OPSAWG Working Group                                          B. Wu, Ed.
Internet-Draft                                                Q. Wu, Ed.
Intended status: Standards Track                                  Huawei
Expires: 23 July 2 August 2022                                 M. Boucadair, Ed.
                                                                  Orange
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                                  B. Wen
                                                                 Comcast
                                                         19
                                                         29 January 2022

    A YANG Model for Network and VPN Service Performance Monitoring
                draft-ietf-opsawg-yang-vpn-service-pm-02
                draft-ietf-opsawg-yang-vpn-service-pm-03

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 performance monitoring (PM) of both
   networks and VPN services that can be used to monitor and manage
   network performance on the topology at higher layer or the service
   topology between VPN sites.

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 23 July 2 August 2022.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Network and VPN Service Performance Monitoring Model Usage  .   3   4
     3.1.  Collecting Data via Pub/Sub Mechanism . . . . . . . . . .   5
     3.2.  Collecting Data via Retrieval Methods On-demand . . . . . . . . . .   5 . . . . . .   6
   4.  Description of The Data Model . . . . . . . . . . . . . . . .   5   6
     4.1.  Layering Relationship between Multiple Layers of
           Topology  . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Network Level . . . . . . . . . . . . . . . . . . . . . .   7   8
     4.3.  Node Level  . . . . . . . . . . . . . . . . . . . . . . .   8
     4.4.  Link and Termination Point Level  . . . . . . . . . . . .   9
   5.  Network and VPN Service Performance Monitoring YANG Module  .  12  13
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  25  27
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  26  28
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  27  28
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  27  28
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  27  29
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  27  29
     10.2.  Informative References . . . . . . . . . . . . . . . . .  29  30
   Appendix A.  Illustrating Examples  . . . . . . . . . . . . . . .  30  32
     A.1.  VPN Performance Subscription Example of Pub/Sub Retrieval  . . . . . . . . . . . . . .  30  32
     A.2.  Example of RPC-based Retrieval  . . VPN Performance Snapshot . . . . . . . . . . .  32  33
     A.3.  Example of Percentile Monitoring  . . . . . . . . . . . .  34  35
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  34  35

1.  Introduction

   [RFC8969] describes a framework for automating service and network
   management with YANG 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).

   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 for both network and
   VPN service performance 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 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]
   and draws on relevant YANG 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 following terms are defined in [RFC7950] and are used in 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].

2.1.  Acronyms

   The following acronyms are used in the document:

   L2VPN   Layer 2 Virtual Private Network
   L3VPN   Layer 3 Virtual Private Network
   L2NM    L2VPN Network Model
   L3NM    L3VPN Network Model
   MPLS    Multiprotocol Label Switching
   OAM     Operations, Administration, and Maintenance
   OWAMP   One-Way Active Measurement Protocol
   PE      Provider Edge
   PM      Performance Monitoring
   SLA     Service Level Agreements
   TE      Traffic Engineering
   TWAMP   Two-Way Active Measurement Protocol
   VPLS    Virtual Private LAN Service
   VPN     Virtual Private Network

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).

                            +---------------+
                            |   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 a set of performance
   information to the above layer.  Such 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 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 One-Way Active
   Measurement Protocol (OWAMP) [RFC4656], Two-Way Active Measurement
   Protocol (TWAMP) [RFC5357], and Multiprotocol Label Switching (MPLS)
   Loss and Delay Measurement [RFC6374].  The performance monitoring
   information reflecting the quality of the network or VPN service
   (e.g., end-to-
   end 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), [RFC7471] [RFC8570] [RFC8571] or LMAP
   [RFC8194].

   The measurement and report intervals that are associated with these
   performance data usually depend on the configuration 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 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 On-demand

   To obtain a snapshot of a large amount of performance data from a
   network element (including network controllers), topology or VPN network, service-assurance applications may use methods such as retrieving performance data
   retrieve information using the network and VPN service PM model
   through a NETCONF [RFC6241] or
   RPC commands defined as part of YANG models. a RESTCONF [RFC8040] interface.

