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

Document Type Active Internet-Draft (opsawg WG)
Authors Bo Wu  , Qin Wu  , Mohamed Boucadair  , Oscar de Dios  , Bin Wen  , Chang Liu  , Honglei Xu 
Last updated 2021-07-06
Replaces draft-www-opsawg-yang-vpn-service-pm
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OPSAWG Working Group                                          B. Wu, Ed.
Internet-Draft                                                Q. Wu, Ed.
Intended status: Standards Track                                  Huawei
Expires: January 7, 2022                               M. Boucadair, Ed.
                                                                  Orange
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                                  B. Wen
                                                                 Comcast
                                                                  C. Liu
                                                            China Unicom
                                                                   H. Xu
                                                           China Telecom
                                                            July 6, 2021

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

Abstract

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

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

Status of This Memo

   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."

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

Copyright Notice

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

   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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

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

1.  Introduction

   [RFC8969] describes a framework for automating service and network
   management with YANG models, proposing the performance measurement
   telemetry model to be tied with the service, such as Layer 3 VPN and

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   Layer 2 VPN, or network models to monitor the overall network
   performance or Service Level Agreements (SLA).

   This document defines a YANG module [RFC7950] for both network
   performance monitoring and VPN service performance monitoring.  This
   module can be used to monitor and manage network performance on the
   topology level or the service topology between VPN sites, in
   particular.

   This document does not introduce new metrics for network performance
   or mechanisms for measuring network performance, but uses the
   existing mechanisms and statistics to show the performance monitoring
   statistics at the network and service layers.  The YANG module
   defined in this document is designed as an augmentation to the
   network topology YANG model defined in [RFC8345].

   This document uses the common VPN YANG module defined in
   [I-D.ietf-opsawg-vpn-common].

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

2.  Terminology

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

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

3.  Network and VPN Service Performance Monitoring Model Usage

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

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

                     Figure 1: Reference Architecture

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

   Before using the network and VPN service PM model, the mapping
   between the VPN service topology and the underlying physical network
   should be setup.  Also, the performance monitoring data per link in
   the underlying network can be collected using network performance
   measurement method such as MPLS Loss and Delay Measurement [RFC6374].

   The performance monitoring information reflecting the quality of the
   network or VPN service (e.g., end to end network performance data
   between source node and destination node in the network or between
   VPN sites) can be computed and aggregated, for example, the
   information from Traffic Engineering Database (TED), defined in
   [RFC7471], [RFC8570], or [RFC8571] or LMAP [RFC8194].

   The measurement and report intervals that are associated with these
   performance data usually depend on the configuration parameters.

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3.1.  Collecting Data via Pub/Sub Mechanism

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

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

3.2.  Collecting Data via Retrieval Methods

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

4.  Description of The Data Model

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

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

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

                       Figure 2: Module Augmentation

4.1.  Layering Relationship between Multiple Layers of Topology

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

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   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]-  /
          /      /    \       :   /    /   :            :    /
         /      /      \  S1A  :: : : : : :             :   /
        /S1B-[VN2]____[VN1]--   /    /   : :            :  /
       +--------:-------:------+    +---:----:----------:-+
                :        :       :: : :       :         :
                :         :    :              :         :
      Site-1A   :  +-------:--: ----- -------- : -------:-----+ Site-1C
        [CE1]___: /__ ___ [N1]__________________ [N2]__ :___ /__[CE3]
                :/      /  / \             _____/ /    :    /
      [CE5]___  : ___  /  /    \     _____/      /   ::    /
    Site-2A    /:        /       \  /           /   :     /
              / :                [N5]          /   :     /
             /   :     /       __/ \__        /   :     /
            /     :   /    ___/       \__    /   :     /
   Site-1B /       : / ___/              \  /   :     /  Site-2B
    [CE2]-/------- [N4]_________________ [N3]:::-----/----[CE4]
         +------------------------------------------+

       Legend: N:node  VN:VPN-Node

    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.

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4.2.  Network Level

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

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

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

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

              Figure 4: Network Level View of the Hierarchies

4.3.  Node Level

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

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

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

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

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

               Figure 5: Node Level View of the Hierarchies

4.4.  Link and Termination Point Level

   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.

