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<!DOCTYPE html>
<html lang="en" class="RFC">
<head>
<meta charset="utf-8">
<meta content="Common,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>RFC 9314: YANG Data Model for Bidirectional Forwarding Detection (BFD)</title>
<meta content="Mahesh Jethanandani" name="author">
<meta content="Reshad Rahman" name="author">
<meta content="Lianshu Zheng" name="author">
<meta content="Santosh Pallagatti" name="author">
<meta content="Greg Mirsky" name="author">
<meta content='
       This document defines a YANG data model that can be used to configure
      and manage Bidirectional Forwarding Detection (BFD). 
       The YANG modules in this document conform to the Network Management
      Datastore Architecture (NMDA) (RFC 8342). This document updates "YANG Data Model for Bidirectional Forwarding Detection (BFD)" (RFC 9127). 
    ' name="description">
<meta content="xml2rfc 3.14.2" name="generator">
<meta content="Liveliness check" name="keyword">
<meta content="BGP" name="keyword">
<meta content="OSPF" name="keyword">
<meta content="IS-IS" name="keyword">
<meta content="TCP-AO" name="keyword">
<meta content="MD5" name="keyword">
<meta content="9314" name="rfc.number">
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<link href="rfc9314.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*

  NOTE: Changes at the bottom of this file overrides some earlier settings.

  Once the style has stabilized and has been adopted as an official RFC style,
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*/

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}

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/* This is commented out here, as the string-set: doesn't
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/* Changes introduced to fix issues found during implementation */
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a.toplink {
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/* Fix the dl styling to match the RFC 7992 attributes */
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dl.dlNewline > dt {
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/* Provide styling for table cell text alignment */
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table td.text-right,
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/* With it being possible to set tables with alignment
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table {
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}

/* Avoid reference text that sits in a block with very wide left margin,
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}

/* Control caption placement */
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/* Limit the width of the author address vcard, so names in right-to-left
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address.vcard {
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}

/* For address alignment dependent on LTR or RTL scripts */
address div.left {
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}
address div.right {
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}

/* Provide table alignment support.  We can't use the alignX classes above
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table.right {
 margin-left: auto;
 margin-right: 0;
}
table.center {
 margin-left: auto;
 margin-right: auto;
}
table.left {
 margin-left: 0;
 margin-right: auto;
}

/* Give the table caption label the same styling as the figcaption */
caption a[href] {
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}

