<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE rfc [
  <!ENTITY nbsp    "&#160;">
  <!ENTITY zwsp   "&#8203;">
  <!ENTITY nbhy   "&#8209;">
  <!ENTITY wj     "&#8288;">
]>
<?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?>
<!-- generated by https://github.com/cabo/kramdown-rfc version 1.7.2 (Ruby 3.2.2) -->
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-ietf-opsawg-ntw-attachment-circuit-03" category="std" consensus="true" submissionType="IETF" tocInclude="true" sortRefs="true" symRefs="true" version="3">
  <!-- xml2rfc v2v3 conversion 3.18.2 -->
  <front>
    <title abbrev="A YANG Network Model for ACs">A Network YANG Data Model for Attachment Circuits</title>
    <seriesInfo name="Internet-Draft" value="draft-ietf-opsawg-ntw-attachment-circuit-03"/>
    <author fullname="Mohamed Boucadair" role="editor">
      <organization>Orange</organization>
      <address>
        <email>mohamed.boucadair@orange.com</email>
      </address>
    </author>
    <author fullname="Richard Roberts">
      <organization>Juniper</organization>
      <address>
        <email>rroberts@juniper.net</email>
      </address>
    </author>
    <author fullname="Oscar Gonzalez de Dios">
      <organization>Telefonica</organization>
      <address>
        <email>oscar.gonzalezdedios@telefonica.com</email>
      </address>
    </author>
    <author fullname="Samier Barguil Giraldo">
      <organization>Nokia</organization>
      <address>
        <email>samier.barguil_giraldo@nokia.com</email>
      </address>
    </author>
    <author fullname="Bo Wu">
      <organization>Huawei Technologies</organization>
      <address>
        <email>lana.wubo@huawei.com</email>
      </address>
    </author>
    <date year="2023" month="November" day="30"/>
    <area>Operations and Management</area>
    <workgroup>Operations and Management Area Working Group</workgroup>
    <keyword>Slice Service</keyword>
    <keyword>L3VPN</keyword>
    <keyword>L2VPN</keyword>
    <abstract>
      <?line 93?>

<t>This document specifies a network model for attachment circuits. The model can be used for the provisioning of attachment circuits prior or during service provisioning (e.g., Network Slice Service). A companion service model is specified in I-D.ietf-opsawg-teas-attachment-circuit.</t>
      <t>The module augments the Service Attachment Point (SAP) model with the detailed information for the provisioning of attachment circuits in Provider Edges (PEs).</t>
    </abstract>
    <note removeInRFC="true">
      <name>Discussion Venues</name>
      <t>Discussion of this document takes place on the
    Operations and Management Area Working Group Working Group mailing list (opsawg@ietf.org),
    which is archived at <eref target="https://mailarchive.ietf.org/arch/browse/opsawg/"/>.</t>
      <t>Source for this draft and an issue tracker can be found at
    <eref target="https://github.com/boucadair/attachment-circuit-model"/>.</t>
    </note>
  </front>
  <middle>
    <?line 99?>

<section anchor="introduction">
      <name>Introduction</name>
      <t>Connectivity services are provided by networks to customers via
   dedicated terminating points, such as Service Functions <xref target="RFC7665"/>,
   customer edges (CEs), peer Autonomous System Border Routers (ASBRs),
   data centers gateways, or Internet Exchange Points.</t>
      <t>The procedure to provision a service in a service provider network may depend on the practices adopted by a service provider, including the flow put in place for the provisioning of advanced network services and how they are bound to an Attachment Circuit (AC). For example, the same attachment circuit may host multiple services (e.g., Layer 2 Virtual Private Network (VPN), Slice Service, or Layer 3 VPN). In order to avoid service interference and redundant information in various locations, a service provider may expose an interface to manage ACs network-wide. Customers can then request a standalone attachment circuit to be put in place, and then refer to that attachment circuit when requesting services to be bound to that AC. <xref target="I-D.ietf-opsawg-teas-attachment-circuit"/> specifies a data model for managing attachment circuits as a service.</t>
      <t><xref target="sec-module"/> specifies a network model for attachment circuits ("ietf-ac-ntw"). The model can be used for the provisioning of ACs prior or during service provisioning.</t>
      <t>The document leverages <xref target="RFC9182"/> and <xref target="RFC9291"/> by adopting an AC provisioning structure that uses data nodes that are defined in these RFCs. Some refinements were introduced to cover, not only conventional service provider networks, but also specifics of other target deployments (cloud, for example).</t>
      <t>The AC network model is designed as an augmnetation to the Service Attachment Point (SAP) model <xref target="RFC9408"/>. An attachment circuit can be bound to a single or multiple SAPs. Likewise, the model is designed to accomdate deployments where a SAP can be bound to one or multiple ACs (e.g., a parent AC and its child ACs).</t>
      <figure anchor="sap-ac-ntw">
        <name>Attachment Circuits Examples</name>
        <artset>
          <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="464" width="536" viewBox="0 0 536 464" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
              <path d="M 8,208 L 8,240" fill="none" stroke="black"/>
              <path d="M 40,208 L 40,240" fill="none" stroke="black"/>
              <path d="M 64,208 L 64,240" fill="none" stroke="black"/>
              <path d="M 80,176 L 80,208" fill="none" stroke="black"/>
              <path d="M 80,240 L 80,256" fill="none" stroke="black"/>
              <path d="M 80,288 L 80,368" fill="none" stroke="black"/>
              <path d="M 96,160 L 96,240" fill="none" stroke="black"/>
              <path d="M 112,112 L 112,160" fill="none" stroke="black"/>
              <path d="M 128,160 L 128,192" fill="none" stroke="black"/>
              <path d="M 152,32 L 152,64" fill="none" stroke="black"/>
              <path d="M 168,64 L 168,112" fill="none" stroke="black"/>
              <path d="M 184,32 L 184,64" fill="none" stroke="black"/>
              <path d="M 192,160 L 192,192" fill="none" stroke="black"/>
              <path d="M 192,352 L 192,384" fill="none" stroke="black"/>
              <path d="M 192,416 L 192,448" fill="none" stroke="black"/>
              <path d="M 208,384 L 208,416" fill="none" stroke="black"/>
              <path d="M 216,112 L 216,152" fill="none" stroke="black"/>
              <path d="M 224,160 L 224,192" fill="none" stroke="black"/>
              <path d="M 224,352 L 224,384" fill="none" stroke="black"/>
              <path d="M 224,416 L 224,448" fill="none" stroke="black"/>
              <path d="M 240,80 L 240,112" fill="none" stroke="black"/>
              <path d="M 240,176 L 240,256" fill="none" stroke="black"/>
              <path d="M 240,288 L 240,368" fill="none" stroke="black"/>
              <path d="M 272,80 L 272,112" fill="none" stroke="black"/>
              <path d="M 296,176 L 296,256" fill="none" stroke="black"/>
              <path d="M 296,288 L 296,368" fill="none" stroke="black"/>
              <path d="M 312,160 L 312,192" fill="none" stroke="black"/>
              <path d="M 312,352 L 312,384" fill="none" stroke="black"/>
              <path d="M 328,96 L 328,160" fill="none" stroke="black"/>
              <path d="M 328,384 L 328,432" fill="none" stroke="black"/>
              <path d="M 344,160 L 344,192" fill="none" stroke="black"/>
              <path d="M 344,352 L 344,384" fill="none" stroke="black"/>
              <path d="M 360,352 L 360,384" fill="none" stroke="black"/>
              <path d="M 360,416 L 360,448" fill="none" stroke="black"/>
              <path d="M 376,384 L 376,416" fill="none" stroke="black"/>
              <path d="M 384,80 L 384,112" fill="none" stroke="black"/>
              <path d="M 392,352 L 392,384" fill="none" stroke="black"/>
              <path d="M 392,416 L 392,448" fill="none" stroke="black"/>
              <path d="M 408,352 L 408,384" fill="none" stroke="black"/>
              <path d="M 416,80 L 416,112" fill="none" stroke="black"/>
              <path d="M 424,384 L 424,432" fill="none" stroke="black"/>
              <path d="M 440,304 L 440,384" fill="none" stroke="black"/>
              <path d="M 456,176 L 456,256" fill="none" stroke="black"/>
              <path d="M 456,288 L 456,304" fill="none" stroke="black"/>
              <path d="M 456,344 L 456,368" fill="none" stroke="black"/>
              <path d="M 472,304 L 472,336" fill="none" stroke="black"/>
              <path d="M 496,304 L 496,336" fill="none" stroke="black"/>
              <path d="M 528,304 L 528,336" fill="none" stroke="black"/>
              <path d="M 152,32 L 184,32" fill="none" stroke="black"/>
              <path d="M 152,64 L 184,64" fill="none" stroke="black"/>
              <path d="M 240,80 L 272,80" fill="none" stroke="black"/>
              <path d="M 384,80 L 416,80" fill="none" stroke="black"/>
              <path d="M 272,96 L 384,96" fill="none" stroke="black"/>
              <path d="M 112,112 L 216,112" fill="none" stroke="black"/>
              <path d="M 240,112 L 272,112" fill="none" stroke="black"/>
              <path d="M 384,112 L 416,112" fill="none" stroke="black"/>
              <path d="M 96,160 L 128,160" fill="none" stroke="black"/>
              <path d="M 192,160 L 224,160" fill="none" stroke="black"/>
              <path d="M 312,160 L 344,160" fill="none" stroke="black"/>
              <path d="M 80,176 L 96,176" fill="none" stroke="black"/>
              <path d="M 128,176 L 192,176" fill="none" stroke="black"/>
              <path d="M 224,176 L 240,176" fill="none" stroke="black"/>
              <path d="M 296,176 L 312,176" fill="none" stroke="black"/>
              <path d="M 344,176 L 456,176" fill="none" stroke="black"/>
              <path d="M 96,192 L 128,192" fill="none" stroke="black"/>
              <path d="M 192,192 L 224,192" fill="none" stroke="black"/>
              <path d="M 312,192 L 344,192" fill="none" stroke="black"/>
              <path d="M 8,208 L 40,208" fill="none" stroke="black"/>
              <path d="M 64,208 L 96,208" fill="none" stroke="black"/>
              <path d="M 40,224 L 64,224" fill="none" stroke="black"/>
              <path d="M 8,240 L 40,240" fill="none" stroke="black"/>
              <path d="M 64,240 L 96,240" fill="none" stroke="black"/>
              <path d="M 80,256 L 240,256" fill="none" stroke="black"/>
              <path d="M 296,256 L 456,256" fill="none" stroke="black"/>
              <path d="M 80,288 L 240,288" fill="none" stroke="black"/>
              <path d="M 296,288 L 456,288" fill="none" stroke="black"/>
              <path d="M 440,304 L 472,304" fill="none" stroke="black"/>
              <path d="M 496,304 L 528,304" fill="none" stroke="black"/>
              <path d="M 472,320 L 496,320" fill="none" stroke="black"/>
              <path d="M 440,336 L 472,336" fill="none" stroke="black"/>
              <path d="M 496,336 L 528,336" fill="none" stroke="black"/>
              <path d="M 192,352 L 224,352" fill="none" stroke="black"/>
              <path d="M 312,352 L 344,352" fill="none" stroke="black"/>
              <path d="M 360,352 L 392,352" fill="none" stroke="black"/>
              <path d="M 408,352 L 440,352" fill="none" stroke="black"/>
              <path d="M 80,368 L 192,368" fill="none" stroke="black"/>
              <path d="M 224,368 L 240,368" fill="none" stroke="black"/>
              <path d="M 296,368 L 312,368" fill="none" stroke="black"/>
              <path d="M 344,368 L 360,368" fill="none" stroke="black"/>
              <path d="M 392,368 L 408,368" fill="none" stroke="black"/>
              <path d="M 440,368 L 456,368" fill="none" stroke="black"/>
              <path d="M 192,384 L 224,384" fill="none" stroke="black"/>
              <path d="M 312,384 L 344,384" fill="none" stroke="black"/>
              <path d="M 360,384 L 392,384" fill="none" stroke="black"/>
              <path d="M 408,384 L 440,384" fill="none" stroke="black"/>
              <path d="M 192,416 L 224,416" fill="none" stroke="black"/>
              <path d="M 360,416 L 392,416" fill="none" stroke="black"/>
              <path d="M 224,432 L 264,432" fill="none" stroke="black"/>
              <path d="M 288,432 L 328,432" fill="none" stroke="black"/>
              <path d="M 392,432 L 424,432" fill="none" stroke="black"/>
              <path d="M 192,448 L 224,448" fill="none" stroke="black"/>
              <path d="M 360,448 L 392,448" fill="none" stroke="black"/>
              <path d="M 200,160 C 208.83064,160 216,152.83064 216,144" fill="none" stroke="black"/>
              <g class="text">
                <text x="168" y="52">CE6</text>
                <text x="148" y="84">ac</text>
                <text x="256" y="100">CE5</text>
                <text x="400" y="100">CE2</text>
                <text x="340" y="132">ac</text>
                <text x="112" y="180">sap</text>
                <text x="208" y="180">sap</text>
                <text x="328" y="180">sap</text>
                <text x="24" y="228">CE1</text>
                <text x="80" y="228">sap</text>
                <text x="160" y="228">PE1</text>
                <text x="384" y="228">PE2</text>
                <text x="52" y="244">ac</text>
                <text x="484" y="308">ac</text>
                <text x="168" y="324">PE3</text>
                <text x="376" y="324">PE4</text>
                <text x="456" y="324">sap</text>
                <text x="512" y="324">CE5</text>
                <text x="208" y="372">sap</text>
                <text x="328" y="372">sap</text>
                <text x="376" y="372">sap</text>
                <text x="424" y="372">sap</text>
                <text x="220" y="404">ac</text>
                <text x="388" y="404">ac</text>
                <text x="436" y="404">ac</text>
                <text x="208" y="436">CE3</text>
                <text x="276" y="436">ac</text>
                <text x="376" y="436">CE4</text>
              </g>
            </svg>
          </artwork>
          <artwork type="ascii-art" align="center"><![CDATA[
                  .---.
                  |CE6|
                  '-+-'
                 ac |        .---.             .---.
                    |        |CE5+------+------+CE2|
             .------+-----.  '---'      |      '---'
             |            |             |ac
             |            |             |
           .-+-.       .-+-.          .-+-.
         .-+sap+-------+sap+-.      .-+sap+-------------.
         | '---'       '---' |      | '---'             |
.---.  .-+-.                 |      |                   |
|CE1+--+sap|      PE1        |      |         PE2       |
'---'ac'-+-'                 |      |                   |
         '-------------------'      '-------------------'

         .-------------------.      .-------------------.
         |                   |      |                 .-+-.ac.---.
         |         PE3       |      |        PE4      |sap+--+CE5|
         |                   |      |                 '---'  '---'
         |             .---. |      | .---. .---. .---. |
         '-------------+sap+-'      '-+sap+-+sap+-+sap+-'
                       '-+-'          '-+-' '-+-' '-+-'
                         |ac            |     |ac   |ac
                       .-+-.            |   .-+-.   |
                       |CE3+-----ac-----'   |CE4+---'
                       '---'                '---'
]]></artwork>
        </artset>
      </figure>
      <t>The AC network model uses the AC common model defined in <xref target="I-D.ietf-opsawg-teas-common-ac"/>.</t>
      <t>The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in <xref target="RFC8342"/>.</t>
      <t>Sample examples are provided in <xref target="sec-examples"/>.</t>
    </section>
    <section anchor="conventions-and-definitions">
      <name>Conventions and Definitions</name>
      <t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as
described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they
appear in all capitals, as shown here.</t>
      <?line -18?>