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     augment /nw:networks/nw:network/nt:link:
       +--rw pm-attributes
          +--rw low-percentile?         percentile
          +--rw middle-percentile?      percentile
          +--rw high-percentile?        percentile
          +--ro pm-source?              string
          +--ro reference-time?         yang:date-and-time
          +--ro measurement-interval?   uint32
          +--ro pm-statistics
          |  +--ro loss-statistics
          |  |  +--ro packet-loss-count?          yang:counter64
          |  |  +--ro packet-reorder-count?       yang:counter64
          |  |  +--ro packets-out-of-seq-count?   yang:counter64
          |  |  +--ro packets-dup-count?          yang:counter64
          |  |  +--ro loss-ratio?                 percentage
          |  +--ro delay-statistics
          |  |  +--ro direction?                 identityref
          |  |  +--ro unit-value?                identityref
          |  |  +--ro min-delay-value?           yang:gauge64
          |  |  +--ro max-delay-value?           yang:gauge64
          |  |  +--ro low-delay-percentile?      yang:gauge64
          |  |  +--ro middle-delay-percentile?   yang:gauge64
          |  |  +--ro high-delay-percentile?     yang:gauge64
          |  +--ro jitter-statistics
          |     +--ro unit-value?                 identityref
          |     +--ro min-jitter-value?           yang:gauge32
          |     +--ro max-jitter-value?           yang:gauge32
          |     +--ro low-jitter-percentile?      yang:gauge32
          |     +--ro middle-jitter-percentile?   yang:gauge32
          |     +--ro high-jitter-percentile?     yang:gauge32
          +--ro protocol-type?          identityref
     augment /nw:networks/nw:network/nw:node/nt:termination-point:
       +--ro pm-statistics
          +--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 View of the hierarchies

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

   Percentile parameters:  The module supports reporting delay and
      jitter metric by percentile values.  By default, low percentile
      (10th percentile), mid percentile (50th percentile), high
      percentile (90th percentile) are used.  Setting a percentile into
      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" "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.

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

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

   "protocol-type":  Indicates 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],

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      which describes the transport technology to carry the traffic of
      the VPN service.

   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.

5.  Network and VPN Service Performance Monitoring YANG Module

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

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

  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Types";
  }
  import ietf-vpn-common {
    prefix vpn-common;
    reference
      "RFC CCCC: A Layer 2/3 VPN Common YANG Model";
  }
  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";
  }

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  import ietf-lime-time-types {
    prefix lime;
    reference
      "RFC 8532: Generic YANG Data Model for the Management of
                 Operations, Administration, and Maintenance
                 (OAM) Protocols That Use Connectionless Communications";
  }

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

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

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (http://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX; see
     the RFC itself for full legal notices.";

  revision 2021-07-06 {
    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 {

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

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

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

  identity direction {
    description
      "Base identity for measurement direction including
       one-way measurement and two-way measurement.";
  }

  identity one-way {
    base direction;
    description
      "Identity for one-way measurement.";
  }

  identity two-way {
    base direction;
    description
      "Identity for two-way measurement.";
  }

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

  typedef percentile {
    type decimal64 {
      fraction-digits 5;
    }

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    description
      "The percentile is a statistical value that indicates that a
       certain percentage of a set of data falls below it.";
  }

  grouping vpn-summary-statistics {
    description
      "VPN Statistics grouping used for network topology
       augmentation.";
    container vpn-summary-statistics {
      config false;
      description
        "Container for VPN summary statistics.";
      container ipv4 {
        leaf maximum-routes {
          type uint32;
          description
            "Total routes for the VPN.";
        }
        leaf total-active-routes {
          type uint32;
          description
            "Total active routes for the VPN.";
        }
        description
          "IPv4-specific parameters.";
      }
      container ipv6 {
        leaf maximum-routes {
          type uint32;
          description
            "Total routes for the VPN.";
        }
        leaf total-active-routes {
          type uint32;
          description
            "Total active 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 {