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]:::           /    /S2A             S2B  /
        /         \   :::::     /    / _[VN1]______[VN3]_  /
       /           \       :   /    /   :            :    /Service    / Overlay
      /             \       :: : : : : :             :   /
     /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]
      +------------------------------------------+

    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' 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] 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.

   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 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].  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, the model defines 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 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? intermediate-percentile?       percentile
          +--rw high-percentile?               percentile
          +--rw measurement-interval?          uint32
          +--ro reference-time? start-time?                    yang:date-and-time
          +--ro end-time?                      yang:date-and-time
          +--ro pm-source?                     identityref
          +--ro one-way-pm-statistics
          |  +--ro loss-statistics
          |  |  +--ro packet-loss-count?   yang:counter64
          |  |  +--ro loss-ratio?          percentage
          |  +--ro delay-statistics
          |  |  +--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? intermediate-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? intermediate-jitter-percentile?   yang:gauge32
          |     +--ro high-jitter-percentile?           yang:gauge32
          +--ro vpn-underlay-transport-type?   identityref
          +--ro vpn-one-way-pm-statistics* [class-id]
             +--ro class-id             string
             +--ro loss-statistics
             |  +--ro packet-loss-count?   yang:counter64
             |  +--ro loss-ratio?          percentage
             +--ro delay-statistics
             |  +--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? intermediate-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? intermediate-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 intermediate percentile (50th percentile), high
      percentile (90th percentile) are used.  Setting a percentile 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., 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" "start-time", "end-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"):  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 e.g.,OAM mechanisms
      specified
      referenced in [I-D.ietf-opsawg-l3sm-l3nm], or Ethernet service OAM
      specified
      [ITU-T-Y-1731] referenced in [I-D.ietf-opsawg-l2nm].
      Alternatively, the data can be based upon the underlay technology
      OAM mechanisms, for example,
      GRE Generic Routing Encapsulation (GRE)
      tunnel OAM.

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

   Reference

   Start time ("reference-time"): ("start-time"):  Indicates the start time of the
      performance measurement for link statistics.  For termination
      point metrics, this parameter indicates

   End time ("end-time"):  Indicates the end time of the performance
      measurement for link statistics.

   Reference time ("reference-time"):  Indicates the timestamp when the
      counters are obtained.

   Loss 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:  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:  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.

   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.  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 [I-D.ietf-opsawg-vpn-common].

   <CODE BEGINS> file "ietf-network-vpn-pm@2021-01-18.yang" "ietf-network-vpn-pm@2021-01-28.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 XXXX: CCCC: A Layer 2/3 VPN Common YANG Model.";
       // RFC Ed.: replace XXXX CCCC 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) 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).
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX; XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); 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 2022-01-18 2022-01-28 {
       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
         "Provider Edge (PE) node type.";
       reference
         "RFC 4026: Provider Provisioned
          Virtual Private Network (VPN) Terminology";
     }

     identity asbr p {
       base node-type;
       description
         "Autonomous System Border Router (ASBR)
         "Provider router node type.";
       reference
         "RFC 4026: Provider Provisioned
          Virtual Private Network (VPN) Terminology";
     }

     identity p asbr {
       base node-type;
       description
         "P
         "Autonomous System Border Router (ASBR) node type.";
       reference
         "RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs)";
     }

     identity pm-source-type {
       description
         "Base identity from which specific performance monitoring
          mechanism types are derived.";
     }