<t>The reader should be familiar with the terms defined in <xref section="2" sectionFormat="of" target="RFC9408"/>.</t>
      <t>This document uses the term "network model" as defined in <xref section="2.1" sectionFormat="of" target="RFC8969"/>.</t>
      <t>The meanings of the symbols in the YANG tree diagrams are defined in <xref target="RFC8340"/>.</t>
      <t>In addition, this document uses the following terms:</t>
      <dl>
        <dt>Bearer:</dt>
        <dd>
          <t>A physical or logical link that connects a customer node (or site) to a provider network.</t>
        </dd>
        <dt/>
        <dd>
          <t>A bearer can be a wireless or wired link. One or multiple technologies can be used to build a bearer. The bearer type can be specified by a customer.</t>
        </dd>
        <dt/>
        <dd>
          <t>The operator allocates a unique bearer reference to identify a bearer within its network (e.g., customer line identifier). Such a reference can be retrieved by a customer and then used in subsequent service placement requests to unambiguously identify where a service is to be bound.</t>
        </dd>
        <dt/>
        <dd>
          <t>The concept of bearer can be generalized to refer to the required underlying connection for the provisioning of an attachment circuit.</t>
        </dd>
        <dt/>
        <dd>
          <t>One or multiple attachment circuits may be hosted over the same bearer (e.g., multiple Virtual Local Area Networks (VLANs) on the same bearer that is provided by a physical link).</t>
        </dd>
        <dt>Network controller:</dt>
        <dd>
          <t>Denotes a functional entity responsible for the management of the service provider network. One or multiple network controllers can be deployed in a service provider network.</t>
        </dd>
        <dt>Service orchestrator:</dt>
        <dd>
          <t>Refers to a functional entity that interacts with the customer of a network service.</t>
        </dd>
        <dt/>
        <dd>
          <t>A service orchestrator is typically responsible for the attachment circuits, the Provider Edge (PE) selection, and requesting the activation of the requested services to a network controller.</t>
        </dd>
        <dt/>
        <dd>
          <t>A service orchestrator may interact with one or more network controllers.</t>
        </dd>
        <dt>Service provider network:</dt>
        <dd>
          <t>A network that is able to provide network services (e.g., L2VPN, L3VPN, or Network Slice Services).</t>
        </dd>
        <dt>Service provider:</dt>
        <dd>
          <t>A service provider that offers network services (e.g., L2VPN, L3VPN, or Network Slice Services).</t>
        </dd>
      </dl>
    </section>
    <section anchor="sample-uses-of-the-attachment-circuit-data-models">
      <name>Sample Uses of the Attachment Circuit Data Models</name>
      <t><xref target="_u-ex"/> shows the positioning of the AC network model in the overall service delivery process. The "ietf-ac-ntw" is a network model which augments the SAP with a comprehensive set of parameters to reflect the attachment circuits that are in place in a network. The model also maintains the mapping with the service references that are used to expose these ACs to customers. Whether the same naming conventions to reference an AC are used in the service and network layers is deployment-specific.</t>
      <figure anchor="_u-ex">
        <name>An Example of the Network AC Model Usage</name>
        <artset>
          <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="656" width="512" viewBox="0 0 512 656" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
              <path d="M 8,560 L 8,592" fill="none" stroke="black"/>
              <path d="M 48,560 L 48,592" fill="none" stroke="black"/>
              <path d="M 96,432 L 96,480" fill="none" stroke="black"/>
              <path d="M 104,320 L 104,368" fill="none" stroke="black"/>
              <path d="M 120,544 L 120,608" fill="none" stroke="black"/>
              <path d="M 136,368 L 136,432" fill="none" stroke="black"/>
              <path d="M 136,480 L 136,536" fill="none" stroke="black"/>
              <path d="M 176,288 L 176,320" fill="none" stroke="black"/>
              <path d="M 176,432 L 176,480" fill="none" stroke="black"/>
              <path d="M 208,32 L 208,64" fill="none" stroke="black"/>
              <path d="M 208,112 L 208,160" fill="none" stroke="black"/>
              <path d="M 208,208 L 208,256" fill="none" stroke="black"/>
              <path d="M 208,376 L 208,496" fill="none" stroke="black"/>
              <path d="M 232,320 L 232,368" fill="none" stroke="black"/>
              <path d="M 272,64 L 272,112" fill="none" stroke="black"/>
              <path d="M 272,160 L 272,208" fill="none" stroke="black"/>
              <path d="M 272,256 L 272,288" fill="none" stroke="black"/>
              <path d="M 296,320 L 296,368" fill="none" stroke="black"/>
              <path d="M 336,32 L 336,64" fill="none" stroke="black"/>
              <path d="M 336,112 L 336,160" fill="none" stroke="black"/>
              <path d="M 336,208 L 336,256" fill="none" stroke="black"/>
              <path d="M 368,288 L 368,320" fill="none" stroke="black"/>
              <path d="M 368,368 L 368,536" fill="none" stroke="black"/>
              <path d="M 384,544 L 384,608" fill="none" stroke="black"/>
              <path d="M 424,320 L 424,368" fill="none" stroke="black"/>
              <path d="M 456,560 L 456,592" fill="none" stroke="black"/>
              <path d="M 496,560 L 496,592" fill="none" stroke="black"/>
              <path d="M 208,32 L 336,32" fill="none" stroke="black"/>
              <path d="M 208,64 L 336,64" fill="none" stroke="black"/>
              <path d="M 208,112 L 336,112" fill="none" stroke="black"/>
              <path d="M 208,160 L 336,160" fill="none" stroke="black"/>
              <path d="M 208,208 L 336,208" fill="none" stroke="black"/>
              <path d="M 208,256 L 336,256" fill="none" stroke="black"/>
              <path d="M 176,288 L 368,288" fill="none" stroke="black"/>
              <path d="M 104,320 L 232,320" fill="none" stroke="black"/>
              <path d="M 296,320 L 424,320" fill="none" stroke="black"/>
              <path d="M 104,368 L 232,368" fill="none" stroke="black"/>
              <path d="M 296,368 L 424,368" fill="none" stroke="black"/>
              <path d="M 96,432 L 176,432" fill="none" stroke="black"/>
              <path d="M 96,480 L 176,480" fill="none" stroke="black"/>
              <path d="M 120,544 L 384,544" fill="none" stroke="black"/>
              <path d="M 8,560 L 48,560" fill="none" stroke="black"/>
              <path d="M 456,560 L 496,560" fill="none" stroke="black"/>
              <path d="M 48,576 L 120,576" fill="none" stroke="black"/>
              <path d="M 384,576 L 456,576" fill="none" stroke="black"/>
              <path d="M 8,592 L 48,592" fill="none" stroke="black"/>
              <path d="M 456,592 L 496,592" fill="none" stroke="black"/>
              <path d="M 120,608 L 384,608" fill="none" stroke="black"/>
              <g class="text">
                <text x="268" y="52">Customer</text>
                <text x="108" y="84">Customer</text>
                <text x="176" y="84">Service</text>
                <text x="232" y="84">Model</text>
                <text x="96" y="100">e.g.,</text>
                <text x="164" y="100">slice-svc,</text>
                <text x="240" y="100">ac-svc,</text>
                <text x="296" y="100">and</text>
                <text x="356" y="100">bearer-svc</text>
                <text x="272" y="132">Service</text>
                <text x="272" y="148">Orchestration</text>
                <text x="112" y="180">Network</text>
                <text x="168" y="180">Model</text>
                <text x="32" y="196">e.g.,</text>
                <text x="100" y="196">l3vpn-ntw,</text>
                <text x="164" y="196">sap,</text>
                <text x="200" y="196">and</text>
                <text x="244" y="196">ac-ntw</text>
                <text x="264" y="228">Network</text>
                <text x="272" y="244">Orchestration</text>
                <text x="56" y="276">Network</text>
                <text x="144" y="276">Configuration</text>
                <text x="224" y="276">Model</text>
                <text x="164" y="340">Domain</text>
                <text x="364" y="340">Domain</text>
                <text x="168" y="356">Orchestration</text>
                <text x="360" y="356">Orchestration</text>
                <text x="36" y="388">Device</text>
                <text x="64" y="404">Configuration</text>
                <text x="32" y="420">Model</text>
                <text x="132" y="452">Config</text>
                <text x="136" y="468">Manager</text>
                <text x="256" y="516">NETCONF/CLI................</text>
                <text x="376" y="516">.</text>
                <text x="208" y="532">|</text>
                <text x="84" y="564">Bearer</text>
                <text x="420" y="564">Bearer</text>
                <text x="28" y="580">CE#1</text>
                <text x="248" y="580">Network</text>
                <text x="476" y="580">CE#2</text>
                <text x="28" y="628">Site</text>
                <text x="56" y="628">A</text>
                <text x="476" y="628">Site</text>
                <text x="504" y="628">B</text>
              </g>
            </svg>
          </artwork>
          <artwork type="ascii-art" align="center"><![CDATA[
                          .---------------.
                          |   Customer    |
                          '-------+-------'
          Customer Service Model  |
          e.g., slice-svc, ac-svc,| and bearer-svc
                          .-------+-------.
                          |    Service    |
                          | Orchestration |
                          '-------+-------'
           Network Model          |
  e.g., l3vpn-ntw, sap, and ac-ntw|
                          .-------+-------.
                          |   Network     |
                          | Orchestration |
                          '-------+-------'
    Network Configuration Model   |
                      .-----------+-----------.
                      |                       |
             .--------+------.       .--------+------.
             |    Domain     |       |     Domain    |
             | Orchestration |       | Orchestration |
             '---+-----------'       '--------+------'
  Device         |        |                   |
  Configuration  |        |                   |
  Model          |        |                   |
            .----+----.   |                   |
            | Config  |   |                   |
            | Manager |   |                   |
            '----+----'   |                   |
                 |        |                   |
                 | NETCONF/CLI..................
                 |        |                   |
               .--------------------------------.
 .----. Bearer |                                | Bearer .----.
 |CE#1+--------+            Network             +--------+CE#2|
 '----'        |                                |        '----'
               '--------------------------------'
  Site A                                                  Site B
]]></artwork>
        </artset>
      </figure>
    </section>
    <section anchor="description-of-the-attachment-circuit-yang-module">
      <name>Description of the Attachment Circuit YANG Module</name>
      <t>The full tree diagram of the module can be generated using the
"pyang" tool <xref target="PYANG"/>.  That tree is not included here because it is
too long (<xref section="3.3" sectionFormat="of" target="RFC8340"/>).  Instead, subtrees are provided in the following subsections
for the reader's convenience.</t>
      <section anchor="overall-structure-of-the-module">
        <name>Overall Structure of the Module</name>
        <t>The overall tree structure of the module is shown in <xref target="o-ntw-tree"/>.</t>
        <figure anchor="o-ntw-tree">
          <name>Overall Tree Structure</name>
          <artwork><![CDATA[
augment /nw:networks/nw:network:
  +--rw specific-provisioning-profiles
  |  ...
  +--rw ac-profile* [name]
     ...
augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
  +--rw ac* [name]
     +--rw name                 string
     +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
     +--rw ac-profile* [profile-id]
     |  +--rw profile-id    -> /nw:networks/network/ac-profile/name
     +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
     +--rw peer-sap-id*         string
     +--rw group* [group-id]
     |  +--rw group-id      string
     |  +--rw precedence?   identityref
     +--rw status
     |  +--rw admin-status
     |  |  +--rw status?        identityref
     |  |  +--rw last-change?   yang:date-and-time
     |  +--ro oper-status
     |     +--ro status?        identityref
     |     +--ro last-change?   yang:date-and-time
     +--rw description?         string
     +--rw l2-connection
     |  ...
     +--rw ip-connection
     |  ...
     +--rw routing-protocols
     |  ...
     +--rw oam
     |  ...
     +--rw security
     |  ...
     +--rw service
        ...
]]></artwork>
        </figure>
        <t>The full tree of the 'ac-ntw' is provided in <xref target="AC-Ntw-Tree"/>.</t>
        <t>A node can host one or more SAPs. As per <xref target="RFC9408"/>, a SAP is an abstraction of the network
reference points (the PE side of an AC, in the context of this document) where network services can be delivered and/or are delivered to customers. Each SAP terminates one or multiple ACs. Each AC in turn may be terminated by one or more peer SAPs ('peer-sap'). In order to expose such AC/SAP binding information, the SAP model <xref target="RFC9408"/> is augmented with required AC-related information.</t>
        <t>Unlike the AC service model <xref target="I-D.ietf-opsawg-teas-attachment-circuit"/>, an AC is uniquely identified by a name within the scope of a node, not a network. A textual description of the AC may be provided ('description').</t>
        <t>Also, in order to ease the correlation between the AC exposed at the service layer and the one that is actually provisioned in the network operation, a reference to the AC exposed to the customer ('ac-svc-ref') is stored in the 'ietf-ac-ntw' module.</t>
        <t>A controller may indicate a filter based on the service type (e.g., Network Slice or L3VPN) to retrieve the list of available ACs for that service.</t>
        <t>In order to factorize common data that is provisioned for a group of ACs, a set of profiles (<xref target="sec-profiles"/>) can be defined at the network level, and then called under the node level. The information contained in a profile is thus inherited, unless the corresponding data node is refined at the AC level. In such a case, the value provided at the AC level takes precedence over the global one.</t>
        <t>In contexts where the same AC is terminated by multiple peer SAPs (e.g., an AC with multiple CEs) but a subset of them have specific information, the module allows operators to:</t>
        <ul spacing="normal">
          <li>
            <t>Define a parent AC that may list all these CEs as peer SAPs.</t>
          </li>
          <li>
            <t>Create individual ACs that are bound to the parent AC using 'ac-parent-ref'.</t>
          </li>
          <li>
            <t>Indicate for each individual ACs one or a subset of the CEs as peer SAPs. All these individual ACs will inherit the properties of the parent AC.</t>
          </li>
        </ul>
        <t>Whenever a parent AC is deleted, then all child ACs of that AC <bcp14>MUST</bcp14> be deleted.</t>
        <t>An AC may belong to one or multiple groups <xref target="RFC9181"/>. For example, the 'group-id' is used to associate redundancy or protection constraints with ACs.</t>
        <t>The status of an AC can be tracked using 'status'. Both operational status and administrative status are maintained. A mismatch between the administrative status vs. the operational status can be used as a trigger to detect anomalies.</t>
        <t>An AC can be characterized using Layer 2 connectivity (<xref target="sec-l2"/>), Layer 3 connectivity (<xref target="sec-l3"/>), routing protocols (<xref target="sec-rtg"/>), OAM (<xref target="sec-oam"/>), security (<xref target="sec-sec"/>), and service (<xref target="sec-svc"/>) considerations.</t>
      </section>
      <section anchor="sec-profiles">
        <name>Provisioning Profiles</name>
        <t>The specific provisioning profiles tree structure is shown in <xref target="profiles-tree"/>.</t>
        <figure anchor="profiles-tree">
          <name>Profiles Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network:
    +--rw specific-provisioning-profiles
    |  +--rw valid-provider-identifiers
    |     +--rw encryption-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw qos-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw bfd-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw forwarding-profile-identifier* [id]
    |     |  +--rw id    string
    |     +--rw routing-profile-identifier* [id]
    |        +--rw id    string
    +--rw ac-profile* [name]
       ...
]]></artwork>
        </figure>
        <t>The exact definition of these profiles is local to each service provider. The model only includes an identifier for these profiles in order to ease identifying and binding local policies when building an AC. As shown in <xref target="profiles-tree"/>, the following identifiers can be included:</t>
        <dl>
          <dt>'encryption-profile-identifier':</dt>
          <dd>
            <t>An encryption profile refers to a set of policies related to the encryption schemes and setup that can be applied on the AC.</t>
          </dd>
          <dt>'qos-profile-identifier':</dt>
          <dd>
            <t>A Quality of Service (QoS) profile refers to a set of policies such as classification, marking, and actions (e.g., <xref target="RFC3644"/>).</t>
          </dd>
          <dt>'bfd-profile-identifier':</dt>
          <dd>
            <t>A Bidirectional Forwarding Detection (BFD) profile refers to a set of BFD policies <xref target="RFC5880"/> that can be invoked when building an AC.</t>
          </dd>
          <dt>'forwarding-profile-identifier':</dt>
          <dd>
            <t>A forwarding profile refers to the policies that apply to the forwarding of packets conveyed over an AC. Such policies may consist of, for example, applying Access Control Lists (ACLs).</t>
          </dd>
          <dt>'routing-profile-identifier':</dt>
          <dd>
            <t>A routing profile refers to a set of routing policies that will be invoked (e.g., BGP policies) for an AC.</t>
          </dd>
        </dl>
      </section>
      <section anchor="sec-l2">
        <name>L2 Connection</name>
        <t>The 'l2-connection' container is used to manage the Layer 2 properties of an AC. The  Layer 2 connection tree structure is shown in <xref target="l2-tree"/>.</t>
        <figure anchor="l2-tree">
          <name>Layer 2 Connection Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  +--rw encapsulation
       |  |  +--rw encap-type?        identityref
       |  |  +--rw dot1q
       |  |  |  +--rw tag-type?         identityref
       |  |  |  +--rw cvlan-id?         uint16
       |  |  |  +--rw tag-operations
       |  |  |     +--rw (op-choice)?
       |  |  |     |  +--:(pop)
       |  |  |     |  |  +--rw pop?         empty
       |  |  |     |  +--:(push)
       |  |  |     |  |  +--rw push?        empty
       |  |  |     |  +--:(translate)
       |  |  |     |     +--rw translate?   empty
       |  |  |     +--rw tag-1?             dot1q-types:vlanid
       |  |  |     +--rw tag-1-type?
       |  |  |     |       dot1q-types:dot1q-tag-type
       |  |  |     +--rw tag-2?             dot1q-types:vlanid
       |  |  |     +--rw tag-2-type?
       |  |  |             dot1q-types:dot1q-tag-type
       |  |  +--rw priority-tagged
       |  |  |  +--rw tag-type?   identityref
       |  |  +--rw qinq
       |  |     +--rw tag-type?         identityref
       |  |     +--rw svlan-id          uint16
       |  |     +--rw cvlan-id          uint16
       |  |     +--rw tag-operations
       |  |        +--rw (op-choice)?
       |  |        |  +--:(pop)
       |  |        |  |  +--rw pop?         uint8
       |  |        |  +--:(push)
       |  |        |  |  +--rw push?        empty
       |  |        |  +--:(translate)
       |  |        |     +--rw translate?   uint8
       |  |        +--rw tag-1?             dot1q-types:vlanid
       |  |        +--rw tag-1-type?
       |  |        |       dot1q-types:dot1q-tag-type
       |  |        +--rw tag-2?             dot1q-types:vlanid
       |  |        +--rw tag-2-type?
       |  |                dot1q-types:dot1q-tag-type
       |  +--rw (l2-service)?
       |  |  +--:(l2-tunnel-service)
       |  |  |  +--rw l2-tunnel-service
       |  |  |     +--rw type?         identityref
       |  |  |     +--rw pseudowire
       |  |  |     |  +--rw vcid?      uint32
       |  |  |     |  +--rw far-end?   union
       |  |  |     +--rw vpls
       |  |  |     |  +--rw vcid?      uint32
       |  |  |     |  +--rw far-end*   union
       |  |  |     +--rw vxlan
       |  |  |        +--rw vni-id             uint32
       |  |  |        +--rw peer-mode?         identityref
       |  |  |        +--rw peer-ip-address*   inet:ip-address
       |  |  +--:(l2vpn)
       |  |     +--rw l2vpn-id?            vpn-common:vpn-id
       |  +--rw l2-termination-point?      string
       |  +--rw local-bridge-reference?    string
       |  +--rw bearer-reference?          string
       |  |       {vpn-common:bearer-reference}?
       |  +--rw lag-interface {vpn-common:lag-interface}?
       |     +--rw lag-interface-id?   string
       |     +--rw member-link-list
       |        +--rw member-link* [name]
       |           +--rw name    string
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
        </figure>
        <t>The 'encapsulation' container specifies the Layer 2 encapsulation to use (if any) and allows the configuration of the relevant tags. Also, the model supports tag manipulation operations (e.g., tag rewrite).</t>
        <t>The 'l2-tunnel-service' container is used to specify the required parameters to set a Layer tunneling service (e.g., a Virtual Private LAN Service (VPLS), a Virtual eXtensible Local Area Network (VXLAN), or a pseudowire (<xref section="6.1" sectionFormat="of" target="RFC8077"/>)). 'l2vpn-id' is used to identify a L2VPN service that is associated with an Integrated Routing and Bridging (IRB) interface.</t>
        <t>To accommodate implementations that require internal bridging, a local bridge reference can be specified in 'local-bridge-reference'. Such a reference may be a local bridge domain.</t>
        <t>A reference to the bearer is maintained using 'bearer-reference'.</t>
      </section>
      <section anchor="sec-l3">
        <name>IP Connection</name>
        <t>This 'ip-connection' container is used to group Layer 3 connectivity information, particularly the IP addressing information, of an AC.</t>
        <t>The  Layer 3 connection tree structure is shown in <xref target="l3-tree"/>.</t>
        <figure anchor="l3-tree">
          <name>IP Connection Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  +--rw l3-termination-point?   string
       |  +--rw ipv4 {vpn-common:ipv4}?
       |  |  +--rw local-address?
       |  |  |       inet:ipv4-address
       |  |  +--rw prefix-length?                           uint8
       |  |  +--rw address-allocation-type?
       |  |  |       identityref
       |  |  +--rw (allocation-type)?
       |  |     +--:(dynamic)
       |  |     |  +--rw (address-assign)?
       |  |     |  |  +--:(number)
       |  |     |  |  |  +--rw number-of-dynamic-address?   uint16
       |  |     |  |  +--:(explicit)
       |  |     |  |     +--rw customer-addresses
       |  |     |  |        +--rw address-pool* [pool-id]
       |  |     |  |           +--rw pool-id          string
       |  |     |  |           +--rw start-address
       |  |     |  |           |       inet:ipv4-address
       |  |     |  |           +--rw end-address?
       |  |     |  |                   inet:ipv4-address
       |  |     |  +--rw (provider-dhcp)?
       |  |     |  |  +--:(dhcp-service-type)
       |  |     |  |  |  +--rw dhcp-service-type?
       |  |     |  |  |          enumeration
       |  |     |  |  +--:(service-type)
       |  |     |  |     +--rw (service-type)?
       |  |     |  |        +--:(relay)
       |  |     |  |           +--rw server-ip-address*
       |  |     |  |                   inet:ipv4-address
       |  |     |  +--rw (dhcp-relay)?
       |  |     |     +--:(customer-dhcp-servers)
       |  |     |        +--rw customer-dhcp-servers
       |  |     |           +--rw server-ip-address*
       |  |     |                   inet:ipv4-address
       |  |     +--:(static-addresses)
       |  |        +--rw address* [address-id]
       |  |           +--rw address-id          string
       |  |           +--rw customer-address?   inet:ipv4-address
       |  +--rw ipv6 {vpn-common:ipv6}?
       |     +--rw local-address?
       |     |       inet:ipv6-address
       |     +--rw prefix-length?                           uint8
       |     +--rw address-allocation-type?
       |     |       identityref
       |     +--rw (allocation-type)?
       |        +--:(dynamic)
       |        |  +--rw (address-assign)?
       |        |  |  +--:(number)
       |        |  |  |  +--rw number-of-dynamic-address?   uint16
       |        |  |  +--:(explicit)
       |        |  |     +--rw customer-addresses
       |        |  |        +--rw address-pool* [pool-id]
       |        |  |           +--rw pool-id          string
       |        |  |           +--rw start-address
       |        |  |           |       inet:ipv6-address
       |        |  |           +--rw end-address?
       |        |  |                   inet:ipv6-address
       |        |  +--rw (provider-dhcp)?
       |        |  |  +--:(dhcp-service-type)
       |        |  |  |  +--rw dhcp-service-type?
       |        |  |  |          enumeration
       |        |  |  +--:(service-type)
       |        |  |     +--rw (service-type)?
       |        |  |        +--:(relay)
       |        |  |           +--rw server-ip-address*
       |        |  |                   inet:ipv6-address
       |        |  +--rw (dhcp-relay)?
       |        |     +--:(customer-dhcp-servers)
       |        |        +--rw customer-dhcp-servers
       |        |           +--rw server-ip-address*
       |        |                   inet:ipv6-address
       |        +--:(static-addresses)
       |           +--rw address* [address-id]
       |              +--rw address-id          string
       |              +--rw customer-address?   inet:ipv6-address
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
        </figure>
        <t>A distinct Layer 3 interface other than the interface indicated under the 'l2-connection' container may be needed to terminate the Layer 3 connectivity. The identifier of such an interface is included in 'l3-termination-point'. For example, this data node can be used to carry the identifier of a bridge domain interface.</t>
        <t>This container can include IPv4, IPv6, or both if dual-stack is enabled. For both IPv4 and IPv6, the IP connection supports three IP address assignment modes for customer addresses: provider DHCP, DHCP relay, and static addressing. Note that for the IPv6 case, Stateless Address Autoconfiguration (SLAAC) <xref target="RFC4862"/> can be used.</t>
        <t>For both IPv4 and IPv6, 'address-allocation-type' is used to indicate the IP address allocation mode to activate for an AC. The allocated address represents the PE interface address configuration. When 'address-allocation-type' is set to 'provider-dhcp', DHCP assignments can be made locally or by an external DHCP server. Such behavior is controlled by setting 'dhcp-service-type'.</t>
        <t>For IPv6, if 'address-allocation-type' is set to 'slaac', the Prefix Information option of Router Advertisements that will be issued for SLAAC purposes will carry the IPv6 prefix that is determined by 'local-address' and 'prefix-length'. For example, if 'local-address' is set to '2001:db8:0:1::1' and 'prefix-length' is set to '64', the IPv6 prefix that will be used is '2001:db8:0:1::/64'.</t>
        <t>In some deployment contexts (e.g., network merging), multiple IP subnets may be used in a transition period. For such deployments, multiple ACs (typically, two) with overlapping information may be maintained during a transition period. The correlation between these ACs may rely upon the same "ac-svc-ref".</t>
      </section>
      <section anchor="sec-rtg">
        <name>Routing</name>
        <t>The overall routing subtree structure is shown in <xref target="rtg-tree"/>.</t>
        <figure anchor="rtg-tree">
          <name>Routing Tree Structure</name>
          <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
        </figure>
        <t>Multiple routing instances ('routing-protocol') can be defined, each uniquely identified
by an 'id'. Specifically, each instance is uniquely identified to accommodate scenarios
where multiple instances of the same routing protocol have to be configured on the same AC.</t>
        <t>The type of a routing instance is indicated in 'type'.
The values of this attribute are those defined in <xref target="RFC9181"/> (the
'routing-protocol-type' identity). Specific data nodes are then provided
as a function of the 'type'. See more details in the following subsections.</t>
        <t>One or multiple routing profiles ('routing-profiles') can be provided for
a given routing instance.</t>
        <section anchor="sec-static-rtg">
          <name>Static Routing</name>
          <t>The static routing subtree structure is shown in <xref target="static-tree"/>.</t>
          <figure anchor="static-tree">
            <name>Static Routing Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  +--rw cascaded-lan-prefixes
       |     |     +--rw ipv4-lan-prefixes* [lan next-hop]
       |     |     |       {vpn-common:ipv4}?
       |     |     |  +--rw lan           inet:ipv4-prefix
       |     |     |  +--rw lan-tag?      string
       |     |     |  +--rw next-hop      union
       |     |     |  +--rw metric?       uint32
       |     |     |  +--rw bfd-enable?   boolean {vpn-common:bfd}?
       |     |     |  +--rw preference?   uint32
       |     |     |  +--rw status
       |     |     |     +--rw admin-status
       |     |     |     |  +--rw status?        identityref
       |     |     |     |  +--rw last-change?   yang:date-and-time
       |     |     |     +--ro oper-status
       |     |     |        +--ro status?        identityref
       |     |     |        +--ro last-change?   yang:date-and-time
       |     |     +--rw ipv6-lan-prefixes* [lan next-hop]
       |     |             {vpn-common:ipv6}?
       |     |        +--rw lan           inet:ipv4-prefix
       |     |        +--rw lan-tag?      string
       |     |        +--rw next-hop      union
       |     |        +--rw metric?       uint32
       |     |        +--rw bfd-enable?   boolean {vpn-common:bfd}?
       |     |        +--rw preference?   uint32
       |     |        +--rw status
       |     |           +--rw admin-status
       |     |           |  +--rw status?        identityref
       |     |           |  +--rw last-change?   yang:date-and-time
       |     |           +--ro oper-status
       |     |              +--ro status?        identityref
       |     |              +--ro last-change?   yang:date-and-time
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following data nodes can be defined for a given IP prefix:</t>
          <dl>
            <dt>'lan-tag':</dt>
            <dd>
              <t>Indicates a local tag (e.g., "myfavorite-lan") that is used to enforce local policies.</t>
            </dd>
            <dt>'next-hop':</dt>
            <dd>
              <t>Indicates the next hop to be used for the static route.</t>
            </dd>
            <dt/>
            <dd>
              <t>It can be identified by an IP address, a predefined next-hop type (e.g., 'discard' or 'local-link'), etc.</t>
            </dd>
            <dt>'bfd-enable':</dt>
            <dd>
              <t>Indicates whether BFD is enabled or disabled for this static route entry.</t>
            </dd>
            <dt>'metric':</dt>
            <dd>
              <t>Indicates the metric associated with the static route entry. This metric is used when the route is exported into an IGP.</t>
            </dd>
            <dt>'preference':</dt>
            <dd>
              <t>Indicates the preference associated with the static route entry.</t>
            </dd>
            <dt/>
            <dd>
              <t>This preference is used to select a preferred route among routes to the same destination prefix.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Used to convey the status of a static route entry. This data node can also be used to control the (de)activation of individual static route entries.</t>
            </dd>
          </dl>
        </section>
        <section anchor="sec-bgp-rtg">
          <name>BGP</name>
          <t>The BGP routing subtree structure is shown in <xref target="bgp-tree"/>.</t>
          <figure anchor="bgp-tree">
            <name>BGP Routing Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  +--rw description?              string
       |     |  +--rw apply-policy
       |     |  |  +--rw import-policy*           leafref
       |     |  |  +--rw default-import-policy?   default-policy-type
       |     |  |  +--rw export-policy*           leafref
       |     |  |  +--rw default-export-policy?   default-policy-type
       |     |  +--rw local-as?                 inet:as-number
       |     |  +--rw peer-as                   inet:as-number
       |     |  +--rw address-family?           identityref
       |     |  +--rw multihop?                 uint8
       |     |  +--rw as-override?              boolean
       |     |  +--rw allow-own-as?             uint8
       |     |  +--rw prepend-global-as?        boolean
       |     |  +--rw send-default-route?       boolean
       |     |  +--rw site-of-origin?           rt-types:route-origin
       |     |  +--rw ipv6-site-of-origin?
       |     |  |       rt-types:ipv6-route-origin
       |     |  +--rw redistribute-connected* [address-family]
       |     |  |  +--rw address-family    identityref
       |     |  |  +--rw enable?           boolean
       |     |  +--rw bgp-max-prefix
       |     |  |  +--rw max-prefix?          uint32
       |     |  |  +--rw warning-threshold?   decimal64
       |     |  |  +--rw violate-action?      enumeration
       |     |  |  +--rw restart-timer?       uint32
       |     |  +--rw bgp-timers
       |     |     +--rw keepalive?   uint16
       |     |     +--rw hold-time?   uint16
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  +--rw peer-groups
       |     |  |  +--rw peer-group* [name]
       |     |  |     +--rw name                      string
       |     |  |     +--rw local-address?            union
       |     |  |     +--rw description?              string
       |     |  |     +--rw apply-policy
       |     |  |     |  +--rw import-policy*           leafref
       |     |  |     |  +--rw default-import-policy?
       |     |  |     |  |       default-policy-type
       |     |  |     |  +--rw export-policy*           leafref
       |     |  |     |  +--rw default-export-policy?
       |     |  |     |          default-policy-type
       |     |  |     +--rw local-as?                 inet:as-number
       |     |  |     +--rw peer-as                   inet:as-number
       |     |  |     +--rw address-family?           identityref
       |     |  |     +--rw multihop?                 uint8
       |     |  |     +--rw as-override?              boolean
       |     |  |     +--rw allow-own-as?             uint8
       |     |  |     +--rw prepend-global-as?        boolean
       |     |  |     +--rw send-default-route?       boolean
       |     |  |     +--rw site-of-origin?
       |     |  |     |       rt-types:route-origin
       |     |  |     +--rw ipv6-site-of-origin?
       |     |  |     |       rt-types:ipv6-route-origin
       |     |  |     +--rw redistribute-connected* [address-family]
       |     |  |     |  +--rw address-family    identityref
       |     |  |     |  +--rw enable?           boolean
       |     |  |     +--rw bgp-max-prefix
       |     |  |     |  +--rw max-prefix?          uint32
       |     |  |     |  +--rw warning-threshold?   decimal64
       |     |  |     |  +--rw violate-action?      enumeration
       |     |  |     |  +--rw restart-timer?       uint32
       |     |  |     +--rw bgp-timers
       |     |  |     |  +--rw keepalive?   uint16
       |     |  |     |  +--rw hold-time?   uint16
       |     |  |     +--rw authentication
       |     |  |        +--rw enable?            boolean
       |     |  |        +--rw keying-material
       |     |  |           +--rw (option)?
       |     |  |              +--:(ao)
       |     |  |              |  +--rw enable-ao?          boolean
       |     |  |              |  +--rw ao-keychain?
       |     |  |              |          key-chain:key-chain-ref
       |     |  |              +--:(md5)
       |     |  |              |  +--rw md5-keychain?
       |     |  |              |          key-chain:key-chain-ref
       |     |  |              +--:(explicit)
       |     |  |                 +--rw key-id?             uint32
       |     |  |                 +--rw key?                string
       |     |  |                 +--rw crypto-algorithm?
       |     |  |                         identityref
       |     |  +--rw neighbor* [remote-address]
       |     |     +--rw remote-address            inet:ip-address
       |     |     +--rw local-address?            union
       |     |     +--rw peer-group?
       |     |     |       -> ../../peer-groups/peer-group/name
       |     |     +--rw description?              string
       |     |     +--rw apply-policy
       |     |     |  +--rw import-policy*           leafref
       |     |     |  +--rw default-import-policy?
       |     |     |  |       default-policy-type
       |     |     |  +--rw export-policy*           leafref
       |     |     |  +--rw default-export-policy?
       |     |     |          default-policy-type
       |     |     +--rw local-as?                 inet:as-number
       |     |     +--rw peer-as                   inet:as-number
       |     |     +--rw address-family?           identityref
       |     |     +--rw multihop?                 uint8
       |     |     +--rw as-override?              boolean
       |     |     +--rw allow-own-as?             uint8
       |     |     +--rw prepend-global-as?        boolean
       |     |     +--rw send-default-route?       boolean
       |     |     +--rw site-of-origin?
       |     |     |       rt-types:route-origin
       |     |     +--rw ipv6-site-of-origin?
       |     |     |       rt-types:ipv6-route-origin
       |     |     +--rw redistribute-connected* [address-family]
       |     |     |  +--rw address-family    identityref
       |     |     |  +--rw enable?           boolean
       |     |     +--rw bgp-max-prefix
       |     |     |  +--rw max-prefix?          uint32
       |     |     |  +--rw warning-threshold?   decimal64
       |     |     |  +--rw violate-action?      enumeration
       |     |     |  +--rw restart-timer?       uint32
       |     |     +--rw bgp-timers
       |     |     |  +--rw keepalive?   uint16
       |     |     |  +--rw hold-time?   uint16
       |     |     +--rw authentication
       |     |     |  +--rw enable?            boolean
       |     |     |  +--rw keying-material
       |     |     |     +--rw (option)?
       |     |     |        +--:(ao)
       |     |     |        |  +--rw enable-ao?          boolean
       |     |     |        |  +--rw ao-keychain?
       |     |     |        |          key-chain:key-chain-ref
       |     |     |        +--:(md5)
       |     |     |        |  +--rw md5-keychain?
       |     |     |        |          key-chain:key-chain-ref
       |     |     |        +--:(explicit)
       |     |     |           +--rw key-id?             uint32
       |     |     |           +--rw key?                string
       |     |     |           +--rw crypto-algorithm?   identityref
       |     |     +--rw status
       |     |        +--rw admin-status
       |     |        |  +--rw status?        identityref
       |     |        |  +--rw last-change?   yang:date-and-time
       |     |        +--ro oper-status
       |     |           +--ro status?        identityref
       |     |           +--ro last-change?   yang:date-and-time
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following data nodes are supported for each 'peer-group':</t>
          <dl>
            <dt>'name':</dt>
            <dd>
              <t>Defines a name for the peer group.</t>
            </dd>
            <dt>'local-address':</dt>
            <dd>
              <t>Specifies an address or a reference to an interface to use when establishing the BGP transport session.</t>
            </dd>
            <dt>'description':</dt>
            <dd>
              <t>Includes a description of the peer group.</t>
            </dd>
            <dt>'apply-policy':</dt>
            <dd>
              <t>Lists a set of import/export policies <xref target="RFC9067"/> to apply for this group.</t>
            </dd>
            <dt>'local-as':</dt>
            <dd>
              <t>Indicates a local AS Number (ASN).</t>
            </dd>
            <dt>'peer-as':</dt>
            <dd>
              <t>Indicates the peer's ASN.</t>
            </dd>
            <dt>'address-family':</dt>
            <dd>
              <t>Indicates the address family of the peer.  It can
   be set to 'ipv4', 'ipv6', or 'dual-stack'.</t>
            </dd>
            <dt/>
            <dd>
              <t>This address family will be used together with the 'vpn-type' to
    derive the appropriate Address Family Identifiers (AFIs) /
    Subsequent Address Family Identifiers (SAFIs) that will be part of
   the derived device configurations (e.g., unicast IPv4 MPLS L3VPN
    (AFI,SAFI = 1,128) as defined in <xref section="4.3.4" sectionFormat="of" target="RFC4364"/>).</t>
            </dd>
            <dt>'multihop':</dt>
            <dd>
              <t>Indicates the number of allowed IP hops to reach a BGP peer.</t>
            </dd>
            <dt>'as-override':</dt>
            <dd>
              <t>If set, this parameter indicates whether ASN override
   is enabled, i.e., replacing the ASN of the customer specified in
   the AS_PATH BGP attribute with the ASN identified in the 'local-
   as' attribute.</t>
            </dd>
            <dt>'allow-own-as':</dt>
            <dd>
              <t>Used in some topologies (e.g., hub-and-spoke) to
   allow the provider's ASN to be included in the AS_PATH BGP
   attribute received from a peer.  Loops are prevented by setting
   'allow-own-as' to a maximum number of the provider's ASN
   occurrences.  By default, this parameter is set to '0' (that is,
   reject any AS_PATH attribute that includes the provider's ASN).</t>
            </dd>
            <dt>'prepend-global-as':</dt>
            <dd>
              <t>When distinct ASNs are configured at the
   node and AC levels, this parameter controls whether
   the ASN provided at the node level is prepended to the AS_PATH
   attribute.</t>
            </dd>
            <dt>'send-default-route':</dt>
            <dd>
              <t>Controls whether default routes can be advertised to the peer.</t>
            </dd>
            <dt>'site-of-origin':</dt>
            <dd>
              <t>Meant to uniquely identify the set of routes
   learned from a site via a particular AC.  It is used
   to prevent routing loops (<xref section="7" sectionFormat="of" target="RFC4364"/>).  The Site of
   Origin attribute is encoded as a Route Origin Extended Community.</t>
            </dd>
            <dt>'ipv6-site-of-origin':</dt>
            <dd>
              <t>Carries an IPv6 Address Specific BGP Extended
    Community that is used to indicate the Site of Origin <xref target="RFC5701"/>.  It is used to prevent routing loops.</t>
            </dd>
            <dt>'redistribute-connected':</dt>
            <dd>
              <t>Controls whether the AC is advertised to other PEs.</t>
            </dd>
          </dl>
          <t>'bgp-max-prefix':  Controls the behavior when a prefix maximum is
      reached.</t>
          <dl>
            <dt>'max-prefix':</dt>
            <dd>
              <t>Indicates the maximum number of BGP prefixes
    allowed in a session for this group.  If the limit is reached, the
    action indicated in 'violate-action' will be followed.</t>
            </dd>
            <dt>'warning-threshold':</dt>
            <dd>
              <t>A warning notification is triggered when this limit is reached.</t>
            </dd>
          </dl>
          <artwork><![CDATA[
'violate-action':
:  Indicates which action to execute when the
     maximum number of BGP prefixes is reached.  Examples of such
     actions include sending a warning message, discarding extra
     paths from the peer, or restarting the session.

