OPSAWG Working Group                                          B. Wu, Ed.
Internet-Draft                                                Q. Wu, Ed.
Intended status: Standards Track                                  Huawei
Expires: 10 October 2022                               M. Boucadair, Ed.
                                                                  Orange
                                                     O. Gonzalez de Dios
                                                              Telefonica
                                                                  B. Wen
                                                                 Comcast
                                                            8 April 2022


    A YANG Model for Network and VPN Service Performance Monitoring
                draft-ietf-opsawg-yang-vpn-service-pm-05

Abstract

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

Status of This Memo

   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 10 October 2022.

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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Network and VPN Service Performance Monitoring Model Usage  .   4
     3.1.  Collecting Data via Pub/Sub Mechanism . . . . . . . . . .   5
     3.2.  Collecting Data On-demand . . . . . . . . . . . . . . . .   6
   4.  Description of The Data Model . . . . . . . . . . . . . . . .   6
     4.1.  Layering Relationship between Multiple Layers of
           Topology  . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Network Level . . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  Node Level  . . . . . . . . . . . . . . . . . . . . . . .   9
     4.4.  Link and Termination Point Level  . . . . . . . . . . . .  10
   5.  Network and VPN Service Performance Monitoring YANG Module  .  14
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  29
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  30
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  30
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  30
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  31
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  31
     10.2.  Informative References . . . . . . . . . . . . . . . . .  33
   Appendix A.  Illustrating Examples  . . . . . . . . . . . . . . .  35
     A.1.  VPN Performance Subscription Example  . . . . . . . . . .  35
     A.2.  Example of VPN Performance Snapshot . . . . . . . . . . .  36
     A.3.  Example of Percentile Monitoring  . . . . . . . . . . . .  38
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  38

1.  Introduction

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

   The performance of VPN services is associated with the performance
   changes of the underlay network that carries VPN services, such as
   the delay of the underlay tunnels and the packet loss status of the



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   device interfaces.  Additionally, the integration of Layer 2/Layer 3
   VPN performance and network performance data enables the orchestrator
   to subscribe to VPN service performance in a unified manner.
   Therefore, this document defines a YANG module for both network and
   VPN service performance monitoring (PM).  The module can be used to
   monitor and manage network performance on the topology level or the
   service topology between VPN sites, in particular.

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

   The YANG module defined in this document is designed as an
   augmentation to the network topology YANG model defined in [RFC8345]
   and draws on relevant YANG types defined in [RFC6991], [RFC8345],
   [RFC8532], and [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].

2.1.  Acronyms

   The following acronyms are used in the document:

   L2VPN   Layer 2 Virtual Private Network
   L3VPN   Layer 3 Virtual Private Network
   L2NM    L2VPN Network Model
   L3NM    L3VPN Network Model
   MPLS    Multiprotocol Label Switching



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   OAM     Operations, Administration, and Maintenance
   OWAMP   One-Way Active Measurement Protocol
   PE      Provider Edge
   PM      Performance Monitoring
   SLA     Service Level Agreements
   TWAMP   Two-Way Active Measurement Protocol
   VPLS    Virtual Private LAN Service
   VPN     Virtual Private Network


3.  Network and VPN Service Performance Monitoring Model Usage

   Models are key for automating network management operations.
   According to [RFC8969], together with service and network models,
   performance measurement telemetry models are needed to monitor
   network performance to meet specific service requirements (typically
   captured in an SLA).

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

                   Figure 1: Reference Architecture

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



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

   The network or VPN performance data can be based on different
   sources.  For example, the performance monitoring data per link in
   the underlying network 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], and Multiprotocol Label Switching (MPLS) Loss and Delay
   Measurement [RFC6374].  The performance monitoring information
   reflecting the quality of the network or VPN service (e.g., end-to-
   end network performance data between source node and destination node
   in the network or between VPN sites) can be computed and aggregated,
   for example, using the information from the Traffic Engineering
   Database (TED), [RFC7471] [RFC8570] [RFC8571] or LMAP [RFC8194].

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

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

3.1.  Collecting Data via Pub/Sub Mechanism

   Some applications such as service-assurance applications, which must
   maintain a continuous view of operational data and state, can use the
   subscription model specified in [RFC8641] to subscribe to the
   specific network performance data or VPN service performance data
   they are interested in, at the data source.  For example, network or
   VPN topology updates may be obtained through on-change notifications
   [RFC8641].  For dynamic-changing PM data, various notifications can
   be specified to obtain more complete data.  A periodic notification
   [RFC8641] can be specified to obtain real-time performance data, a
   replay notification defined in [RFC5277] or [RFC8639] can be
   specified to obtain historical data, or alarm notifications [RFC8632]
   can be specified to get alarms for the metrics which exceed or fall
   below the performance threshold.