@media print {
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  /* avoid overwriting the top border line with the ToC header */
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  /* Avoid page breaks inside dl and author address entries */
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}
/* Tweak the bcp14 keyword presentation */
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  font-weight: bold;
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}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
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  padding-top: 31px;
 }
 h3 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
 h4 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
/* Float artwork pilcrow to the right */
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    line-height: 0.7;
    margin-top: 0.15em;
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}
/* Make pilcrows on dd visible */
@media screen {
  dd:hover > a.pilcrow {
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}
/* Make the placement of figcaption match that of a table's caption
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.alignRight.art-text {
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.alignLeft,
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<table class="ears">
<thead><tr>
<td class="left">RFC 9314</td>
<td class="center">BFD YANG</td>
<td class="right">September 2022</td>
</tr></thead>
<tfoot><tr>
<td class="left">Jethanandani, et al.</td>
<td class="center">Standards Track</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-stream">Stream:</dt>
<dd class="stream">Internet Engineering Task Force (IETF)</dd>
<dt class="label-rfc">RFC:</dt>
<dd class="rfc"><a href="https://www.rfc-editor.org/rfc/rfc9314" class="eref">9314</a></dd>
<dt class="label-updates">Updates:</dt>
<dd class="updates">
<a href="https://www.rfc-editor.org/rfc/rfc9127" class="eref">9127</a> </dd>
<dt class="label-category">Category:</dt>
<dd class="category">Standards Track</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2022-09" class="published">September 2022</time>
    </dd>
<dt class="label-issn">ISSN:</dt>
<dd class="issn">2070-1721</dd>
<dt class="label-authors">Authors:</dt>
<dd class="authors">
<div class="author">
      <div class="author-name">M. Jethanandani, <span class="editor">Ed.</span>
</div>
<div class="org">Xoriant Corporation</div>
</div>
<div class="author">
      <div class="author-name">R. Rahman, <span class="editor">Ed.</span>
</div>
</div>
<div class="author">
      <div class="author-name">L. Zheng, <span class="editor">Ed.</span>
</div>
<div class="org">Huawei Technologies</div>
</div>
<div class="author">
      <div class="author-name">S. Pallagatti</div>
<div class="org">VMware</div>
</div>
<div class="author">
      <div class="author-name">G. Mirsky</div>
<div class="org">Ericsson</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 9314</h1>
<h1 id="title">YANG Data Model for Bidirectional Forwarding Detection (BFD)</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document defines a YANG data model that can be used to configure
      and manage Bidirectional Forwarding Detection (BFD).<a href="#section-abstract-1" class="pilcrow">¶</a></p>
<p id="section-abstract-2">The YANG modules in this document conform to the Network Management
      Datastore Architecture (NMDA) (RFC 8342). This document updates "YANG Data Model for Bidirectional Forwarding Detection (BFD)" (RFC 9127).<a href="#section-abstract-2" class="pilcrow">¶</a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
        <h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
        </h2>
<p id="section-boilerplate.1-1">
            This is an Internet Standards Track document.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-2">
            This document is a product of the Internet Engineering Task Force
            (IETF).  It represents the consensus of the IETF community.  It has
            received public review and has been approved for publication by
            the Internet Engineering Steering Group (IESG).  Further
            information on Internet Standards is available in Section 2 of 
            RFC 7841.<a href="#section-boilerplate.1-2" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-3">
            Information about the current status of this document, any
            errata, and how to provide feedback on it may be obtained at
            <span><a href="https://www.rfc-editor.org/info/rfc9314">https://www.rfc-editor.org/info/rfc9314</a></span>.<a href="#section-boilerplate.1-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
        <h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
        </h2>
<p id="section-boilerplate.2-1">
            Copyright (c) 2022 IETF Trust and the persons identified as the
            document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<span><a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a></span>) in effect on the date of
            publication of this document. Please review these documents
            carefully, as they describe your rights and restrictions with
            respect to this document. Code Components extracted from this
            document must include Revised BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Revised BSD License.<a href="#section-boilerplate.2-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
        <a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
        </h2>
<nav class="toc"><ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.1">
            <p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="xref">1</a>.  <a href="#name-introduction" class="xref">Introduction</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.1.2.1">
                <p id="section-toc.1-1.1.2.1.1" class="keepWithNext"><a href="#section-1.1" class="xref">1.1</a>.  <a href="#name-tree-diagrams" class="xref">Tree Diagrams</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1"><a href="#section-2" class="xref">2</a>.  <a href="#name-design-of-the-data-model" class="xref">Design of the Data Model</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1">
                <p id="section-toc.1-1.2.2.1.1"><a href="#section-2.1" class="xref">2.1</a>.  <a href="#name-design-of-the-configuration" class="xref">Design of the Configuration Model</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1.2.1">
                    <p id="section-toc.1-1.2.2.1.2.1.1" class="keepWithNext"><a href="#section-2.1.1" class="xref">2.1.1</a>.  <a href="#name-common-bfd-configuration-pa" class="xref">Common BFD Configuration Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1.2.2">
                    <p id="section-toc.1-1.2.2.1.2.2.1"><a href="#section-2.1.2" class="xref">2.1.2</a>.  <a href="#name-single-hop-ip" class="xref">Single-Hop IP</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1.2.3">
                    <p id="section-toc.1-1.2.2.1.2.3.1"><a href="#section-2.1.3" class="xref">2.1.3</a>.  <a href="#name-multihop-ip" class="xref">Multihop IP</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1.2.4">
                    <p id="section-toc.1-1.2.2.1.2.4.1"><a href="#section-2.1.4" class="xref">2.1.4</a>.  <a href="#name-mpls-label-switched-paths" class="xref">MPLS Label Switched Paths</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.1.2.5">
                    <p id="section-toc.1-1.2.2.1.2.5.1"><a href="#section-2.1.5" class="xref">2.1.5</a>.  <a href="#name-link-aggregation-groups" class="xref">Link Aggregation Groups</a></p>
</li>
                </ul>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.2">
                <p id="section-toc.1-1.2.2.2.1"><a href="#section-2.2" class="xref">2.2</a>.  <a href="#name-design-of-the-operational-s" class="xref">Design of the Operational State Model</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.3">
                <p id="section-toc.1-1.2.2.3.1"><a href="#section-2.3" class="xref">2.3</a>.  <a href="#name-notifications" class="xref">Notifications</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.4">
                <p id="section-toc.1-1.2.2.4.1"><a href="#section-2.4" class="xref">2.4</a>.  <a href="#name-rpc-operations" class="xref">RPC Operations</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.5">
                <p id="section-toc.1-1.2.2.5.1"><a href="#section-2.5" class="xref">2.5</a>.  <a href="#name-bfd-top-level-hierarchy" class="xref">BFD Top-Level Hierarchy</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.6">
                <p id="section-toc.1-1.2.2.6.1"><a href="#section-2.6" class="xref">2.6</a>.  <a href="#name-bfd-ip-single-hop-hierarchy" class="xref">BFD IP Single-Hop Hierarchy</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.7">
                <p id="section-toc.1-1.2.2.7.1"><a href="#section-2.7" class="xref">2.7</a>.  <a href="#name-bfd-ip-multihop-hierarchy" class="xref">BFD IP Multihop Hierarchy</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.8">
                <p id="section-toc.1-1.2.2.8.1"><a href="#section-2.8" class="xref">2.8</a>.  <a href="#name-bfd-over-lag-hierarchy" class="xref">BFD-over-LAG Hierarchy</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.9">
                <p id="section-toc.1-1.2.2.9.1"><a href="#section-2.9" class="xref">2.9</a>.  <a href="#name-bfd-over-mpls-lsps-hierarch" class="xref">BFD-over-MPLS-LSPs Hierarchy</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.10">
                <p id="section-toc.1-1.2.2.10.1"><a href="#section-2.10" class="xref">2.10</a>. <a href="#name-interaction-with-other-yang" class="xref">Interaction with Other YANG Modules</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.10.2.1">
                    <p id="section-toc.1-1.2.2.10.2.1.1"><a href="#section-2.10.1" class="xref">2.10.1</a>.  <a href="#name-ietf-interfaces-module" class="xref">"ietf-interfaces" Module</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.10.2.2">
                    <p id="section-toc.1-1.2.2.10.2.2.1"><a href="#section-2.10.2" class="xref">2.10.2</a>.  <a href="#name-ietf-ip-module" class="xref">"ietf-ip" Module</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.10.2.3">
                    <p id="section-toc.1-1.2.2.10.2.3.1"><a href="#section-2.10.3" class="xref">2.10.3</a>.  <a href="#name-ietf-mpls-module" class="xref">"ietf-mpls" Module</a></p>
</li>
                </ul>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.11">
                <p id="section-toc.1-1.2.2.11.1"><a href="#section-2.11" class="xref">2.11</a>. <a href="#name-bfd-types-yang-module" class="xref">BFD Types YANG Module</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.12">
                <p id="section-toc.1-1.2.2.12.1"><a href="#section-2.12" class="xref">2.12</a>. <a href="#name-bfd-top-level-yang-module" class="xref">BFD Top-Level YANG Module</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.13">
                <p id="section-toc.1-1.2.2.13.1"><a href="#section-2.13" class="xref">2.13</a>. <a href="#name-bfd-ip-single-hop-yang-modu" class="xref">BFD IP Single-Hop YANG Module</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.14">
                <p id="section-toc.1-1.2.2.14.1"><a href="#section-2.14" class="xref">2.14</a>. <a href="#name-bfd-ip-multihop-yang-module" class="xref">BFD IP Multihop YANG Module</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.15">
                <p id="section-toc.1-1.2.2.15.1"><a href="#section-2.15" class="xref">2.15</a>. <a href="#name-bfd-over-lag-yang-module" class="xref">BFD-over-LAG YANG Module</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2.2.16">
                <p id="section-toc.1-1.2.2.16.1"><a href="#section-2.16" class="xref">2.16</a>. <a href="#name-bfd-over-mpls-yang-module" class="xref">BFD-over-MPLS YANG Module</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3">
            <p id="section-toc.1-1.3.1"><a href="#section-3" class="xref">3</a>.  <a href="#name-data-model-examples" class="xref">Data Model Examples</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.1">
                <p id="section-toc.1-1.3.2.1.1"><a href="#section-3.1" class="xref">3.1</a>.  <a href="#name-ip-single-hop" class="xref">IP Single-Hop</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2">
                <p id="section-toc.1-1.3.2.2.1"><a href="#section-3.2" class="xref">3.2</a>.  <a href="#name-ip-multihop" class="xref">IP Multihop</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.3">
                <p id="section-toc.1-1.3.2.3.1"><a href="#section-3.3" class="xref">3.3</a>.  <a href="#name-lag" class="xref">LAG</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.4">
                <p id="section-toc.1-1.3.2.4.1"><a href="#section-3.4" class="xref">3.4</a>.  <a href="#name-mpls" class="xref">MPLS</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.4">
            <p id="section-toc.1-1.4.1"><a href="#section-4" class="xref">4</a>.  <a href="#name-security-considerations" class="xref">Security Considerations</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5">
            <p id="section-toc.1-1.5.1"><a href="#section-5" class="xref">5</a>.  <a href="#name-iana-considerations" class="xref">IANA Considerations</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6">
            <p id="section-toc.1-1.6.1"><a href="#section-6" class="xref">6</a>.  <a href="#name-references" class="xref">References</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6.2.1">
                <p id="section-toc.1-1.6.2.1.1"><a href="#section-6.1" class="xref">6.1</a>.  <a href="#name-normative-references" class="xref">Normative References</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6.2.2">
                <p id="section-toc.1-1.6.2.2.1"><a href="#section-6.2" class="xref">6.2</a>.  <a href="#name-informative-references" class="xref">Informative References</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.7">
            <p id="section-toc.1-1.7.1"><a href="#appendix-A" class="xref">Appendix A</a>.  <a href="#name-echo-function-configuration" class="xref">Echo Function Configuration Example</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.7.2.1">
                <p id="section-toc.1-1.7.2.1.1"><a href="#appendix-A.1" class="xref">A.1</a>.  <a href="#name-example-yang-module-for-bfd" class="xref">Example YANG Module for BFD Echo Function Configuration</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8">
            <p id="section-toc.1-1.8.1"><a href="#appendix-B" class="xref">Appendix B</a>.  <a href="#name-updates-since-rfc-9127" class="xref">Updates since RFC 9127</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9">
            <p id="section-toc.1-1.9.1"><a href="#appendix-C" class="xref"></a><a href="#name-acknowledgments" class="xref">Acknowledgments</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10">
            <p id="section-toc.1-1.10.1"><a href="#appendix-D" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1">This document defines a YANG data model that can be used to configure 
      and manage Bidirectional Forwarding Detection (BFD) <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span>. BFD is a network protocol that is used
      for liveness detection of arbitrary paths between systems. Some examples
      of different types of paths over which we have BFD are as follows:<a href="#section-1-1" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-1-2">
      <li id="section-1-2.1">Two systems directly connected via IP. This is known as BFD over
      single-hop IP, which is also known as <span><a href="#RFC5881" class="xref">BFD for
      IPv4 and IPv6</a> [<a href="#RFC5881" class="xref">RFC5881</a>]</span>.<a href="#section-1-2.1" class="pilcrow">¶</a>
</li>
        <li id="section-1-2.2">Two systems connected via multiple hops as described in <span><a href="#RFC5883" class="xref">"Bidirectional Forwarding Detection
      (BFD) for Multihop Paths"</a> [<a href="#RFC5883" class="xref">RFC5883</a>]</span>.<a href="#section-1-2.2" class="pilcrow">¶</a>
</li>
        <li id="section-1-2.3">Two systems connected via MPLS Label Switched Paths (LSPs) as
      described in <span><a href="#RFC5884" class="xref">"Bidirectional
      Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)"</a> [<a href="#RFC5884" class="xref">RFC5884</a>]</span>.<a href="#section-1-2.3" class="pilcrow">¶</a>
</li>
        <li id="section-1-2.4">Two systems connected via a Link Aggregation Group (LAG) interface
      as described in <span><a href="#RFC7130" class="xref">"Bidirectional
      Forwarding Detection (BFD) on Link Aggregation Group (LAG) Interfaces"</a> [<a href="#RFC7130" class="xref">RFC7130</a>]</span>.<a href="#section-1-2.4" class="pilcrow">¶</a>
</li>
        <li id="section-1-2.5">Two systems connected via pseudowires (PWs). This is known as
      Virtual Circuit Connectivity Verification (VCCV) as described in <span><a href="#RFC5885" class="xref">"Bidirectional
      Forwarding Detection (BFD) for the Pseudowire Virtual
      Circuit Connectivity Verification (VCCV)"</a> [<a href="#RFC5885" class="xref">RFC5885</a>]</span>. This scenario is not
      addressed in this document.<a href="#section-1-2.5" class="pilcrow">¶</a>
</li>
      </ol>
<p id="section-1-3">BFD typically does not operate on its own. Various control protocols,
      also known as BFD clients, use the services provided by BFD for their
      own operation, as described in <span><a href="#RFC5882" class="xref">"Generic Application of Bidirectional Forwarding
      Detection (BFD)"</a> [<a href="#RFC5882" class="xref">RFC5882</a>]</span>. The obvious
      candidates that use BFD are those that do not have "hellos" to detect
      failures, e.g., static routes, and routing protocols whose "hellos" do
      not support sub-second failure detection, e.g., OSPF and IS-IS.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">The YANG modules in this document conform to the <span><a href="#RFC8342" class="xref">Network Management Datastore
      Architecture (NMDA)</a> [<a href="#RFC8342" class="xref">RFC8342</a>]</span>. This means that the data models do not have
      separate top-level or sibling containers for configuration data and
      operational state data.<a href="#section-1-4" class="pilcrow">¶</a></p>
<section id="section-1.1">
        <h3 id="name-tree-diagrams">
<a href="#section-1.1" class="section-number selfRef">1.1. </a><a href="#name-tree-diagrams" class="section-name selfRef">Tree Diagrams</a>
        </h3>
<p id="section-1.1-1">This document uses the graphical representation of data models, as defined in
            <span>[<a href="#RFC8340" class="xref">RFC8340</a>]</span>.<a href="#section-1.1-1" class="pilcrow">¶</a></p>
</section>
</section>
<div id="DESIGN-DATA">
<section id="section-2">
      <h2 id="name-design-of-the-data-model">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-design-of-the-data-model" class="section-name selfRef">Design of the Data Model</a>
      </h2>
<p id="section-2-1">Since BFD is used for liveness detection of various forwarding
      paths, there is no uniform key to identify a BFD session.  Therefore, the BFD
      data model is split into multiple YANG modules where each module
      corresponds to one type of forwarding path. For example, BFD for IP
      single-hop is in one YANG module, and BFD for MPLS is in another YANG
      module. The main difference between these modules is how a BFD session
      is uniquely identified, i.e., the key for the list containing the BFD
      sessions for that forwarding path. To avoid duplication of BFD
      definitions, we have common types and groupings that are used by all
      the modules.<a href="#section-2-1" class="pilcrow">¶</a></p>
<p id="section-2-2">A new control plane protocol, "bfdv1", is defined, and a "bfd" container
      is created under "control-plane-protocol" as specified in <span><a href="#RFC8349" class="xref">"A YANG Data Model for Routing
      Management (NMDA Version)"</a> [<a href="#RFC8349" class="xref">RFC8349</a>]</span>. This new "bfd" container is augmented
      by the following YANG modules for their respective specific information:<a href="#section-2-2" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-2-3">
        <li id="section-2-3.1">The "ietf-bfd-ip-sh" module (<a href="#bfd-ip-single-hop-module" class="xref">Section 2.13</a>) augments
          "/routing/control-plane-protocols/control-plane-protocol/bfd/" with
          the "ip-sh" container for BFD sessions over IP single-hop.<a href="#section-2-3.1" class="pilcrow">¶</a>
</li>
        <li id="section-2-3.2">The "ietf-bfd-ip-mh" module (<a href="#bfd-ip-multihop-module" class="xref">Section 2.14</a>) augments
          "/routing/control-plane-protocols/control-plane-protocol/bfd/" with
          the "ip-mh" container for BFD sessions over IP multihop.<a href="#section-2-3.2" class="pilcrow">¶</a>
</li>
        <li id="section-2-3.3">The "ietf-bfd-lag" module (<a href="#bfd-over-lag-module" class="xref">Section 2.15</a>) augments
          "/routing/control-plane-protocols/control-plane-protocol/bfd/" with
          the "lag" container for BFD sessions over a LAG.<a href="#section-2-3.3" class="pilcrow">¶</a>
</li>
        <li id="section-2-3.4">The "ietf-bfd-mpls" module (<a href="#bfd-over-mpls-module" class="xref">Section 2.16</a>) augments
          "/routing/control-plane-protocols/control-plane-protocol/bfd/" with
          the "mpls" container for BFD-over-MPLS LSPs.<a href="#section-2-3.4" class="pilcrow">¶</a>
</li>
      </ol>
<p id="section-2-4">BFD can operate in the following contexts:<a href="#section-2-4" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-2-5">
        <li id="section-2-5.1">At the network-device level.<a href="#section-2-5.1" class="pilcrow">¶</a>
</li>
        <li id="section-2-5.2">In logical network elements (LNEs) as described in <span><a href="#RFC8530" class="xref">"YANG Model for Logical Network Elements"</a> [<a href="#RFC8530" class="xref">RFC8530</a>]</span>.<a href="#section-2-5.2" class="pilcrow">¶</a>
</li>
        <li id="section-2-5.3">In network instances as described in <span><a href="#RFC8529" class="xref">"YANG Data Model for Network Instances"</a> [<a href="#RFC8529" class="xref">RFC8529</a>]</span>.<a href="#section-2-5.3" class="pilcrow">¶</a>
</li>
      </ol>
<p id="section-2-6"> When used at the network device level, the BFD YANG data model is
        used "as is". When the BFD YANG data model is used in an LNE or network instance, the BFD YANG data model augments
        the mounted routing model for the LNE or network instance.<a href="#section-2-6" class="pilcrow">¶</a></p>
<div id="CFG-MODEL">
<section id="section-2.1">
        <h3 id="name-design-of-the-configuration">
<a href="#section-2.1" class="section-number selfRef">2.1. </a><a href="#name-design-of-the-configuration" class="section-name selfRef">Design of the Configuration Model</a>
        </h3>
<p id="section-2.1-1">The configuration model consists mainly of the parameters specified
        in <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span> -- for example, desired
        minimum transmit interval, required minimum receive interval, and
        detection multiplier.<a href="#section-2.1-1" class="pilcrow">¶</a></p>
<p id="section-2.1-2">BFD clients are applications that use BFD for fast detection of
        failures. Some implementations have BFD session configuration under
        the BFD clients -- for example, BFD session configuration under routing
        applications such as OSPF, IS-IS, or BGP. Other implementations have
        BFD session configuration centralized under BFD, i.e., outside the
        multiple BFD clients.<a href="#section-2.1-2" class="pilcrow">¶</a></p>
<p id="section-2.1-3">The main BFD parameters of interest to a BFD client are those
        related to the
        multiplier and interval(s), since those parameters impact the
        convergence time of the BFD clients when a failure occurs. Other
        parameters, such as BFD authentication, are not specific to the
        requirements of the BFD client. Configuration of BFD for all
        clients should be centralized. However, this is a problem for BFD clients
        that auto-discover their peers. For example, IGPs do not have the
        peer address configured; instead, the IGP is enabled on an interface,
        and the IGP peers are auto-discovered. So, for an operator to configure
        BFD to an IGP peer, the operator would first have to determine the
        peer addresses. And when a new peer is discovered, BFD configuration
        would need to be added. To avoid this issue, we define the grouping
        "client-cfg-parms" in <a href="#BFD-TYPES" class="xref">Section 2.11</a> for BFD clients to
        configure BFD: this allows BFD clients, such as the IGPs, to have
        configuration (multiplier and intervals) for the BFD sessions they
        need. For example, when a new IGP peer is discovered, the IGP would
        create a BFD session to the newly discovered peer; similarly, when
        an IGP peer goes away, the IGP would remove the BFD session to that
        peer. The mechanism for how the BFD sessions are created and removed by
        the BFD clients is outside the scope of this document, but
        this would typically be done by using an API implemented by the BFD module on
        the system. In the case of BFD clients that create BFD sessions via their own
        configuration, authentication parameters (if required) are still
        specified in BFD.<a href="#section-2.1-3" class="pilcrow">¶</a></p>
<div id="BFD-COMMON-CFG">
<section id="section-2.1.1">
          <h4 id="name-common-bfd-configuration-pa">
<a href="#section-2.1.1" class="section-number selfRef">2.1.1. </a><a href="#name-common-bfd-configuration-pa" class="section-name selfRef">Common BFD Configuration Parameters</a>
          </h4>
<p id="section-2.1.1-1">The basic BFD configuration parameters are as follows:<a href="#section-2.1.1-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.1.1-2">
            <dt id="section-2.1.1-2.1">local-multiplier</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.1-2.2">This is the detection time multiplier as defined in <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#section-2.1.1-2.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.1.1-2.3">desired-min-tx-interval</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.1-2.4">This is the Desired Min TX Interval as defined in <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#section-2.1.1-2.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.1.1-2.5">required-min-rx-interval</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.1-2.6">This is the Required Min RX Interval as defined in <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#section-2.1.1-2.6" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
<p id="section-2.1.1-3">Although <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span>
          allows for different values for transmit and receive intervals, some 
          implementations allow users to specify just one interval that is
          used for both transmit and receive intervals, or separate values for
          transmit and receive intervals. The BFD YANG data model supports this:
          there is a choice between "min-interval", used for both transmit and
          receive intervals, and "desired-min-tx-interval" and
          "required-min-rx-interval". This is supported via the
          "base-cfg-parms" grouping (<a href="#BFD-TYPES" class="xref">Section 2.11</a>), which
          is used by the YANG modules for the various forwarding paths.<a href="#section-2.1.1-3" class="pilcrow">¶</a></p>
<p id="section-2.1.1-4">For BFD authentication, we have the following:<a href="#section-2.1.1-4" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.1.1-5">
            <dt id="section-2.1.1-5.1">key-chain</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.1-5.2">This is a reference to "key-chain" as defined in <span><a href="#RFC8177" class="xref">"YANG Data Model for Key
            Chains"</a> [<a href="#RFC8177" class="xref">RFC8177</a>]</span>. The keys, cryptographic algorithms, key lifetime,
            etc. are all defined in the "key-chain" model.<a href="#section-2.1.1-5.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.1.1-5.3">meticulous</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.1-5.4">This enables a meticulous mode as per <span><a href="#RFC5880" class="xref">BFD</a> [<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#section-2.1.1-5.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
</div>
<div id="IP-SH-CFG">
<section id="section-2.1.2">
          <h4 id="name-single-hop-ip">
<a href="#section-2.1.2" class="section-number selfRef">2.1.2. </a><a href="#name-single-hop-ip" class="section-name selfRef">Single-Hop IP</a>
          </h4>
<p id="section-2.1.2-1">For single-hop IP, there is an augment of the "bfd" data node, as
          described in 
          <a href="#DESIGN-DATA" class="xref">Section 2</a>. The "ip-sh" node
          contains a list of IP single-hop sessions where each session is
          uniquely identified by the interface and destination address
          pair. We use the configuration parameters defined in
          <a href="#BFD-COMMON-CFG" class="xref">Section 2.1.1</a>. The "ip-sh" node
          also contains a list of interfaces and is used to specify
          authentication parameters for BFD sessions that are created by BFD
          clients. See <a href="#CFG-MODEL" class="xref">Section 2.1</a>.<a href="#section-2.1.2-1" class="pilcrow">¶</a></p>
<p id="section-2.1.2-2"><span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span> and <span>[<a href="#RFC5881" class="xref">RFC5881</a>]</span> do not specify whether
          the Echo function operates continuously or on demand. Therefore, the mechanism used to
          start and stop the Echo function is implementation specific and should
          be done by augmentation:<a href="#section-2.1.2-2" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-2.1.2-3">
            <li id="section-2.1.2-3.1">Configuration. This is suitable for an Echo function that
            operates continuously. An example is provided in <a href="#ECHO-CONFIG" class="xref">Appendix A</a>.<a href="#section-2.1.2-3.1" class="pilcrow">¶</a>
</li>
            <li id="section-2.1.2-3.2">RPC. This is suitable for an Echo function that operates 
            on demand.<a href="#section-2.1.2-3.2" class="pilcrow">¶</a>
</li>
          </ol>
</section>
</div>
<section id="section-2.1.3">
          <h4 id="name-multihop-ip">
<a href="#section-2.1.3" class="section-number selfRef">2.1.3. </a><a href="#name-multihop-ip" class="section-name selfRef">Multihop IP</a>
          </h4>
<p id="section-2.1.3-1">For multihop IP, there is an augment of the "bfd" data node, as described in
          <a href="#DESIGN-DATA" class="xref">Section 2</a>.<a href="#section-2.1.3-1" class="pilcrow">¶</a></p>
<p id="section-2.1.3-2">Because of multiple paths, there could be multiple multihop IP
          sessions between a source and a destination address. We identify
          this set of sessions as a "session-group". The key for each "session-group" consists
          of the following:<a href="#section-2.1.3-2" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.1.3-3">
            <dt id="section-2.1.3-3.1">Source address</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.3-3.2">Address belonging to the local system as per <span><a href="#RFC5883" class="xref">"Bidirectional Forwarding
            Detection (BFD) for Multihop Paths"</a> [<a href="#RFC5883" class="xref">RFC5883</a>]</span>.<a href="#section-2.1.3-3.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.1.3-3.3">Destination address</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.3-3.4">Address belonging to the remote system as per <span>[<a href="#RFC5883" class="xref">RFC5883</a>]</span>.<a href="#section-2.1.3-3.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
<p id="section-2.1.3-4">We use the configuration parameters defined in <a href="#BFD-COMMON-CFG" class="xref">Section 2.1.1</a>.<a href="#section-2.1.3-4" class="pilcrow">¶</a></p>
<p id="section-2.1.3-5">This document also provides the following parameters:<a href="#section-2.1.3-5" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.1.3-6">
            <dt id="section-2.1.3-6.1">tx-ttl</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.3-6.2">TTL of outgoing BFD control packets.<a href="#section-2.1.3-6.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.1.3-6.3">rx-ttl</dt>
            <dd style="margin-left: 1.5em" id="section-2.1.3-6.4">Minimum TTL of incoming BFD control packets.<a href="#section-2.1.3-6.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
<section id="section-2.1.4">
          <h4 id="name-mpls-label-switched-paths">
<a href="#section-2.1.4" class="section-number selfRef">2.1.4. </a><a href="#name-mpls-label-switched-paths" class="section-name selfRef">MPLS Label Switched Paths</a>
          </h4>
<p id="section-2.1.4-1">Here, we address MPLS LSPs whose 
          Forwarding Equivalence Class (FEC) <span>[<a href="#RFC3031" class="xref">RFC3031</a>]</span> is an IP
          address. The "bfd"
          node (<a href="#DESIGN-DATA" class="xref">Section 2</a>) is augmented
          with "mpls", which contains a list of sessions uniquely identified by
          an IP prefix. Because of multiple paths, there could be multiple
          MPLS sessions to an MPLS FEC. We identify this set of sessions as a
          "session-group".<a href="#section-2.1.4-1" class="pilcrow">¶</a></p>
<p id="section-2.1.4-2">Since these LSPs are unidirectional, there is no LSP
          configuration on the egress node.<a href="#section-2.1.4-2" class="pilcrow">¶</a></p>
<p id="section-2.1.4-3">The BFD parameters for the egress node are added under
          "mpls".<a href="#section-2.1.4-3" class="pilcrow">¶</a></p>
</section>
<section id="section-2.1.5">
          <h4 id="name-link-aggregation-groups">
<a href="#section-2.1.5" class="section-number selfRef">2.1.5. </a><a href="#name-link-aggregation-groups" class="section-name selfRef">Link Aggregation Groups</a>
          </h4>
<p id="section-2.1.5-1">Per <span><a href="#RFC7130" class="xref">"Bidirectional
          Forwarding Detection (BFD) on Link Aggregation Group (LAG)
          Interfaces"</a> [<a href="#RFC7130" class="xref">RFC7130</a>]</span>, configuring BFD on a LAG consists of having micro-BFD
          sessions on each LAG member link. Since the BFD parameters are an
          attribute of the LAG, they should be under the LAG. However, there is
          no LAG YANG data model that we can augment. So, a "lag" data node is
          added to the "bfd" node; see <a href="#DESIGN-DATA" class="xref">Section 2</a>. The configuration is per LAG: we have a list of
          LAGs. The destination IP address of the micro-BFD sessions is
          configured per LAG and per address family (IPv4 and IPv6).<a href="#section-2.1.5-1" class="pilcrow">¶</a></p>
</section>
</section>
</div>
<section id="section-2.2">
        <h3 id="name-design-of-the-operational-s">
<a href="#section-2.2" class="section-number selfRef">2.2. </a><a href="#name-design-of-the-operational-s" class="section-name selfRef">Design of the Operational State Model</a>
        </h3>
<p id="section-2.2-1">The operational state model contains both the overall statistics for
        the BFD sessions running on the device and the per-session operational
        information.<a href="#section-2.2-1" class="pilcrow">¶</a></p>
<p id="section-2.2-2">The overall statistics for the BFD sessions consist of the number of BFD
        sessions, the number of BFD sessions that are up, etc. This information is available
        globally (i.e., for all BFD sessions) under the "bfd" node 
        (<a href="#DESIGN-DATA" class="xref">Section 2</a>) and also per type of
        forwarding path.<a href="#section-2.2-2" class="pilcrow">¶</a></p>
<p id="section-2.2-3">For each BFD session, three main categories of operational state
        data are shown.<a href="#section-2.2-3" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-2.2-4">
       <li id="section-2.2-4.1">The first category includes fundamental information regarding a BFD session, such as
        the local discriminator, the remote discriminator, and the ability to
        support Demand mode.<a href="#section-2.2-4.1" class="pilcrow">¶</a>
</li>
          <li id="section-2.2-4.2">The
        second category includes BFD "session-running" information, e.g., the
        remote BFD state and the diagnostic code received. Another example is
        the actual transmit interval between the control packets, which may be
        different from the configured desired minimum transmit
        interval. Similar examples include the actual receive interval
        between the control packets and the actual transmit interval between
        the Echo packets.<a href="#section-2.2-4.2" class="pilcrow">¶</a>
</li>
          <li id="section-2.2-4.3"> The third category contains the detailed statistics
        for the session, e.g., when the session transitioned up/down and how
        long it has been in that state.<a href="#section-2.2-4.3" class="pilcrow">¶</a>
</li>
        </ol>
<p id="section-2.2-5">For some path types, there may be more than one session on the
        virtual path to the destination. For example, with IP multihop and
        MPLS LSPs, there could be multiple BFD sessions from the source to the
        same destination to test the various paths (ECMP) to the destination.
        This is represented by having multiple "sessions" under each
        "session-group".<a href="#section-2.2-5" class="pilcrow">¶</a></p>
</section>
<section id="section-2.3">
        <h3 id="name-notifications">
<a href="#section-2.3" class="section-number selfRef">2.3. </a><a href="#name-notifications" class="section-name selfRef">Notifications</a>
        </h3>
<p id="section-2.3-1">This YANG data model defines notifications to inform end users of
        important events detected during the protocol operation. The
        local discriminator identifies the corresponding BFD session on the
        local system, and the remote discriminator identifies the BFD session
        on the remote system.
        Notifications also give more important details about BFD sessions,
        e.g., new state, time in previous state, network instance, and the
        reason that the BFD session state changed. The notifications are
        defined for each type of forwarding path but use groupings for common
        information.<a href="#section-2.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-2.4">
        <h3 id="name-rpc-operations">
<a href="#section-2.4" class="section-number selfRef">2.4. </a><a href="#name-rpc-operations" class="section-name selfRef">RPC Operations</a>
        </h3>
<p id="section-2.4-1">None.<a href="#section-2.4-1" class="pilcrow">¶</a></p>
</section>
<section id="section-2.5">
        <h3 id="name-bfd-top-level-hierarchy">
<a href="#section-2.5" class="section-number selfRef">2.5. </a><a href="#name-bfd-top-level-hierarchy" class="section-name selfRef">BFD Top-Level Hierarchy</a>
        </h3>
<p id="section-2.5-1">At the "bfd" node under "control-plane-protocol", there is no
        configuration data -- only operational state data. The operational state 
        data consists of overall BFD session statistics, i.e., for BFD on all
        types of forwarding paths.<a href="#section-2.5-1" class="pilcrow">¶</a></p>
<div id="section-2.5-2">
<pre class="lang-yangtree sourcecode">
module: ietf-bfd
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol:
    +--rw bfd
       +--ro summary
          +--ro number-of-sessions?              yang:gauge32
          +--ro number-of-sessions-up?           yang:gauge32
          +--ro number-of-sessions-down?         yang:gauge32
          +--ro number-of-sessions-admin-down?   yang:gauge32
</pre><a href="#section-2.5-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-2.6">
        <h3 id="name-bfd-ip-single-hop-hierarchy">
<a href="#section-2.6" class="section-number selfRef">2.6. </a><a href="#name-bfd-ip-single-hop-hierarchy" class="section-name selfRef">BFD IP Single-Hop Hierarchy</a>
        </h3>
<p id="section-2.6-1">An "ip-sh" node is added under the "bfd" node in
        "control-plane-protocol". The configuration data and operational state data
        for each BFD IP single-hop session are under this "ip-sh" node.<a href="#section-2.6-1" class="pilcrow">¶</a></p>
<div id="section-2.6-2">
<pre class="breakable lang-yangtree sourcecode">
module: ietf-bfd-ip-sh
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/bfd:bfd:
    +--rw ip-sh
       +--ro summary
       |  +--ro number-of-sessions?              yang:gauge32
       |  +--ro number-of-sessions-up?           yang:gauge32
       |  +--ro number-of-sessions-down?         yang:gauge32
       |  +--ro number-of-sessions-admin-down?   yang:gauge32
       +--rw sessions
       |  +--rw session* [interface dest-addr]
       |     +--rw interface                         if:interface-ref
       |     +--rw dest-addr                         inet:ip-address
       |     +--rw source-addr?                      inet:ip-address
       |     +--rw local-multiplier?                 multiplier
       |     +--rw (interval-config-type)?
       |     |  +--:(tx-rx-intervals)
       |     |  |  +--rw desired-min-tx-interval?    uint32
       |     |  |  +--rw required-min-rx-interval?   uint32
       |     |  +--:(single-interval) {single-minimum-interval}?
       |     |     +--rw min-interval?               uint32
       |     +--rw demand-enabled?                   boolean
       |     |       {demand-mode}?
       |     +--rw admin-down?                       boolean
       |     +--rw authentication! {authentication}?
       |     |  +--rw key-chain?    key-chain:key-chain-ref
       |     |  +--rw meticulous?   boolean
       |     +--ro path-type?                        identityref
       |     +--ro ip-encapsulation?                 boolean
       |     +--ro local-discriminator?              discriminator
       |     +--ro remote-discriminator?             discriminator
       |     +--ro remote-multiplier?                multiplier
       |     +--ro demand-capability?                boolean
       |     |       {demand-mode}?
       |     +--ro source-port?                      inet:port-number
       |     +--ro dest-port?                        inet:port-number
       |     +--ro session-running
       |     |  +--ro session-index?                uint32
       |     |  +--ro local-state?                  state
       |     |  +--ro remote-state?                 state
       |     |  +--ro local-diagnostic?
       |     |  |       iana-bfd-types:diagnostic
       |     |  +--ro remote-diagnostic?
       |     |  |       iana-bfd-types:diagnostic
       |     |  +--ro remote-authenticated?         boolean
       |     |  +--ro remote-authentication-type?
       |     |  |       iana-bfd-types:auth-type {authentication}?
       |     |  +--ro detection-mode?               enumeration
       |     |  +--ro negotiated-tx-interval?       uint32
       |     |  +--ro negotiated-rx-interval?       uint32
       |     |  +--ro detection-time?               uint32
       |     |  +--ro echo-tx-interval-in-use?      uint32
       |     |          {echo-mode}?
       |     +--ro session-statistics
       |        +--ro create-time?
       |        |       yang:date-and-time
       |        +--ro last-down-time?
       |        |       yang:date-and-time
       |        +--ro last-up-time?
       |        |       yang:date-and-time
       |        +--ro down-count?                     yang:counter32
       |        +--ro admin-down-count?               yang:counter32
       |        +--ro receive-packet-count?           yang:counter64
       |        +--ro send-packet-count?              yang:counter64
       |        +--ro receive-invalid-packet-count?   yang:counter64
       |        +--ro send-failed-packet-count?       yang:counter64
       +--rw interfaces* [interface]
          +--rw interface         if:interface-ref
          +--rw authentication! {authentication}?
             +--rw key-chain?    key-chain:key-chain-ref
             +--rw meticulous?   boolean