'restart-timer':
:  Indicates, in seconds, the time interval after
  which the BGP session will be reestablished.
]]></artwork>
          <dl>
            <dt>'bgp-timers':</dt>
            <dd>
              <t>Two timers can be captured in this container: (1)
   'hold-time', which is the time interval that will be used for the
   Hold Timer (<xref section="4.2" sectionFormat="of" target="RFC4271"/>) when establishing a BGP
   session and (2) 'keepalive', which is the time interval for the
   KeepaliveTimer between a PE and a BGP peer (<xref section="4.4" sectionFormat="of" target="RFC4271"/>).</t>
            </dd>
            <dt/>
            <dd>
              <t>Both timers are expressed in seconds.</t>
            </dd>
            <dt>'authentication':</dt>
            <dd>
              <t>The module adheres to the recommendations in
   <xref section="13.2" sectionFormat="of" target="RFC4364"/>, as it allows enabling the TCP
   Authentication Option (TCP-AO) <xref target="RFC5925"/> and accommodates the
   installed base that makes use of MD5.  In addition, the module
   includes a provision for using IPsec.</t>
            </dd>
            <dt/>
            <dd>
              <t>This version of the model assumes that parameters specific to the
    TCP-AO are preconfigured as part of the key chain that is
    referenced in the model.  No assumption is made about how such a
    key chain is preconfigured.  However, the structure of the key
    chain should cover data nodes beyond those in <xref target="RFC8177"/>, mainly
    SendID and RecvID (<xref section="3.1" sectionFormat="of" target="RFC5925"/>).</t>
            </dd>
          </dl>
          <t>For each neighbor, the following data nodes are supported in addition to similar parameters that are provided for a peer group:</t>
          <dl>
            <dt>'remote-address':</dt>
            <dd>
              <t>Specifies the remote IP address of a BGP neighbor.</t>
            </dd>
            <dt>'peer-group':</dt>
            <dd>
              <t>A name of a peer group.</t>
            </dd>
            <dt/>
            <dd>
              <t>Parameters that are provided at the 'neighbor' level takes precedence over the ones provided in the peer group.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Indicates the status of the BGP session.</t>
            </dd>
          </dl>
        </section>
        <section anchor="sec-ospf-rtg">
          <name>OSPF</name>
          <t>The OSPF routing subtree structure is shown in <xref target="ospf-tree"/>.</t>
          <figure anchor="ospf-tree">
            <name>OSPF Routing Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-id           yang:dotted-quad
       |     |  +--rw metric?           uint16
       |     |  +--rw max-lsa?          uint32
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-id           yang:dotted-quad
       |     |  +--rw metric?           uint16
       |     |  +--rw sham-links {vpn-common:rtg-ospf-sham-link}?
       |     |  |  +--rw sham-link* [target-site]
       |     |  |     +--rw target-site    string
       |     |  |     +--rw metric?        uint16
       |     |  +--rw max-lsa?          uint32
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key-id?             uint32
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following OSPF data nodes are supported:</t>
          <dl>
            <dt>'address-family':</dt>
            <dd>
              <t>Indicates whether IPv4, IPv6, or both address
   families are to be activated.</t>
            </dd>
            <dt/>
            <dd>
              <t>When the IPv4 or dual-stack address family is requested, it is up
    to the implementation (e.g., network orchestrator) to decide
    whether OSPFv2 <xref target="RFC4577"/> or OSPFv3 <xref target="RFC6565"/> is used to announce
    IPv4 routes.</t>
            </dd>
            <dt>'area-id':</dt>
            <dd>
              <t>Indicates the OSPF Area ID.</t>
            </dd>
            <dt>'metric':</dt>
            <dd>
              <t>Associates a metric with OSPF routes.</t>
            </dd>
            <dt>'sham-links':</dt>
            <dd>
              <t>Used to create OSPF sham links between two ACs sharing the same area and having a backdoor link
   (<xref section="4.2.7" sectionFormat="of" target="RFC4577"/> and <xref section="5" sectionFormat="of" target="RFC6565"/>).</t>
            </dd>
            <dt>'max-lsa':</dt>
            <dd>
              <t>Sets the maximum number of Link State Advertisements
   (LSAs) that the OSPF instance will accept.</t>
            </dd>
            <dt>'authentication':</dt>
            <dd>
              <t>Controls the authentication schemes to be enabled
   for the OSPF instance.  The following options are supported: IPsec
   for OSPFv3 authentication <xref target="RFC4552"/>, and the Authentication
   Trailer for OSPFv2 <xref target="RFC5709"/> <xref target="RFC7474"/> and OSPFv3 <xref target="RFC7166"/>.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Indicates the status of the OSPF routing instance.</t>
            </dd>
          </dl>
        </section>
        <section anchor="sec-isis-rtg">
          <name>IS-IS</name>
          <t>The IS-IS routing subtree structure is shown in <xref target="isis-tree"/>.</t>
          <figure anchor="isis-tree">
            <name>IS-IS Routing Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-address      area-address
       |     |  +--rw level?            identityref
       |     |  +--rw metric?           uint16
       |     |  +--rw mode?             enumeration
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  +--rw address-family?   identityref
       |     |  +--rw area-address      area-address
       |     |  +--rw level?            identityref
       |     |  +--rw metric?           uint16
       |     |  +--rw mode?             enumeration
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key-id?             uint32
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following IS-IS data nodes are supported:</t>
          <dl>
            <dt>'address-family':</dt>
            <dd>
              <t>Indicates whether IPv4, IPv6, or both address families are to be activated.</t>
            </dd>
            <dt>'area-address':</dt>
            <dd>
              <t>Indicates the IS-IS area address.</t>
            </dd>
            <dt>'level':</dt>
            <dd>
              <t>Indicates the IS-IS level: Level 1, Level 2, or both.</t>
            </dd>
            <dt>'metric':</dt>
            <dd>
              <t>Associates a metric with IS-IS routes.</t>
            </dd>
            <dt>'mode':</dt>
            <dd>
              <t>Indicates the IS-IS interface mode type.  It can be set to
   'active' (that is, send or receive IS-IS protocol control packets)
   or 'passive' (that is, suppress the sending of IS-IS updates
   through the interface).</t>
            </dd>
            <dt/>
            <dd>
              <t>'authentication':</t>
            </dd>
            <dt/>
            <dd>
              <t>Controls the authentication schemes to be enabled
   for the IS-IS instance.  Both the specification of a key chain
   <xref target="RFC8177"/> and the direct specification of key and authentication
   algorithms are supported.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Indicates the status of the IS-IS routing instance.</t>
            </dd>
          </dl>
        </section>
        <section anchor="sec-rip-rtg">
          <name>RIP</name>
          <t>The RIP routing subtree structure is shown in <xref target="rip-tree"/>.</t>
          <figure anchor="rip-tree">
            <name>RIP Routing Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  +--rw address-family?   identityref
       |     |  +--rw timers
       |     |  |  +--rw update-interval?     uint16
       |     |  |  +--rw invalid-interval?    uint16
       |     |  |  +--rw holddown-interval?   uint16
       |     |  |  +--rw flush-interval?      uint16
       |     |  +--rw default-metric?   uint8
       |     +--rw vrrp
       |        ...
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  +--rw address-family?   identityref
       |     |  +--rw timers
       |     |  |  +--rw update-interval?     uint16
       |     |  |  +--rw invalid-interval?    uint16
       |     |  |  +--rw holddown-interval?   uint16
       |     |  |  +--rw flush-interval?      uint16
       |     |  +--rw default-metric?   uint8
       |     |  +--rw authentication
       |     |  |  +--rw enable?            boolean
       |     |  |  +--rw keying-material
       |     |  |     +--rw (option)?
       |     |  |        +--:(auth-key-chain)
       |     |  |        |  +--rw key-chain?
       |     |  |        |          key-chain:key-chain-ref
       |     |  |        +--:(auth-key-explicit)
       |     |  |           +--rw key?                string
       |     |  |           +--rw crypto-algorithm?   identityref
       |     |  +--rw status
       |     |     +--rw admin-status
       |     |     |  +--rw status?        identityref
       |     |     |  +--rw last-change?   yang:date-and-time
       |     |     +--ro oper-status
       |     |        +--ro status?        identityref
       |     |        +--ro last-change?   yang:date-and-time
       |     +--rw vrrp
       |        ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following RIP data nodes are supported:</t>
          <dl>
            <dt>'address-family':</dt>
            <dd>
              <t>Indicates whether IPv4, IPv6, or both address
   families are to be activated.  This parameter is used to determine
   whether RIPv2 <xref target="RFC2453"/>, RIP Next Generation (RIPng), or both are
   to be enabled <xref target="RFC2080"/>.</t>
            </dd>
            <dt>'timers':</dt>
            <dd>
              <t>Indicates the following timers (expressed in seconds):
</t>
              <ul spacing="normal">
                <li>
                  <dl>
                    <dt>'update-interval':</dt>
                    <dd>
                      <t>The interval at which RIP updates are sent.</t>
                    </dd>
                  </dl>
                </li>
                <li>
                  <dl>
                    <dt>'invalid-interval':</dt>
                    <dd>
                      <t>The interval before a RIP route is declared invalid.</t>
                    </dd>
                  </dl>
                </li>
                <li>
                  <dl>
                    <dt>'holddown-interval':</dt>
                    <dd>
                      <t>The interval before better RIP routes are released.</t>
                    </dd>
                  </dl>
                </li>
                <li>
                  <dl>
                    <dt>'flush-interval':</dt>
                    <dd>
                      <t>The interval before a route is removed from the routing table.</t>
                    </dd>
                  </dl>
                </li>
              </ul>
            </dd>
            <dt>'default-metric':</dt>
            <dd>
              <t>Sets the default RIP metric.</t>
            </dd>
            <dt>'authentication':</dt>
            <dd>
              <t>Controls the authentication schemes to be enabled for the RIP instance.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Indicates the status of the RIP routing instance.</t>
            </dd>
          </dl>
        </section>
        <section anchor="sec-VRRP-rtg">
          <name>VRRP</name>
          <t>The VRRP subtree structure is shown in <xref target="vrrp-tree"/>.</t>
          <figure anchor="vrrp-tree">
            <name>VRRP Tree Structure</name>
            <artwork><![CDATA[
module: ietf-ac-ntw
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id      string
       |     +--rw type?   identityref
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        +--rw address-family?   identityref
       |        +--rw ping-reply?       boolean
       +--rw oam
          ...
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       ...
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  +--rw routing-protocol* [id]
       |     +--rw id                  string
       |     +--rw type?               identityref
       |     +--rw routing-profiles* [id]
       |     |  +--rw id      leafref
       |     |  +--rw type?   identityref
       |     +--rw static
       |     |  ...
       |     +--rw bgp
       |     |  ...
       |     +--rw ospf
       |     |  ...
       |     +--rw isis
       |     |  ...
       |     +--rw rip
       |     |  ...
       |     +--rw vrrp
       |        +--rw address-family?       identityref
       |        +--rw vrrp-group?           uint8
       |        +--rw backup-peer?          inet:ip-address
       |        +--rw virtual-ip-address*   inet:ip-address
       |        +--rw priority?             uint8
       |        +--rw ping-reply?           boolean
       |        +--rw status
       |           +--rw admin-status
       |           |  +--rw status?        identityref
       |           |  +--rw last-change?   yang:date-and-time
       |           +--ro oper-status
       |              +--ro status?        identityref
       |              +--ro last-change?   yang:date-and-time
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
          </figure>
          <t>The following VRRP data nodes are supported:</t>
          <dl>
            <dt>'address-family':</dt>
            <dd>
              <t>Indicates whether IPv4, IPv6, or both address
   families are to be activated.  Note that VRRP version 3 <xref target="RFC5798"/>
   supports both IPv4 and IPv6.</t>
            </dd>
            <dt>'vrrp-group':</dt>
            <dd>
              <t>Used to identify the VRRP group.</t>
            </dd>
            <dt>'backup-peer':</dt>
            <dd>
              <t>Carries the IP address of the peer.</t>
            </dd>
            <dt>'virtual-ip-address':</dt>
            <dd>
              <t>Includes virtual IP addresses for a single VRRP group.</t>
            </dd>
            <dt>'priority':</dt>
            <dd>
              <t>Assigns the VRRP election priority for the backup virtual router.</t>
            </dd>
            <dt>'ping-reply':</dt>
            <dd>
              <t>Controls whether the VRRP speaker should reply to ping requests.</t>
            </dd>
            <dt>'status':</dt>
            <dd>
              <t>Indicates the status of the VRRP instance.</t>
            </dd>
          </dl>
          <t>Note that no authentication data node is included for VRRP, as there
isn't any type of VRRP authentication at this time (see <xref section="9" sectionFormat="of" target="RFC5798"/>).</t>
        </section>
      </section>
      <section anchor="sec-oam">
        <name>OAM</name>
        <t>The OAM subtree structure is shown in <xref target="oam-tree"/>.</t>
        <figure anchor="oam-tree">
          <name>OAM Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network:
    +--rw ac-profile* [name]
       +--rw name                 string
       +--rw l2-connection
       +--rw ip-connection
       +--rw routing-protocols
       |  ...
       +--rw oam
          +--rw bfd {vpn-common:bfd}?
             +--rw session-type?               identityref
             +--rw desired-min-tx-interval?    uint32
             +--rw required-min-rx-interval?   uint32
             +--rw local-multiplier?           uint8
             +--rw holdtime?                   uint32
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  +--rw bfd
       |     +--rw profile?                    ac-svc:bfd-profile-reference
       |     +--rw session-type?               identityref
       |     +--rw desired-min-tx-interval?    uint32
       |     +--rw required-min-rx-interval?   uint32
       |     +--rw local-multiplier?           uint8
       |     +--rw holdtime?                   uint32
       |     +--rw authentication!
       |     |  +--rw key-chain?    key-chain:key-chain-ref
       |     |  +--rw meticulous?   boolean
       |     +--rw status
       |        +--rw admin-status
       |        |  +--rw status?        identityref
       |        |  +--rw last-change?   yang:date-and-time
       |        +--ro oper-status
       |           +--ro status?        identityref
       |           +--ro last-change?   yang:date-and-time
       +--rw security
       |  ...
       +--rw service
          ...
]]></artwork>
        </figure>
        <t>The following OAM data nodes can be specified:</t>
        <dl>
          <dt>'profile':</dt>
          <dd>
            <t>Refers to a BFD profile (<xref target="sec-profiles"/>).</t>
          </dd>
          <dt>'session-type':</dt>
          <dd>
            <t>Indicates which BFD flavor is used to set up the session (e.g., classic BFD <xref target="RFC5880"/>, Seamless BFD <xref target="RFC7880"/>). By default, it is assumed that the BFD session will follow the behavior specified in <xref target="RFC5880"/>.</t>
          </dd>
          <dt>'desired-min-tx-interval':</dt>
          <dd>
            <t>The minimum interval, in microseconds, to use when transmitting BFD Control packets, less any jitter applied.</t>
          </dd>
          <dt>'required-min-rx-interval':</dt>
          <dd>
            <t>The minimum interval, in microseconds, between received BFD Control packets less any jitter applied by the sender.</t>
          </dd>
          <dt>'local-multiplier':</dt>
          <dd>
            <t>The negotiated transmit interval, multiplied by this value, provides the detection time for the peer.</t>
          </dd>
          <dt>'holdtime':</dt>
          <dd>
            <t>Used to indicate the expected BFD holddown time, in milliseconds.</t>
          </dd>
          <dt>'authentication':</dt>
          <dd>
            <t>Includes the required information to enable the BFD authentication modes discussed in <xref section="6.7" sectionFormat="of" target="RFC5880"/>. In particular, 'meticulous' controls the activation of meticulous mode as discussed in Sections 6.7.3 and 6.7.4 of <xref target="RFC5880"/>.</t>
          </dd>
          <dt>'status':</dt>
          <dd>
            <t>Indicates the status of BFD.</t>
          </dd>
        </dl>
      </section>
      <section anchor="sec-sec">
        <name>Security</name>
        <t>The security subtree structure is shown in <xref target="sec-tree"/>. The 'security' container specifies the authentication and the encryption to be applied to traffic for a given AC. Tthe model can be used to directly control the encryption to be applied (e.g., Layer 2 or Layer 3 encryption) or invoke a local encryption profile.</t>
        <figure anchor="sec-tree">
          <name>Security Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  +--rw encryption {vpn-common:encryption}?
       |  |  +--rw enabled?   boolean
       |  |  +--rw layer?     enumeration
       |  +--rw encryption-profile
       |     +--rw (profile)?
       |        +--:(provider-profile)
       |        |  +--rw profile-name?
       |        |          encryption-profile-reference
       |        +--:(customer-profile)
       |           +--rw customer-key-chain?   key-chain:key-chain-ref
       +--rw service
          ...
]]></artwork>
        </figure>
      </section>
      <section anchor="sec-svc">
        <name>Service</name>
        <t>The service subtree structure is shown in <xref target="svc-tree"/>.</t>
        <figure anchor="svc-tree">
          <name>Service Tree Structure</name>
          <artwork><![CDATA[
  augment /nw:networks/nw:network/nw:node/sap:service/sap:sap:
    +--rw ac* [name]
       +--rw name                 string
       +--rw ac-svc-ref?          ac-svc:attachment-circuit-reference
       +--rw ac-profile* [profile-id]
       |  +--rw profile-id    ac-profile-reference
       +--rw ac-parent-ref?       ac-ntw:attachment-circuit-reference
       +--rw peer-sap-id*         string
       +--rw group* [group-id]
       |  +--rw group-id      string
       |  +--rw precedence?   identityref
       +--rw status
       |  +--rw admin-status
       |  |  +--rw status?        identityref
       |  |  +--rw last-change?   yang:date-and-time
       |  +--ro oper-status
       |     +--ro status?        identityref
       |     +--ro last-change?   yang:date-and-time
       +--rw description?         string
       +--rw l2-connection
       |  ...
       +--rw ip-connection
       |  ...
       +--rw routing-protocols
       |  ...
       +--rw oam
       |  ...
       +--rw security
       |  ...
       +--rw service
          +--rw mtu?                      uint32
          +--rw svc-pe-to-ce-bandwidth {vpn-common:inbound-bw}?
          |  +--rw bandwidth* [bw-type]
          |     +--rw bw-type      identityref
          |     +--rw (type)?
          |        +--:(per-cos)
          |        |  +--rw cos* [cos-id]
          |        |     +--rw cos-id    uint8
          |        |     +--rw cir?      uint64
          |        |     +--rw cbs?      uint64
          |        |     +--rw eir?      uint64
          |        |     +--rw ebs?      uint64
          |        |     +--rw pir?      uint64
          |        |     +--rw pbs?      uint64
          |        +--:(other)
          |           +--rw cir?   uint64
          |           +--rw cbs?   uint64
          |           +--rw eir?   uint64
          |           +--rw ebs?   uint64
          |           +--rw pir?   uint64
          |           +--rw pbs?   uint64
          +--rw svc-ce-to-pe-bandwidth {vpn-common:outbound-bw}?
          |  +--rw bandwidth* [bw-type]
          |     +--rw bw-type      identityref
          |     +--rw (type)?
          |        +--:(per-cos)
          |        |  +--rw cos* [cos-id]
          |        |     +--rw cos-id    uint8
          |        |     +--rw cir?      uint64
          |        |     +--rw cbs?      uint64
          |        |     +--rw eir?      uint64
          |        |     +--rw ebs?      uint64
          |        |     +--rw pir?      uint64
          |        |     +--rw pbs?      uint64
          |        +--:(other)
          |           +--rw cir?   uint64
          |           +--rw cbs?   uint64
          |           +--rw eir?   uint64
          |           +--rw ebs?   uint64
          |           +--rw pir?   uint64
          |           +--rw pbs?   uint64
          +--rw qos {vpn-common:qos}?
          |  +--rw qos-profiles
          |     +--rw qos-profile* [profile]
          |        +--rw profile      qos-profile-reference
          |        +--rw direction?   identityref
          +--rw access-control-list
             +--rw acl-profiles
                +--rw acl-profile* [profile]
                   +--rw profile    forwarding-profile-reference
]]></artwork>
        </figure>
        <t>The description of the service data nodes is as follows:</t>
        <dl>
          <dt>'mtu':</dt>
          <dd>
            <t>Specifies the Layer 2 MTU, in bytes, for the VPN network access.</t>
          </dd>
          <dt>'svc-pe-to-ce-bandwidth' and 'svc-ce-to-pe-bandwidth':</dt>
          <dd>
            <t>Specify the service bandwidth for the L2VPN service.</t>
          </dd>
          <dt/>
          <dd>
            <t>'svc-pe-to-ce-bandwidth' indicates the inbound bandwidth of the connection (i.e., download bandwidth from the service provider to the site).</t>
          </dd>
          <dt/>
          <dd>
            <t>'svc-ce-to-pe-bandwidth' indicates the outbound bandwidth of the connection (i.e., upload bandwidth from the site to the service provider).</t>
          </dd>
          <dt/>
          <dd>
            <t>'svc-pe-to-ce-bandwidth' and 'svc-ce-to-pe-bandwidth' can be represented using the Committed Information Rate (CIR), the Excess Information Rate (EIR), or the Peak Information Rate (PIR).</t>
          </dd>
          <dt/>
          <dd>
            <t>The following types, defined in <xref target="RFC9181"/>, can be used to indicate the bandwidth type:</t>
            <dl>
              <dt>'bw-per-cos':</dt>
              <dd>
                <t>The bandwidth is per CoS.</t>
              </dd>
              <dt>'bw-per-port':</dt>
              <dd>
                <t>The bandwidth is per port.</t>
              </dd>
              <dt>'bw-per-site':</dt>
              <dd>
                <t>The bandwidth is to all peer SAPs that belong to the same site.</t>
              </dd>
              <dt>'bw-per-service':</dt>
              <dd>
                <t>The bandwidth is per service instance that is bound to an AC.</t>
              </dd>
            </dl>
          </dd>
          <dt>'qos':</dt>
          <dd>
            <t>Specifies a list of QoS profiles to apply for this AC.</t>
          </dd>
          <dt>'access-control-list':</dt>
          <dd>
            <t>Specifies a list of ACL profiles to apply for this AC.</t>
          </dd>
        </dl>
      </section>
    </section>
    <section anchor="sec-module">
      <name>YANG Module</name>
      <t>This module uses types defined in <xref target="RFC6991"/>, <xref target="RFC8177"/>, <xref target="RFC8294"/>, <xref target="RFC8343"/>, <xref target="RFC9067"/>, <xref target="RFC9181"/>, <xref target="I-D.ietf-opsawg-teas-common-ac"/>, and <xref target="IEEE802.1Qcp"/>.</t>
      <sourcecode type="yang"><![CDATA[
<CODE BEGINS> file ietf-ac-ntw@2022-11-30.yang
module ietf-ac-ntw {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ac-ntw";
  prefix ac-ntw;