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   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 On-demand

   To obtain a snapshot of a large amount of performance data from a
   network topology or VPN network, 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".

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

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

                       Figure 2: Module Augmentation

4.1.  Layering Relationship between Multiple Layers of Topology

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

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








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

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

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

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

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

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





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   Apart from the association between the VPN topology and the underlay
   topology, VPN Network PM can also provide the performance status of
   the underlay network and VPN services.  For example, network PM can
   provide link PM statistics and port statistics.  VPN PM can provides
   statistics on VPN access interfaces, the number of current VRF routes
   or L2VPN MAC entry of VPN nodes, and performance statistics on the
   logical point-to-point link between source and destination VPN nodes
   or between source and destination VPN access interfaces.  Figure 4
   illustrates an example of VPN PM and the difference between two VPN
   PM measurement methods.  One is the VPN tunnel PM and the other is
   inter-VPN-access interface PM.

          +-----------------------------------------------------+
          |                                                     |
          |                      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
           -:Link

                       Figure 4: An Example of VPN PM

4.2.  Network Level

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

   For VPN service performance monitoring, the container "service-type"
   is defined to indicate the VPN type, e.g., L3VPN or Virtual Private
   LAN Service (VPLS).  The values are taken from [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 5 is a part of ietf-network-vpn-pm tree.  It
   defines the following set of network level attributes:

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

   "vpn-service-topology":  Indicates the type of the VPN topology.
      This model supports "any-to-any", "Hub and Spoke" (where Hubs can
      exchange traffic), and "Hub and Spoke disjoint" (where Hubs cannot
      exchange traffic) that are taken from [RFC9181].  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 5: Network Level YANG Tree of the Hierarchies

4.3.  Node Level

   The tree in Figure 6 is the node part of ietf-network-vpn-pm tree.

   For network performance monitoring, a container of "pm-attributes" is
   augmented to the list of "node" that are defined in [RFC8345].  The
   container includes 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.





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   For VPN service performance monitoring, the model defines one
   attribute:

   "role":  Defines the role in a particular VPN service topology.  The
      roles are taken from [RFC9181] (e.g., any-to-any-role, spoke-role,
      hub-role).

     augment /nw:networks/nw:network/nw:node:
       +--rw pm-attributes
          +--rw node-type?       identityref
          +--ro entry-summary
          |  +--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
          +--rw role?            identityref

             Figure 6: Node Level YANG Tree of the Hierarchies


4.4.  Link and Termination Point Level

   The tree in Figure 7 is the link and termination point (TP) part of
   ietf-network-vpn-pm tree.

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

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

     augment /nw:networks/nw:network/nt:link:
       +--rw pm-attributes
          +--rw low-percentile?                      percentile
          +--rw intermediate-percentile?             percentile
          +--rw high-percentile?                     percentile
          +--rw measurement-interval?                uint32
          +--ro start-time?                          yang:date-and-time
          +--ro end-time?                            yang:date-and-time
          +--ro pm-source?                           identityref
          +--ro one-way-pm-statistics
          |  +--ro loss-statistics
          |  |  +--ro packet-loss-count?   yang:counter64



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          |  |  +--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)?
             +--:(inter-vpn-access-interface)
             |  +--rw inter-vpn-access-interface?    empty
             +--:(underlay-tunnel)
                +--ro vpn-underlay-transport-type?   identityref
     augment /nw:networks/nw:network/nw:node/nt:termination-point:
       +--ro pm-statistics
          +--ro reference-time?             yang:date-and-time
          +--ro inbound-octets?             yang:counter64
          +--ro inbound-unicast?            yang:counter64
          +--ro inbound-nunicast?           yang:counter64
          +--ro inbound-discards?           yang:counter64
          +--ro inbound-errors?             yang:counter64
          +--ro inbound-unknown-protocol?   yang:counter64



