Internet-Draft Network and VPN Service PM YANG January 2022
Wu, et al. Expires 23 July 2022 [Page]
Workgroup:
OPSAWG Working Group
Internet-Draft:
draft-ietf-opsawg-yang-vpn-service-pm-02
Published:
Intended Status:
Standards Track
Expires:
Authors:
B. Wu, Ed.
Huawei
Q. Wu, Ed.
Huawei
M. Boucadair, Ed.
Orange
O. Gonzalez de Dios
Telefonica
B. Wen
Comcast

A YANG Model for Network and VPN Service Performance Monitoring

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 23 July 2022.

Table of Contents

1. Introduction

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

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

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

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

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

2. Terminology

The following terms are defined in [RFC7950] and are used in this specification:

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

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

3. Network and VPN Service Performance Monitoring Model Usage

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

                            +---------------+
                            |   Customer    |
                            +-------+-------+
                                    |
            Customer Service Models |
                                    |
                            +-------+---------+
                            |    Service      |
                            |  Orchestration  |
                            +------+-+--------+
                                   | |
            Network Service Models | | Network and VPN Service PM Models
                                   | |
                            +------+-+--------+
                            |     Network     |
                            |   Controller    |
                            +-------+---------+
                                    |
            +-----------------------+------------------------+
                                  Network
Figure 1: Reference Architecture

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

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

The YANG module defined in this document is designed to derive VPN or network level performance data based on lower-level data collected via monitoring counters of the involved devices. The performance monitoring data per link in the underlying network can be collected using a network performance measurement method such as MPLS 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.

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

3.2. Collecting Data via Retrieval Methods

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

4. Description of The Data Model

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

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

+----------------------+          +-----------------------+
|ietf-network          |          |Network and VPN Service|
|ietf-network-topology |<---------|Performance Monitoring |
+----------------------+ augments |        Model          |
                                  +-----------------------+
Figure 2: Module Augmentation

4.1. Layering Relationship between Multiple Layers of Topology

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

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

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

    Legend:
    N:node   VN:VPN-Node  S:Site
    __  Link
    :   Mapping between networks
Figure 3: Example of Topology Mapping Between VPN Service Topology and Underlying Network

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

VPN 1:
This service topology supports hub-spoke communications for 'customer 1' connecting the customer's access at three sites: 'Site-1A', 'Site-1B', and 'Site-1C'. These sites are connected to nodes that are mapped to node 1 (N1), node 2 (N2), and node 4 (N4) in the underlying physical network. 'Site-1A' plays the role of hub while 'Site-1B' and 'Site-1C' are configured as spoke.
VPN 2:
This service supports any-to-any communications for 'customer 2' connecting the customer's access at two sites: 'Site-2A' and 'Site-2B'. These sites are connected to nodes that are mapped to nodes 1 (N1) and node 3 (N3)5 in the underlying physical network. 'Site-2A' and 'Site-2B' have 'any-to-any' role.

4.2. Network Level

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

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

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

"vpn-id":
Refers to an identifier of VPN service defined in [I-D.ietf-opsawg-vpn-common]). This identifier is used to correlate the performance status with the network service configuration.
"vpn-service-topology":
Indicates the type of the VPN topology. This model supports "any-to-any", "Hub and Spoke" (where Hubs can exchange traffic), and "Hub and Spoke disjoint" (where Hubs cannot exchange traffic) that are taken from [I-D.ietf-opsawg-vpn-common]. These VPN topology types can be used to describe how VPN sites communicate with each other.
module: ietf-network-vpn-pm
  augment /nw:networks/nw:network/nw:network-types:
    +--rw service-type!
       +--rw service-type?   identityref
  augment /nw:networks/nw:network:
    +--rw vpn-pm-attributes
       +--rw vpn-id?                 vpn-common:vpn-id
       +--rw vpn-service-topology?   identityref
Figure 4: Network Level YANG Tree of the Hierarchies