  import ietf-vpn-common {
    prefix vpn-common;
    reference
      "RFC 9181: A Common YANG Data Model for Layer 2 and Layer 3
                 VPNs";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types, Section 4";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }
  import ietf-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the Routing Area";
  }
  import ietf-routing-policy {
    prefix rt-pol;
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ieee802-dot1q-types {
    prefix dot1q-types;
    reference
      "IEEE Std 802.1Qcp: Bridges and Bridged Networks--
                          Amendment 30: YANG Data Model";
  }
  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies, 
                 Section 6.1";
  }
  import ietf-sap-ntw {
    prefix sap;
    reference
      "RFC SSSS: A YANG Network Model for Service Attachment
                 Points (SAPs)";
  }
  import ietf-ac-common {
    prefix ac-common;
    reference
      "RFC CCCC: A Common YANG Data Model for Attachment Circuits";
  }
  import ietf-ac-svc {
    prefix ac-svc;
    reference
      "RFC SSSS: YANG Service Data Models for Attachment Circuits";
  }

  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:   Mohamed Boucadair
               <mailto:mohamed.boucadair@orange.com>
     Author:   Richard Roberts
               <mailto:rroberts@juniper.net>";
  description
    "This YANG module defines a YANG model for the management of
     attachment circuits.

     Copyright (c) 2023 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 xxx; see the
     RFC itself for full legal notices.";

  revision 2023-11-13 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Network Data Model for Attachment Circuits";
  }

  // L2 connection groupings

  /* A set of typedefs to ease referencing cross-modules */

  typedef attachment-circuit-reference {
    type leafref {
      path "/nw:networks/nw:network/nw:node/sap:service/sap:sap"
         + "/ac-ntw:ac/ac-ntw:name";
    }
    description
      "Defines a reference to an attachment circuit that can be used
       by other modules.";
  }

  typedef ac-profile-reference {
    type leafref {
      path "/nw:networks/nw:network/ac-profile/name";
    }
    description
      "Defines a reference to an attachment circuit profile that
       can be used by other modules.";
  }

  typedef encryption-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles" 
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:encryption-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to an encryption profile for referencing
       purposes.";
  }

  typedef qos-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles" 
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:qos-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a QoS profile for referencing purposes.";
  }

  typedef bfd-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles" 
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:bfd-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a BFD profile for referencing purposes.";
  }

  typedef forwarding-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles" 
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:forwarding-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a forwarding profile for referencing
       purposes.";
  }

  typedef routing-profile-reference {
    type leafref {
      path
          "/nw:networks/nw:network"
        + "/ac-ntw:specific-provisioning-profiles" 
        + "/ac-ntw:valid-provider-identifiers"
        + "/ac-ntw:routing-profile-identifier/ac-ntw:id";
    }
    description
      "Defines a type to a routing profile for referencing 
       purposes.";
  }

  // L2 conenction

  grouping l2-connection {
    description
      "Defines Layer 2 protocols and parameters that are required to
       enable AC connectivity.";
    container encapsulation {
      description
        "Container for Layer 2 encapsulation.";
      leaf encap-type {
        type identityref {
          base vpn-common:encapsulation-type;
        }
        description
          "Tagged interface type.";
      }
      container dot1q {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:dot1q')" {
          description
            "Only applies when the type of the tagged interface is
             'dot1q'.";
        }
        description
          "Tagged interface.";
        uses ac-common:dot1q;
        container tag-operations {
          description
            "Sets the tag manipulation policy for this AC. It defines
             a set of tag manipulations that allow for the insertion,
             removal, or rewriting of 802.1Q VLAN tags. These
             operations are indicated for the CE-PE direction.
             By default, tag operations are symmetric. As such, the
             reverse tag operation is assumed on the PE-CE 
             direction.";
          choice op-choice {
            description
              "Selects the tag rewriting policy for an AC.";
            leaf pop {
              type empty;
              description
                "Pop the outer tag.";
            }
            leaf push {
              type empty;
              description
                "Pushes one or two tags defined by the tag-1 and
                 tag-2 leaves.  It is assumed that, absent any
                 policy, the default value of 0 will be used for
                 the PCP  setting.";
            }
            leaf translate {
              type empty;
              description
                "Translates the outer tag to one or two tags. PCP 
                 bits are preserved.";
            }
          }
          leaf tag-1 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A first tag to be used for push or translate 
               operations. This tag will be used as the outermost tag
               as a result of the tag operation.";
          }
          leaf tag-1-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:s-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-1.";
          }
          leaf tag-2 {
            when '(../translate)';
            type dot1q-types:vlanid;
            description
              "A second tag to be used for translation.";
          }
          leaf tag-2-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:c-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-2.";
          }
        }
      }
      container priority-tagged {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:priority-tagged')" {
          description
            "Only applies when the type of the tagged interface is
             'priority-tagged'.";
        }
        description
          "Priority tagged container.";
        uses ac-common:priority-tagged;
      }
      container qinq {
        when "derived-from-or-self(../encap-type, "
           + "'vpn-common:qinq')" {
          description
            "Only applies when the type of the tagged interface is
             'QinQ'.";
        }
        description
          "Includes QinQ parameters.";
        uses ac-common:qinq;
        container tag-operations {
          description
            "Sets the tag manipulation policy for this AC. It defines
             a set of tag manipulations that allow for the insertion,
             removal, or rewriting of 802.1Q VLAN tags. These
             operations are indicated for the CE-PE direction.
             By default, tag operations are symmetric. As such, the
             reverse tag operation is assumed on the PE-CE 
             direction.";
          choice op-choice {
            description
              "Selects the tag rewriting policy for a AC.";
            leaf pop {
              type uint8 {
                range "1|2";
              }
              description
                "Pops one or two tags as a function of the indicated
                 pop value.";
            }
            leaf push {
              type empty;
              description
                "Pushes one or two tags defined by the tag-1 and 
                 tag-2 leaves. It is assumed that, absent any 
                 policy, the default value of 0 will be used for 
                 PCP setting.";
            }
            leaf translate {
              type uint8 {
                range "1|2";
              }
              description
                "Translates one or two outer tags. PCP bits are 
                 preserved. The following operations are supported:

                 - translate 1 with tag-1 leaf is provided: only the 
                   outermost tag is translated to the value in tag-1.