  notifications:
    +---n singlehop-notification
       +--ro local-discr?                 discriminator
       +--ro remote-discr?                discriminator
       +--ro new-state?                   state
       +--ro state-change-reason?         iana-bfd-types:diagnostic
       +--ro time-of-last-state-change?   yang:date-and-time
       +--ro dest-addr?                   inet:ip-address
       +--ro source-addr?                 inet:ip-address
       +--ro session-index?               uint32
       +--ro path-type?                   identityref
       +--ro interface?                   if:interface-ref
       +--ro echo-enabled?                boolean
</pre><a href="#section-2.6-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-2.7">
        <h3 id="name-bfd-ip-multihop-hierarchy">
<a href="#section-2.7" class="section-number selfRef">2.7. </a><a href="#name-bfd-ip-multihop-hierarchy" class="section-name selfRef">BFD IP Multihop Hierarchy</a>
        </h3>
<p id="section-2.7-1">An "ip-mh" node is added under the "bfd" node in
        "control-plane-protocol". The configuration data and operational state data
        for each BFD IP multihop session are under this "ip-mh" node. In the
        operational state model, we support multiple BFD multihop sessions per
        remote address (ECMP); the local discriminator is used as the key.<a href="#section-2.7-1" class="pilcrow">¶</a></p>
<div id="section-2.7-2">
<pre class="breakable lang-yangtree sourcecode">
module: ietf-bfd-ip-mh
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/bfd:bfd:
    +--rw ip-mh
       +--ro summary
       |  +--ro number-of-sessions?              yang:gauge32
       |  +--ro number-of-sessions-up?           yang:gauge32
       |  +--ro number-of-sessions-down?         yang:gauge32
       |  +--ro number-of-sessions-admin-down?   yang:gauge32
       +--rw session-groups
          +--rw session-group* [source-addr dest-addr]
             +--rw source-addr                       inet:ip-address
             +--rw dest-addr                         inet:ip-address
             +--rw local-multiplier?                 multiplier
             +--rw (interval-config-type)?
             |  +--:(tx-rx-intervals)
             |  |  +--rw desired-min-tx-interval?    uint32
             |  |  +--rw required-min-rx-interval?   uint32
             |  +--:(single-interval) {single-minimum-interval}?
             |     +--rw min-interval?               uint32
             +--rw demand-enabled?                   boolean
             |       {demand-mode}?
             +--rw admin-down?                       boolean
             +--rw authentication! {authentication}?
             |  +--rw key-chain?    key-chain:key-chain-ref
             |  +--rw meticulous?   boolean
             +--rw tx-ttl?                           bfd-types:hops
             +--rw rx-ttl                            bfd-types:hops
             +--ro sessions* []
                +--ro path-type?              identityref
                +--ro ip-encapsulation?       boolean
                +--ro local-discriminator?    discriminator
                +--ro remote-discriminator?   discriminator
                +--ro remote-multiplier?      multiplier
                +--ro demand-capability?      boolean {demand-mode}?
                +--ro source-port?            inet:port-number
                +--ro dest-port?              inet:port-number
                +--ro session-running
                |  +--ro session-index?                uint32
                |  +--ro local-state?                  state
                |  +--ro remote-state?                 state
                |  +--ro local-diagnostic?
                |  |       iana-bfd-types:diagnostic
                |  +--ro remote-diagnostic?
                |  |       iana-bfd-types:diagnostic
                |  +--ro remote-authenticated?         boolean
                |  +--ro remote-authentication-type?
                |  |       iana-bfd-types:auth-type {authentication}?
                |  +--ro detection-mode?               enumeration
                |  +--ro negotiated-tx-interval?       uint32
                |  +--ro negotiated-rx-interval?       uint32
                |  +--ro detection-time?               uint32
                |  +--ro echo-tx-interval-in-use?      uint32
                |          {echo-mode}?
                +--ro session-statistics
                   +--ro create-time?
                   |       yang:date-and-time
                   +--ro last-down-time?
                   |       yang:date-and-time
                   +--ro last-up-time?
                   |       yang:date-and-time
                   +--ro down-count?
                   |       yang:counter32
                   +--ro admin-down-count?
                   |       yang:counter32
                   +--ro receive-packet-count?
                   |       yang:counter64
                   +--ro send-packet-count?
                   |       yang:counter64
                   +--ro receive-invalid-packet-count?
                   |       yang:counter64
                   +--ro send-failed-packet-count?
                           yang:counter64