4.3. Node Level

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

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

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

"role":
Defines the role in a particular VPN service topology. The roles are taken from [I-D.ietf-opsawg-vpn-common] (e.g., any-to-any-role, spoke-role, hub-role).
"vpn-summary-statistics":
Lists a set of IPv4 statistics, IPv6 statistics, and MAC statistics. These statistics are specified separately.
  augment /nw:networks/nw:network/nw:node:
    +--rw pm-attributes
       +--rw node-type?                identityref
       +--rw role?                     identityref
       +--ro vpn-summary-statistics
          +--ro ipv4
          |  +--ro maximum-routes?        uint32
          |  +--ro total-active-routes?   uint32
          +--ro ipv6
          |  +--ro maximum-routes?        uint32
          |  +--ro total-active-routes?   uint32
          +--ro mac-num
             +--ro mac-num-limit?          uint32
             +--ro total-active-mac-num?   uint32
Figure 5: Node Level YANG Tree of the Hierarchies

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

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

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

  augment /nw:networks/nw:network/nt:link:
    +--rw pm-attributes
       +--rw low-percentile?                percentile
       +--rw middle-percentile?             percentile
       +--rw high-percentile?               percentile
       +--rw measurement-interval?          uint32
       +--ro reference-time?                yang:date-and-time
       +--ro pm-source?                     identityref
       +--ro one-way-pm-statistics
       |  +--ro loss-statistics
       |  |  +--ro packet-loss-count?   yang:counter64
       |  |  +--ro loss-ratio?          percentage
       |  +--ro delay-statistics
       |  |  +--ro unit-value?                identityref
       |  |  +--ro min-delay-value?           yang:gauge64
       |  |  +--ro max-delay-value?           yang:gauge64
       |  |  +--ro low-delay-percentile?      yang:gauge64
       |  |  +--ro middle-delay-percentile?   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 vpn-underlay-transport-type?   identityref
       +--ro vpn-one-way-pm-statistics* [class-id]
          +--ro class-id             string
          +--ro loss-statistics
          |  +--ro packet-loss-count?   yang:counter64
          |  +--ro loss-ratio?          percentage
          +--ro delay-statistics
          |  +--ro unit-value?                identityref
          |  +--ro min-delay-value?           yang:gauge64
          |  +--ro max-delay-value?           yang:gauge64
          |  +--ro low-delay-percentile?      yang:gauge64
          |  +--ro middle-delay-percentile?   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
  augment /nw:networks/nw:network/nw:node/nt:termination-point:
    +--ro pm-statistics
       +--ro reference-time?             yang:date-and-time
       +--ro inbound-octets?             yang:counter64
       +--ro inbound-unicast?            yang:counter64
       +--ro inbound-nunicast?           yang:counter64
       +--ro inbound-discards?           yang:counter32
       +--ro inbound-errors?             yang:counter64
       +--ro inbound-unknown-protocol?   yang:counter64
       +--ro outbound-octets?            yang:counter64
       +--ro outbound-unicast?           yang:counter64
       +--ro outbound-nunicast?          yang:counter64
       +--ro outbound-discards?          yang:counter64
       +--ro outbound-errors?            yang:counter64
       +--ro vpn-network-access* [network-access-id]
          +--ro network-access-id           vpn-common:vpn-id
          +--ro reference-time?             yang:date-and-time
          +--ro inbound-octets?             yang:counter64
          +--ro inbound-unicast?            yang:counter64
          +--ro inbound-nunicast?           yang:counter64
          +--ro inbound-discards?           yang:counter32
          +--ro inbound-errors?             yang:counter64
          +--ro inbound-unknown-protocol?   yang:counter64
          +--ro outbound-octets?            yang:counter64
          +--ro outbound-unicast?           yang:counter64
          +--ro outbound-nunicast?          yang:counter64
          +--ro outbound-discards?          yang:counter64
          +--ro outbound-errors?            yang:counter64
Figure 6: Link and Termination point Level YANG Tree of the hierarchies

