



OPSAWG Working Group                                          B. Wu, Ed.
Internet-Draft                                                Q. Wu, Ed.
Intended status: Standards Track                                  Huawei
Expires: 15 May 2023                                   M. Boucadair, Ed.
                                                                  Orange
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                                  B. Wen
                                                                 Comcast
                                                        11 November 2022


    A YANG Model for Network and VPN Service Performance Monitoring
                draft-ietf-opsawg-yang-vpn-service-pm-15

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
   underlay networks and overlay VPN services that can be used to
   monitor and manage network performance on the topology of both
   layers.

Status of This Memo

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

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

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

   This Internet-Draft will expire on 15 May 2023.

Copyright Notice

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





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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Network and VPN Service Performance Monitoring Model Usage  .   4
     3.1.  Collecting Data via Pub/Sub Mechanism . . . . . . . . . .   6
     3.2.  Collecting Data On Demand . . . . . . . . . . . . . . . .   6
   4.  Description of The Data Model . . . . . . . . . . . . . . . .   6
     4.1.  Layering Relationship between Multiple Layers of
           Topology  . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Network Level Performance Monitoring Augmentation . . . .   9
     4.3.  Node Level Performance Monitoring Augmentation  . . . . .  10
     4.4.  Link and Termination Point Level Performance Monitoring
           Augmentation  . . . . . . . . . . . . . . . . . . . . . .  11
   5.  Network and VPN Service Performance Monitoring YANG Module  .  16
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  32
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  34
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  34
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  34
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  35
     10.2.  Informative References . . . . . . . . . . . . . . . . .  37
   Appendix A.  Illustrative Examples  . . . . . . . . . . . . . . .  39
     A.1.  VPN Performance Subscription Example  . . . . . . . . . .  39
     A.2.  Example of VPN Performance Snapshot . . . . . . . . . . .  40
     A.3.  Example of Percentile Monitoring  . . . . . . . . . . . .  42
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  43

1.  Introduction

   [RFC8969] describes a framework for automating service and network
   management with YANG [RFC7950] models.  It defines that the
   performance measurement telemetry model should be tied to the
   services (such as a Layer 3 VPN or Layer 2 VPN) or to the network
   models to monitor the overall network performance and the Service
   Level Agreements (SLAs).





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   The performance of VPN services is associated with the performance
   changes of the underlay networks that carries VPN services.  For
   example, link delay between Provider Edge (PE) and Provider (P)
   devices and packet loss status on Layer 2 and Layer 3 interfaces
   connecting PEs and Customer Edge (CE) devices directly impact VPN
   service performance.  Additionally, the integration of Layer 2/Layer
   3 VPN performance and network performance data enables the
   orchestrator to monitor consistently.  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.

   The base model presented here can be extended to include technology-
   specific details, e.g., adding Explicit Congestion Notification (ECN)
   statistics for Layer 3 networks or VPN services to support
   performance-sensitive applications.

   This document does not introduce new metrics for network performance
   or mechanisms for measuring network performance, but uses the
   existing mechanisms and statistics to monitor the performance of the
   network and the services.

   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 [RFC9181].

   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].




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2.1.  Acronyms

   The following acronyms are used in the document:

   CE      Customer Edge, as defined in [RFC4026]
   L2VPN   Layer 2 Virtual Private Network, as defined in [RFC4026]
   L3VPN   Layer 3 Virtual Private Network, as defined in [RFC4026]
   L2NM    L2VPN Network Model
   L3NM    L3VPN Network Model
   MPLS    Multiprotocol Label Switching
   OAM     Operations, Administration, and Maintenance
   OSPF    Open Shortest Path First
   OWAMP   One-Way Active Measurement Protocol, as defined in [RFC4656]
   P       Provider Router, as defined in [RFC4026]
   PE      Provider Edge, as defined in [RFC4026]
   PM      Performance Monitoring
   SLA     Service Level Agreement
   TP      Termination Point, as defined in [RFC8345] section 4.2
   TWAMP   Two-Way Active Measurement Protocol, as defined in [RFC5357]
   VPLS    Virtual Private LAN Service, as defined in [RFC4026]
   VPN     Virtual Private Network


3.  Network and VPN Service Performance Monitoring Model Usage

   Models are key for automating network management operations
   (Section 3 of [RFC8969]).  Particularly, 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).





















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

    Figure 1: An Example Architecture with a Service Orchestrator

   The network and VPN service performance monitoring (PM) model can be
   used to expose operational performance information to the layer
   above, e.g., to an orchestrator or other BSS/OSS client application,
   via standard network management APIs.  Figure 1 shows an example
   usage in a layered model architecture described in [RFC8309].

   Before using the model, the controller needs to establish topology
   visibility of the network and VPN.  For example, the controller can
   use network information from [RFC8345], [I-D.ietf-opsawg-sap] or VPN
   information from the L3VPN Network Model (L3NM) [RFC9182] and the
   L2VPN Network Model (L2NM) [RFC9291].  Then the controller derives
   network or VPN level performance data by aggregating (and filtering)
   lower-level data collected via monitoring counters of the devices
   involved.