                 - translate 2 with both tag-1 and tag-2 leaves are 
                   provided: both outer and inner tags are translated
                   to the values in tag-1 and tag-2, respectively.

                 - translate 2 with tag-1 leaf is provided: the 
                   outer tag is popped while the inner tag is 
                   translated to the value in tag-1.";
            }
          }
          leaf tag-1 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A first tag to be used for push or translate 
               operations. This tag will be used as the outermost tag
               as a result of the tag operation.";
          }
          leaf tag-1-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:s-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-1.";
          }
          leaf tag-2 {
            when 'not(../pop)';
            type dot1q-types:vlanid;
            description
              "A second tag to be used for push or translate 
               operations.";
          }
          leaf tag-2-type {
            type dot1q-types:dot1q-tag-type;
            default "dot1q-types:c-vlan";
            description
              "Specifies a specific 802.1Q tag type of tag-2.";
          }
        }
      }
    }
    choice l2-service {
      description
        "The Layer 2 connectivity service can be provided by 
         indicating a pointer to an L2VPN or by specifying a Layer 2
         tunnel service.";
      container l2-tunnel-service {
        description
          "Defines a Layer 2 tunnel termination.";
        uses ac-common:l2-tunnel-service;
      }
      case l2vpn {
        leaf l2vpn-id {
          type vpn-common:vpn-id;
          description
            "Indicates the L2VPN service associated with an 
             Integrated Routing and Bridging (IRB) interface.";
        }
      }
    }
  }

  grouping l2-connection-if-ref {
    description
      "Specifies Layer 2 connection paramters with interface 
       references.";
    uses l2-connection;
    leaf l2-termination-point {
      type string;
      description
        "Specifies a reference to a local Layer 2 termination point,
         such as a Layer 2 sub-interface.";
    }
    leaf local-bridge-reference {
      type string;
      description
        "Specifies a local bridge reference to accommodate, e.g.,
         implementations that require internal bridging.
         A reference may be a local bridge domain.";
    }
    leaf bearer-reference {
      if-feature "vpn-common:bearer-reference";
      type string;
      description
        "This is an internal reference for the service provider to
         identify the bearer associated with this AC.";
    }
    container lag-interface {
      if-feature "vpn-common:lag-interface";
      description
        "Container for configuration of Link Aggregation Group (LAG)
         interface attributes.";
      leaf lag-interface-id {
        type string;
        description
          "LAG interface identifier.";
      }
      container member-link-list {
        description
          "Container for the member link list.";
        list member-link {
          key "name";
          description
            "Member link.";
          leaf name {
            type string;
            description
              "Member link name.";
          }
        }
      }
    }
  }

  // IPv4 connection groupings

  grouping ipv4-connection {
    description
      "IPv4-specific parameters.";
    leaf local-address {
      type inet:ipv4-address;
      description
        "The IP address used at the provider's interface.";
    }
    uses ac-common:ipv4-allocation-type;
    choice allocation-type {
      description
        "Choice of the IPv4 address allocation.";
      case dynamic {
        description
          "When the addresses are allocated by DHCP or other
           dynamic means local to the infrastructure.";
        choice address-assign {
          description
            "A choice for how IPv4 addresses are assigned.";
          case number {
            leaf number-of-dynamic-address {
              type uint16;
              description
                "Specifies the number of IP addresses to be  
                 assigned to the customer on this access.";
            }
          }
          case explicit {
            container customer-addresses {
              description
                "Container for customer addresses to be allocated
                 using DHCP.";
              list address-pool {
                key "pool-id";
                description
                  "Describes IP addresses to be dyncamically 
                   allocated.

                   When only 'start-address' is present, it 
                   represents a single address.

                   When both 'start-address' and 'end-address' are
                   specified, it implies a range inclusive of both
                   addresses.";
                leaf pool-id {
                  type string;
                  description
                    "A pool identifier for the address range from
                     'start-address' to 'end-address'.";
                }
                leaf start-address {
                  type inet:ipv4-address;
                  mandatory true;
                  description
                    "Indicates the first address in the pool.";
                }
                leaf end-address {
                  type inet:ipv4-address;
                  description
                    "Indicates the last address in the pool.";
                }
              }
            }
          }
        }
        choice provider-dhcp {
          description
            "Parameters related to DHCP-allocated addresses.
             IP addresses are allocated by DHCP, which is provided
             by the operator.";
          leaf dhcp-service-type {
            type enumeration {
              enum server {
                description
                  "Local DHCP server.";
              }
              enum relay {
                description
                  "Local DHCP relay.  DHCP requests are relayed to a
                   provider's server.";
              }
            }
            description
              "Indicates the type of DHCP service to be enabled on
               this access.";
          }
          choice service-type {
            description
              "Choice based on the DHCP service type.";
            case relay {
              description
                "Container for a list of the provider's DHCP servers
                 (i.e., 'dhcp-service-type' is set to 'relay').";
              leaf-list server-ip-address {
                type inet:ipv4-address;
                description
                  "IPv4 addresses of the provider's DHCP server, for
                   use by the local DHCP relay.";
              }
            }
          }
        }
        choice dhcp-relay {
          description
            "The DHCP relay is provided by the operator.";
          container customer-dhcp-servers {
            description
              "Container for a list of the customer's DHCP servers.";
            leaf-list server-ip-address {
              type inet:ipv4-address;
              description
                "IPv4 addresses of the customer's DHCP server.";
            }
          }
        }
      }
      case static-addresses {
        description
          "Lists the IPv4 addresses that are used.";
        list address {
          key "address-id";
          ordered-by user;
          description
            "Lists the IPv4 addresses that are used. The first 
             address of the list is the primary address of the 
             connection.";
          leaf address-id {
            type string;
            description
              "An identifier of the static IPv4 address.";
          }
          leaf customer-address {
            type inet:ipv4-address;
            description
              "An IPv4 address of the customer side.";
          }
        }
      }
    }
  }

  grouping ipv6-connection {
    description
      "IPv6-specific parameters.";
    leaf local-address {
      type inet:ipv6-address;
      description
        "IPv6 address of the provider side.";
    }
    uses ac-common:ipv6-allocation-type;
    choice allocation-type {
      description
        "Choice of the IPv6 address allocation.";
      case dynamic {
        description
          "When the addresses are allocated by DHCP or other
           dynamic means local to the infrastructure.";
        choice address-assign {
          description
            "A choice for how IPv6 addresses are assigned.";
          case number {
            leaf number-of-dynamic-address {
              type uint16;
              description
                "Specifies the number of IP addresses to be 
                 assigned to the customer on this access.";
            }
          }
          case explicit {
            container customer-addresses {
              description
                "Container for customer addresses to be allocated
                 using DHCP.";
              list address-pool {
                key "pool-id";
                description
                  "Describes IP addresses to be dyncamically 
                   allocated.

                   When only 'start-address' is present, it 
                   represents a single address.

                   When both 'start-address' and 'end-address' are
                   specified, it implies a range inclusive of both
                   addresses.";
                leaf pool-id {
                  type string;
                  description
                    "A pool identifier for the address range from
                     'start-address' to 'end-address'.";
                }
                leaf start-address {
                  type inet:ipv6-address;
                  mandatory true;
                  description
                    "Indicates the first address in the pool.";
                }
                leaf end-address {
                  type inet:ipv6-address;
                  description
                    "Indicates the last address in the pool.";
                }
              }
            }
          }
        }
        choice provider-dhcp {
          description
            "Parameters related to DHCP-allocated addresses.
             IP addresses are allocated by DHCP, which is provided
             by the operator.";
          leaf dhcp-service-type {
            type enumeration {
              enum server {
                description
                  "Local DHCP server.";
              }
              enum relay {
                description
                  "Local DHCP relay. DHCP requests are relayed to
                   a provider's server.";
              }
            }
            description
              "Indicates the type of DHCP service to
               be enabled on this access.";
          }
          choice service-type {
            description
              "Choice based on the DHCP service type.";
            case relay {
              description
                "Container for a list of the provider's DHCP servers
                 (i.e., 'dhcp-service-type' is set to 'relay').";
              leaf-list server-ip-address {
                type inet:ipv6-address;
                description
                  "IPv6 addresses of the provider's DHCP server, for
                   use by the local DHCP relay.";
              }
            }
          }
        }
        choice dhcp-relay {
          description
            "The DHCP relay is provided by the operator.";
          container customer-dhcp-servers {
            description
              "Container for a list of the customer's DHCP servers.";
            leaf-list server-ip-address {
              type inet:ipv6-address;
              description
                "IPv6 addresses of the customer's DHCP server.";
            }
          }
        }
      }
      case static-addresses {
        description
          "Lists the IPv4 addresses that are used.";
        list address {
          key "address-id";
          ordered-by user;
          description
            "Lists the IPv6 addresses that are used. The first 
             address of the list is the primary address of 
             the connection.";
          leaf address-id {
            type string;
            description
              "An identifier of the static IPv4 address.";
          }
          leaf customer-address {
            type inet:ipv6-address;
            description
              "An IPv6 address of the customer side.";
          }
        }
      }
    }
  }

  grouping ip-connection {
    description
      "Defines IP connection parameters.";
    leaf l3-termination-point {
      type string;
      description
        "Specifies a reference to a local Layer 3 termination point,
         such as a bridge domain interface.";
    }
    container ipv4 {
      if-feature "vpn-common:ipv4";
      description
        "IPv4-specific parameters.";
      uses ipv4-connection;
    }
    container ipv6 {
      if-feature "vpn-common:ipv6";
      description
        "IPv6-specific parameters.";
      uses ipv6-connection;
    }
  }

  /* Routing */
  //BGP base parameters

  grouping bgp-base {
    description
      "Configuration specific to BGP.";
    leaf description {
      type string;
      description
        "Includes a description of the BGP session. This description 
         is meant to be used for diagnostic purposes. The semantic 
         of the description is local to an implementation.";
    }
    uses rt-pol:apply-policy-group;
    leaf local-as {
      type inet:as-number;
      description
        "Indicates a local AS Number (ASN), if an ASN distinct from
         the ASN configured at the AC level is needed.";
    }
    leaf peer-as {
      type inet:as-number;
      mandatory true;
      description
        "Indicates the customer's ASN when the customer requests BGP
         routing.";
    }
    leaf address-family {
      type identityref {
        base vpn-common:address-family;
      }
      description
        "This node contains the address families to be activated.
         'dual-stack' means that both IPv4 and IPv6 will be
         activated.";
    }
    leaf multihop {
      type uint8;
      description
        "Describes the number of IP hops allowed between a given BGP
         neighbor and the PE.";
    }
    leaf as-override {
      type boolean;
      description
        "Defines whether ASN override is enabled, i.e., replacing the
         ASN of the customer specified in the AS_PATH attribute with
         the local ASN.";
    }
    leaf allow-own-as {
      type uint8;
      description
        "If set, specifies the maximum number of occurrences of the
         provider's ASN that are permitted within the AS_PATH
         before it is rejected.";
    }
    leaf prepend-global-as {
      type boolean;
      description
        "In some situations, the ASN that is provided at the node
         level may be distinct from the ASN configured at the AC.
         When such ASNs are provided, they are both prepended to the
         BGP route updates for this AC. To disable that behavior,
         'prepend-global-as' must be set to 'false'.  In such a
         case, the ASN that is provided at the node level is not
         prepended to the BGP route updates for this access.";
    }
    leaf send-default-route {
      type boolean;
      description
        "Defines whether default routes can be advertised to a peer.
         If set, the default routes are advertised to a peer.";
    }
    leaf site-of-origin {
      when "../address-family = 'vpn-common:ipv4' "
         + "or 'vpn-common:dual-stack'" {
        description
          "Only applies if IPv4 is activated.";
      }
      type rt-types:route-origin;
      description
        "The Site of Origin attribute is encoded as a Route Origin
         Extended Community. It is meant to uniquely identify the
         set of routes learned from a site via a particular AC and
         is used to prevent routing loops.";
      reference
        "RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs),
                   Section 7";
    }
    leaf ipv6-site-of-origin {
      when "../address-family = 'vpn-common:ipv6' "
         + "or 'vpn-common:dual-stack'" {
        description
          "Only applies if IPv6 is activated.";
      }
      type rt-types:ipv6-route-origin;
      description
        "The IPv6 Site of Origin attribute is encoded as an IPv6 
         Route Origin Extended Community.  It is meant to uniquely 
         identify the set of routes learned from a site.";
      reference
        "RFC 5701: IPv6 Address Specific BGP Extended Community
                   Attribute";
    }
    list redistribute-connected {
      key "address-family";
      description
        "Indicates, per address family, the policy to follow for
         connected routes.";
      leaf address-family {
        type identityref {
          base vpn-common:address-family;
        }
        description
          "Indicates the address family.";
      }
      leaf enable {
        type boolean;
        description
          "Enables the redistribution of connected routes.";
      }
    }
    container bgp-max-prefix {
      description
        "Controls the behavior when a prefix maximum is reached.";
      leaf max-prefix {
        type uint32;
        description
          "Indicates the maximum number of BGP prefixes allowed in 
           the BGP session.

           It allows control of how many prefixes can be received 
           from a neighbor.

           If the limit is exceeded, the action indicated in
           'violate-action' will be followed.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 8.2.2";
      }
      leaf warning-threshold {
        type decimal64 {
          fraction-digits 5;
          range "0..100";
        }
        units "percent";
        description
          "When this value is reached, a warning notification will be
           triggered.";
      }
      leaf violate-action {
        type enumeration {
          enum warning {
            description
              "Only a warning message is sent to the peer when the
               limit is exceeded.";
          }
          enum discard-extra-paths {
            description
              "Discards extra paths when the limit is exceeded.";
          }
          enum restart {
            description
              "The BGP session restarts after the indicated time
               interval.";
          }
        }
        description
          "If the BGP neighbor 'max-prefix' limit is reached, the 
           action indicated in 'violate-action' will be followed.";
      }
      leaf restart-timer {
        type uint32;
        units "seconds";
        description
          "Time interval after which the BGP session will be
           reestablished.";
      }
    }
    container bgp-timers {
      description
        "Includes two BGP timers.";
      leaf keepalive {
        type uint16 {
          range "0..21845";
        }
        units "seconds";
        description
          "This timer indicates the KEEPALIVE messages' frequency
           between a PE and a BGP peer.

           If set to '0', it indicates that KEEPALIVE messages are
           disabled.

           It is suggested that the maximum time between KEEPALIVE
           messages be one-third of the Hold Time interval.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 4.4";
      }
      leaf hold-time {
        type uint16 {
          range "0 | 3..65535";
        }
        units "seconds";
        description
          "Indicates the maximum number of seconds that may elapse
           between the receipt of successive KEEPALIVE and/or UPDATE
           messages from the peer.

           The Hold Time must be either zero or at least three
           seconds.";
        reference
          "RFC 4271: A Border Gateway Protocol 4 (BGP-4),
                     Section 4.2";
      }
    }
  }

  // RIP base parameters

  grouping rip-base {
    description
      "Configuration specific to RIP routing.";
    leaf address-family {
      type identityref {
        base vpn-common:address-family;
      }
      description
        "Indicates whether IPv4, IPv6, or both address families are
         to be activated.";
    }
    container timers {
      description
        "Indicates the RIP timers.";
      reference
        "RFC 2453: RIP Version 2";
      leaf update-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Indicates the RIP update time, i.e., the amount of time
           for which RIP updates are sent.";
      }
      leaf invalid-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "The interval before a route is declared invalid after no
           updates are received. This value is at least three times
           the value for the 'update-interval' argument.";
      }
      leaf holddown-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Specifies the interval before better routes are 
           released.";
      }
      leaf flush-interval {
        type uint16 {
          range "1..32767";
        }
        units "seconds";
        description
          "Indicates the RIP flush timer, i.e., the amount of time
           that must elapse before a route is removed from the
           routing table.";
      }
    }
    leaf default-metric {
      type uint8 {
        range "0..16";
      }
      description
        "Sets the default metric.";
    }
  }