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          +--ro outbound-octets?            yang:counter64
          +--ro outbound-unicast?           yang:counter64
          +--ro outbound-nunicast?          yang:counter64
          +--ro outbound-discards?          yang:counter64
          +--ro outbound-errors?            yang:counter64
          +--ro vpn-network-access* [network-access-id]
             +--ro network-access-id           vpn-common:vpn-id
             +--ro reference-time?             yang:date-and-time
             +--ro inbound-octets?             yang:counter64
             +--ro inbound-unicast?            yang:counter64
             +--ro inbound-nunicast?           yang:counter64
             +--ro inbound-discards?           yang:counter64
             +--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 7: Link and Termination point Level YANG Tree of the
                                hierarchies

   For the data nodes of 'link' depicted in Figure 7, 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), intermediate percentile (50th percentile), high
      percentile (90th percentile) are used.  Setting a percentile to
      0.00 indicates the client is not interested in receiving
      particular percentile.  If all percentile nodes are set to 0.00,
      this represents that no percentile related nodes will be reported
      for a given performance metric (e.g., one-way delay, one-way delay
      variation) and only peak/min values will be reported.  For
      example, a client can inform the server that it is interested in
      receiving only high percentiles.  Then for a given link, at a
      given "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.

   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]



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      referenced in [I-D.ietf-opsawg-l2nm].  Alternatively, the data can
      be based upon the underlay technology OAM mechanisms, for example,
      Generic Routing Encapsulation (GRE) tunnel OAM.

   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.

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

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

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

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

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

   VPN PM type ("vpn-pm-type"):  Indicates the VPN performance type,












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      which can be inter-vpn-access-interface PM or VPN underlay-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 connections between a source and a
      destination VPN access interfaces.  And the underlay-tunnel PM is
      to monitor the performance of underlay tunnels of VPNs.  The
      inter-VPN-access-interface PM includes PE-PE monitoring.
      Therefore, only one of the two methods is needed , and the model
      defines "choice" to indicate these two methods, which also allows
      other methods to be extended.

   VPN underlay transport type ("vpn-underlay-transport-type"):  Indicat
      es the abstract link protocol-type of a VPN, such as GRE or IP-in-
      IP.  The leaf refers to an identifier of the "underlay-transport"
      defined in [RFC9181], which describes the transport technology to
      carry the traffic of the VPN service.

   For the data nodes of 'termination-point' depicted in Figure 7, the
   module defines the following minimal set of statistics:

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

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

   VPN network access ("vpn-network-access"):  Lists counters of the VPN
      network access defined in [RFC9182] or [I-D.ietf-opsawg-l2nm].
      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.

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@2021-04-08.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;



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       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>

        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.



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        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 2022-04-08 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: A YANG Model for Network and VPN Service
          Performance Monitoring";
     }

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

     identity pe {
       base node-type;
       description
         "Provider Edge (PE) node type.";
       reference
         "RFC 4026: Provider Provisioned
          Virtual Private Network (VPN) Terminology";
     }

     identity p {
       base node-type;
       description
         "Provider router node type.";
       reference
         "RFC 4026: Provider Provisioned
          Virtual Private Network (VPN) Terminology";



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     }

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



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       reference
         "ITU-T Y.1731: Operations, administration and
          maintenance (OAM) functions and mechanisms
          for Ethernet-based networks";
     }

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

     typedef percentile {
       type decimal64 {
         fraction-digits 2;
         range "0..100";
       }
       description
         "The percentile is a value between 0 and 100,
          e.g. 10.00, 99.90 ,99.99 etc..
          For example, for a given one-way delay measurement,
          if the percentile is set to 95.00 and
          the 95th percentile one-way delay is 2 milliseconds,
          then the 95 percent of 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 {
           leaf maximum-routes {
             type uint32;
             description
               "Indicates the maximum number of IPv4 routes
                for the VPN.";
           }
           leaf total-active-routes {
             type uint32;
             description



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

     grouping link-loss-statistics {
       description
         "Grouping for per link error statistics.";
       container loss-statistics {
         description
           "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";



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         leaf packet-loss-count {
           type yang:counter64;
           description
             "Total received packet drops count.";
         }
         leaf loss-ratio {
           type percentage;
           description
             "Loss ratio of the packets. Express as percentage
              of packets lost with respect to packets sent.";
         }
       }
     }

     grouping link-delay-statistics {
       description
         "Grouping for per link delay statistics.";
       container delay-statistics {
         description
           "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 s, ms, ns, etc.";
         }
         leaf min-delay-value {
           type yang:gauge64;
           description
             "Minimum observed one-way delay.";
         }
         leaf max-delay-value {
           type yang:gauge64;
           description
             "Maximum observed one-way delay.";
         }
         leaf low-delay-percentile {
           type yang:gauge64;
           description
             "Low percentile of observed one-way delay with
              specific measurement method.";