   The network or VPN performance data can be based on different
   sources.  For example, the performance monitoring data per link in
   the underlying networks can be collected using a network performance
   measurement method such as One-Way Active Measurement Protocol
   (OWAMP) [RFC4656], Two-Way Active Measurement Protocol (TWAMP)
   [RFC5357], Simple Two-way Active Measurement Protocol (STAMP)
   [RFC8762], Multiprotocol Label Switching (MPLS) Loss and Delay
   Measurement [RFC6374] or In Situ OAM (IOAM) [RFC9197].  The
   performance monitoring information reflecting the quality of the
   network or VPN service (e.g., network performance data between source



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   node and destination node in the networks 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 (Large-Scale Measurement Platform) [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 network-wide measurement intervals to align
   measurement requirements for networks or VPN services.

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.  For example, networks or
   VPN topologies updates may be obtained through on-change
   notifications [RFC8641].  For dynamic PM data, e.g.  VRF routes or
   MAC entries, link metrics, and interface metrics, various
   notifications can be specified to obtain more complete data.  A
   periodic notification [RFC8641] can be specified to obtain real-time
   performance data.  For devices/controllers that maintain historical
   performance data for a period of time, a replay notification
   [RFC5277] or [RFC8639] can be used to obtain the historical data.
   And alarm notifications [RFC8632] can be specified to get alarms for
   the metrics which exceed or fall below the performance threshold.

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

3.2.  Collecting Data On Demand

   To obtain a snapshot of performance data from a network topology or a
   VPN service topology, service-assurance applications may retrieve
   information using the network and VPN service PM model through a
   NETCONF [RFC6241] or a RESTCONF [RFC8040] interface.  For example, a
   specified "link-id" of a VPN can be used as a filter in a RESTCONF
   GET request to retrieve per-link VPN PM data.

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"
   modules.



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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 abstract topology for a service layer above Layer 1
   (L1), Layer 2 (L2), and Layer 3 (L3) underlay topologies.  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 L3 topology.

   Figure 2 illustrates an example of a topology hierarchy that maps
   between the VPN service topology and an underlying Layer 3 network
   topology:

                        VPN 1                       VPN 2
             +------------------------+   +------------------------+
            /                        /   /                        /
           / S1C_[VN3]..........    /   /                        /
          /         \          :   /   / S2A_[VN1]____[VN3]_S2B /
         /           \         :  /   /        *        *      /
        /             \        :............ * ....     *     /
       / S1B_[VN2]____[VN1]_S1A /   /       *     :     *    /
      +---------:-------:------+   +-------*------:-----*---+
                :        :      * * *  * *        :     *
                :         :   *                   :     *
      Site-1A   :  +-------:-*--------------------:-----*-----+ Site-1C
        [CE1]___:_/_______[N1]___________________[N2]___*____/__[CE3]
                :/       / / \             _____//      *   /
      [CE5]_____:_______/ /    \     _____/     /     *    /
    Site-2A    /:        /       \  /          /    *     /
              / :                [N5]         /   *      /
             /   :     /       __/ \__       /  *       /
            /     :   /    ___/       \__   / *        /
   Site-1B /       : / ___/              \ /*         /  Site-2B
   [CE2]__/________[N4]__________________[N3]________/____[CE4]
         /                                          /
        +------------------------------------------+
                                      L3 Topology

       Legend:
       N:Node   VN:VPN-Node  S:Site  CE:Customer Edge
       __    Link within a network layer
       :    Mapping between VPN 1 service topology and L3 topology
       *    Mapping between VPN 2 service topology and L3 topology





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         Figure 2: Example of Topology Mapping Between VPN Service
                      Topology and Underlying Network

   As shown in Figure 2, two VPN services topologies are built on top of
   one underlying Layer 3 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 Layer 3 network.  'Site-1A' plays the role of
      hub while 'Site-1B' and 'Site-1C' are configured as spoke.

   VPN 2:  This service topology 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) in the underlying Layer 3
      network.  'Site-2A' and 'Site-2B' have 'any-to-any' role.

   Based on the association between the VPN service topologies and the
   underlying network topologies, the VPN Network PM YANG module extends
   the performance status of the underlay networks and VPN services.
   For example, the module can provide link PM statistics and port
   statistics of an underlay network, e.g.  Layer 1, Layer 2, Layer 3,
   OSPF networks.  And it can also provide VPN PM statistics, which can
   be further split into PM for the VPN tunnel and PM at the VPN PE
   access node, as illustrated in the following diagram.
























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          +-----------------------------------------------------+
          |                                                     |
          |                      VPN2 Link                      |
          |              |<-------------------->|               |
          |              |                      |               |
          |      VPN2+---+---+              +---+---+VPN2       |
          |       TP1| VN1   |  Tunnel PM   |  VN3  |TP2        |
          |       ---+ PE A  |==============|  PE B +----       |
          |vpn-access+-------+              +-------+ vpn-access|
          |-interface|                              | -interface|
          |          |##############################|           |
          |          |inter-vpn-access-interface PM |           |
          |                                                     |
          +-----------------------------------------------------+
          |                                                     |
          |                                                     |
   +----+ |        TP+-----+ Link  +---+ Link  +-----+TP        | +----+
   | CE4+-+----------+ N1  +-------+-N2+-------+  N3 +----------+-+CE5 |
   +----+ |       1-1+-----+1-2 2-1+---+2-2 3-1+-----+3-2       | +----+
          |                                                     |
          |                                                     |
          +-----------------------------------------------------+
          Legend:
           N:node   VN:VPN-Node TP:Termination Point
           -:Link

                       Figure 3: An Example of VPN PM

   Figure 3 illustrates an example of VPN PM and two VPN PM measurement
   methods including the VPN tunnel PM and the inter-VPN-access
   interface PM.  VPN PM can also provide statistics on VPN access
   interfaces, the number of current VRF routes or L2VPN MAC entry of
   VPN node.