  notifications:
    +---n multihop-notification
       +--ro local-discr?                 discriminator
       +--ro remote-discr?                discriminator
       +--ro new-state?                   state
       +--ro state-change-reason?         iana-bfd-types:diagnostic
       +--ro time-of-last-state-change?   yang:date-and-time
       +--ro dest-addr?                   inet:ip-address
       +--ro source-addr?                 inet:ip-address
       +--ro session-index?               uint32
       +--ro path-type?                   identityref
</pre><a href="#section-2.7-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-2.8">
        <h3 id="name-bfd-over-lag-hierarchy">
<a href="#section-2.8" class="section-number selfRef">2.8. </a><a href="#name-bfd-over-lag-hierarchy" class="section-name selfRef">BFD-over-LAG Hierarchy</a>
        </h3>
<p id="section-2.8-1">A "lag" node is added under the "bfd" node in
        "control-plane-protocol". The configuration data and operational state data
        for each BFD LAG session are under this "lag" node.<a href="#section-2.8-1" class="pilcrow">¶</a></p>
<div id="section-2.8-2">
<pre class="breakable lang-yangtree sourcecode">
module: ietf-bfd-lag
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/bfd:bfd:
    +--rw lag
       +--rw micro-bfd-ipv4-session-statistics
       |  +--ro summary
       |     +--ro number-of-sessions?              yang:gauge32
       |     +--ro number-of-sessions-up?           yang:gauge32
       |     +--ro number-of-sessions-down?         yang:gauge32
       |     +--ro number-of-sessions-admin-down?   yang:gauge32
       +--rw micro-bfd-ipv6-session-statistics
       |  +--ro summary
       |     +--ro number-of-sessions?              yang:gauge32
       |     +--ro number-of-sessions-up?           yang:gauge32
       |     +--ro number-of-sessions-down?         yang:gauge32
       |     +--ro number-of-sessions-admin-down?   yang:gauge32
       +--rw sessions
          +--rw session* [lag-name]
             +--rw lag-name                          if:interface-ref
             +--rw ipv4-dest-addr?
             |       inet:ipv4-address
             +--rw ipv6-dest-addr?
             |       inet:ipv6-address
             +--rw local-multiplier?                 multiplier
             +--rw (interval-config-type)?
             |  +--:(tx-rx-intervals)
             |  |  +--rw desired-min-tx-interval?    uint32
             |  |  +--rw required-min-rx-interval?   uint32
             |  +--:(single-interval) {single-minimum-interval}?
             |     +--rw min-interval?               uint32
             +--rw demand-enabled?                   boolean
             |       {demand-mode}?
             +--rw admin-down?                       boolean
             +--rw authentication! {authentication}?
             |  +--rw key-chain?    key-chain:key-chain-ref
             |  +--rw meticulous?   boolean
             +--rw use-ipv4?                         boolean
             +--rw use-ipv6?                         boolean
             +--ro member-links* [member-link]
                +--ro member-link       if:interface-ref
                +--ro micro-bfd-ipv4
                |  +--ro path-type?              identityref
                |  +--ro ip-encapsulation?       boolean
                |  +--ro local-discriminator?    discriminator
                |  +--ro remote-discriminator?   discriminator
                |  +--ro remote-multiplier?      multiplier
                |  +--ro demand-capability?      boolean
                |  |       {demand-mode}?
                |  +--ro source-port?            inet:port-number
                |  +--ro dest-port?              inet:port-number
                |  +--ro session-running
                |  |  +--ro session-index?                uint32
                |  |  +--ro local-state?                  state
                |  |  +--ro remote-state?                 state
                |  |  +--ro local-diagnostic?
                |  |  |       iana-bfd-types:diagnostic
                |  |  +--ro remote-diagnostic?
                |  |  |       iana-bfd-types:diagnostic
                |  |  +--ro remote-authenticated?         boolean
                |  |  +--ro remote-authentication-type?
                |  |  |       iana-bfd-types:auth-type
                |  |  |       {authentication}?
                |  |  +--ro detection-mode?               enumeration
                |  |  +--ro negotiated-tx-interval?       uint32
                |  |  +--ro negotiated-rx-interval?       uint32
                |  |  +--ro detection-time?               uint32
                |  |  +--ro echo-tx-interval-in-use?      uint32
                |  |          {echo-mode}?
                |  +--ro session-statistics
                |     +--ro create-time?
                |     |       yang:date-and-time
                |     +--ro last-down-time?
                |     |       yang:date-and-time
                |     +--ro last-up-time?
                |     |       yang:date-and-time
                |     +--ro down-count?
                |     |       yang:counter32
                |     +--ro admin-down-count?
                |     |       yang:counter32
                |     +--ro receive-packet-count?
                |     |       yang:counter64
                |     +--ro send-packet-count?
                |     |       yang:counter64
                |     +--ro receive-invalid-packet-count?
                |     |       yang:counter64
                |     +--ro send-failed-packet-count?
                |             yang:counter64
                +--ro micro-bfd-ipv6
                   +--ro path-type?              identityref
                   +--ro ip-encapsulation?       boolean
                   +--ro local-discriminator?    discriminator
                   +--ro remote-discriminator?   discriminator
                   +--ro remote-multiplier?      multiplier
                   +--ro demand-capability?      boolean
                   |       {demand-mode}?
                   +--ro source-port?            inet:port-number
                   +--ro dest-port?              inet:port-number
                   +--ro session-running
                   |  +--ro session-index?                uint32
                   |  +--ro local-state?                  state
                   |  +--ro remote-state?                 state
                   |  +--ro local-diagnostic?
                   |  |       iana-bfd-types:diagnostic
                   |  +--ro remote-diagnostic?
                   |  |       iana-bfd-types:diagnostic
                   |  +--ro remote-authenticated?         boolean
                   |  +--ro remote-authentication-type?
                   |  |       iana-bfd-types:auth-type
                   |  |       {authentication}?
                   |  +--ro detection-mode?               enumeration
                   |  +--ro negotiated-tx-interval?       uint32
                   |  +--ro negotiated-rx-interval?       uint32
                   |  +--ro detection-time?               uint32
                   |  +--ro echo-tx-interval-in-use?      uint32
                   |          {echo-mode}?
                   +--ro session-statistics
                      +--ro create-time?
                      |       yang:date-and-time
                      +--ro last-down-time?
                      |       yang:date-and-time
                      +--ro last-up-time?
                      |       yang:date-and-time
                      +--ro down-count?
                      |       yang:counter32
                      +--ro admin-down-count?
                      |       yang:counter32
                      +--ro receive-packet-count?
                      |       yang:counter64
                      +--ro send-packet-count?
                      |       yang:counter64
                      +--ro receive-invalid-packet-count?
                      |       yang:counter64
                      +--ro send-failed-packet-count?
                              yang:counter64