     identity pm-source-bgpls {
       base pm-source-type;
       description
         "Indicates BGP-LS as the performance monitoring metric source";
       reference
         "RFC8571:
         "RFC 8571: BGP - Link State (BGP-LS) Advertisement of
           IGP Traffic Engineering Performance Metric Extensions";
     }
     identity pm-source-twamp pm-source-owamp {
       base pm-source-type;
       description
         "Indicates Two-Way One-Way Active Measurement Protocol(TWAMP) Protocol(OWAMP)
          as the performance monitoring metric source.";
       reference
         "RFC5357: :
         "RFC 4656: A Two-Way One-Way Active Measurement Protocol (TWAMP)"; (OWAMP)";
     }

     identity pm-source-y-1731 pm-source-twamp {
       base pm-source-type;
       description
         "Indicates Ethernet Two-Way Active Measurement Protocol(TWAMP)
          as the performance monitoring metric source.";
       reference
         "RFC 5357: 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"; Y.1731: Operations, administration and
          maintenance (OAM) functions and mechanisms
          for Ethernet-based networks";
     }

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

     typedef percentile {
       type decimal64 {
         fraction-digits 5; 2;
         range "1..100"; "0..100";
       }
       description
         "The percentile is a statistical value that indicates that a
          certain percentage of between 0 and 100,
          e.g. 10.00, 99.90 ,99.99 etc..
          For example, for a given one-way delay measurement,
          if the percentile is set to 95.00 and
          the 95th percentile one-way delay is 2 milliseconds,
          then the 95 percent of data falls below it."; the sample value
          is less than or equal to 2 milliseconds.";
     }

     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
               "Indicates the maximum number of IPv4 routes
                for the VPN.";
           }
           leaf total-active-routes {
             type uint32;
             description
               "Indicates total active IPv4 routes for the VPN.";
           }
           description
             "IPv4-specific parameters.";
         }
         container ipv6 {
           leaf maximum-routes {
             type uint32;
             description
               "Indicates the maximum number of IPv6 routes
                for the VPN.";
           }
           leaf total-active-routes {
             type uint32;
             description
               "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-loss-statistics {
       description
         "Grouping for per link error statistics.";
       container loss-statistics {
         description
           "Per link
           "Link loss statistics."; summarized information. By default,
            one way measurement protocol (e.g., OWAMP) is used
            to measure one-way packet loss.";
         reference
           "RFC 4656: A One-way Active Measurement Protocol (OWAMP)";
         leaf packet-loss-count {
           type yang:counter64;
           description
             "Total received packet drops 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.";
       container delay-statistics {
         description
           "Link delay summarized information. By default,
            one way measurement protocol (e.g., OWAMP) is used
            to measure delay.";
         reference
           "RFC 4656: A One-way Active Measurement Protocol (OWAMP)";
         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 observed one-way delay.";
         }
         leaf max-delay-value {
           type yang:gauge64;
           description
             "Maximum observed one-way delay.";
         }
         leaf low-delay-percentile {
           type yang:gauge64;
           description
             "Low percentile of observed one-way delay with
              specific measurement method.";
         }
         leaf middle-delay-percentile intermediate-delay-percentile {
           type yang:gauge64;
           description
             "Middle
             "Intermediate percentile of observed one-way delay with
              specific measurement method.";
         }
         leaf high-delay-percentile {
           type yang:gauge64;
           description
             "High percentile of observed one-way delay with
              specific measurement method.";
         }
       }
     }

     grouping link-jitter-statistics {
       description
         "Grouping for per link jitter statistics.";
       container jitter-statistics {
         description
           "Link jitter summarized information. By default,
            jitter is measured using one-way IP Packet
            Delay Variation (IPDV).";
         reference
           "RFC 3393: IP Packet Delay Variation Metric
            for IP Performance Metrics (IPPM)";