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

Percentile parameters:
The module supports reporting delay and jitter metric by percentile values. By default, low percentile (10th percentile), mid percentile (50th percentile), high percentile (90th percentile) are used. Setting a percentile to 0.00 indicates the client is not interested in receiving particular percentile. If all percentile nodes are set to 0.00, this represents that no percentile related nodes will be reported for a given performance metric (e.g., one-way delay, one-way delay variation) and only peak/min values will be reported. For example, a client can inform the server that it is interested in receiving only high percentiles. Then for a given link, at a given "reference-time" 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 specified in [I-D.ietf-opsawg-l3sm-l3nm], or Ethernet service OAM specified in [I-D.ietf-opsawg-l2nm]. Alternatively, the data can be based upon the underlay technology OAM mechanisms, for example, GRE tunnel OAM.
Measurement interval ("measurement-interval"):
Specifies the performance measurement interval, in seconds.
Reference time ("reference-time"):
Indicates the start time of the performance measurement for link statistics. For termination point metrics, this parameter indicates the timestamp when the counters are obtained.
Loss statistics:
A set of one-way loss statistics attributes that are used to measure end to end loss between VPN sites or between any two network nodes. The exact loss value or the loss percentage can be reported.
Delay statistics:
A set of one-way delay statistics attributes that are used to measure end to end latency between VPN sites or between any two network nodes. The peak/min values or percentile values can be reported.
Jitter statistics:
A set of one-way IP Packet Delay Variation [RFC3393] statistics attributes that are used to measure end to end jitter between VPN sites or between any two network nodes. The peak/min values or percentile values can be reported.
VPN underlay transport type ("vpn-underlay-transport-type"):
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], which describes the transport technology to carry the traffic of the VPN service.
VPN PM statistics ("vpn-unidirectional-pm-statistics"):
Lists performance measurement statistics for the abstract underlay link between VPN PEs with given "class-id" names. The list is defined separately from "one-way-pm-statistics", which is used to collect generic metrics for unspecified "class-id" names.

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

Inbound statistics:
A set of inbound statistics attributes that are used to measure the inbound statistics of the termination point, such as received packets, received packets with errors, etc.
Outbound statistics:
A set of outbound statistics attributes that are used to measure the outbound statistics of the termination point, such as sent packets, packets that could not be sent due to errors, etc.
VPN network access ("vpn-network-access"):
Lists counters of the VPN network access defined in [I-D.ietf-opsawg-l3sm-l3nm] or [I-D.ietf-opsawg-l2nm]. When multiple VPN network accesses are created using the same physical port, finer-grained metrics can be monitored.

5. Network and VPN Service Performance Monitoring YANG Module

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

<CODE BEGINS> file "ietf-network-vpn-pm@2021-01-18.yang"

module ietf-network-vpn-pm {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm";
  prefix nvp;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  grouping vpn-summary-statistics {
    description
      "VPN Statistics grouping used for network topology
       augmentation.";
    container vpn-summary-statistics {
      config false;
      description
        "Container for VPN summary statistics.";
      container ipv4 {
        leaf maximum-routes {
          type uint32;
          description
            "Indicates the maximum number of IPv4 routes for the VPN.";
        }
        leaf total-active-routes {
          type uint32;
          description
            "Indicates total active IPv4 routes for the VPN.";
        }
        description
          "IPv4-specific parameters.";
      }
      container ipv6 {
        leaf maximum-routes {
          type uint32;
          description
            "Indicates the maximum number of IPv6 routes for the VPN.";
        }
        leaf total-active-routes {
          type uint32;
          description
            "Indicates total active IPv6 routes for the VPN.";
        }
        description
          "IPv6-specific parameters.";
      }
      container mac-num {
        leaf mac-num-limit {
          type uint32;
          description
            "Maximum number of MAC addresses.";
        }
        leaf total-active-mac-num {
          type uint32;
          description
            "Total active MAC entries for the VPN.";
        }
        description
          "MAC statistics.";
      }
    }
  }