  // routing profile

  grouping routing-profile {
    description
      "Defines routing protocols.";
    list routing-protocol {
      key "id";
      description
        "List of routing protocols used on the AC.";
      leaf id {
        type string;
        description
          "Unique identifier for the routing protocol.";
      }
      leaf type {
        type identityref {
          base vpn-common:routing-protocol-type;
        }
        description
          "Type of routing protocol.";
      }
      container bgp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:bgp-routing')" {
          description
            "Only applies when the protocol is BGP.";
        }
        description
          "Configuration specific to BGP.";
        uses bgp-base;
      }
      container ospf {
        when "derived-from-or-self(../type, "
           + "'vpn-common:ospf-routing')" {
          description
            "Only applies when the protocol is OSPF.";
        }
        description
          "Configuration specific to OSPF.";
        uses ac-common:ospf-basic;
        leaf max-lsa {
          type uint32 {
            range "1..4294967294";
          }
          description
            "Maximum number of allowed Link State Advertisements
             (LSAs) that the OSPF instance will accept.";
        }
      }
      container isis {
        when "derived-from-or-self(../type, "
           + "'vpn-common:isis-routing')" {
          description
            "Only applies when the protocol is IS-IS.";
        }
        description
          "Configuration specific to IS-IS.";
        uses ac-common:isis-basic;
        leaf level {
          type identityref {
            base vpn-common:isis-level;
          }
          description
            "Can be 'level-1', 'level-2', or 'level-1-2'.";
          reference
            "RFC 9181: A Common YANG Data Model for Layer 2 
                       and Layer 3 VPNs";
        }
        leaf metric {
          type uint16;
          description
            "Metric of the AC. It is used in the routing state
             calculation and path selection.";
        }
        leaf mode {
          type enumeration {
            enum active {
              description
                "The interface sends or receives IS-IS protocol
                 control packets.";
            }
            enum passive {
              description
                "Suppresses the sending of IS-IS updates through the
                 specified interface.";
            }
          }
          description
            "IS-IS interface mode type.";
        }
      }
      container rip {
        when "derived-from-or-self(../type, "
           + "'vpn-common:rip-routing')" {
          description
            "Only applies when the protocol is RIP.";
        }
        description
          "Configuration specific to RIP routing.";
        uses rip-base;
      }
      container vrrp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:vrrp-routing')" {
          description
            "Only applies when the protocol is the Virtual Router
             Redundancy Protocol (VRRP).";
        }
        description
          "Configuration specific to VRRP.";
        reference
          "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6";
        leaf address-family {
          type identityref {
            base vpn-common:address-family;
          }
          description
            "Indicates whether IPv4, IPv6, or both address families
             are to be enabled.";
        }
        leaf ping-reply {
          type boolean;
          description
            "Controls whether the VRRP speaker should reply to ping
             requests.";
        }
      }
    }
  }

  grouping routing {
    description
      "Defines routing protocols.";
    list routing-protocol {
      key "id";
      description
        "List of routing protocols used on the AC.";
      leaf id {
        type string;
        description
          "Unique identifier for the routing protocol.";
      }
      leaf type {
        type identityref {
          base vpn-common:routing-protocol-type;
        }
        description
          "Type of routing protocol.";
      }
      list routing-profiles {
        key "id";
        description
          "Routing profiles.";
        leaf id {
          type routing-profile-reference;
          description
            "Routing profile to be used.";
        }
        leaf type {
          type identityref {
            base vpn-common:ie-type;
          }
          description
            "Import, export, or both.";
        }
      }
      container static {
        when "derived-from-or-self(../type, "
           + "'vpn-common:static-routing')" {
          description
            "Only applies when the protocol is a static routing
             protocol.";
        }
        description
          "Configuration specific to static routing.";
        container cascaded-lan-prefixes {
          description
            "LAN prefixes from the customer.";
          list ipv4-lan-prefixes {
            if-feature "vpn-common:ipv4";
            key "lan next-hop";
            description
              "List of LAN prefixes for the site.";
            uses ac-common:ipv4-static-rtg-entry;
            leaf bfd-enable {
              if-feature "vpn-common:bfd";
              type boolean;
              description
                "Enables BFD.";
            }
            leaf preference {
              type uint32;
              description
                "Indicates the preference associated with the static
                 route.";
            }
            uses vpn-common:service-status;
          }
          list ipv6-lan-prefixes {
            if-feature "vpn-common:ipv6";
            key "lan next-hop";
            description
              "List of LAN prefixes for the site.";
            uses ac-common:ipv4-static-rtg-entry;
            leaf bfd-enable {
              if-feature "vpn-common:bfd";
              type boolean;
              description
                "Enables BFD.";
            }
            leaf preference {
              type uint32;
              description
                "Indicates the preference associated with the static
                 route.";
            }
            uses vpn-common:service-status;
          }
        }
      }
      container bgp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:bgp-routing')" {
          description
            "Only applies when the protocol is BGP.";
        }
        description
          "Configuration specific to BGP.";
        container peer-groups {
          description
            "Configuration for BGP peer-groups";
          list peer-group {
            key "name";
            description
              "List of BGP peer-groups configured on the local 
               system - uniquely identified by peer-group name";
            leaf name {
              type string;
              description
                "Name of the BGP peer-group";
            }
            leaf local-address {
              type union {
                type inet:ip-address;
                type if:interface-ref;
              }
              description
                "Sets the local IP address to use for the BGP 
                 transport session. This may be expressed as either 
                 an IP address or a reference to an interface.";
            }
            uses bgp-base;
            uses ac-common:bgp-authentication;
          }
        }
        list neighbor {
          key "remote-address";
          description
            "List of BGP neighbors.";
          leaf remote-address {
            type inet:ip-address;
            description
              "The remote IP address of this entry's BGP peer.";
          }
          leaf local-address {
            type union {
              type inet:ip-address;
              type if:interface-ref;
            }
            description
              "Sets the local IP address to use for
               the BGP transport session.  This may be
               expressed as either an IP address or a
               reference to an interface.";
          }
          leaf peer-group {
            type leafref {
              path "../../peer-groups/peer-group/name";
            }
            description
              "The peer-group with which this neighbor is
               associated.";
          }
          uses bgp-base;
          uses ac-common:bgp-authentication;
          uses vpn-common:service-status;
        }
      }
      container ospf {
        when "derived-from-or-self(../type, "
           + "'vpn-common:ospf-routing')" {
          description
            "Only applies when the protocol is OSPF.";
        }
        description
          "Configuration specific to OSPF.";
        uses ac-common:ospf-basic;
        container sham-links {
          if-feature "vpn-common:rtg-ospf-sham-link";
          description
            "List of sham links.";
          reference
            "RFC 4577: OSPF as the Provider/Customer Edge Protocol
                       for BGP/MPLS IP Virtual Private Networks
                       (VPNs), Section 4.2.7
             RFC 6565: OSPFv3 as a Provider Edge to Customer Edge
                       (PE-CE) Routing Protocol, Section 5";
          list sham-link {
            key "target-site";
            description
              "Creates a sham link with another
               site.";
            leaf target-site {
              type string;
              description
                "Target site for the sham link connection. The site
                 is referred to by its identifier.";
            }
            leaf metric {
              type uint16;
              description
                "Metric of the sham link. It is used in the routing
                 state calculation and path selection.";
              reference
                "RFC 4577: OSPF as the Provider/Customer Edge 
                           Protocol for BGP/MPLS IP Virtual Private
                           Networks (VPNs), Section 4.2.7.3
                 RFC 6565: OSPFv3 as a Provider Edge to Customer Edge
                           (PE-CE) Routing Protocol, Section 5.2";
            }
          }
        }
        leaf max-lsa {
          type uint32 {
            range "1..4294967294";
          }
          description
            "Maximum number of allowed Link State Advertisements
             (LSAs) that the OSPF instance will accept.";
        }
        uses ac-common:ospf-authentication;
        uses vpn-common:service-status;
      }
      container isis {
        when "derived-from-or-self(../type, "
           + "'vpn-common:isis-routing')" {
          description
            "Only applies when the protocol is
             IS-IS.";
        }
        description
          "Configuration specific to IS-IS.";
        uses ac-common:isis-basic;
        leaf level {
          type identityref {
            base vpn-common:isis-level;
          }
          description
            "Can be 'level-1', 'level-2', or 'level-1-2'.";
          reference
            "RFC 9181: A Common YANG Data Model for Layer 2 and
                       Layer 3 VPNs";
        }
        leaf metric {
          type uint16;
          description
            "Metric of the PE-CE link. It is used in the routing 
             state calculation and path selection.";
        }
        leaf mode {
          type enumeration {
            enum active {
              description
                "The interface sends or receives
                 IS-IS protocol control packets.";
            }
            enum passive {
              description
                "Suppresses the sending of IS-IS
                 updates through the specified
                 interface.";
            }
          }
          description
            "IS-IS interface mode type.";
        }
        uses ac-common:isis-authentication;
        uses vpn-common:service-status;
      }
      container rip {
        when "derived-from-or-self(../type, "
           + "'vpn-common:rip-routing')" {
          description
            "Only applies when the protocol is RIP.
             For IPv4, the model assumes that RIP
             version 2 is used.";
        }
        description
          "Configuration specific to RIP routing.";
        uses rip-base;
        uses ac-common:rip-authentication;
        uses vpn-common:service-status;
      }
      container vrrp {
        when "derived-from-or-self(../type, "
           + "'vpn-common:vrrp-routing')" {
          description
            "Only applies when the protocol is the VRRP.";
        }
        description
          "Configuration specific to VRRP.";
        reference
          "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                     Version 3 for IPv4 and IPv6";
        leaf address-family {
          type identityref {
            base vpn-common:address-family;
          }
          description
            "Indicates whether IPv4, IPv6, or both address families
             are to be enabled.";
        }
        leaf vrrp-group {
          type uint8 {
            range "1..255";
          }
          description
            "Includes the VRRP group identifier.";
        }
        leaf backup-peer {
          type inet:ip-address;
          description
            "Indicates the IP address of the peer.";
        }
        leaf-list virtual-ip-address {
          type inet:ip-address;
          description
            "Virtual IP addresses for a single VRRP
             group.";
          reference
            "RFC 5798: Virtual Router Redundancy Protocol (VRRP)
                       Version 3 for IPv4 and IPv6, Sections 1.2
                       and 1.3";
        }
        leaf priority {
          type uint8 {
            range "1..254";
          }
          description
            "Sets the local priority of the VRRP speaker.";
        }
        leaf ping-reply {
          type boolean;
          description
            "Controls whether the VRRP speaker should reply to ping
             requests.";
        }
        uses vpn-common:service-status;
      }
    }
  }

  // OAM

  grouping bfd {
    description
      "Grouping for BFD.";
    leaf session-type {
      type identityref {
        base vpn-common:bfd-session-type;
      }
      description
        "Specifies the BFD session type.";
    }
    leaf desired-min-tx-interval {
      type uint32;
      units "microseconds";
      description
        "The minimum interval between transmissions of BFD Control
         packets, as desired by the operator.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf required-min-rx-interval {
      type uint32;
      units "microseconds";
      description
        "The minimum interval between received BFD Control packets 
         that the PE should support.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf local-multiplier {
      type uint8 {
        range "1..255";
      }
      description
        "Specifies the detection multiplier that is transmitted to a
         BFD peer.

         The detection interval for the receiving BFD peer is
         calculated by multiplying the value of the negotiated
         transmission interval by the received detection multiplier
         value.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.7";
    }
    leaf holdtime {
      type uint32;
      units "milliseconds";
      description
        "Expected BFD holdtime.

         The customer may impose some fixed values for the holdtime
         period if the provider allows the customer to use this
         function.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
                   Section 6.8.18";
    }
  }

  // OAM

  grouping oam {
    description
      "Defines the Operations, Administration, and Maintenance
       (OAM) mechanisms used.";
    container bfd {
      description
        "Container for BFD.";
      leaf profile {
        type bfd-profile-reference;
        description
          "Well-known service provider profile name.";
      }
      uses bfd;
      container authentication {
        presence "Enables BFD authentication";
        description
          "Parameters for BFD authentication.";
        leaf key-chain {
          type key-chain:key-chain-ref;
          description
            "Name of the key chain.";
        }
        leaf meticulous {
          type boolean;
          description
            "Enables meticulous mode.";
          reference
            "RFC 5880: Bidirectional Forwarding Detection (BFD),
                       Section 6.7";
        }
      }
      uses vpn-common:service-status;
    }
  }

  // security

  grouping security {
    description
      "Security parameters for an AC.";
    container encryption {
      if-feature "vpn-common:encryption";
      description
        "Container for AC encryption.";
      leaf enabled {
        type boolean;
        description
          "If set to 'true', traffic encryption on the connection is
           required. Otherwise, it is disabled.";
      }
      leaf layer {
        when "../enabled = 'true'" {
          description
            "Included only when encryption is enabled.";
        }
        type enumeration {
          enum layer2 {
            description
              "Encryption occurs at Layer 2.";
          }
          enum layer3 {
            description
              "Encryption occurs at Layer 3. For example, IPsec
               may be used when a customer requests Layer 3
               encryption.";
          }
        }
        description
          "Indicates the layer on which encryption is applied.";
      }
    }
    container encryption-profile {
      when "../encryption/enabled = 'true'" {
        description
          "Indicates the layer on which encryption is enabled.";
      }
      description
        "Container for the encryption profile.";
      choice profile {
        description
          "Choice for the encryption profile.";
        case provider-profile {
          leaf profile-name {
            type encryption-profile-reference;
            description
              "Name of the provider's profile to be applied.";
          }
        }
        case customer-profile {
          leaf customer-key-chain {
            type key-chain:key-chain-ref;
            description
              "Customer-supplied key chain.";
          }
        }
      }
    }
  }

  // AC profile

  grouping ac-profile {
    description
      "Grouping for attachment circuit profiles.";
    container l2-connection {
      description
        "Defines Layer 2 protocols and parameters that
         are required to enable AC connectivity.";
      //uses l2-connection;
    }
    container ip-connection {
      description
        "Defines IP connection parameters.";
      //uses l3-connection;
    }
    container routing-protocols {
      description
        "Defines routing protocols.";
      uses routing-profile;
    }
    container oam {
      description
        "Defines the OAM mechanisms used for the AC profile.";
      container bfd {
        if-feature "vpn-common:bfd";
        description
          "Container for BFD.";
        uses bfd;
      }
    }
  }

  //AC network provisioning 

  grouping ac {
    description
      "Grouping for attachment circuits.";
    leaf description {
      type string;
      description
        "Associates a description with an AC.";
    }
    container l2-connection {
      description
        "Defines Layer 2 protocols and parameters that are required
         to enable AC connectivity.";
      uses l2-connection-if-ref;
    }
    container ip-connection {
      description
        "Defines IP connection parameters.";
      uses ip-connection;
    }
    container routing-protocols {
      description
        "Defines routing protocols.";
      uses routing;
    }
    container oam {
      description
        "Defines the OAM mechanisms used for the AC.";
      uses oam;
    }
    container security {
      description
        "AC-specific security parameters.";
      uses security;
    }
    container service {
      description
        "AC-specific bandwith parameters.";
      leaf mtu {
        type uint32;
        units "bytes";
        description
          "Layer 2 MTU.";
      }
      uses ac-svc:bandwidth;
      container qos {
        if-feature "vpn-common:qos";
        description
          "QoS configuration.";
        container qos-profiles {
          description
            "QoS profile configuration.";
          list qos-profile {
            key "profile";
            description
              "Points to a QoS profile.";
            leaf profile {
              type qos-profile-reference;
              description
                "QoS profile to be used.";
            }
            leaf direction {
              type identityref {
                base vpn-common:qos-profile-direction;
              }
              description
                "The direction to which the QoS profile
                 is applied.";
            }
          }
        }
      }
      container access-control-list {
        description
          "Container for the Access Control List (ACL).";
        container acl-profiles {
          description
            "ACL profile configuration.";
          list acl-profile {
            key "profile";
            description
              "Points to an ACL profile.";
            leaf profile {
              type forwarding-profile-reference;
              description
                "Forwarding profile to be used.";
            }
          }
        }
      }
    }
  }

  augment "/nw:networks/nw:network" {
    description
      "Add a list of profiles.";
    container specific-provisioning-profiles {
      description
        "Contains a set of valid profiles to reference in the AC
         activation.";
      uses ac-common:ac-profile-cfg;
    }
    list ac-profile {
      key "name";
      description
        "Specifies a list of AC profiles.";
      leaf name {
        type string;
        description
          "Name of the AC.";
      }
      uses ac-ntw:ac-profile;
    }
  }

  augment "/nw:networks/nw:network/nw:node"
        + "/sap:service/sap:sap" {
    when '../../../nw:network-types/sap:sap-network' {
      description
        "Augmentation parameters apply only for SAP networks.";
    }
    description
      "Augments SAPs with AC provisioning details.";
    list ac {
      key "name";
      description
        "List of ACs.";
      leaf name {
        type string;
        description
          "A name that identifies the AC locally.";
      }
      leaf ac-svc-ref {
        type ac-svc:attachment-circuit-reference;
        description
          "A reference to the AC as exposed at the service level.";
      }
      list ac-profile {
        key "profile-id";
        description
          "List of AC profiles.";
        leaf profile-id {
          type ac-profile-reference;
          description
            "A reference to an AC profile.";
        }
      }
      leaf ac-parent-ref {
        type ac-ntw:attachment-circuit-reference;
        description
          "Specifies the parent AC that is inherited by an AC.
           Parent ACs are used, e.g., in contexts where multiple
           CEs are terminating the same AC, but some specific
           information is required for each peer SAP.";
      }
      leaf-list peer-sap-id {
        type string;
        description
          "One or more peer SAPs can be indicated.";
      }
      list group {
        key "group-id";
        description
          "List of group-ids.";
        leaf group-id {
          type string;
          description
            "Indicates the group-id to which the AC belongs.";
        }
        leaf precedence {
          type identityref {
            base ac-common:precedence-type;
          }
          description
            "Defines redundancy of an AC.";
        }
      }
      uses vpn-common:service-status;
      uses ac-ntw:ac;
    }
  }
}
<CODE ENDS>
]]></sourcecode>
    </section>
    <section anchor="security-considerations">
      <name>Security Considerations</name>
      <t>The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF <xref target="RFC6241"/> or RESTCONF <xref target="RFC8040"/>.  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) <xref target="RFC6242"/>.  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   <xref target="RFC8446"/>.</t>
      <t>The Network Configuration Access Control Model (NACM) <xref target="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.</t>
      <t>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)
   and delete operations to these data nodes without proper protection
   or authentication can have a negative effect on network operations.
   These are the subtrees and data nodes and their sensitivity/
   vulnerability in the "ietf-ac-ntw" module:</t>
      <dl>
        <dt>'specific-provisioning-profiles':</dt>
        <dd>
          <t>This container includes a set of sensitive data that
 influence how an AC is delivered.  For example, an
 attacker who has access to these data nodes may be able to
 manipulate routing policies, QoS policies, or encryption
 properties. These data nodes are defined with "nacm:default-deny-
 write" tagging <xref target="I-D.ietf-opsawg-teas-common-ac"/>.</t>
        </dd>
        <dt>'ac':</dt>
        <dd>
          <t>An attacker who is able to access network nodes can
 undertake various attacks, such as modify the attributes of an AC (e.g.,
 QoS, bandwidth, routing protocols, keying material), leading to
 malfunctioning of services that are delivered over that AC and therefore to Service Level
 Agreement (SLA) violations.  In addition, an attacker could
 attempt to add a new AC.
    : In addition to using NACM to prevent unauthorized access, such
 activity can be detected by adequately monitoring and tracking
 network configuration changes.</t>
        </dd>
      </dl>
      <t>Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  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 in the "ietf-ac-svc" module:</t>
      <dl>
        <dt>'ac':</dt>
        <dd>
          <t>Unauthorized access to this subtree can disclose the identity
 of a customer 'peer-sap-id'.</t>
        </dd>
        <dt>'l2-connection' and 'ip-connection':</dt>
        <dd>
          <t>An attacker can retrieve
privacy-related information, which can be used to track a
customer.  Disclosing such information may be considered a
violation of the customer-provider trust relationship.</t>
        </dd>
        <dt>'keying-material':</dt>
        <dd>
          <t>An attacker can retrieve the cryptographic keys
protecting an AC (routing, in particular). These keys could
be used to inject spoofed routing  advertisements.</t>
        </dd>
      </dl>
      <t>Several data nodes ('bgp', 'ospf', 'isis', and 'rip') rely upon <xref target="RFC8177"/> for authentication purposes. As such, the AC network module inherits the security considerations discussed in Section 5 of <xref target="RFC8177"/>. Also, these data nodes support supplying explicit keys as strings in ASCII format. The use of keys in hexadecimal string format would afford greater key entropy with the same number of key-string octets. However, such a format is not included in this version of the AC network model, because it is not supported by the underlying device modules (e.g., <xref target="RFC8695"/>).</t>
    </section>
    <section anchor="iana-considerations">
      <name>IANA Considerations</name>
      <t>IANA is requested to register the following URI in the "ns" subregistry within
   the "IETF XML Registry" <xref target="RFC3688"/>:</t>
      <artwork><![CDATA[
   URI:  urn:ietf:params:xml:ns:yang:ietf-ac-ntw
   Registrant Contact:  The IESG.
   XML:  N/A; the requested URI is an XML namespace.
]]></artwork>
      <t>IANA is requested to register the following YANG module in the "YANG Module
   Names" subregistry <xref target="RFC6020"/> within the "YANG Parameters" registry:</t>
      <artwork><![CDATA[
   Name:  ietf-ac-ntw
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-ac-ntw
   Prefix:  ac-ntw
   Maintained by IANA?  N
   Reference:  RFC XXXX
]]></artwork>
    </section>
  </middle>
  <back>
    <references>
      <name>References</name>
      <references anchor="sec-normative-references">
        <name>Normative References</name>
        <reference anchor="IEEE802.1Qcp" target="https://doi.org/10.1109/IEEESTD.2018.8467507">
          <front>
            <title>IEEE Standard for Local and metropolitan area networks--Bridges and Bridged Networks--Amendment 30: YANG Data Model</title>
            <author>
              <organization>IEEE</organization>
            </author>
            <date year="2018" month="September"/>
          </front>
        </reference>
        <reference anchor="I-D.ietf-opsawg-teas-attachment-circuit">
          <front>
            <title>YANG Data Models for 'Attachment Circuits'-as-a-Service (ACaaS)</title>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization>Orange</organization>
            </author>
            <author fullname="Richard Roberts" initials="R." surname="Roberts">
              <organization>Juniper</organization>
            </author>
            <author fullname="Oscar Gonzalez de Dios" initials="O. G." surname="de Dios">
              <organization>Telefonica</organization>
            </author>
            <author fullname="Samier Barguil" initials="S." surname="Barguil">
              <organization>Nokia</organization>
            </author>
            <author fullname="Bo Wu" initials="B." surname="Wu">
              <organization>Huawei Technologies</organization>
            </author>
            <date day="27" month="November" year="2023"/>
            <abstract>
              <t>   This document specifies a YANG service data model for Attachment
   Circuits (ACs).  This model can be used for the provisioning of ACs
   before or during service provisioning (e.g., Network Slice Service).
   The document also specifies a service model for managing bearers over
   which ACs are established.