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         }
         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 s, ms, ns, etc.";
         }
         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 {



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           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 reference-time {
         type yang:date-and-time;
         config false;
         description
           "Indicates the time when the statistics are collected.";
       }
       leaf inbound-octets {
         type yang:counter64;
         description
           "The total number of octets received on the
            interface, including framing characters.";
       }
       leaf inbound-unicast {
         type yang:counter64;
         description
           "The total number of inbound unicast packets.";
       }
       leaf inbound-nunicast {
         type yang:counter64;
         description
           "The total number of inbound non-unicast
            (i.e., broadcast or 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



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            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-nunicast {
         type yang:counter64;
         description
           "The total number of outbound non unicast
            (i.e., broadcast or 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



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         "Grouping for interface service telemetry.";
     }

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

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

     augment "/nw:networks/nw:network/nw:node" {



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       description
         "Augments the network node with other general attributes.";
       container pm-attributes {
         leaf node-type {
           type identityref {
             base node-type;
           }
           description
             "Node type, e.g., PE, P, ASBR.";
         }
         description
           "Container for node attributes.";
         uses entry-summary;
       }
     }

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

     augment "/nw:networks/nw:network/nt:link" {
       description
         "Augments the network topology link with performance
          monitoring attributes.";
       container pm-attributes {
         description
           "Container for PM attributes.";
         leaf low-percentile {
           type percentile;
           default "10.00";
           description
             "Low percentile to report. Setting low-percentile
              into 0.00 indicates the client is not interested
              in receiving low percentile.";
         }



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         leaf intermediate-percentile {
           type percentile;
           default "50.00";
           description
             "Intermediate percentile to report. Setting
              intermediate-percentile into 0.00 indicates the client
              is not interested in receiving intermediate percentile.";
         }
         leaf high-percentile {
           type percentile;
           default "95.00";
           description
             "High percentile to report. Setting high-percentile
              into 0.00 indicates the client is not interested in
              receiving high percentile.";
         }
         leaf measurement-interval {
           type uint32 {
             range "1..max";
           }
           units "seconds";
           default "60";
           description
             "Indicates the time interval to perform PM measurement.";
         }
         leaf start-time {
           type yang:date-and-time;
           config false;
           description
             "The time that the current measurement started.";
         }
         leaf end-time {
           type yang:date-and-time;
           config false;
           description
             "The time that the current measurement ended.";
         }
         leaf pm-source {
           type identityref {
             base pm-source-type;
           }
           config false;
           description
             "The OAM tool used to collect the PM data.";
         }
         container one-way-pm-statistics {
           config false;
           description



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             "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;
         }
       }
     }

     augment "/nw:networks/nw:network/nt:link/pm-attributes" {
       when '../../nw:network-types/nvp:service-type' {
         description
           "Augments only for VPN Network topology.";
       }
       description
         "Augments the network topology link with VPN service
          performance monitoring attributes.";
       choice vpn-pm-type {
         description
           "The VPN PM type of this logical point-to-point
            unidirectional VPN link.";
         case inter-vpn-access-interface {
           leaf inter-vpn-access-interface {
             type empty;
             description
               "This is a placeholder for inter-vpn-access-interface PM.
                There is no technology to be defined.";
           }
         }
         case underlay-tunnel {
           leaf vpn-underlay-transport-type {
             type identityref {
               base vpn-common:protocol-type;
             }



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             config false;
             description
               "The leaf indicates the underlay transport type of
                a VPN service, e.g., GRE, LDP, etc.";
           }
         }
       }
     }

     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-type' {
         description
           "Augments only for VPN Network topology.";
       }
       description
         "Augments the network topology termination-point with
          VPN service performance monitoring attributes";
       list vpn-network-access {
         key "network-access-id";
         description
           "The list of PM based on VPN network accesses.";
         leaf network-access-id {
           type vpn-common:vpn-id;
           description
             "References to an identifier for the VPN network
              access, e.g. L3VPN or VPLS.";
         }
         uses tp-svc-telemetry;
       }
     }
   }
   <CODE ENDS>






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6.  Security Considerations

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

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

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees with the write
   operation that can be exploited to impact the network monitoring:

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

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

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

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

   *  /nw:networks/nw:network/nw:node/nt:termination-point/nvp:pm-
      statistics"

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  The nodes
   reveals the quality of a service that is operated by an operator.  It
   is thus important to control read access (e.g., via get, get-config,
   or notification) to these data nodes.  These are the subtrees and
   data nodes and their sensitivity/vulnerability:

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





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

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

7.  IANA Considerations

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

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

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

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

8.  Acknowledgements

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

9.  Contributors

   The following authors contributed significantly to this document:












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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: xuhl.bri@chinatelecom.cn

10.  References

10.1.  Normative References

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

   [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>.