4.2.  Network Level Performance Monitoring Augmentation

   The model can be used for performance monitoring both for the
   underlay networks and the VPN services, which would be separate
   entries in the network list [RFC8345].  The differences are as
   follows:

   *  When the "service" presence container is absent, then it indicates
      performance monitoring of the network itself.

   *  When the "service" presence container is present, then it
      indicates performance monitoring of the VPN service specified by
      the "service-type" leaf, e.g. , L3VPN or Virtual Private LAN
      Service (VPLS).  The values are taken from [RFC9181].  When a



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      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
   also defines the following set of network level attributes:

   "vpn-id":  Refers to an identifier of VPN service defined in
      [RFC9181].  This identifier is used to correlate the performance
      status with the network service configuration.

   "vpn-service-topology":  Indicates the type of the VPN service
      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
      [RFC9181].  These VPN service 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!
          +--rw service-type            identityref
          +--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 Performance Monitoring Augmentation

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

   For network performance monitoring, the module defines the following
   attributes:

   "node-type":  Indicates the device type of Provider Edge (PE),
      Provider (P) device, or Autonomous System Border Router (ASBR) as
      defined in [RFC4026] and [RFC4364], so that the performance metric
      between any two nodes each with specific node type can be
      reported.

   "entry-summary":  Lists a set of IPv4 statistics, IPv6 statistics,
      and MAC statistics.  The detailed statistics are specified
      separately.

   For VPN service topology, the module defines one attribute:

   "role":  Defines the role in a particular VPN service topology.  The




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      roles are taken from [RFC9181] (e.g., any-to-any-role, spoke-role,
      hub-role).

     augment /nw:networks/nw:network/nw:node:
       +--rw node-type?       identityref
       +--ro entry-summary
          +--ro ipv4-num
          |  +--ro maximum-routes?        uint32
          |  +--ro total-active-routes?   uint32
          +--ro ipv6-num
          |  +--ro maximum-routes?        uint32
          |  +--ro total-active-routes?   uint32
          +--ro mac-num
             +--ro maximum-mac-entries?        uint32
             +--ro total-active-mac-entries?   uint32
     augment /nw:networks/nw:network/nw:node:
       +--rw role?   identityref

             Figure 5: Node Level YANG Tree of the Hierarchies


4.4.  Link and Termination Point Level Performance Monitoring
      Augmentation

   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 defined in this
   module.

   The performance data of a link is a collection of counters and gauges
   that report the performance status.  All these metrics are defined as
   unidirectional metrics.

  augment /nw:networks/nw:network/nt:link:
    +--rw perf-mon
       +--rw low-percentile?            percentile
       +--rw intermediate-percentile?   percentile
       +--rw high-percentile?           percentile
       +--rw measurement-interval?      uint32
       +--ro pm* [pm-type]
       |  +--ro pm-type          identityref
       |  +--ro pm-attributes
       |     +--ro start-time?                        yang:date-and-time
       |     +--ro end-time?                          yang:date-and-time
       |     +--ro pm-source?                         identityref
       |     +--ro one-way-pm-statistics



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       |     |  +--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 intermediate-delay-percentile?   yang:gauge64
       |     |  |  +--ro high-delay-percentile?           yang:gauge64
       |     |  +--ro jitter-statistics
       |     |     +--ro unit-value?                       identityref
       |     |     +--ro min-jitter-value?                 yang:gauge64
       |     |     +--ro max-jitter-value?                 yang:gauge64
       |     |     +--ro low-jitter-percentile?            yang:gauge64
       |     |     +--ro intermediate-jitter-percentile?   yang:gauge64
       |     |     +--ro high-jitter-percentile?           yang:gauge64
       |     +--ro one-way-pm-statistics-per-class* [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 intermediate-delay-percentile?   yang:gauge64
       |        |  +--ro high-delay-percentile?           yang:gauge64
       |        +--ro jitter-statistics
       |           +--ro unit-value?                       identityref
       |           +--ro min-jitter-value?                 yang:gauge64
       |           +--ro max-jitter-value?                 yang:gauge64
       |           +--ro low-jitter-percentile?            yang:gauge64
       |           +--ro intermediate-jitter-percentile?   yang:gauge64
       |           +--ro high-jitter-percentile?           yang:gauge64
       +--rw vpn-pm-type
          +--rw inter-vpn-access-interface
          |  +--rw inter-vpn-access-interface?   empty
          +--rw vpn-tunnel!
             +--ro vpn-tunnel-type?   identityref
  augment /nw:networks/nw:network/nw:node/nt:termination-point:
    +--ro pm-statistics
       +--ro last-updated?               yang:date-and-time
       +--ro inbound-octets?             yang:counter64
       +--ro inbound-unicast?            yang:counter64
       +--ro inbound-broadcast?          yang:counter64
       +--ro inbound-multicast?          yang:counter64