   Also, the document specifies a set of reusable groupings.  Whether
   other service models reuse structures defined in the AC models or
   simply include an AC reference is a design choice of these service
   models.  Utilizing the AC service model to manage ACs over which a
   service is delivered has the advantage of decoupling service
   management from upgrading AC components to incorporate recent AC
   technologies or features.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-opsawg-teas-attachment-circuit-02"/>
        </reference>
        <reference anchor="RFC9182">
          <front>
            <title>A YANG Network Data Model for Layer 3 VPNs</title>
            <author fullname="S. Barguil" initials="S." surname="Barguil"/>
            <author fullname="O. Gonzalez de Dios" initials="O." role="editor" surname="Gonzalez de Dios"/>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="L. Munoz" initials="L." surname="Munoz"/>
            <author fullname="A. Aguado" initials="A." surname="Aguado"/>
            <date month="February" year="2022"/>
            <abstract>
              <t>As a complement to the Layer 3 Virtual Private Network Service Model (L3SM), which is used for communication between customers and service providers, this document defines an L3VPN Network Model (L3NM) that can be used for the provisioning of Layer 3 Virtual Private Network (L3VPN) services within a service provider network. The model provides a network-centric view of L3VPN services.</t>
              <t>The L3NM is meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices. The model can also facilitate communication between a service orchestrator and a network controller/orchestrator.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9182"/>
          <seriesInfo name="DOI" value="10.17487/RFC9182"/>
        </reference>
        <reference anchor="RFC9291">
          <front>
            <title>A YANG Network Data Model for Layer 2 VPNs</title>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="O. Gonzalez de Dios" initials="O." role="editor" surname="Gonzalez de Dios"/>
            <author fullname="S. Barguil" initials="S." surname="Barguil"/>
            <author fullname="L. Munoz" initials="L." surname="Munoz"/>
            <date month="September" year="2022"/>
            <abstract>
              <t>This document defines an L2VPN Network Model (L2NM) that can be used to manage the provisioning of Layer 2 Virtual Private Network (L2VPN) services within a network (e.g., a service provider network). The L2NM complements the L2VPN Service Model (L2SM) by providing a network-centric view of the service that is internal to a service provider. The L2NM is particularly meant to be used by a network controller to derive the configuration information that will be sent to relevant network devices.</t>
              <t>Also, this document defines a YANG module to manage Ethernet segments and the initial versions of two IANA-maintained modules that include a set of identities of BGP Layer 2 encapsulation types and pseudowire types.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9291"/>
          <seriesInfo name="DOI" value="10.17487/RFC9291"/>
        </reference>
        <reference anchor="RFC9408">
          <front>
            <title>A YANG Network Data Model for Service Attachment Points (SAPs)</title>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="O. Gonzalez de Dios" initials="O." surname="Gonzalez de Dios"/>
            <author fullname="S. Barguil" initials="S." surname="Barguil"/>
            <author fullname="Q. Wu" initials="Q." surname="Wu"/>
            <author fullname="V. Lopez" initials="V." surname="Lopez"/>
            <date month="June" year="2023"/>
            <abstract>
              <t>This document defines a YANG data model for representing an abstract view of the provider network topology that contains the points from which its services can be attached (e.g., basic connectivity, VPN, network slices). Also, the model can be used to retrieve the points where the services are actually being delivered to customers (including peer networks).</t>
              <t>This document augments the 'ietf-network' data model defined in RFC 8345 by adding the concept of Service Attachment Points (SAPs). The SAPs are the network reference points to which network services, such as Layer 3 Virtual Private Network (L3VPN) or Layer 2 Virtual Private Network (L2VPN), can be attached. One or multiple services can be bound to the same SAP. Both User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) are supported in the SAP data model.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9408"/>
          <seriesInfo name="DOI" value="10.17487/RFC9408"/>
        </reference>
        <reference anchor="I-D.ietf-opsawg-teas-common-ac">
          <front>
            <title>A Common YANG Data Model for Attachment Circuits</title>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization>Orange</organization>
            </author>
            <author fullname="Richard Roberts" initials="R." surname="Roberts">
              <organization>Juniper</organization>
            </author>
            <author fullname="Oscar Gonzalez de Dios" initials="O. G." surname="de Dios">
              <organization>Telefonica</organization>
            </author>
            <author fullname="Samier Barguil" initials="S." surname="Barguil">
              <organization>Nokia</organization>
            </author>
            <author fullname="Bo Wu" initials="B." surname="Wu">
              <organization>Huawei Technologies</organization>
            </author>
            <date day="28" month="November" year="2023"/>
            <abstract>
              <t>   The document specifies a common Attachment Circuits (ACs) YANG
   module, which is designed with the intent to be reusable by other
   models.  For example, this common model can be reused by service
   models to expose ACs as a service, service models that require
   binding a service to a set of ACs, network and device models to
   provision ACs, etc.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-opsawg-teas-common-ac-02"/>
        </reference>
        <reference anchor="RFC8342">
          <front>
            <title>Network Management Datastore Architecture (NMDA)</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="P. Shafer" initials="P." surname="Shafer"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8342"/>
          <seriesInfo name="DOI" value="10.17487/RFC8342"/>
        </reference>
        <reference anchor="RFC2119">
          <front>
            <title>Key words for use in RFCs to Indicate Requirement Levels</title>
            <author fullname="S. Bradner" initials="S." surname="Bradner"/>
            <date month="March" year="1997"/>
            <abstract>
              <t>In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC8174">
          <front>
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
            <author fullname="B. Leiba" initials="B." surname="Leiba"/>
            <date month="May" year="2017"/>
            <abstract>
              <t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
        <reference anchor="RFC9181">
          <front>
            <title>A Common YANG Data Model for Layer 2 and Layer 3 VPNs</title>
            <author fullname="S. Barguil" initials="S." surname="Barguil"/>
            <author fullname="O. Gonzalez de Dios" initials="O." role="editor" surname="Gonzalez de Dios"/>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="Q. Wu" initials="Q." surname="Wu"/>
            <date month="February" year="2022"/>
            <abstract>
              <t>This document defines a common YANG module that is meant to be reused by various VPN-related modules such as Layer 3 VPN and Layer 2 VPN network models.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9181"/>
          <seriesInfo name="DOI" value="10.17487/RFC9181"/>
        </reference>
        <reference anchor="RFC5880">
          <front>
            <title>Bidirectional Forwarding Detection (BFD)</title>
            <author fullname="D. Katz" initials="D." surname="Katz"/>
            <author fullname="D. Ward" initials="D." surname="Ward"/>
            <date month="June" year="2010"/>
            <abstract>
              <t>This document describes a protocol intended to detect faults in the bidirectional path between two forwarding engines, including interfaces, data link(s), and to the extent possible the forwarding engines themselves, with potentially very low latency. It operates independently of media, data protocols, and routing protocols. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5880"/>
          <seriesInfo name="DOI" value="10.17487/RFC5880"/>
        </reference>
        <reference anchor="RFC8077">
          <front>
            <title>Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)</title>
            <author fullname="L. Martini" initials="L." role="editor" surname="Martini"/>
            <author fullname="G. Heron" initials="G." role="editor" surname="Heron"/>
            <date month="February" year="2017"/>
            <abstract>
              <t>Layer 2 services (such as Frame Relay, Asynchronous Transfer Mode, and Ethernet) can be emulated over an MPLS backbone by encapsulating the Layer 2 Protocol Data Units (PDUs) and then transmitting them over pseudowires (PWs). It is also possible to use pseudowires to provide low-rate Time-Division Multiplexed and Synchronous Optical NETworking circuit emulation over an MPLS-enabled network. This document specifies a protocol for establishing and maintaining the pseudowires, using extensions to the Label Distribution Protocol (LDP). Procedures for encapsulating Layer 2 PDUs are specified in other documents.</t>
              <t>This document is a rewrite of RFC 4447 for publication as an Internet Standard.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="84"/>
          <seriesInfo name="RFC" value="8077"/>
          <seriesInfo name="DOI" value="10.17487/RFC8077"/>
        </reference>
        <reference anchor="RFC9067">
          <front>
            <title>A YANG Data Model for Routing Policy</title>
            <author fullname="Y. Qu" initials="Y." surname="Qu"/>
            <author fullname="J. Tantsura" initials="J." surname="Tantsura"/>
            <author fullname="A. Lindem" initials="A." surname="Lindem"/>
            <author fullname="X. Liu" initials="X." surname="Liu"/>
            <date month="October" year="2021"/>
            <abstract>
              <t>This document defines a YANG data model for configuring and managing routing policies in a vendor-neutral way. The model provides a generic routing policy framework that can be extended for specific routing protocols using the YANG 'augment' mechanism.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9067"/>
          <seriesInfo name="DOI" value="10.17487/RFC9067"/>
        </reference>
        <reference anchor="RFC4364">
          <front>
            <title>BGP/MPLS IP Virtual Private Networks (VPNs)</title>
            <author fullname="E. Rosen" initials="E." surname="Rosen"/>
            <author fullname="Y. Rekhter" initials="Y." surname="Rekhter"/>
            <date month="February" year="2006"/>
            <abstract>
              <t>This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers. This method uses a "peer model", in which the customers' edge routers (CE routers) send their routes to the Service Provider's edge routers (PE routers); there is no "overlay" visible to the customer's routing algorithm, and CE routers at different sites do not peer with each other. Data packets are tunneled through the backbone, so that the core routers do not need to know the VPN routes. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4364"/>
          <seriesInfo name="DOI" value="10.17487/RFC4364"/>
        </reference>
        <reference anchor="RFC5701">
          <front>
            <title>IPv6 Address Specific BGP Extended Community Attribute</title>
            <author fullname="Y. Rekhter" initials="Y." surname="Rekhter"/>
            <date month="November" year="2009"/>
            <abstract>
              <t>Current specifications of BGP Extended Communities (RFC 4360) support the IPv4 Address Specific Extended Community, but do not support an IPv6 Address Specific Extended Community. The lack of an IPv6 Address Specific Extended Community may be a problem when an application uses the IPv4 Address Specific Extended Community, and one wants to use this application in a pure IPv6 environment. This document defines a new BGP attribute, the IPv6 Address Specific Extended Community, that addresses this problem. The IPv6 Address Specific Extended Community is similar to the IPv4 Address Specific Extended Community, except that it carries an IPv6 address rather than an IPv4 address. [STANDARDS TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5701"/>
          <seriesInfo name="DOI" value="10.17487/RFC5701"/>
        </reference>
        <reference anchor="RFC4271">
          <front>
            <title>A Border Gateway Protocol 4 (BGP-4)</title>
            <author fullname="Y. Rekhter" initials="Y." role="editor" surname="Rekhter"/>
            <author fullname="T. Li" initials="T." role="editor" surname="Li"/>
            <author fullname="S. Hares" initials="S." role="editor" surname="Hares"/>
            <date month="January" year="2006"/>
            <abstract>
              <t>This document discusses the Border Gateway Protocol (BGP), which is an inter-Autonomous System routing protocol.</t>
              <t>The primary function of a BGP speaking system is to exchange network reachability information with other BGP systems. This network reachability information includes information on the list of Autonomous Systems (ASes) that reachability information traverses. This information is sufficient for constructing a graph of AS connectivity for this reachability from which routing loops may be pruned, and, at the AS level, some policy decisions may be enforced.</t>
              <t>BGP-4 provides a set of mechanisms for supporting Classless Inter-Domain Routing (CIDR). These mechanisms include support for advertising a set of destinations as an IP prefix, and eliminating the concept of network "class" within BGP. BGP-4 also introduces mechanisms that allow aggregation of routes, including aggregation of AS paths.</t>
              <t>This document obsoletes RFC 1771. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4271"/>
          <seriesInfo name="DOI" value="10.17487/RFC4271"/>
        </reference>
        <reference anchor="RFC5925">
          <front>
            <title>The TCP Authentication Option</title>
            <author fullname="J. Touch" initials="J." surname="Touch"/>
            <author fullname="A. Mankin" initials="A." surname="Mankin"/>
            <author fullname="R. Bonica" initials="R." surname="Bonica"/>
            <date month="June" year="2010"/>
            <abstract>
              <t>This document specifies the TCP Authentication Option (TCP-AO), which obsoletes the TCP MD5 Signature option of RFC 2385 (TCP MD5). TCP-AO specifies the use of stronger Message Authentication Codes (MACs), protects against replays even for long-lived TCP connections, and provides more details on the association of security with TCP connections than TCP MD5. TCP-AO is compatible with either a static Master Key Tuple (MKT) configuration or an external, out-of-band MKT management mechanism; in either case, TCP-AO also protects connections when using the same MKT across repeated instances of a connection, using traffic keys derived from the MKT, and coordinates MKT changes between endpoints. The result is intended to support current infrastructure uses of TCP MD5, such as to protect long-lived connections (as used, e.g., in BGP and LDP), and to support a larger set of MACs with minimal other system and operational changes. TCP-AO uses a different option identifier than TCP MD5, even though TCP-AO and TCP MD5 are never permitted to be used simultaneously. TCP-AO supports IPv6, and is fully compatible with the proposed requirements for the replacement of TCP MD5. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5925"/>
          <seriesInfo name="DOI" value="10.17487/RFC5925"/>
        </reference>
        <reference anchor="RFC8177">
          <front>
            <title>YANG Data Model for Key Chains</title>
            <author fullname="A. Lindem" initials="A." role="editor" surname="Lindem"/>
            <author fullname="Y. Qu" initials="Y." surname="Qu"/>
            <author fullname="D. Yeung" initials="D." surname="Yeung"/>
            <author fullname="I. Chen" initials="I." surname="Chen"/>
            <author fullname="J. Zhang" initials="J." surname="Zhang"/>
            <date month="June" year="2017"/>
            <abstract>
              <t>This document describes the key chain YANG data model. Key chains are commonly used for routing protocol authentication and other applications requiring symmetric keys. A key chain is a list containing one or more elements containing a Key ID, key string, send/accept lifetimes, and the associated authentication or encryption algorithm. By properly overlapping the send and accept lifetimes of multiple key chain elements, key strings and algorithms may be gracefully updated. By representing them in a YANG data model, key distribution can be automated.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8177"/>
          <seriesInfo name="DOI" value="10.17487/RFC8177"/>
        </reference>
        <reference anchor="RFC4577">
          <front>
            <title>OSPF as the Provider/Customer Edge Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)</title>
            <author fullname="E. Rosen" initials="E." surname="Rosen"/>
            <author fullname="P. Psenak" initials="P." surname="Psenak"/>
            <author fullname="P. Pillay-Esnault" initials="P." surname="Pillay-Esnault"/>
            <date month="June" year="2006"/>
            <abstract>
              <t>Many Service Providers offer Virtual Private Network (VPN) services to their customers, using a technique in which customer edge routers (CE routers) are routing peers of provider edge routers (PE routers). The Border Gateway Protocol (BGP) is used to distribute the customer's routes across the provider's IP backbone network, and Multiprotocol Label Switching (MPLS) is used to tunnel customer packets across the provider's backbone. This is known as a "BGP/MPLS IP VPN". The base specification for BGP/MPLS IP VPNs presumes that the routing protocol on the interface between a PE router and a CE router is BGP. This document extends that specification by allowing the routing protocol on the PE/CE interface to be the Open Shortest Path First (OSPF) protocol.</t>
              <t>This document updates RFC 4364. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4577"/>
          <seriesInfo name="DOI" value="10.17487/RFC4577"/>
        </reference>
        <reference anchor="RFC6565">
          <front>
            <title>OSPFv3 as a Provider Edge to Customer Edge (PE-CE) Routing Protocol</title>
            <author fullname="P. Pillay-Esnault" initials="P." surname="Pillay-Esnault"/>
            <author fullname="P. Moyer" initials="P." surname="Moyer"/>
            <author fullname="J. Doyle" initials="J." surname="Doyle"/>
            <author fullname="E. Ertekin" initials="E." surname="Ertekin"/>
            <author fullname="M. Lundberg" initials="M." surname="Lundberg"/>
            <date month="June" year="2012"/>
            <abstract>
              <t>Many Service Providers (SPs) offer Virtual Private Network (VPN) services to their customers using a technique in which Customer Edge (CE) routers are routing peers of Provider Edge (PE) routers. The Border Gateway Protocol (BGP) is used to distribute the customer's routes across the provider's IP backbone network, and Multiprotocol Label Switching (MPLS) is used to tunnel customer packets across the provider's backbone. Support currently exists for both IPv4 and IPv6 VPNs; however, only Open Shortest Path First version 2 (OSPFv2) as PE-CE protocol is specified. This document extends those specifications to support OSPF version 3 (OSPFv3) as a PE-CE routing protocol. The OSPFv3 PE-CE functionality is identical to that of OSPFv2 except for the differences described in this document. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6565"/>
          <seriesInfo name="DOI" value="10.17487/RFC6565"/>
        </reference>
        <reference anchor="RFC4552">
          <front>
            <title>Authentication/Confidentiality for OSPFv3</title>
            <author fullname="M. Gupta" initials="M." surname="Gupta"/>
            <author fullname="N. Melam" initials="N." surname="Melam"/>
            <date month="June" year="2006"/>
            <abstract>
              <t>This document describes means and mechanisms to provide authentication/confidentiality to OSPFv3 using an IPv6 Authentication Header/Encapsulating Security Payload (AH/ESP) extension header. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4552"/>
          <seriesInfo name="DOI" value="10.17487/RFC4552"/>
        </reference>
        <reference anchor="RFC5709">
          <front>
            <title>OSPFv2 HMAC-SHA Cryptographic Authentication</title>
            <author fullname="M. Bhatia" initials="M." surname="Bhatia"/>
            <author fullname="V. Manral" initials="V." surname="Manral"/>
            <author fullname="M. Fanto" initials="M." surname="Fanto"/>
            <author fullname="R. White" initials="R." surname="White"/>
            <author fullname="M. Barnes" initials="M." surname="Barnes"/>
            <author fullname="T. Li" initials="T." surname="Li"/>
            <author fullname="R. Atkinson" initials="R." surname="Atkinson"/>
            <date month="October" year="2009"/>
            <abstract>
              <t>This document describes how the National Institute of Standards and Technology (NIST) Secure Hash Standard family of algorithms can be used with OSPF version 2's built-in, cryptographic authentication mechanism. This updates, but does not supercede, the cryptographic authentication mechanism specified in RFC 2328. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5709"/>
          <seriesInfo name="DOI" value="10.17487/RFC5709"/>
        </reference>
        <reference anchor="RFC7474">
          <front>
            <title>Security Extension for OSPFv2 When Using Manual Key Management</title>
            <author fullname="M. Bhatia" initials="M." surname="Bhatia"/>
            <author fullname="S. Hartman" initials="S." surname="Hartman"/>
            <author fullname="D. Zhang" initials="D." surname="Zhang"/>
            <author fullname="A. Lindem" initials="A." role="editor" surname="Lindem"/>
            <date month="April" year="2015"/>
            <abstract>
              <t>The current OSPFv2 cryptographic authentication mechanism as defined in RFCs 2328 and 5709 is vulnerable to both inter-session and intra- session replay attacks when using manual keying. Additionally, the existing cryptographic authentication mechanism does not cover the IP header. This omission can be exploited to carry out various types of attacks.</t>
              <t>This document defines changes to the authentication sequence number mechanism that will protect OSPFv2 from both inter-session and intra- session replay attacks when using manual keys for securing OSPFv2 protocol packets. Additionally, we also describe some changes in the cryptographic hash computation that will eliminate attacks resulting from OSPFv2 not protecting the IP header.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7474"/>
          <seriesInfo name="DOI" value="10.17487/RFC7474"/>
        </reference>
        <reference anchor="RFC7166">
          <front>
            <title>Supporting Authentication Trailer for OSPFv3</title>
            <author fullname="M. Bhatia" initials="M." surname="Bhatia"/>
            <author fullname="V. Manral" initials="V." surname="Manral"/>
            <author fullname="A. Lindem" initials="A." surname="Lindem"/>
            <date month="March" year="2014"/>
            <abstract>
              <t>Currently, OSPF for IPv6 (OSPFv3) uses IPsec as the only mechanism for authenticating protocol packets. This behavior is different from authentication mechanisms present in other routing protocols (OSPFv2, Intermediate System to Intermediate System (IS-IS), RIP, and Routing Information Protocol Next Generation (RIPng)). In some environments, it has been found that IPsec is difficult to configure and maintain and thus cannot be used. This document defines an alternative mechanism to authenticate OSPFv3 protocol packets so that OSPFv3 does not depend only upon IPsec for authentication.</t>
              <t>The OSPFv3 Authentication Trailer was originally defined in RFC 6506. This document obsoletes RFC 6506 by providing a revised definition, including clarifications and refinements of the procedures.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7166"/>
          <seriesInfo name="DOI" value="10.17487/RFC7166"/>
        </reference>
        <reference anchor="RFC2453">
          <front>
            <title>RIP Version 2</title>
            <author fullname="G. Malkin" initials="G." surname="Malkin"/>
            <date month="November" year="1998"/>
            <abstract>
              <t>This document specifies an extension of the Routing Information Protocol (RIP) to expand the amount of useful information carried in RIP messages and to add a measure of security. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="56"/>
          <seriesInfo name="RFC" value="2453"/>
          <seriesInfo name="DOI" value="10.17487/RFC2453"/>
        </reference>
        <reference anchor="RFC2080">
          <front>
            <title>RIPng for IPv6</title>
            <author fullname="G. Malkin" initials="G." surname="Malkin"/>
            <author fullname="R. Minnear" initials="R." surname="Minnear"/>
            <date month="January" year="1997"/>
            <abstract>
              <t>This document specifies a routing protocol for an IPv6 internet. It is based on protocols and algorithms currently in wide use in the IPv4 Internet [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2080"/>
          <seriesInfo name="DOI" value="10.17487/RFC2080"/>
        </reference>
        <reference anchor="RFC5798">
          <front>
            <title>Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6</title>
            <author fullname="S. Nadas" initials="S." role="editor" surname="Nadas"/>
            <date month="March" year="2010"/>
            <abstract>
              <t>This memo defines the Virtual Router Redundancy Protocol (VRRP) for IPv4 and IPv6. It is version three (3) of the protocol, and it is based on VRRP (version 2) for IPv4 that is defined in RFC 3768 and in "Virtual Router Redundancy Protocol for IPv6". VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IPv4 or IPv6 address(es) associated with a virtual router is called the Master, and it forwards packets sent to these IPv4 or IPv6 addresses. VRRP Master routers are configured with virtual IPv4 or IPv6 addresses, and VRRP Backup routers infer the address family of the virtual addresses being carried based on the transport protocol. Within a VRRP router, the virtual routers in each of the IPv4 and IPv6 address families are a domain unto themselves and do not overlap. The election process provides dynamic failover in the forwarding responsibility should the Master become unavailable. For IPv4, the advantage gained from using VRRP is a higher-availability default path without requiring configuration of dynamic routing or router discovery protocols on every end-host. For IPv6, the advantage gained from using VRRP for IPv6 is a quicker switchover to Backup routers than can be obtained with standard IPv6 Neighbor Discovery mechanisms. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5798"/>
          <seriesInfo name="DOI" value="10.17487/RFC5798"/>
        </reference>
        <reference anchor="RFC6991">
          <front>
            <title>Common YANG Data Types</title>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <date month="July" year="2013"/>
            <abstract>
              <t>This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6991"/>
          <seriesInfo name="DOI" value="10.17487/RFC6991"/>
        </reference>
        <reference anchor="RFC8294">
          <front>
            <title>Common YANG Data Types for the Routing Area</title>
            <author fullname="X. Liu" initials="X." surname="Liu"/>
            <author fullname="Y. Qu" initials="Y." surname="Qu"/>
            <author fullname="A. Lindem" initials="A." surname="Lindem"/>
            <author fullname="C. Hopps" initials="C." surname="Hopps"/>
            <author fullname="L. Berger" initials="L." surname="Berger"/>
            <date month="December" year="2017"/>
            <abstract>
              <t>This document defines a collection of common data types using the YANG data modeling language. These derived common types are designed to be imported by other modules defined in the routing area.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8294"/>
          <seriesInfo name="DOI" value="10.17487/RFC8294"/>
        </reference>
        <reference anchor="RFC8343">
          <front>
            <title>A YANG Data Model for Interface Management</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document defines a YANG data model for the management of network interfaces. It is expected that interface-type-specific data models augment the generic interfaces data model defined in this document. The data model includes definitions for configuration and system state (status information and counters for the collection of statistics).</t>
              <t>The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in RFC 8342.</t>
              <t>This document obsoletes RFC 7223.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8343"/>
          <seriesInfo name="DOI" value="10.17487/RFC8343"/>
        </reference>
        <reference anchor="RFC6241">
          <front>
            <title>Network Configuration Protocol (NETCONF)</title>
            <author fullname="R. Enns" initials="R." role="editor" surname="Enns"/>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <author fullname="A. Bierman" initials="A." role="editor" surname="Bierman"/>
            <date month="June" year="2011"/>
            <abstract>
              <t>The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6241"/>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
        </reference>
        <reference anchor="RFC8040">
          <front>
            <title>RESTCONF Protocol</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <date month="January" year="2017"/>
            <abstract>
              <t>This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8040"/>
          <seriesInfo name="DOI" value="10.17487/RFC8040"/>
        </reference>
        <reference anchor="RFC6242">
          <front>
            <title>Using the NETCONF Protocol over Secure Shell (SSH)</title>
            <author fullname="M. Wasserman" initials="M." surname="Wasserman"/>
            <date month="June" year="2011"/>
            <abstract>
              <t>This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6242"/>
          <seriesInfo name="DOI" value="10.17487/RFC6242"/>
        </reference>
        <reference anchor="RFC8446">
          <front>
            <title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
            <author fullname="E. Rescorla" initials="E." surname="Rescorla"/>
            <date month="August" year="2018"/>
            <abstract>
              <t>This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t>
              <t>This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8446"/>
          <seriesInfo name="DOI" value="10.17487/RFC8446"/>
        </reference>
        <reference anchor="RFC8341">
          <front>
            <title>Network Configuration Access Control Model</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.</t>
              <t>This document obsoletes RFC 6536.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="91"/>
          <seriesInfo name="RFC" value="8341"/>
          <seriesInfo name="DOI" value="10.17487/RFC8341"/>
        </reference>
        <reference anchor="RFC3688">
          <front>
            <title>The IETF XML Registry</title>
            <author fullname="M. Mealling" initials="M." surname="Mealling"/>
            <date month="January" year="2004"/>
            <abstract>
              <t>This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="81"/>
          <seriesInfo name="RFC" value="3688"/>
          <seriesInfo name="DOI" value="10.17487/RFC3688"/>
        </reference>
        <reference anchor="RFC6020">
          <front>
            <title>YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)</title>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <date month="October" year="2010"/>
            <abstract>
              <t>YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6020"/>
          <seriesInfo name="DOI" value="10.17487/RFC6020"/>
        </reference>
      </references>
      <references anchor="sec-informative-references">
        <name>Informative References</name>
        <reference anchor="AC-Ntw-Tree" target="https://github.com/boucadair/attachment-circuit-model/blob/main/yang/full-trees/ac-ntw-without-groupings.txt">
          <front>
            <title>Full Network Attachment Circuit Tree Structure</title>
            <author>
              <organization/>
            </author>
            <date year="2023"/>
          </front>
        </reference>
        <reference anchor="PYANG" target="https://github.com/mbj4668/pyang">
          <front>
            <title>pyang</title>
            <author>
              <organization/>
            </author>
            <date year="2023"/>
          </front>
        </reference>
        <reference anchor="RFC7665">
          <front>
            <title>Service Function Chaining (SFC) Architecture</title>
            <author fullname="J. Halpern" initials="J." role="editor" surname="Halpern"/>
            <author fullname="C. Pignataro" initials="C." role="editor" surname="Pignataro"/>
            <date month="October" year="2015"/>
            <abstract>
              <t>This document describes an architecture for the specification, creation, and ongoing maintenance of Service Function Chains (SFCs) in a network. It includes architectural concepts, principles, and components used in the construction of composite services through deployment of SFCs, with a focus on those to be standardized in the IETF. This document does not propose solutions, protocols, or extensions to existing protocols.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7665"/>
          <seriesInfo name="DOI" value="10.17487/RFC7665"/>
        </reference>
        <reference anchor="RFC8969">
          <front>
            <title>A Framework for Automating Service and Network Management with YANG</title>
            <author fullname="Q. Wu" initials="Q." role="editor" surname="Wu"/>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="D. Lopez" initials="D." surname="Lopez"/>
            <author fullname="C. Xie" initials="C." surname="Xie"/>
            <author fullname="L. Geng" initials="L." surname="Geng"/>
            <date month="January" year="2021"/>
            <abstract>
              <t>Data models provide a programmatic approach to represent services and networks. Concretely, they can be used to derive configuration information for network and service components, and state information that will be monitored and tracked. Data models can be used during the service and network management life cycle (e.g., service instantiation, service provisioning, service optimization, service monitoring, service diagnosing, and service assurance). Data models are also instrumental in the automation of network management, and they can provide closed-loop control for adaptive and deterministic service creation, delivery, and maintenance.</t>
              <t>This document describes a framework for service and network management automation that takes advantage of YANG modeling technologies. This framework is drawn from a network operator perspective irrespective of the origin of a data model; thus, it can accommodate YANG modules that are developed outside the IETF.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8969"/>
          <seriesInfo name="DOI" value="10.17487/RFC8969"/>
        </reference>
        <reference anchor="RFC8340">
          <front>
            <title>YANG Tree Diagrams</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="L. Berger" initials="L." role="editor" surname="Berger"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="215"/>
          <seriesInfo name="RFC" value="8340"/>
          <seriesInfo name="DOI" value="10.17487/RFC8340"/>
        </reference>
        <reference anchor="RFC3644">
          <front>
            <title>Policy Quality of Service (QoS) Information Model</title>
            <author fullname="Y. Snir" initials="Y." surname="Snir"/>
            <author fullname="Y. Ramberg" initials="Y." surname="Ramberg"/>
            <author fullname="J. Strassner" initials="J." surname="Strassner"/>
            <author fullname="R. Cohen" initials="R." surname="Cohen"/>
            <author fullname="B. Moore" initials="B." surname="Moore"/>
            <date month="November" year="2003"/>
            <abstract>
              <t>This document presents an object-oriented information model for representing Quality of Service (QoS) network management policies. This document is based on the IETF Policy Core Information Model and its extensions. It defines an information model for QoS enforcement for differentiated and integrated services using policy. It is important to note that this document defines an information model, which by definition is independent of any particular data storage mechanism and access protocol.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="3644"/>
          <seriesInfo name="DOI" value="10.17487/RFC3644"/>
        </reference>
        <reference anchor="RFC4862">
          <front>
            <title>IPv6 Stateless Address Autoconfiguration</title>
            <author fullname="S. Thomson" initials="S." surname="Thomson"/>
            <author fullname="T. Narten" initials="T." surname="Narten"/>
            <author fullname="T. Jinmei" initials="T." surname="Jinmei"/>
            <date month="September" year="2007"/>
            <abstract>
              <t>This document specifies the steps a host takes in deciding how to autoconfigure its interfaces in IP version 6. The autoconfiguration process includes generating a link-local address, generating global addresses via stateless address autoconfiguration, and the Duplicate Address Detection procedure to verify the uniqueness of the addresses on a link. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4862"/>
          <seriesInfo name="DOI" value="10.17487/RFC4862"/>
        </reference>
        <reference anchor="RFC7880">
          <front>
            <title>Seamless Bidirectional Forwarding Detection (S-BFD)</title>
            <author fullname="C. Pignataro" initials="C." surname="Pignataro"/>
            <author fullname="D. Ward" initials="D." surname="Ward"/>
            <author fullname="N. Akiya" initials="N." surname="Akiya"/>
            <author fullname="M. Bhatia" initials="M." surname="Bhatia"/>
            <author fullname="S. Pallagatti" initials="S." surname="Pallagatti"/>
            <date month="July" year="2016"/>
            <abstract>
              <t>This document defines Seamless Bidirectional Forwarding Detection (S-BFD), a simplified mechanism for using BFD with a large proportion of negotiation aspects eliminated, thus providing benefits such as quick provisioning, as well as improved control and flexibility for network nodes initiating path monitoring.</t>
              <t>This document updates RFC 5880.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7880"/>
          <seriesInfo name="DOI" value="10.17487/RFC7880"/>
        </reference>
        <reference anchor="RFC8695">
          <front>
            <title>A YANG Data Model for the Routing Information Protocol (RIP)</title>
            <author fullname="X. Liu" initials="X." surname="Liu"/>
            <author fullname="P. Sarda" initials="P." surname="Sarda"/>
            <author fullname="V. Choudhary" initials="V." surname="Choudhary"/>
            <date month="February" year="2020"/>
            <abstract>
              <t>This document describes a data model for the management of the Routing Information Protocol (RIP). Both RIP version 2 and RIPng are covered. The data model includes definitions for configuration, operational state, and Remote Procedure Calls (RPCs).</t>
              <t>The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8695"/>
          <seriesInfo name="DOI" value="10.17487/RFC8695"/>
        </reference>
      </references>
    </references>
    <?line 3806?>