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          type uint32;
          description
            "Total active MAC entries for the VPN.";
        }
        description
          "MAC statistics.";
      }
    }
  }

  grouping link-error-statistics {
    description
      "Grouping for per link error statistics.";
    container loss-statistics {
      description
        "Per link loss statistics.";
      leaf packet-loss-count {
        type yang:counter64;
        description
          "Total received packet drops count.";
      }
      leaf packet-reorder-count {
        type yang:counter64;
        description
          "Total received packet reordered count.";
      }
      leaf packets-out-of-seq-count {
        type yang:counter64;
        description
          "Total received out of sequence count.";
      }
      leaf packets-dup-count {
        type yang:counter64;
        description
          "Total received packet duplicates count.";
      }
      leaf loss-ratio {
        type percentage;
        description
          "Loss ratio of the packets. Express as percentage
           of packets lost with respect to packets sent.";
      }
    }
  }

  grouping link-delay-statistics {
    description
      "Grouping for per link delay statistics";

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

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           specific measurement method.";
      }
    }
  }

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

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  grouping tp-svc-telemetry {
    leaf inbound-octets {
      type yang:counter64;
      description
        "The total number of octets received on the
         interface, including framing characters.";
    }
    leaf inbound-unicast {
      type yang:counter64;
      description
        "Inbound unicast packets were received, and delivered
         to a higher layer during the last period.";
    }
    leaf inbound-nunicast {
      type yang:counter64;
      description
        "The number of non-unicast (i.e., subnetwork-
         broadcast or subnetwork-multicast) packets
         delivered to a higher-layer protocol.";
    }
    leaf inbound-discards {
      type yang:counter32;
      description
        "The number of inbound packets which were chosen
         to be discarded even though no errors had been
         detected to prevent their being deliverable to a
         higher-layer protocol.";
    }
    leaf inbound-errors {
      type yang:counter64;
      description
        "The number of inbound packets that contained
         errors preventing them from being deliverable to a
         higher-layer protocol.";
    }
    leaf inbound-unknown-protocol {
      type yang:counter64;
      description
        "The number of packets received via the interface
         which were discarded because of an unknown or
         unsupported protocol.";
    }
    leaf outbound-octets {
      type yang:counter64;
      description
        "The total number of octets transmitted out of the
         interface, including framing characters.";
    }

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

  augment "/nw:networks/nw:network/nw:network-types" {
    description
      "Defines the service topologies types";
    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,

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           e.g., L3VPN, VPLS, etc.";
      }
      description
        "Container for VPN service type.";
    }
  }

  augment "/nw:networks/nw:network" {
    when 'nw:network-types/nvp:service-type' {
      description
        "Augment only for VPN Network topology.";
    }
    description
      "Augment 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
      "Augment 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.";
    }
  }

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  augment "/nw:networks/nw:network/nw:node/pm-attributes" {
    when '../../nw:network-types/nvp:service-type' {
      description
        "Augment only for VPN node attributes.";
    }
    description
      "Augment 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
      "Augment 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 {
        type percentile;
        default "50.00";
        description
          "Middle percentile to report. Setting middle-percentile
           into 0.00 indicates the client is not interested in receiving
           middle percentile.";
      }
      leaf high-percentile {
        type percentile;
        default "90.00";
        description
          "High percentile to report. Setting high-percentile
           into 0.00 indicates the client is not interested in receiving
           high percentile";

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      }
      leaf pm-source {
        type string;
        config false;
        description
          "The OAM tool used to collect the PM data.";
      }
      leaf reference-time {
        type yang:date-and-time;
        config false;
        description
          "The time that the current Measurement Interval started.";
      }
      leaf measurement-interval {
        type uint32;
        units "seconds";
        default "60";
        config false;
        description
          "Interval to calculate performance metric.";
      }
      container pm-statistics {
        config false;
        uses link-error-statistics;
        uses link-delay-statistics;
        uses link-jitter-statistics;
        description
          "Container for service telemetry attributes.";
      }
    }
  }

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

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  }

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

<CODE ENDS>

6.  Security Considerations

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

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

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

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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

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

      Michale Wang
      Huawei
      Email:wangzitao@huawei.com

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

10.  References

10.1.  Normative References

   [I-D.ietf-opsawg-vpn-common]
              Barguil, S., Dios, O. G. D., Boucadair, M., and Q. Wu, "A
              Layer 2/3 VPN Common YANG Model", draft-ietf-opsawg-vpn-
              common-07 (work in progress), April 2021.

   [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>.

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   [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>.

   [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>.