         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 observed one-way jitter.";
         }
         leaf max-jitter-value {
           type yang:gauge32;
           description
             "Maximum observed one-way jitter.";
         }
         leaf low-jitter-percentile {
           type yang:gauge32;
           description
             "Low percentile of observed one-way jitter.";
         }
         leaf middle-jitter-percentile intermediate-jitter-percentile {
           type yang:gauge32;
           description
             "Middle
             "Intermediate percentile of observed one-way jitter.";
         }
         leaf high-jitter-percentile {
           type yang:gauge32;
           description
             "High percentile of 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
           "The total number of inbound unicast packets were received, and delivered
            to a higher layer during the last period."; packets.";
       }
       leaf inbound-nunicast {
         type yang:counter64;
         description
           "The total number of non-unicast
            (i.e., subnetwork- broadcast or subnetwork-multicast) packets
            delivered to a higher-layer protocol."; multicast) packets.";
       }
       leaf inbound-discards {
         type yang:counter32;
         description
           "The number of inbound packets which that were chosen to be
            discarded even though no errors had been
            detected to prevent their being deliverable to detected.
            One possible reason for discarding such a
            higher-layer protocol.";
            packet could be to free up buffer space";
       }
       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."; errors.";
       }
       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."; outbound unicast packets.";
       }
       leaf outbound-nunicast {
         type yang:counter64;
         description
           "The total number of packets that higher-level
            protocols requested be transmitted to a non- outbound non unicast
            (i.e., a subnetwork-broadcast or
            subnetwork-multicast) address, including those
            that were discarded broadcast or not sent."; multicast) packets.";

       }
       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.";
            errors.";
       }
       description
         "Grouping for interface service telemetry.";
     }

     augment "/nw:networks/nw:network/nw:network-types" {
       description
         "Defines the service topologies types.";
       container service-type {
         presence "Indicates network service 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
           "Augments only for VPN Network topology.";
       }
       description
         "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.";
         }
         description
           "Container for VPN topology attributes.";
       }
     }

     augment "/nw:networks/nw:network/nw:node" {
       description
         "Augments the network node with other general 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
           "Augments only for VPN node attributes.";
       }
       description
         "Augments the network node with VPN specific 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
         "Augments the network topology link with performance
          monitoring 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 intermediate-percentile {
           type percentile;
           default "50.00";
           description
             "Middle
             "Intermediate percentile to report. Setting middle-percentile
              intermediate-percentile into 0.00 indicates the client
              is not interested in receiving
              middle intermediate percentile.";
         }
         leaf high-percentile {
           type percentile;
           default "95.00";
           description
             "High percentile to report. Setting high-percentile
              into 0.00 indicates the client is not interested in
              receiving high percentile.";
         }
         leaf measurement-interval {
           type uint32;
           units "seconds";
           default "60";
           description
             "Indicates the time interval to perform PM measurement.";
         }
         leaf reference-time start-time {
           type yang:date-and-time;
           config false;
           description
             "The time that the current measurement-interval measurement started.";
         }
         leaf end-time {
           type yang:date-and-time;
           config false;
           description
             "The time that the current measurement ended.";
         }
         leaf pm-source {
           type identityref {
             base pm-source-type;
           }
           config false;
           description
             "The OAM tool used to collect the PM data.";
         }
         container one-way-pm-statistics {
           config false;
           description
             "Container for link telemetry attributes.";
           uses 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
           "Augments only for VPN Network topology.";
       }
       description
         "Augments the network topology link with VPN service
          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/nw:node/nt:termination-point/pm-statistics" "/nw:networks/nw:network/nw:node"
           + "/nt:termination-point/pm-statistics" {
       when '../../../nw:network-types/nvp:service-type' {
         description
           "Augments only for VPN Network topology.";
       }
       description
         "Augments the network topology termination-point with
          VPN service performance monitoring attributes";
       list vpn-network-access {
         key "network-access-id";
         description
           "The list of PM based on VPN network accesses.";
         leaf network-access-id {
           type vpn-common:vpn-id;
           description
             "References to an identifier for the VPN network
              access, e.g. L3VPN or VPLS.";
         }
         uses tp-svc-telemetry;
       }
     }
   }
   <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].  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:

   *  "/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", Work in 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", Work in
              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", Work in
              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>.