   [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>.

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

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

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

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

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





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   [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>.

   [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-netmod-node-tags]
              Wu, Q., Claise, B., Liu, P., Du, Z., and M. Boucadair,
              "Self-Describing Data Object Tags in YANG Data Models",
              Work in Progress, Internet-Draft, draft-ietf-netmod-node-
              tags-06, 21 February 2022,
              <https://www.ietf.org/archive/id/draft-ietf-netmod-node-
              tags-06.txt>.

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

   [I-D.ietf-opsawg-sap]
              Boucadair, M., Dios, O. G. D., Barguil, S., Wu, Q., and V.
              Lopez, "A Network YANG Model for Service Attachment Points
              (SAPs)", Work in Progress, Internet-Draft, draft-ietf-
              opsawg-sap-03, 21 March 2022,
              <https://www.ietf.org/archive/id/draft-ietf-opsawg-sap-
              03.txt>.

   [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>.

   [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>.

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





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

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

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

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

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

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

   [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>.





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Appendix A.  Illustrating Examples


A.1.  VPN Performance Subscription Example

   The example shown in Figure 8 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-topo:networks":{
            "network":{
               "network-id":"l3-network",
               "ietf-network-vpn-pm:service-type":{
                  "ietf-vpn-common:l3vpn":{}
               },
               "node":[
                  {
                     "node-id":"A",
                     "ietf-network-vpn-pm:pm-attributes":{
                        "node-type":"PE"
                     },
                     "termination-point":{
                        "tp-id":"1-0-1"
                     }
                  },
                  {
                     "node-id":"B",
                     "ietf-network-vpn-pm:pm-attributes":{
                        "node-type":"PE"
                     },
                     "termination-point":{
                        "tp-id":"2-0-1"
                     }
                  }
               ],
               "link":{
                  "link-id":"A-B",
                  "source":{
                     "source-node":"A"
                  },
                  "destination":{
                     "dest-node":"B"



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                  },
                  "ietf-network-vpn-pm:pm-attributes":{
                     "one-way-pm-statistics":{
                        "loss-statistics":{
                           "packet-loss-count":{}
                        }
                     },
                     "vpn-underlay-transport-type":"ietf-vpn-common:gre"
                  }
               }
            }
         }
      },
      "ietf-yang-push:periodic":{
         "ietf-yang-push:period":"500"
      }
   }
}

                     Figure 8: Pub/Sub Retrieval

A.2.  Example of VPN Performance Snapshot

   This example, depicted in Figure 9, 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-topo:networks": {
           "network": {
             "network-id": "foo:vpn1",
             "node": [
               {
                 "node-id": "A",
                 "ietf-network-vpn-pm:pm-attributes": {
                   "node-type": "PE"
                 },
                 "termination-point": {
                   "tp-id": "1-0-1",
                   "ietf-network-vpn-pm:pm-statistics": {
                     "inbound-octets": "100",
                     "outbound-octets": "150"
                   }
                 }
               },
               {
                 "node-id": "B",
                 "ietf-network-vpn-pm:pm-attributes": {
                   "node-type": "PE"
                 },
                 "termination-point": {
                   "tp-id": "2-0-1",
                   "ietf-network-vpn-pm:pm-statistics": {
                     "inbound-octets": "150",
                     "outbound-octets": "100"
                   }
                 }
               }
             ],
             "link": {
               "link-id": "A-B",
               "source": { "source-node": "A" },
               "destination": { "dest-node": "B" },
               "ietf-network-pm:pm-attributes": {
                 "one-way-pm-statistics": {
                   "loss-statistics": { "packet-loss-count": "120" }
                 },
                 "vpn-underlay-transport-type": "ietf-vpn-common:gre"
               }
             }
           }
         }
   }

                                  Figure 9



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A.3.  Example of Percentile Monitoring

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

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


Authors' Addresses

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






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   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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