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       +--ro inbound-discards?           yang:counter64
       +--ro inbound-errors?             yang:counter64
       +--ro inbound-unknown-protocol?   yang:counter64
       +--ro outbound-octets?            yang:counter64
       +--ro outbound-unicast?           yang:counter64
       +--ro outbound-broadcast?         yang:counter64
       +--ro outbound-multicast?         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 last-updated?               yang:date-and-time
          +--ro inbound-octets?             yang:counter64
          +--ro inbound-unicast?            yang:counter64
          +--ro inbound-broadcast?          yang:counter64
          +--ro inbound-multicast?          yang:counter64
          +--ro inbound-discards?           yang:counter64
          +--ro inbound-errors?             yang:counter64
          +--ro inbound-unknown-protocol?   yang:counter64
          +--ro outbound-octets?            yang:counter64
          +--ro outbound-unicast?           yang:counter64
          +--ro outbound-broadcast?         yang:counter64
          +--ro outbound-multicast?         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

















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      jitter metric by percentile values.  There are three percentile
      values for configuring various percentile reporting levels.  By
      default, low percentile (10th percentile), intermediate percentile
      (50th percentile), high percentile (90th percentile) are used.
      Configuring a percentile to 0.000 indicates the client is not
      interested in receiving particular percentile.  If all percentile
      nodes are configured to 0.000, 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 "start-time", "end-time" and
      "measurement-interval", the 'high-delay-percentile' and 'high-
      jitter-percentile' will be reported.  An example to illustrate the
      use of percentiles is provided in Appendix A.3.

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

   Start time ("start-time"):  Indicates the start time of the
      performance measurement for link statistics.

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

   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
      referenced in [RFC9182], or Ethernet service OAM [ITU-T-Y-1731]
      referenced in [RFC9291].  Alternatively, the data can be based
      upon the underlay technology OAM mechanisms, for example, Generic
      Routing Encapsulation (GRE) tunnel OAM.

   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.



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   PM statistics per class:  "one-way-pm-statistics-per-class" lists
      performance measurement statistics for the topology link or the
      abstract 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.

   VPN PM type ("vpn-pm-type"):  Indicates the VPN performance type,
      which can be "inter-vpn-access-interface" PM or "vpn-tunnel" PM.
      These two methods are common VPN measurement methods.  The "inter-
      VPN-access-interface" PM is to monitor the performance of logical
      point-to-point VPN connections between a source and a destination
      VPN access interfaces.  And the "vpn-tunnel" PM is to monitor the
      performance of VPN tunnels.  The "inter-VPN-access-interface" PM
      includes PE-PE monitoring.  Therefore, usually only one of the two
      methods is used.  The "inter-VPN-access-interface" PM is defined
      as an empty leaf, which is not bound to a specific VPN access
      interface.  The source or destination VPN access interface of the
      measurement can be augmented as needed.

   VPN tunnel type ("vpn-tunnel-type"):  Indicates 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 [RFC9181],
      which describes the transport technology to carry the traffic of
      the VPN service.  In the case of multiple types of tunnels between
      a single pair of VPN nodes, a separate link for each type of
      tunnel can be created.

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

   Last updated time ("last-updated"):  Indicates the date and time when
      the counters were last updated.

   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 the L3NM [RFC9182] or the L2NM
      [RFC9291].  When multiple VPN network accesses are created using
      the same physical port, finer-grained metrics can be monitored.
      If a TP is associated with only a single VPN, this list is not
      required.



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5.  Network and VPN Service Performance Monitoring YANG Module

   The "ietf-network-vpn-pm" module uses types defined in [RFC8345],
   [RFC6991], [RFC8532], and [RFC9181].

   <CODE BEGINS> file "ietf-network-vpn-pm@2022-11-11.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 9181: A Common YANG Data Model for Layer 2 and
          Layer 3 VPNs.";
     }
     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 (Operations and Management Area Working Group)";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/opsawg/>
        WG List:  <mailto:opsawg@ietf.org>




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        Editor: Bo Wu
             <lana.wubo@huawei.com>
        Editor: Mohamed Boucadair
             <mohamed.boucadair@orange.com>
        Editor: Qin Wu
             <bill.wu@huawei.com>
        Author: Oscar Gonzalez de Dios
             <oscar.gonzalezdedios@telefonica.com>
        Author: Bin Wen
             <bin_wen@comcast.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 Revised BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
           (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX
        (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 2022-11-11 {
       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;