   [ITU-T-Y-1731]
              ITU-T, "Operator Ethernet Service Definition", August
              2015, <https://www.itu.int/rec/T-REC-Y.1731/en>.

   [RFC4656]  Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
              Zekauskas, "A One-way Active Measurement Protocol
              (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006,
              <https://www.rfc-editor.org/info/rfc4656>.

   [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>.

   [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.  VPN Performance Subscription 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">
                    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>
                      <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>

   POST /restconf/operations
        /ietf-subscribed-notifications:establish-subscription
{
   "ietf-subscribed-notifications:input":{
      "stream-subtree-filter":{
         "ietf-network-topo:networks":{
            "network":{
               "network-id":"l3-network",
               "ietf-network-vpn-pm:service-type":{
                  "ietf-vpn-common:l3vpn":{}
               },
               "node":[
                  {
                     "node-id":"A",
                     "ietf-network-vpn-pm:pm-attributes":{
                        "node-type":"PE"
                     },
                     "termination-point":{
                        "tp-id":"1-0-1",
                     }
                  },
                  {
                     "node-id":"B",
                     "ietf-network-vpn-pm:pm-attributes":{
                        "node-type":"PE"
                     },
                     "termination-point":{
                        "tp-id":"2-0-1",
                     }
                  }
               ],
               "link":{
                  "link-id":"A-B",
                  "source":{
                     "source-node":"A"
                  },
                  "destination":{
                     "dest-node":"B"
                  },
                  "ietf-network-vpn-pm:pm-attributes":{
                     "one-way-pm-statistics":{
                        "loss-statistics":{
                           "packet-loss-count":{}
                        }
                     },
                     "vpn-underlay-transport-type":"ietf-vpn-common:gre"
                  }
               }
            }
         }
      },
      "ietf-yang-push:periodic":{
         "ietf-yang-push:period":"500"
      }
   }
}

                     Figure 7: Pub/Sub Retrieval

A.2.  Example of RPC-based Retrieval VPN Performance Snapshot

   This example, depicted in Figure 8, illustrates how an VPN PM instance
   example in which a client can use
   the RPC model uses RESTCONF [RFC8040] to fetch the
   performance data on demand.  For example, of the
   client requests "packet-loss-count" between 'source-node' A link and
   'dest-node' B that belong TP belonged 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>
          <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> "VPN1".

   {
         "ietf-network-topo:networks": {
           "network": {
             "network-id": "vpn1",
             "node": [
               {
                 "node-id": "A",
                 "ietf-network-vpn-pm:pm-attributes": {
                   "node-type": "PE"
                 },
                 "termination-point": {
                   "tp-id": "1-0-1",
                   "ietf-network-vpn-pm:pm-statistics": {
                     "inbound-octets": "100",
                     "outbound-octets": "150"
                   }
                 }
               },
               {
                 "node-id": "B",
                 "ietf-network-vpn-pm:pm-attributes": {
                   "node-type": "PE"
                 },
                 "termination-point": {
                   "tp-id": "2-0-1",
                   "ietf-network-vpn-pm:pm-statistics": {
                     "inbound-octets": "150",
                     "outbound-octets": "100"
                   }
                 }
               }
             ],
             "link": {
               "link-id": "A-B",
               "source": { "source-node": "A" },
               "destination": { "dest-node": "B" },
               "ietf-network-pm:pm-attributes": {
                 "one-way-pm-statistics": {
                   "loss-statistics": { "packet-loss-count": "120" }
                 },
                 "vpn-underlay-transport-type": "ietf-vpn-common:gre"
               },
             }
           }
         }
   }

                                  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:pm-attributes":{
               "low-percentile":"20.00",
               "middle-percentile":"50.00",
               "high-percentile":"90.00",
               "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",
            }
         }
         "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, 210012
   China

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

   Email: oscar.gonzalezdedios@telefonica.com

   Bin Wen
   Comcast

   Email: bin_wen@comcast.com