  notifications:
    +---n lag-notification
       +--ro local-discr?                 discriminator
       +--ro remote-discr?                discriminator
       +--ro new-state?                   state
       +--ro state-change-reason?         iana-bfd-types:diagnostic
       +--ro time-of-last-state-change?   yang:date-and-time
       +--ro dest-addr?                   inet:ip-address
       +--ro source-addr?                 inet:ip-address
       +--ro session-index?               uint32
       +--ro path-type?                   identityref
       +--ro lag-name?                    if:interface-ref
       +--ro member-link?                 if:interface-ref
</pre><a href="#section-2.8-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-2.9">
        <h3 id="name-bfd-over-mpls-lsps-hierarch">
<a href="#section-2.9" class="section-number selfRef">2.9. </a><a href="#name-bfd-over-mpls-lsps-hierarch" class="section-name selfRef">BFD-over-MPLS-LSPs Hierarchy</a>
        </h3>
<p id="section-2.9-1">An "mpls" node is added under the "bfd" node in
        "control-plane-protocol". The configuration is per MPLS FEC under this
        "mpls" node. In the operational state model, we support multiple BFD
        sessions per MPLS FEC (ECMP); the local discriminator is used as the key.
        The "mpls" node can be used in a network device (top level) or can be
        mounted in an LNE or network instance.<a href="#section-2.9-1" class="pilcrow">¶</a></p>
<div id="section-2.9-2">
<pre class="breakable lang-yangtree sourcecode">
module: ietf-bfd-mpls
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/bfd:bfd:
    +--rw mpls
       +--ro summary
       |  +--ro number-of-sessions?              yang:gauge32
       |  +--ro number-of-sessions-up?           yang:gauge32
       |  +--ro number-of-sessions-down?         yang:gauge32
       |  +--ro number-of-sessions-admin-down?   yang:gauge32
       +--rw egress
       |  +--rw enabled?                          boolean
       |  +--rw local-multiplier?                 multiplier
       |  +--rw (interval-config-type)?
       |  |  +--:(tx-rx-intervals)
       |  |  |  +--rw desired-min-tx-interval?    uint32
       |  |  |  +--rw required-min-rx-interval?   uint32
       |  |  +--:(single-interval) {single-minimum-interval}?
       |  |     +--rw min-interval?               uint32
       |  +--rw authentication! {authentication}?
       |     +--rw key-chain?    key-chain:key-chain-ref
       |     +--rw meticulous?   boolean
       +--rw session-groups
          +--rw session-group* [mpls-fec]
             +--rw mpls-fec                          inet:ip-prefix
             +--rw local-multiplier?                 multiplier
             +--rw (interval-config-type)?
             |  +--:(tx-rx-intervals)
             |  |  +--rw desired-min-tx-interval?    uint32
             |  |  +--rw required-min-rx-interval?   uint32
             |  +--:(single-interval) {single-minimum-interval}?
             |     +--rw min-interval?               uint32
             +--rw demand-enabled?                   boolean
             |       {demand-mode}?
             +--rw admin-down?                       boolean
             +--rw authentication! {authentication}?
             |  +--rw key-chain?    key-chain:key-chain-ref
             |  +--rw meticulous?   boolean
             +--ro sessions* []
                +--ro path-type?              identityref
                +--ro ip-encapsulation?       boolean
                +--ro local-discriminator?    discriminator
                +--ro remote-discriminator?   discriminator
                +--ro remote-multiplier?      multiplier
                +--ro demand-capability?      boolean {demand-mode}?
                +--ro source-port?            inet:port-number
                +--ro dest-port?              inet:port-number
                +--ro session-running
                |  +--ro session-index?                uint32
                |  +--ro local-state?                  state
                |  +--ro remote-state?                 state
                |  +--ro local-diagnostic?
                |  |       iana-bfd-types:diagnostic
                |  +--ro remote-diagnostic?
                |  |       iana-bfd-types:diagnostic
                |  +--ro remote-authenticated?         boolean
                |  +--ro remote-authentication-type?
                |  |       iana-bfd-types:auth-type {authentication}?
                |  +--ro detection-mode?               enumeration
                |  +--ro negotiated-tx-interval?       uint32
                |  +--ro negotiated-rx-interval?       uint32
                |  +--ro detection-time?               uint32
                |  +--ro echo-tx-interval-in-use?      uint32
                |          {echo-mode}?
                +--ro session-statistics
                |  +--ro create-time?
                |  |       yang:date-and-time
                |  +--ro last-down-time?
                |  |       yang:date-and-time
                |  +--ro last-up-time?
                |  |       yang:date-and-time
                |  +--ro down-count?
                |  |       yang:counter32
                |  +--ro admin-down-count?
                |  |       yang:counter32
                |  +--ro receive-packet-count?
                |  |       yang:counter64
                |  +--ro send-packet-count?
                |  |       yang:counter64
                |  +--ro receive-invalid-packet-count?
                |  |       yang:counter64
                |  +--ro send-failed-packet-count?
                |          yang:counter64
                +--ro mpls-dest-address?      inet:ip-address

