between nodes ('node-id') A
   and B in the L3 network topology.  The performance monitoring
   parameter that the client is interested in is end-to-end loss.

    <rpc netconf:message-id="101"
       xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
       <establish-subscription
      xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
          <stream-subtree-filter>
             <networks
        xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo">
                <network>
                 <network-id>l3-network</network-id>
                 <service-type
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                    L3VPN
                    ietf-vpn-common:l3vpn
                 </service-type>
                   <node>
                     <node-id>A</node-id>
                     <pm-attributes>
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                       <node-type>pe</node-type>
                     </pm-attributes>
                     <termination-point
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                      <tp-id>1-0-1</tp-id>
                      <pm-statistics
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                       <inbound-octets>150</inbound-octets>
                       <outbound-octets>100</outbound-octets>
                      </pm-statistics>
                     </termination-point>
                    </node>
                   <node>
                     <node-id>B</node-id>
                     <pm-attributes>
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                      <node-type>pe</node-type>
                     </pm-attributes>
                       <termination-point
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                         <tp-id>2-0-1</tp-id>
                         <pm-statistics
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                           <inbound-octets>150</inbound-octets>
                           <outbound-octets>100</outbound-octets>
                         </pm-statistics>
                      </termination-point>
                    </node>
                    <link
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                     <link-id>A-B</link-id>
                      <source>
                        <source-node>A</source-node>
                      </source>
                      <destination>
                       <dest-node>B</dest-node>
                      </destination>
                      <protocol-type>mpls-te</protocol-type>
                      <vpn-underlay-transport-type>mpls-te</vpn-underlay-transport-type>
                      <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                        <one-way-pm-statistics>
                          <loss-statistics>
                           <packet-loss-count>100</packet-loss-count>
                          </loss-statistics>
                        </one-way-pm-statistics>
                      </pm-attributes>
                    </link>
                </network>
              </networks>
           </stream-subtree-filter>
         <period
           xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
          500
       </period>
       </establish-subscription>
    </rpc>

                     Figure 7: Pub/Siub Pub/Sub Retrieval

A.2.  Example of RPC-based Retrieval

   This example, depicted in Figure 8, illustrates how a the client can use
   the RPC model to fetch performance data on demand.  For example, the
   client requests "packet-loss-count" between 'source-node' A and
   'dest-node' B that belong to the same VPN ('VPN1').

 <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
        message-id="1">
   <report
        xmlns="urn:ietf:params:xml:ns:yang:example-service-pm-report">
      <networks xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo">
        <network>
         <network-id>vpn1</network-id>
         <node>
          <node-id>A</node-id>
          <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <node-type>pe</node-type>

          </pm-attribtues>
          <termination-point
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
           <tp-id>1-0-1</tp-id>
           <pm-statistics
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <inbound-octets>100</inbound-octets>
            <outbound-octets>150</outbound-octets>
           </pm-statistics>
          </termination-point>
         </node>
         <node>
          <node-id>B</node-id>
          <pm-attributes
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <node-type>pe</node-type>
          </pm-attribtues>
          <termination-point
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
           <tp-id>2-0-1</tp-id>
           <pm-statistics
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <inbound-octets>150</inbound-octets>
            <outbound-octets>100</outbound-octets>
           </pm-statistics>
          </termination-point>
         </node>
         <link>
         <link-id>A-B</link-id>
          <source>
           <source-node>A</source-node>
          </source>
          <destination>
           <dest-node>B</dest-node>
          </destination>
          <-type>mpls-te</link-type>
          <pm-attributes
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-pm">
            <one-way-pm-statistics>
               <loss-statistics>
                 <packet-loss-count>120</packet-loss-count>
               </loss-statistics>
             </one-way-pm-statistics>
           </pm-attributes>
           <vpn-underlay-transport-type>mpls-te</vpn-underlay-transport-type>
         </link>
       </network>
     </report>
   </rpc>
                               Figure 8

A.3.  Example of Percentile Monitoring

   The following shows an example of a percentile measurement for a VPN
   link.

{
   "ietf-network-topology:link":[
      {
         "link-id":"vpn1-link1",
         "source":{
            "source-node":"vpn-node1"
         },
         "destination":{
            "dest-node":"vpn-node3"
         },
            "ietf-network-vpn-pm:protocol-type":"gre",
         "ietf-network-vpn-pm:pm-attributes":{
            "low-percentile":"20.00",
            "middle-percentile":"50.00",
            "high-percentile":"90.00",
               "pm-statistics:delay-statistics":{
                  "direction":"one-way",
                  "unit-values":"milliseconds",
            "one-way-pm-statistics:delay-statistics":{
               "unit-values":"lime:milliseconds",
               "min-delay-value":"43",
               "max-delay-value":"99",
               "low-delay-percentile":"64",
               "middle-delay-percentile":"77",
               "high-delay-percentile":"98"
            }
         }
         "ietf-network-vpn-pm:vpn-underlay-transport-type":"ietf-vpn-common:gre",
      }
   ]
}

Authors' Addresses

   Bo Wu (editor)
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu
   Nanjing
   Jiangsu, 210012
   China

   Email: lana.wubo@huawei.com
   Qin Wu (editor)
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu
   Nanjing
   Jiangsu, 210012
   China

   Email: bill.wu@huawei.com

   Mohamed Boucadair (editor)
   Orange
   Rennes 35000
   France

   Email: mohamed.boucadair@orange.com

   Oscar Gonzalez de Dios
   Telefonica
   Madrid
   ES
   Spain

   Email: oscar.gonzalezdedios@telefonica.com

   Bin Wen
   Comcast

   Email: bin_wen@comcast.com

   Change Liu
   China Unicom

   Email: liuc131@chinaunicom.cn

   Honglei Xu
   China Telecom

   Email: xuhl.bri@chinatelecom.cn