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       description
         "Provider Edge (PE) node type. A PE is the device
          or set of devices at the edge of the provider network with the
          functionality that is needed to interface with the customer.";
     }

     identity p {
       base node-type;
       description
         "Provider router node type. That is, a router
          in the core network that does not have interfaces
          directly toward a customer.";
     }

     identity asbr {
       base node-type;
       description
         "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
         "RFC 8571: BGP - Link State (BGP-LS) Advertisement of
           IGP Traffic Engineering Performance Metric Extensions";
     }

     identity pm-source-owamp {
       base pm-source-type;
       description
         "Indicates One-Way Active Measurement Protocol(OWAMP)
          as the performance monitoring metric source.";
       reference
         "RFC 4656: A One-Way Active Measurement Protocol (OWAMP)";
     }

     identity pm-source-twamp {
       base pm-source-type;



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       description
         "Indicates 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-stamp {
       base pm-source-type;
       description
         "Indicates Simple Two-way Active Measurement Protocol(STAMP)
          as the performance monitoring metric source.";
       reference
         "RFC 8762: Simple Two-Way Active Measurement Protocol";
     }

     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: Operations, administration and
          maintenance (OAM) functions and mechanisms
          for Ethernet-based networks";
     }

     identity pm-source-ioam {
       base pm-source-type;
       description
         "Indicates In Situ Operations, Administration, and Maintenance
          (IOAM) as the performance monitoring metric source.";
       reference
         "RFC 9197: Data Fields for In Situ Operations, Administration,
          and Maintenance (IOAM)";
     }

     identity pm-type {
       description
         "Base identity for PM type.";
     }

     identity pm-type-network-link {
       base pm-type;
       description
         "Indicates that the PM type is for the link in
          the network topology.";
     }



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     identity pm-type-vpn-inter-access {
       base pm-type;
       description
         "Indicates that the PM type is for logical point-to-point VPN
          connections between a source and a destination VPN access
          interfaces.";
     }

     identity pm-type-vpn-tunnel {
       base pm-type;
       description
         "Indicates that the PM type is for VPN tunnels.";
     }

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

     typedef percentile {
       type decimal64 {
         fraction-digits 3;
         range "0..100";
       }
       description
         "The percentile is a value between 0 and 100
          to 3 decimal places, e.g. 10.000, 99.900 ,99.990, etc.
          For example, for a given one-way delay measurement,
          if the percentile is set to 95.000 and the 95th percentile
          one-way delay is 2 milliseconds, then the 95 percent of
          the sample value is less than or equal to 2 milliseconds.";
     }

     grouping entry-summary {
       description
         "Entry summary grouping used for network topology
          augmentation.";
       container entry-summary {
         config false;
         description
           "Container for VPN or network entry summary.";
         container ipv4-num {
           leaf maximum-routes {
             type uint32;



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             description
               "Indicates the maximum number of IPv4 routes
                for the VPN or network.";
           }
           leaf total-active-routes {
             type uint32;
             description
               "Indicates total active IPv4 routes
                for the VPN or network.";
           }
           description
             "IPv4-specific parameters.";
         }
         container ipv6-num {
           leaf maximum-routes {
             type uint32;
             description
               "Indicates the maximum number of IPv6 routes
                for the VPN or network.";
           }
           leaf total-active-routes {
             type uint32;
             description
               "Indicates total active IPv6 routes
                for the VPN or network.";
           }
           description
             "IPv6-specific parameters.";
         }
         container mac-num {
           leaf maximum-mac-entries {
             type uint32;
             description
               "Indicates the maximum number of MAC entries
                for the VPN or network.";
           }
           leaf total-active-mac-entries {
             type uint32;
             description
               "Indicates the total active MAC entries
                for the VPN or network.";
           }
           description
             "MAC statistics.";
         }
       }
     }




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     grouping link-loss-statistics {
       description
         "Grouping for per link error statistics.";
       container loss-statistics {
         description
           "One-way link loss summarized information.";
         reference
           "RFC 4656: A One-way Active Measurement Protocol (OWAMP)
            ITU-T Y.1731: Operations, administration and
            maintenance (OAM) functions and mechanisms
            for Ethernet-based networks";
         leaf packet-loss-count {
           type yang:counter64;
           description
             "Total number of lost packets.";
         }
         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
           "One-way link delay summarized information.";
         reference
           "RFC 4656: A One-way Active Measurement Protocol (OWAMP)
            ITU-T Y.1731: Operations, administration and
            maintenance (OAM) functions and mechanisms
            for Ethernet-based networks";
         leaf unit-value {
           type identityref {
             base lime:time-unit-type;
           }
           default "lime:milliseconds";
           description
             "Time units, where the options are hours, minutes, seconds,
              milliseconds, microseconds, and nanoseconds.";
         }
         leaf min-delay-value {
           type yang:gauge64;
           description



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             "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 intermediate-delay-percentile {
           type yang:gauge64;
           description
             "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
           "One-way link jitter summarized information.";
         reference
           "RFC 3393: IP Packet Delay Variation Metric
            for IP Performance Metrics (IPPM)
            RFC 4656: A One-way Active Measurement Protocol (OWAMP)
            ITU-T Y.1731: Operations, administration and
            maintenance (OAM) functions and mechanisms
            for Ethernet-based networks";
         leaf unit-value {
           type identityref {
             base lime:time-unit-type;
           }
           default "lime:milliseconds";
           description
             "Time units, where the options are hours, minutes, seconds,