  notifications:
    +---n mpls-notification
       +--ro local-discr?                 discriminator
       +--ro remote-discr?                discriminator
       +--ro new-state?                   state
       +--ro state-change-reason?         iana-bfd-types:diagnostic
       +--ro time-of-last-state-change?   yang:date-and-time
       +--ro dest-addr?                   inet:ip-address
       +--ro source-addr?                 inet:ip-address
       +--ro session-index?               uint32
       +--ro path-type?                   identityref
       +--ro mpls-dest-address?           inet:ip-address
</pre><a href="#section-2.9-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-2.10">
        <h3 id="name-interaction-with-other-yang">
<a href="#section-2.10" class="section-number selfRef">2.10. </a><a href="#name-interaction-with-other-yang" class="section-name selfRef">Interaction with Other YANG Modules</a>
        </h3>
<p id="section-2.10-1"><span><a href="#RFC8532" class="xref">"Generic YANG Data Model for the Management
        of Operations, Administration, and Maintenance (OAM) Protocols That
        Use Connectionless Communications"</a> [<a href="#RFC8532" class="xref">RFC8532</a>]</span> describes how the 
        Layer-Independent OAM Management in the Multi-Layer Environment (LIME)
        connectionless OAM model could be extended to support BFD.<a href="#section-2.10-1" class="pilcrow">¶</a></p>
<p id="section-2.10-2">Also, the operation of the BFD data model depends on configuration
        parameters that are defined in other YANG modules.<a href="#section-2.10-2" class="pilcrow">¶</a></p>
<section id="section-2.10.1">
          <h4 id="name-ietf-interfaces-module">
<a href="#section-2.10.1" class="section-number selfRef">2.10.1. </a><a href="#name-ietf-interfaces-module" class="section-name selfRef">"ietf-interfaces" Module</a>
          </h4>
<p id="section-2.10.1-1">The following boolean configuration is defined in <span><a href="#RFC8343" class="xref">"A YANG Data Model for Interface Management"</a> [<a href="#RFC8343" class="xref">RFC8343</a>]</span>:<a href="#section-2.10.1-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.10.1-2">
            <dt id="section-2.10.1-2.1">/if:interfaces/if:interface/if:enabled</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.1-2.2">If this configuration is set to "false", no BFD packets can be
            transmitted or received on that interface.<a href="#section-2.10.1-2.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
<section id="section-2.10.2">
          <h4 id="name-ietf-ip-module">
<a href="#section-2.10.2" class="section-number selfRef">2.10.2. </a><a href="#name-ietf-ip-module" class="section-name selfRef">"ietf-ip" Module</a>
          </h4>
<p id="section-2.10.2-1">The following boolean configuration is defined in <span><a href="#RFC8344" class="xref">"A YANG Data Model for IP Management"</a> [<a href="#RFC8344" class="xref">RFC8344</a>]</span>:<a href="#section-2.10.2-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.10.2-2">
            <dt id="section-2.10.2-2.1">/if:interfaces/if:interface/ip:ipv4/ip:enabled</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.2-2.2">If this configuration is set to "false", no BFD IPv4 packets
            can be transmitted or received on that interface.<a href="#section-2.10.2-2.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.10.2-2.3">/if:interfaces/if:interface/ip:ipv4/ip:forwarding</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.2-2.4">If this configuration is set to "false", no BFD IPv4 packets
            can be transmitted or received on that interface.<a href="#section-2.10.2-2.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.10.2-2.5">/if:interfaces/if:interface/ip:ipv6/ip:enabled</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.2-2.6">If this configuration is set to "false", no BFD IPv6 packets
            can be transmitted or received on that interface.<a href="#section-2.10.2-2.6" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-2.10.2-2.7">/if:interfaces/if:interface/ip:ipv6/ip:forwarding</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.2-2.8">If this configuration is set to "false", no BFD IPv6 packets
            can be transmitted or received on that interface.<a href="#section-2.10.2-2.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
<section id="section-2.10.3">
          <h4 id="name-ietf-mpls-module">
<a href="#section-2.10.3" class="section-number selfRef">2.10.3. </a><a href="#name-ietf-mpls-module" class="section-name selfRef">"ietf-mpls" Module</a>
          </h4>
<p id="section-2.10.3-1">The following boolean configuration is defined in <span><a href="#RFC8960" class="xref">"A YANG Data Model for MPLS Base"</a> [<a href="#RFC8960" class="xref">RFC8960</a>]</span>:<a href="#section-2.10.3-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-2.10.3-2">
            <dt id="section-2.10.3-2.1">/rt:routing/mpls:mpls/mpls:interfaces/mpls:interface/mpls:mpls-enabled</dt>
            <dd style="margin-left: 1.5em" id="section-2.10.3-2.2">If this configuration is set to "false", no BFD MPLS packets
            can be transmitted or received on that interface.<a href="#section-2.10.3-2.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
</section>
<div id="BFD-TYPES">
<section id="section-2.11">
        <h3 id="name-bfd-types-yang-module">
<a href="#section-2.11" class="section-number selfRef">2.11. </a><a href="#name-bfd-types-yang-module" class="section-name selfRef">BFD Types YANG Module</a>
        </h3>
<p id="section-2.11-1">This YANG module imports typedefs from <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span> and <span>[<a href="#RFC8177" class="xref">RFC8177</a>]</span>.
        It also imports definitions from
        <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span>, <span>[<a href="#RFC5881" class="xref">RFC5881</a>]</span>,
        <span>[<a href="#RFC5883" class="xref">RFC5883</a>]</span>, <span>[<a href="#RFC5884" class="xref">RFC5884</a>]</span>, and
        <span>[<a href="#RFC7130" class="xref">RFC7130</a>]</span>, as well as the
        "control-plane-protocol" identity from
        <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, and references <span>[<a href="#RFC9127" class="xref">RFC9127</a>]</span>.<a href="#section-2.11-1" class="pilcrow">¶</a></p>
<div id="section-2.11-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd-types@2022-09-22.yang"