<section anchor="sec-examples">
      <name>Examples</name>
      <section anchor="vpls">
        <name>VPLS</name>
        <t>Let's consider the example depicted in <xref target="ex-topo"/> with two customer terminating points (CE1 and CE2). Let's also assume that the bearers to attach these CEs to the provider network are already in place. References to the identify these bearers are shown in the figure.</t>
        <figure anchor="ex-topo">
          <name>Topology Example</name>
          <artwork align="center"><![CDATA[
            .-----.   .--------------.   .-----.
.----.      | PE1 +===+              +===+ PE2 |      .----.
| CE1+------+"450"|   |     MPLS     |   |"451"+------+ CE2|
'----'   ^  '-----'   |              |   '-----'   ^  '----'
         |            |     Core     |             |  
    Bearer:1234       '--------------'         Bearer:5678
]]></artwork>
        </figure>
        <t>The AC service model <xref target="I-D.ietf-opsawg-teas-attachment-circuit"/> can be used by the provider to manage and expose the ACs over existing bearers as shown in <xref target="ex-ac"/>.</t>
        <figure anchor="ex-ac">
          <name>ACs Created Using ACaaS</name>
          <artwork align="center"><![CDATA[
{
   "ietf-ac-svc:attachment-circuits":{
      "ac-group-profile":[
         {
            "name":"an-ac-profile",
            "l2-connection":{
               "encapsulation":{
                  "encap-type":"ietf-vpn-common:dot1q",
                  "dot1q":{
                     "tag-type":"ietf-vpn-common:c-vlan",
                     "cvlan-id":550
                  }
               }
            },
            "service":{
               "mtu":1550,
               "svc-pe-to-ce-bandwidth":{
                  "pe-to-ce-bandwidth":[
                     {
                        "bw-type":"ietf-vpn-common:bw-per-port",
                        "cir":"20480000"
                     }
                  ]
               },
               "svc-ce-to-pe-bandwidth":{
                  "ce-to-pe-bandwidth":[
                     {
                        "bw-type":"ietf-vpn-common:bw-per-port",
                        "cir":"20480000"
                     }
                  ]
               },
               "qos":{
                  "qos-profile":{
                     "qos-profile":[
                        {
                           "profile":"QoS_Profile_A",
                           "direction":"ietf-vpn-common:both"
                        }
                     ]
                  }
               }
            }
         }
      ],
      "ac":[
         {
            "name":"ac-1",
            "description":"First attachment",
            "ac-group-profile":["an-ac-profile"],
            "l2-connection":{
               "bearer-reference":"1234"
            }
         },
         {
            "name":"ac-2",
            "description":"Second attachment",
            "ac-group-profile": ["an-ac-profile"],
            "l2-connection":{
               "bearer-reference":"5678"
            }
         }
      ]
   }
}
]]></artwork>
        </figure>
        <t>The provisionned AC at PE1 can be retrieved using the AC network model as depicted in <xref target="ex-acntw-query"/>. A similar query can be used for the AC at PE2.</t>
        <figure anchor="ex-acntw-query">
          <name>Example of AC Network Response (Message Body)</name>
          <artwork align="center"><![CDATA[
=============== NOTE: '\' line wrapping per RFC 8792 ================

{
   "ietf-sap-ntw:service":[
      {
         "service-type":"ietf-vpn-common:vpls",
         "sap":[
            {
               "sap-id":"sap#1",
               "peer-sap-id":[
                  "ce-1"
               ],
               "description":"A parent SAP",
               "attachment-interface":"GE0/6/1",
               "interface-type":"ietf-sap-ntw:phy",
               "role":"ietf-sap-ntw:uni",
               "allows-child-saps":true,
               "sap-status":{
                  "status":"ietf-vpn-common:op-up"
               }
            },
            {
               "sap-id":"sap#11",
               "description":"A child SAP",
               "parent-termination-point":"GE0/6/4",
               "attachment-interface":"GE0/6/4.2",
               "interface-type":"ietf-sap-ntw:logical",
               "encapsulation-type":"ietf-vpn-common:vlan-type",
               "sap-status":{
                  "status":"ietf-vpn-common:op-up"
               },
               "ietf-ac-ntw:ac":[
                  {
                     "name":"ac-11",
                     "ac-svc-ref":"ac-1",
                     "peer-sap-id":[
                        "ce-1"
                     ],
                     "status":{
                        "admin-status":{
                           "status":"ietf-vpn-common:admin-up"
                        },
                        "oper-status":{
                           "status":"ietf-vpn-common:op-up"
                        }
                     },
                     "l2-connection":{
                        "encapsulation":{
                           "encap-type":"ietf-vpn-common:dot1q",
                           "dot1q":{
                              "tag-type":"ietf-vpn-common:c-vlan",
                              "cvlan-id":550
                           }
                        },
                        "bearer-reference":"1234"
                     },
                     "service":{
                        "mtu":1550,
                        "svc-pe-to-ce-bandwidth":{
                           "pe-to-ce-bandwidth":[
                              {
                                 "cir":"20480000"
                              }
                           ]
                        },
                        "svc-ce-to-pe-bandwidth":{
                           "ce-to-pe-bandwidth":[
                              {
                                 "cir":"20480000"
                              }
                           ]
                        },
                        "qos":{
                           "qos-profile":{
                              "qos-profile":[
                                 {
                                    "profile":"QoS_Profile_A",
                                    "direction":"ietf-vpn-common:\
                                                                both"
                                 }
                              ]
                           }
                        }
                     }
                  }
               ]
            }
         ]
      }
   ]
}
]]></artwork>
        </figure>
      </section>
      <section anchor="parent-ac">
        <name>Parent AC</name>
        <t>In reference to the topology depicted in <xref target="sap-ac-ntw"/>, PE2 has a SAP which terminates an AC with two peer SAPs (CE2 and CE5). In order to control data that is specific to each of these peer SAPs over the same AC, child ACs can be instantiated as depicted in <xref target="ex-parent-ac"/>.</t>
        <figure anchor="ex-parent-ac">
          <name>Example of Child ACs</name>
          <artwork align="center"><![CDATA[
{
   "ietf-sap-ntw:service":[
      {
         "service-type":"ietf-vpn-common:l3vpn",
         "sap":[
            {
               "sap-id":"sap#14587",
               "description":"A SAP",
               "parent-termination-point":"GE0/6/4",
               "attachment-interface":"GE0/6/4.2",
               "interface-type":"ietf-sap-ntw:logical",
               "encapsulation-type":"ietf-vpn-common:vlan-type",
               "sap-status":{
                  "status":"ietf-vpn-common:op-up"
               },
               "ietf-ac-ntw:ac":[
                  {
                     "name":"ac-1",
                     "peer-sap-id":[
                        "CE2",
                        "CE5"
                     ],
                     "status":{
                        "admin-status":{
                           "status":"ietf-vpn-common:admin-up"
                        },
                        "oper-status":{
                           "status":"ietf-vpn-common:op-up"
                        }
                     },
                     "l2-connection":{
                        "encapsulation":{
                           "encap-type":"ietf-vpn-common:dot1q",
                           "dot1q":{
                              "tag-type":"ietf-vpn-common:c-vlan",
                              "cvlan-id":550
                           }
                        },
                        "bearer-reference":"1234"
                     }
                  },
                  {
                     "name":"ac-1-to-ce2",
                     "ac-parent-ref":"ac-1",
                     "peer-sap-id":[
                        "CE2"
                     ]
                  },
                  {
                     "name":"ac-1-to-ce5",
                     "ac-parent-ref":"ac-1",
                     "peer-sap-id":[
                        "CE5"
                     ]
                  }
               ]
            }
         ]
      }
   ]
}
]]></artwork>
        </figure>
      </section>
    </section>
    <section numbered="false" anchor="acknowledgments">
      <name>Acknowledgments</name>
      <t>This document builds on <xref target="RFC9182"/> and <xref target="RFC9291"/>.</t>
      <t>Thanks to Moti Morgenstern for the review and comments.</t>
    </section>
    <section anchor="contributors" numbered="false" toc="include" removeInRFC="false">
      <name>Contributors</name>
      <contact initials="V." surname="Lopez" fullname="Victor Lopez">
        <organization>Nokia</organization>
        <address>
          <email>victor.lopez@nokia.com</email>
        </address>
      </contact>
      <contact fullname="Ivan Bykov">
        <organization>Ribbon Communications</organization>
        <address>
          <email>Ivan.Bykov@rbbn.com</email>
        </address>
      </contact>
      <contact fullname="Qin Wu">
        <organization>Huawei</organization>
        <address>
          <email>bill.wu@huawei.com</email>
        </address>
      </contact>
      <contact fullname="Ogaki Kenichi">
        <organization>KDDI</organization>
        <address>
          <email>ke-oogaki@kddi.com</email>
        </address>
      </contact>
      <contact fullname="Luis Angel Munoz">
        <organization>Vodafone</organization>
        <address>
          <email>luis-angel.munoz@vodafone.com</email>
        </address>
      </contact>
    </section>
  </back>
  <!-- ##markdown-source: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-->

</rfc>