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              milliseconds, microseconds, and nanoseconds.";
         }
         leaf min-jitter-value {
           type yang:gauge64;
           description
             "Minimum observed one-way jitter.";
         }
         leaf max-jitter-value {
           type yang:gauge64;
           description
             "Maximum observed one-way jitter.";
         }
         leaf low-jitter-percentile {
           type yang:gauge64;
           description
             "Low percentile of observed one-way jitter.";
         }
         leaf intermediate-jitter-percentile {
           type yang:gauge64;
           description
             "Intermediate percentile of observed one-way jitter.";
         }
         leaf high-jitter-percentile {
           type yang:gauge64;
           description
             "High percentile of observed one-way jitter.";
         }
       }
     }

     grouping tp-svc-telemetry {
       leaf last-updated {
         type yang:date-and-time;
         config false;
         description
           "Indicates the date and time when the counters were
            last updated.";
       }
       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
           "The total number of inbound unicast packets.";



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       }
       leaf inbound-broadcast {
         type yang:counter64;
         description
           "The total number of inbound broadcast packets.";
       }
       leaf inbound-multicast {
         type yang:counter64;
         description
           "The total number of inbound multicast packets.";
       }
       leaf inbound-discards {
         type yang:counter64;
         description
           "The number of inbound packets that were chosen to be
            discarded even though no errors had been detected.
            Possible reasons for discarding such a packet could
            be to free up buffer space, not enough buffer for
            too much data, etc.";
       }
       leaf inbound-errors {
         type yang:counter64;
         description
           "The number of inbound packets that contained 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 outbound unicast packets.";
       }
       leaf outbound-broadcast {
         type yang:counter64;
         description
           "The total number of outbound broadcast packets.";
       }



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       leaf outbound-multicast {
         type yang:counter64;
         description
           "The total number of outbound 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.
            Possible reasons for discarding such a packet could
            be to free up buffer space, not enough buffer for
            too much data, etc.";
       }
       leaf outbound-errors {
         type yang:counter64;
         description
           "The number of outbound packets that contained
            errors.";
       }
       description
         "Grouping for interface service telemetry.";
     }

     augment "/nw:networks/nw:network/nw:network-types" {
       description
         "Defines the service topologies types.";
       container service {
         presence
           "Presence of the container indicates performance monitoring
            of the VPN service, and absence of the container indicates
            performance monitoring of the network itself.";
         description
           "Container for VPN service.";
         leaf service-type {
           type identityref {
             base vpn-common:service-type;
           }
           mandatory true;
           description
             "This indicates the network service type,
              e.g., L3VPN, VPLS, etc.";
         }
         leaf vpn-id {
           type vpn-common:vpn-id;
           description
             "VPN identifier.";



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         }
         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.";
         }
       }
     }

     augment "/nw:networks/nw:network/nw:node" {
       description
         "Augments the network node with other general attributes.";
       leaf node-type {
         type identityref {
           base node-type;
         }
         description
           "Node type, e.g., PE, P, ASBR.";
       }
       uses entry-summary;
     }

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

     augment "/nw:networks/nw:network/nt:link" {
       description
         "Augments the network topology link with performance
          monitoring attributes.";
       container perf-mon {
         description



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           "Container for PM attributes.";
         leaf low-percentile {
           type percentile;
           default "10.000";
           description
             "Low percentile to report. Setting low-percentile
              to 0.000 indicates the client is not interested
              in receiving low percentile.";
         }
         leaf intermediate-percentile {
           type percentile;
           default "50.000";
           description
             "Intermediate percentile to report. Setting
              intermediate-percentile to 0.000 indicates the client
              is not interested in receiving intermediate percentile.";
         }
         leaf high-percentile {
           type percentile;
           default "95.000";
           description
             "High percentile to report. Setting high-percentile
              to 0.000 indicates the client is not interested in
              receiving high percentile.";
         }
         leaf measurement-interval {
           type uint32 {
             range "1..max";
           }
           units "seconds";
           default "60";
           description
             "Indicates the time interval to perform PM
              measurement over.";
         }
         list pm {
           key "pm-type";
           config false;
           description
             "The list of PM based on PM type";
           leaf pm-type {
             type identityref {
               base pm-type;
             }
             config false;
             description
               "The PM type of the measured PM attributes";
           }



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           container pm-attributes {
             description
               "Container for PM attributes.";
             leaf start-time {
               type yang:date-and-time;
               config false;
               description
                 "The date and time the measurement last started.";
             }
             leaf end-time {
               type yang:date-and-time;
               config false;
               description
                 "The date and time the measurement last 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;
             }
             list one-way-pm-statistics-per-class {
               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;
             }
           }