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

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

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

  grouping tp-svc-telemetry {
    leaf reference-time {
      type yang:date-and-time;
      config false;
      description
        "Indicates the time when the statistics are collected.";
    }
    leaf inbound-octets {
      type yang:counter64;
      description
        "The total number of octets received on the
         interface, including framing characters.";
    }
    leaf inbound-unicast {
      type yang:counter64;
      description
        "Inbound unicast packets were received, and delivered
         to a higher layer during the last period.";
    }
    leaf inbound-nunicast {
      type yang:counter64;
      description
        "The number of non-unicast (i.e., subnetwork-
         broadcast or subnetwork-multicast) packets
         delivered to a higher-layer protocol.";
    }
    leaf inbound-discards {
      type yang:counter32;
      description
        "The number of inbound packets which were chosen
         to be discarded even though no errors had been
         detected to prevent their being deliverable to a
         higher-layer protocol.";
    }
    leaf inbound-errors {
      type yang:counter64;
      description
        "The number of inbound packets that contained
         errors preventing them from being deliverable to a
         higher-layer protocol.";
    }
    leaf inbound-unknown-protocol {
      type yang:counter64;
      description
        "The number of packets received via the interface
         which were discarded because of an unknown or
         unsupported protocol.";
    }
    leaf outbound-octets {
      type yang:counter64;
      description
        "The total number of octets transmitted out of the
         interface, including framing characters.";
    }
    leaf outbound-unicast {
      type yang:counter64;
      description
        "The total number of packets that higher-level
         protocols requested be transmitted to a
         subnetwork-unicast address, including those that
         were discarded or not sent.";
    }
    leaf outbound-nunicast {
      type yang:counter64;
      description
        "The total number of packets that higher-level
         protocols requested be transmitted to a non-
         unicast (i.e., a subnetwork-broadcast or
         subnetwork-multicast) address, including those
         that were discarded or not sent.";
    }
    leaf outbound-discards {
      type yang:counter64;
      description
        "The number of outbound packets which were chosen
         to be discarded even though no errors had been
         detected to prevent their being transmitted. One
         possible reason for discarding such a packet could
         be to free up buffer space.";
    }
    leaf outbound-errors {
      type yang:counter64;
      description
        "The number of outbound packets that contained
         errors preventing them from being deliverable to a
         higher-layer protocol.";
    }
    description
      "Grouping for interface service telemetry.";
  }

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

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

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

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

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

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

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

  augment "/nw:networks/nw:network/nw:node/nt:termination-point/pm-statistics" {
    when '../../../nw:network-types/nvp:service-type' {
      description
        "Augments only for VPN Network topology.";
    }
    description
      "Augments the network topology termination-point with
       VPN service performance monitoring attributes";
    list vpn-network-access {
      key "network-access-id";
      description
        "The list of PM based on VPN network accesses.";
      leaf network-access-id {
        type vpn-common:vpn-id;
        description
          "References to an identifier for the VPN network
           access, e.g. L3VPN or VPLS.";
      }
      uses tp-svc-telemetry;
    }
  }
}


<CODE ENDS>

6. Security Considerations

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

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

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

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:

7. IANA Considerations

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

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

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

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

8. Acknowledgements

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

9. Contributors

The following authors contributed significantly to this document:

   Michale Wang
   Huawei
   Email:wangzitao@huawei.com

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

   Change Liu
   China Unicom
   Email: liuc131@chinaunicom.cn

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

10. References

10.1. Normative References

[I-D.ietf-opsawg-vpn-common]
Barguil, S., Dios, O. G. D., Boucadair, M., and Q. Wu, "A Layer 2/3 VPN Common YANG Model", Work in Progress, Internet-Draft, draft-ietf-opsawg-vpn-common-12, , <https://www.ietf.org/archive/id/draft-ietf-opsawg-vpn-common-12.txt>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3393]
Demichelis, C. and P. Chimento, "IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)", RFC 3393, DOI 10.17487/RFC3393, , <https://www.rfc-editor.org/info/rfc3393>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <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, , <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, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <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, , <https://www.rfc-editor.org/info/rfc6374>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <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, , <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, , <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, , <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, , <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, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8641>.