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   [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-opsawg-l2nm]
              Barguil, S., Dios, O. G. D., Boucadair, M., and L. A.
              Munoz, "A Layer 2 VPN Network YANG Model", draft-ietf-
              opsawg-l2nm-02 (work in progress), April 2021.

   [I-D.ietf-opsawg-l3sm-l3nm]
              Barguil, S., Dios, O. G. D., Boucadair, M., Munoz, L. A.,
              and A. Aguado, "A Layer 3 VPN Network YANG Model", draft-
              ietf-opsawg-l3sm-l3nm-08 (work in progress), April 2021.

   [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>.

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

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

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

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

Appendix A.  Illustrating Examples

A.1.  Example of Pub/Sub Retrieval

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

    <rpc netconf:message-id="101"
       xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
       <establish-subscription
      xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
          <stream-subtree-filter>
             <networks
        xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo">
                <network>
                 <network-id>l3-network</network-id>
                 <service-type
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                    L3VPN
                 </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>

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                     </pm-attributes>
                     <termination-point
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                      <tp-id>1-0-1</tp-id>
                      <pm-statistics
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                       <inbound-octets>150</inbound-octets>
                       <outbound-octets>100</outbound-octets>
                      </pm-statistics>
                     </termination-point>
                    </node>
                   <node>
                     <node-id>B</node-id>
                     <pm-attributes>
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                      <node-type>pe</node-type>
                     </pm-attributes>
                       <termination-point
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                         <tp-id>2-0-1</tp-id>
                         <pm-statistics
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                           <inbound-octets>150</inbound-octets>
                           <outbound-octets>100</outbound-octets>
                         </pm-statistics>
                      </termination-point>
                    </node>
                    <link
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                     <link-id>A-B</link-id>
                      <source>
                        <source-node>A</source-node>
                      </source>
                      <destination>
                       <dest-node>B</dest-node>
                      </destination>
                      <protocol-type>mpls-te</protocol-type>
                      <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                        <loss-statistics>
                         <packet-loss-count>100</packet-loss-count>
                        </loss-statistics>
                      </pm-attributes>
                    </link>
                </network>
              </networks>
           </stream-subtree-filter>
         <period

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           xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
          500
       </period>
       </establish-subscription>
    </rpc>

                       Figure 7: Pub/Siub Retrieval

A.2.  Example of RPC-based Retrieval

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

  <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
         message-id="1">
    <report
         xmlns="urn:ietf:params:xml:ns:yang:example-service-pm-report">
       <networks xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo">
         <network>
          <network-id>vpn1</network-id>
          <node>
           <node-id>A</node-id>
           <pm-attributes
                xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
             <node-type>pe</node-type>
           </pm-attribtues>
           <termination-point
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
            <tp-id>1-0-1</tp-id>
            <pm-statistics
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
             <inbound-octets>100</inbound-octets>
             <outbound-octets>150</outbound-octets>
            </pm-statistics>
           </termination-point>
          </node>
          <node>
           <node-id>B</node-id>
           <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
             <node-type>pe</node-type>
           </pm-attribtues>
           <termination-point
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
            <tp-id>2-0-1</tp-id>
            <pm-statistics

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                xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
             <inbound-octets>150</inbound-octets>
             <outbound-octets>100</outbound-octets>
            </pm-statistics>
           </termination-point>
          </node>
          <link>
          <link-id>A-B</link-id>
           <source>
            <source-node>A</source-node>
           </source>
           <destination>
            <dest-node>B</dest-node>
           </destination>
          <-type>mpls-te</link-type>
           <pm-attributes
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-pm">
            <loss-statistics>
             <packet-loss-count>120</packet-loss-count>
            </loss-statistics>
           </pm-attributes>
          </link>
        </network>
      </report>
    </rpc>

                                 Figure 8

A.3.  Example of Percentile Monitoring

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

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

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

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   Mohamed Boucadair (editor)
   Orange
   Rennes 35000
   France

   Email: mohamed.boucadair@orange.com

   Oscar Gonzalez de Dios
   Telefonica
   Madrid
   ES

   Email: oscar.gonzalezdedios@telefonica.com

   Bin Wen
   Comcast

   Email: bin_wen@comcast.com

   Change Liu
   China Unicom

   Email: liuc131@chinaunicom.cn

   Honglei Xu
   China Telecom

   Email: xuhl.bri@chinatelecom.cn

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