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         }
       }
     }

     augment "/nw:networks/nw:network/nt:link/perf-mon" {
       when '../../nw:network-types/nvp:service' {
         description
           "Augments for VPN service PM.";
       }
       description
         "Augments the network topology link with VPN service
          performance monitoring attributes.";
       container vpn-pm-type {
         description
           "The VPN PM type of this logical point-to-point
            unidirectional VPN link.";
         container inter-vpn-access-interface {
           description
             "Indicates inter-vpn-access-interface PM, which is to
              monitor the performance of logical point-to-point VPN
              connections between a source and a destination
              VPN access interfaces.";
           leaf inter-vpn-access-interface {
             type empty;
             description
               "This is a placeholder for inter-vpn-access-interface PM,
                which is not bound to a specific VPN access interface.
                The source or destination VPN access interface
                of the measurement can be augmented as needed.";
           }
         }
         container vpn-tunnel {
           presence "Enables VPN tunnel PM";
           description
             "Indicates VPN tunnel PM, which is to monitor
              the performance of VPN tunnels.";
           leaf vpn-tunnel-type {
             type identityref {
               base vpn-common:protocol-type;
             }
             config false;
             description
               "The leaf indicates the VPN tunnel type, e.g.,
                Generic Routing Encapsulation (GRE),
                Generic Network Virtualization Encapsulation (Geneve),
                etc.";
           }
         }



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       }
     }

     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" {
       when '../../../nw:network-types/nvp:service' {
         description
           "Augments for VPN service PM.";
       }
       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
             "The reference to an identifier for the VPN network
              access.";
         }
         uses tp-svc-telemetry;
       }
     }
   }
   <CODE ENDS>











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6.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  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 Network Configuration Access Control Model (NACM) [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 write operates can lead to
   inaccurate or incomplete network measurements which can impact the
   visibility and decisions this data would be used to inform.
   Unauthorized write access to the following subtrees could have the
   following impacts:


























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   +--------+----------------------+------------------------------+

   | Access |      Node            |   Potential impact           |

   +--------+----------------------+------------------------------+

   |    /nw:networks/nw:network/nw:network-types                  |

   | write  | service type         | disable VPN PM               |

   | write  | VPN identifier       | disable VPN PM               |

   | write  | VPN service topology | render data unusable         |

   +--------+----------------------+------------------------------+
   |    /nw:networks/nw:network/nw:node                           |

   | write  | node type            | render data unusable         |

   | write  | VPN topology role    | render data unusable         |

   +--------+----------------------+------------------------------+
   |    /nw:networks/nw:network/nw:link/nvp:perf-mon              |

   | write  | percentile           | impact reporting cadence     |

   | write  | measurement interval | impact monitoring fidelity   |

   | write  | vpn-pm-type          | impact monitoring fidelity   |

   +--------+----------------------+------------------------------+

   Some readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It thus might
   be important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  When using, the trade-off between
   confidentiality and proper monitoring of performance needs to be
   considered.  Unauthorized access to the following subtrees could have
   the following impacts:

   *  "/nw:networks/nw:network/nw:node": Unauthorized read access to
      this subtree can disclose the operational state information of
      underlay network instances or VPN instances.

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



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

   This YANG module does not define any RPC (Remote Procedure Call)
   operations and Actions.

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, Tom Petch, Greg Mirsky, Roque
   Gagliano, Erez Segev, and Dhruv Dhody for reviewing and providing
   important input to this document.

   This work was partially supported by the European Commission under
   Horizon 2020 grant agreement number 101015857 Secured autonomic
   traffic management for a Tera of SDN flows (Teraflow).

9.  Contributors

   The following authors contributed significantly to this document:










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      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: xuhl6@chinatelecom.cn

10.  References

10.1.  Normative References

   [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>.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <https://www.rfc-editor.org/info/rfc4364>.

   [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>.

   [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>.




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   [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>.

   [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>.

   [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>.








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   [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>.

   [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>.

   [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>.

   [RFC8762]  Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
              Two-Way Active Measurement Protocol", RFC 8762,
              DOI 10.17487/RFC8762, March 2020,
              <https://www.rfc-editor.org/info/rfc8762>.

   [RFC9181]  Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M.,
              Ed., and Q. Wu, "A Common YANG Data Model for Layer 2 and
              Layer 3 VPNs", RFC 9181, DOI 10.17487/RFC9181, February
              2022, <https://www.rfc-editor.org/info/rfc9181>.

10.2.  Informative References

   [I-D.ietf-opsawg-sap]
              Boucadair, M., de Dios, O. G., Barguil, S., Wu, Q., and V.
              Lopez, "A YANG Network Model for Service Attachment Points
              (SAPs)", Work in Progress, Internet-Draft, draft-ietf-
              opsawg-sap-10, 4 October 2022,
              <https://www.ietf.org/archive/id/draft-ietf-opsawg-sap-
              10.txt>.

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

   [RFC4026]  Andersson, L. and T. Madsen, "Provider Provisioned Virtual
              Private Network (VPN) Terminology", RFC 4026,
              DOI 10.17487/RFC4026, March 2005,
              <https://www.rfc-editor.org/info/rfc4026>.






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   [RFC5277]  Chisholm, S. and H. Trevino, "NETCONF Event
              Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
              <https://www.rfc-editor.org/info/rfc5277>.

   [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>.

   [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>.

   [RFC8632]  Vallin, S. and M. Bjorklund, "A YANG Data Model for Alarm
              Management", RFC 8632, DOI 10.17487/RFC8632, September
              2019, <https://www.rfc-editor.org/info/rfc8632>.

   [RFC8639]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Subscription to YANG Notifications",
              RFC 8639, DOI 10.17487/RFC8639, September 2019,
              <https://www.rfc-editor.org/info/rfc8639>.