10.2. Informative References

[I-D.ietf-netmod-node-tags]
Wu, Q., Claise, B., Liu, P., Du, Z., and M. Boucadair, "Self Describing Data Object Tags", Work in Progress, Internet-Draft, draft-ietf-netmod-node-tags-04, , <https://www.ietf.org/archive/id/draft-ietf-netmod-node-tags-04.txt>.
[I-D.ietf-opsawg-l2nm]
Barguil, S., Dios, O. G. D., Boucadair, M., and L. A. Munoz, "A Layer 2 VPN Network YANG Model", Work in Progress, Internet-Draft, draft-ietf-opsawg-l2nm-12, , <https://www.ietf.org/archive/id/draft-ietf-opsawg-l2nm-12.txt>.
[I-D.ietf-opsawg-l3sm-l3nm]
Barguil, S., Dios, O. G. D., Boucadair, M., Munoz, L. A., and A. Aguado, "A Layer 3 VPN Network YANG Model", Work in Progress, Internet-Draft, draft-ietf-opsawg-l3sm-l3nm-18, , <https://www.ietf.org/archive/id/draft-ietf-opsawg-l3sm-l3nm-18.txt>.
[RFC5357]
Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, DOI 10.17487/RFC5357, , <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, , <https://www.rfc-editor.org/info/rfc7471>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <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, , <https://www.rfc-editor.org/info/rfc8194>.
[RFC8309]
Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, , <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, , <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, , <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, , <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">
                    ietf-vpn-common:l3vpn
                 </service-type>
                   <node>
                     <node-id>A</node-id>
                     <pm-attributes>
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                       <node-type>pe</node-type>
                     </pm-attributes>
                     <termination-point
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                      <tp-id>1-0-1</tp-id>
                      <pm-statistics
      xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                       <inbound-octets>150</inbound-octets>
                       <outbound-octets>100</outbound-octets>
                      </pm-statistics>
                     </termination-point>
                    </node>
                   <node>
                     <node-id>B</node-id>
                     <pm-attributes>
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                      <node-type>pe</node-type>
                     </pm-attributes>
                       <termination-point
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                         <tp-id>2-0-1</tp-id>
                         <pm-statistics
           xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                           <inbound-octets>150</inbound-octets>
                           <outbound-octets>100</outbound-octets>
                         </pm-statistics>
                      </termination-point>
                    </node>
                    <link
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
                     <link-id>A-B</link-id>
                      <source>
                        <source-node>A</source-node>
                      </source>
                      <destination>
                       <dest-node>B</dest-node>
                      </destination>
                      <vpn-underlay-transport-type>mpls-te</vpn-underlay-transport-type>
                      <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
                        <one-way-pm-statistics>
                          <loss-statistics>
                           <packet-loss-count>100</packet-loss-count>
                          </loss-statistics>
                        </one-way-pm-statistics>
                      </pm-attributes>
                    </link>
                </network>
              </networks>
           </stream-subtree-filter>
         <period
           xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
          500
       </period>
       </establish-subscription>
    </rpc>
Figure 7: Pub/Sub Retrieval

A.2. Example of RPC-based Retrieval

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

 <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
        message-id="1">
   <report
        xmlns="urn:ietf:params:xml:ns:yang:example-service-pm-report">
      <networks xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo">
        <network>
         <network-id>vpn1</network-id>
         <node>
          <node-id>A</node-id>
          <pm-attributes
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <node-type>pe</node-type>
          </pm-attribtues>
          <termination-point
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
           <tp-id>1-0-1</tp-id>
           <pm-statistics
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <inbound-octets>100</inbound-octets>
            <outbound-octets>150</outbound-octets>
           </pm-statistics>
          </termination-point>
         </node>
         <node>
          <node-id>B</node-id>
          <pm-attributes
              xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <node-type>pe</node-type>
          </pm-attribtues>
          <termination-point
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology">
           <tp-id>2-0-1</tp-id>
           <pm-statistics
               xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm">
            <inbound-octets>150</inbound-octets>
            <outbound-octets>100</outbound-octets>
           </pm-statistics>
          </termination-point>
         </node>
         <link>
         <link-id>A-B</link-id>
          <source>
           <source-node>A</source-node>
          </source>
          <destination>
           <dest-node>B</dest-node>
          </destination>
          <pm-attributes
             xmlns="urn:ietf:params:xml:ns:yang:ietf-network-pm">
            <one-way-pm-statistics>
               <loss-statistics>
                 <packet-loss-count>120</packet-loss-count>
               </loss-statistics>
             </one-way-pm-statistics>
           </pm-attributes>
           <vpn-underlay-transport-type>mpls-te</vpn-underlay-transport-type>
         </link>
       </network>
     </report>
   </rpc>
Figure 8

A.3. Example of Percentile Monitoring

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

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

Authors' Addresses

Bo Wu (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Qin Wu (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Mohamed Boucadair (editor)
Orange
Rennes 35000
France
Oscar Gonzalez de Dios
Telefonica
Madrid
Spain
Bin Wen
Comcast