module ietf-bfd-types {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-types";
  prefix bfd-types;

  import iana-bfd-types {
    prefix iana-bfd-types;
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains a collection of BFD-specific YANG data type
     definitions, as per RFC 5880, and also groupings that are common
     to other BFD YANG modules.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 5880: Bidirectional Forwarding Detection (BFD)
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "This revision is not backwards compatible with the
       previous version of this model.

       This revision adds an 'if-feature' statement called
       'client-base-cfg-parms' for client configuration parameters.
       Clients expecting to use those parameters now need to
       verify that the server declares support of the feature
       before depending on the presence of the parameters.

       The change was introduced for clients that do not need
       them and have to deviate to prevent them from being
       included.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Feature definitions
   */

  feature single-minimum-interval {
    description
      "This feature indicates that the server supports configuration
       of one minimum interval value that is used for both transmit
       and receive minimum intervals.";
  }

  feature authentication {
    description
      "This feature indicates that the server supports BFD
       authentication.";
    reference
      "RFC 5880: Bidirectional Forwarding Detection (BFD),
       Section 6.7";
  }

  feature demand-mode {
    description
      "This feature indicates that the server supports BFD Demand
       mode.";
    reference
      "RFC 5880: Bidirectional Forwarding Detection (BFD),
       Section 6.6";
  }

  feature echo-mode {
    description
      "This feature indicates that the server supports BFD Echo
       mode.";
    reference
      "RFC 5880: Bidirectional Forwarding Detection (BFD),
       Section 6.4";
  }

  feature client-base-cfg-parms {
    description
      "This feature allows protocol models to configure BFD client
       session parameters.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
                 Detection (BFD).";
  }

  /*
   * Identity definitions
   */

  identity bfdv1 {
    base rt:control-plane-protocol;
    description
      "BFD protocol version 1.";
    reference
      "RFC 5880: Bidirectional Forwarding Detection (BFD)";
  }

  identity path-type {
    description
      "Base identity for the BFD path type.  The path type indicates
       the type of path on which BFD is running.";
  }

  identity path-ip-sh {
    base path-type;
    description
      "BFD on IP single-hop.";
    reference
      "RFC 5881: Bidirectional Forwarding Detection (BFD)
       for IPv4 and IPv6 (Single Hop)";
  }

  identity path-ip-mh {
    base path-type;
    description
      "BFD on IP multihop paths.";
    reference
      "RFC 5883: Bidirectional Forwarding Detection (BFD) for
       Multihop Paths";
  }

  identity path-mpls-te {
    base path-type;
    description
      "BFD on MPLS Traffic Engineering.";
    reference
      "RFC 5884: Bidirectional Forwarding Detection (BFD)
       for MPLS Label Switched Paths (LSPs)";
  }

  identity path-mpls-lsp {
    base path-type;
    description
      "BFD on an MPLS Label Switched Path.";
    reference
      "RFC 5884: Bidirectional Forwarding Detection (BFD)
       for MPLS Label Switched Paths (LSPs)";
  }

  identity path-lag {
    base path-type;
    description
      "Micro-BFD on LAG member links.";
    reference
      "RFC 7130: Bidirectional Forwarding Detection (BFD) on
       Link Aggregation Group (LAG) Interfaces";
  }

  identity encap-type {
    description
      "Base identity for BFD encapsulation type.";
  }

  identity encap-ip {
    base encap-type;
    description
      "BFD with IP encapsulation.";
  }

  /*
   * Type definitions
   */

  typedef discriminator {
    type uint32;
    description
      "BFD Discriminator as described in RFC 5880.";
    reference
      "RFC 5880: Bidirectional Forwarding Detection (BFD)";
  }

  typedef state {
    type enumeration {
      enum adminDown {
        value 0;
        description
          "'adminDown' state.";
      }
      enum down {
        value 1;
        description
          "'Down' state.";
      }
      enum init {
        value 2;
        description
          "'Init' state.";
      }
      enum up {
        value 3;
        description
          "'Up' state.";
      }
    }
    description
      "BFD states as defined in RFC 5880.";
  }

  typedef multiplier {
    type uint8 {
      range "1..255";
    }
    description
      "BFD multiplier as described in RFC 5880.";
  }

  typedef hops {
    type uint8 {
      range "1..255";
    }
    description
      "This corresponds to Time To Live for IPv4 and corresponds to
       the hop limit for IPv6.";
  }

  /*
   * Groupings
   */

  grouping auth-parms {
    description
      "Grouping for BFD authentication parameters
       (see Section 6.7 of RFC 5880).";
    container authentication {
      if-feature "authentication";
      presence "Enables BFD authentication (see Section 6.7
                of RFC 5880).";
      description
        "Parameters for BFD authentication.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD),
         Section 6.7";
      leaf key-chain {
        type key-chain:key-chain-ref;
        description
          "Name of the 'key-chain' as per RFC 8177.";
      }
      leaf meticulous {
        type boolean;
        description
          "Enables a meticulous mode as per Section 6.7 of
           RFC 5880.";
      }
    }
  }

  grouping base-cfg-parms {
    description
      "BFD grouping for base configuration parameters.";
    leaf local-multiplier {
      type multiplier;
      default "3";
      description
        "Multiplier transmitted by the local system.";
    }
    choice interval-config-type {
      default "tx-rx-intervals";
      description
        "Two interval values or one value used for both transmit and
         receive.";
      case tx-rx-intervals {
        leaf desired-min-tx-interval {
          type uint32;
          units "microseconds";
          default "1000000";
          description
            "Desired minimum transmit interval of control packets.";
        }
        leaf required-min-rx-interval {
          type uint32;
          units "microseconds";
          default "1000000";
          description
            "Required minimum receive interval of control packets.";
        }
      }
      case single-interval {
        if-feature "single-minimum-interval";
        leaf min-interval {
          type uint32;
          units "microseconds";
          default "1000000";
          description
            "Desired minimum transmit interval and required
             minimum receive interval of control packets.";
        }
      }
    }
  }

  grouping client-cfg-parms {
    description
      "BFD grouping for configuration parameters
       used by BFD clients, e.g., IGP or MPLS.";
    leaf enabled {
      type boolean;
      default "false";
      description
        "Indicates whether BFD is enabled.";
    }
    uses base-cfg-parms {
      if-feature "client-base-cfg-parms";
    }
  }

  grouping common-cfg-parms {
    description
      "BFD grouping for common configuration parameters.";
    uses base-cfg-parms;
    leaf demand-enabled {
      if-feature "demand-mode";
      type boolean;
      default "false";
      description
        "To enable Demand mode.";
    }
    leaf admin-down {
      type boolean;
      default "false";
      description
        "Indicates whether the BFD session is administratively
         down.";
    }
    uses auth-parms;
  }