   [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>.

   [RFC9182]  Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M.,
              Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model
              for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182,
              February 2022, <https://www.rfc-editor.org/info/rfc9182>.

   [RFC9197]  Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
              Ed., "Data Fields for In Situ Operations, Administration,
              and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
              May 2022, <https://www.rfc-editor.org/info/rfc9197>.






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   [RFC9291]  Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil,
              S., and L. Munoz, "A YANG Network Data Model for Layer 2
              VPNs", RFC 9291, DOI 10.17487/RFC9291, September 2022,
              <https://www.rfc-editor.org/info/rfc9291>.

Appendix A.  Illustrative Examples


A.1.  VPN Performance Subscription Example

   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.

      POST /restconf/operations
           /ietf-subscribed-notifications:establish-subscription

   {
     "ietf-subscribed-notifications:input": {
       "stream-subtree-filter": {
         "ietf-network:networks": {
           "network": {
             "network-id": "foo:vpn1",
             "ietf-network-vpn-pm:service": {
               "service-type": "ietf-vpn-common:l3vpn"
             },
             "node": [
               {
                 "node-id": "A",
                 "ietf-network-vpn-pm:node-type": "PE",
                 "termination-point": [
                   {
                     "tp-id": "1-0-1"
                   }
                 ]
               },
               {
                 "node-id": "B",
                 "ietf-network-vpn-pm:node-type": "PE",
                 "termination-point": [
                   {
                     "tp-id": "2-0-1"
                   }
                 ]
               }
             ],
             "ietf-network-topology:link": [



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               {
                 "link-id": "A-B",
                 "source": {
                   "source-node": "A"
                 },
                 "destination": {
                   "dest-node": "B"
                 },
                 "ietf-network-vpn-pm:perf-mon": {
                   "pm": [
                     {
                       "pm-type": "pm-type-vpn-tunnel",
                       "pm-attributes": {
                         "one-way-pm-statistics": {
                           "loss-statistics": {
                             "packet-loss-count": {}
                           }
                         }
                       }
                     }
                   ],
                   "vpn-pm-type": {
                     "vpn-tunnel": {
                       "vpn-tunnel-type": "ietf-vpn-common:gre"
                     }
                   }
                 }
               }
             ]
           }
         },
         "ietf-yang-push:periodic": {
           "ietf-yang-push:period": "500"
         }
       }
     }
   }

                        Figure 7: Pub/Sub Retrieval

A.2.  Example of VPN Performance Snapshot

   This example, depicted in Figure 8, illustrates an VPN PM instance
   example in which a client uses RESTCONF [RFC8040] to fetch the
   performance data of the link and TP belonged to "VPN1".






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   {
     "ietf-network:networks": {
       "network": {
         "network-id": "foo:vpn1",
         "node": [
           {
             "node-id": "A",
             "ietf-network-vpn-pm: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:node-type": "PE",
             "termination-point": [
               {
                 "tp-id": "2-0-1",
                 "ietf-network-vpn-pm:pm-statistics": {
                   "inbound-octets": "150",
                   "outbound-octets": "100"
                 }
               }
             ]
           }
         ],
         "ietf-network-topology:link": [
           {
             "link-id": "A-B",
             "source": {
               "source-node": "A"
             },
             "destination": {
               "dest-node": "B"
             },
             "ietf-network-pm:perf-mon": {
               "pm": [
                 {
                   "pm-type": "pm-type-vpn-tunnel",
                   "pm-attributes": {
                     "one-way-pm-statistics": {
                       "loss-statistics": {



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                         "packet-loss-count": "120"
                       }
                     }
                   }
                 }
               ],
               "vpn-pm-type": {
                 "vpn-tunnel": {
                   "vpn-tunnel-type": "ietf-vpn-common:gre"
                 }
               }
             }
           }
         ]
       }
     }
   }

                                  Figure 8

A.3.  Example of Percentile Monitoring

   This is an example of percentile measurement data that could be
   returned for a link foo:vpn1-link1 between vpn-node1 and vpn-node3.



























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   {
     "ietf-network-topology:link": [
       {
         "link-id": "foo:vpn1-link1",
         "source": {
           "source-node": "vpn-node1"
         },
         "destination": {
           "dest-node": "vpn-node3"
         },
         "ietf-network-vpn-pm:perf-mon": {
           "low-percentile": "20.000",
           "intermediate-percentile": "50.000",
           "high-percentile": "90.000",
           "pm": [
             {
               "pm-type": "pm-type-vpn-inter-access",
               "pm-attributes": {
                 "one-way-pm-statistics": {
                   "delay-statistics": {
                     "unit-value": "lime:milliseconds",
                     "min-delay-value": "43",
                     "max-delay-value": "99",
                     "low-delay-percentile": "64",
                     "intermediate-delay-percentile": "77",
                     "high-delay-percentile": "98"
                   }
                 }
               }
             }
           ],
           "vpn-pm-type": {
             "inter-vpn-access-interface": {
               "inter-vpn-access-interface": [null]
             }
           }
         }
       }
     ]
   }


Authors' Addresses








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   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
















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