  grouping all-session {
    description
      "BFD session operational information.";
    leaf path-type {
      type identityref {
        base path-type;
      }
      config false;
      description
        "BFD path type.  This indicates the path type that BFD is
         running on.";
    }
    leaf ip-encapsulation {
      type boolean;
      config false;
      description
        "Indicates whether BFD encapsulation uses IP.";
    }
    leaf local-discriminator {
      type discriminator;
      config false;
      description
        "Local discriminator.";
    }
    leaf remote-discriminator {
      type discriminator;
      config false;
      description
        "Remote discriminator.";
    }
    leaf remote-multiplier {
      type multiplier;
      config false;
      description
        "Remote multiplier.";
    }
    leaf demand-capability {
      if-feature "demand-mode";
      type boolean;
      config false;
      description
        "Local Demand mode capability.";
    }
    leaf source-port {
      when "../ip-encapsulation = 'true'" {
        description
          "Source port valid only when IP encapsulation is used.";
      }
      type inet:port-number;
      config false;
      description
        "Source UDP port.";
    }
    leaf dest-port {
      when "../ip-encapsulation = 'true'" {
        description
          "Destination port valid only when IP encapsulation
           is used.";
      }
      type inet:port-number;
      config false;
      description
        "Destination UDP port.";
    }
    container session-running {
      config false;
      description
        "BFD 'session-running' information.";
      leaf session-index {
        type uint32;
        description
          "An index used to uniquely identify BFD sessions.";
      }
      leaf local-state {
        type state;
        description
          "Local state.";
      }
      leaf remote-state {
        type state;
        description
          "Remote state.";
      }
      leaf local-diagnostic {
        type iana-bfd-types:diagnostic;
        description
          "Local diagnostic.";
      }
      leaf remote-diagnostic {
        type iana-bfd-types:diagnostic;
        description
          "Remote diagnostic.";
      }
      leaf remote-authenticated {
        type boolean;
        description
          "Indicates whether incoming BFD control packets are
           authenticated.";
      }
      leaf remote-authentication-type {
        when "../remote-authenticated = 'true'" {
          description
            "Only valid when incoming BFD control packets are
             authenticated.";
        }
        if-feature "authentication";
        type iana-bfd-types:auth-type;
        description
          "Authentication type of incoming BFD control packets.";
      }
      leaf detection-mode {
        type enumeration {
          enum async-with-echo {
            value 1;
            description
              "Async with echo.";
          }
          enum async-without-echo {
            value 2;
            description
              "Async without echo.";
          }
          enum demand-with-echo {
            value 3;
            description
              "Demand with echo.";
          }
          enum demand-without-echo {
            value 4;
            description
              "Demand without echo.";
          }
        }
        description
          "Detection mode.";
      }
      leaf negotiated-tx-interval {
        type uint32;
        units "microseconds";
        description
          "Negotiated transmit interval.";
      }
      leaf negotiated-rx-interval {
        type uint32;
        units "microseconds";
        description
          "Negotiated receive interval.";
      }
      leaf detection-time {
        type uint32;
        units "microseconds";
        description
          "Detection time.";
      }
      leaf echo-tx-interval-in-use {
        when "../../path-type = 'bfd-types:path-ip-sh'" {
          description
            "Echo is supported for IP single-hop only.";
        }
        if-feature "echo-mode";
        type uint32;
        units "microseconds";
        description
          "Echo transmit interval in use.";
      }
    }
    container session-statistics {
      config false;
      description
        "BFD per-session statistics.";
      leaf create-time {
        type yang:date-and-time;
        description
          "Time and date when this session was created.";
      }
      leaf last-down-time {
        type yang:date-and-time;
        description
          "Time and date of the last time this session went down.";
      }
      leaf last-up-time {
        type yang:date-and-time;
        description
          "Time and date of the last time this session went up.";
      }
      leaf down-count {
        type yang:counter32;
        description
          "The number of times this session has transitioned to the
           'down' state.";
      }
      leaf admin-down-count {
        type yang:counter32;
        description
          "The number of times this session has transitioned to the
           'admin-down' state.";
      }
      leaf receive-packet-count {
        type yang:counter64;
        description
          "Count of received packets in this session.  This includes
           valid and invalid received packets.";
      }
      leaf send-packet-count {
        type yang:counter64;
        description
          "Count of sent packets in this session.";
      }
      leaf receive-invalid-packet-count {
        type yang:counter64;
        description
          "Count of invalid received packets in this session.";
      }
      leaf send-failed-packet-count {
        type yang:counter64;
        description
          "Count of packets that failed to be sent in this session.";
      }
    }
  }

  grouping session-statistics-summary {
    description
      "Grouping for session statistics summary.";
    container summary {
      config false;
      description
        "BFD session statistics summary.";
      leaf number-of-sessions {
        type yang:gauge32;
        description
          "Number of BFD sessions.";
      }
      leaf number-of-sessions-up {
        type yang:gauge32;
        description
          "Number of BFD sessions currently in the 'Up' state
           (as defined in RFC 5880).";
      }
      leaf number-of-sessions-down {
        type yang:gauge32;
        description
          "Number of BFD sessions currently in the 'Down' or 'Init'
           state but not 'adminDown' (as defined in RFC 5880).";
      }
      leaf number-of-sessions-admin-down {
        type yang:gauge32;
        description
          "Number of BFD sessions currently in the 'adminDown' state
           (as defined in RFC 5880).";
      }
    }
  }

  grouping notification-parms {
    description
      "This group describes common parameters that will be sent
       as part of BFD notifications.";
    leaf local-discr {
      type discriminator;
      description
        "BFD local discriminator.";
    }
    leaf remote-discr {
      type discriminator;
      description
        "BFD remote discriminator.";
    }
    leaf new-state {
      type state;
      description
        "Current BFD state.";
    }
    leaf state-change-reason {
      type iana-bfd-types:diagnostic;
      description
        "Reason for the BFD state change.";
    }
    leaf time-of-last-state-change {
      type yang:date-and-time;
      description
        "Calendar time of the most recent previous state change.";
    }
    leaf dest-addr {
      type inet:ip-address;
      description
        "BFD peer address.";
    }
    leaf source-addr {
      type inet:ip-address;
      description
        "BFD local address.";
    }
    leaf session-index {
      type uint32;
      description
        "An index used to uniquely identify BFD sessions.";
    }
    leaf path-type {
      type identityref {
        base path-type;
      }
      description
        "BFD path type.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.11-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<section id="section-2.12">
        <h3 id="name-bfd-top-level-yang-module">
<a href="#section-2.12" class="section-number selfRef">2.12. </a><a href="#name-bfd-top-level-yang-module" class="section-name selfRef">BFD Top-Level YANG Module</a>
        </h3>
<p id="section-2.12-1">This YANG module imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>. It also references
        <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#section-2.12-1" class="pilcrow">¶</a></p>
<div id="section-2.12-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd@2022-09-22.yang"

module ietf-bfd {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd";
  prefix bfd;

  import ietf-bfd-types {
    prefix bfd-types;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains the YANG definition for BFD parameters as
     per RFC 5880.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 5880: Bidirectional Forwarding Detection (BFD)
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "Updating reference to RFC 9314.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol" {
    when "derived-from-or-self(rt:type, 'bfd-types:bfdv1')" {
      description
        "This augmentation is only valid for a control plane protocol
         instance of BFD (type 'bfdv1').";
    }
    description
      "BFD augmentation.";
    container bfd {
      description
        "BFD top-level container.";
      uses bfd-types:session-statistics-summary;
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.12-2" class="pilcrow">¶</a>
</div>
</section>
<div id="bfd-ip-single-hop-module">
<section id="section-2.13">
        <h3 id="name-bfd-ip-single-hop-yang-modu">
<a href="#section-2.13" class="section-number selfRef">2.13. </a><a href="#name-bfd-ip-single-hop-yang-modu" class="section-name selfRef">BFD IP Single-Hop YANG Module</a>
        </h3>
<p id="section-2.13-1">This YANG module imports "interface-ref" from <span>[<a href="#RFC8343" class="xref">RFC8343</a>]</span> and typedefs from <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>.  It also imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, and it references
        <span>[<a href="#RFC5881" class="xref">RFC5881</a>]</span>.<a href="#section-2.13-1" class="pilcrow">¶</a></p>
<div id="section-2.13-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd-ip-sh@2022-09-22.yang"

module ietf-bfd-ip-sh {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh";
  prefix bfd-ip-sh;

  import ietf-bfd-types {
    prefix bfd-types;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-bfd {
    prefix bfd;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains the YANG definition for BFD IP single-hop
     as per RFC 5881.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 5881: Bidirectional Forwarding Detection (BFD)
     for IPv4 and IPv6 (Single Hop)
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "Updating reference to RFC 9314.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Augments
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/bfd:bfd" {
    description
      "BFD augmentation for IP single-hop.";
    container ip-sh {
      description
        "BFD IP single-hop top-level container.";
      uses bfd-types:session-statistics-summary;
      container sessions {
        description
          "BFD IP single-hop sessions.";
        list session {
          key "interface dest-addr";
          description
            "List of IP single-hop sessions.";
          leaf interface {
            type if:interface-ref;
            description
              "Interface on which the BFD session is running.";
          }
          leaf dest-addr {
            type inet:ip-address;
            description
              "IP address of the peer.";
          }
          leaf source-addr {
            type inet:ip-address;
            description
              "Local IP address.";
          }
          uses bfd-types:common-cfg-parms;
          uses bfd-types:all-session;
        }
      }
      list interfaces {
        key "interface";
        description
          "List of interfaces.";
        leaf interface {
          type if:interface-ref;
          description
            "BFD information for this interface.";
        }
        uses bfd-types:auth-parms;
      }
    }
  }

  /*
   * Notifications
   */

  notification singlehop-notification {
    description
      "Notification for BFD single-hop session state change.  An
       implementation may rate-limit notifications, e.g., when a
       session is continuously changing state.";
    uses bfd-types:notification-parms;
    leaf interface {
      type if:interface-ref;
      description
        "Interface to which this BFD session belongs.";
    }
    leaf echo-enabled {
      type boolean;
      description
        "Indicates whether Echo was enabled for BFD.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.13-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="bfd-ip-multihop-module">
<section id="section-2.14">
        <h3 id="name-bfd-ip-multihop-yang-module">
<a href="#section-2.14" class="section-number selfRef">2.14. </a><a href="#name-bfd-ip-multihop-yang-module" class="section-name selfRef">BFD IP Multihop YANG Module</a>
        </h3>
<p id="section-2.14-1">This YANG module imports typedefs from
        <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>. It also imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, and it references
        <span>[<a href="#RFC5883" class="xref">RFC5883</a>]</span>.<a href="#section-2.14-1" class="pilcrow">¶</a></p>
<div id="section-2.14-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd-ip-mh@2022-09-22.yang"

module ietf-bfd-ip-mh {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh";
  prefix bfd-ip-mh;

  import ietf-bfd-types {
    prefix bfd-types;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-bfd {
    prefix bfd;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains the YANG definition for BFD IP multihop
     as per RFC 5883.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 5883: Bidirectional Forwarding Detection (BFD) for
     Multihop Paths
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "Updating reference to RFC 9314.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Augments
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/bfd:bfd" {
    description
      "BFD augmentation for IP multihop.";
    container ip-mh {
      description
        "BFD IP multihop top-level container.";
      uses bfd-types:session-statistics-summary;
      container session-groups {
        description
          "BFD IP multihop session groups.";
        list session-group {
          key "source-addr dest-addr";
          description
            "Group of BFD IP multihop sessions (for ECMP).  A
             group of sessions is between one source and one
             destination.  Each session has a different field
             in the UDP/IP header for ECMP.";
          leaf source-addr {
            type inet:ip-address;
            description
              "Local IP address.";
          }
          leaf dest-addr {
            type inet:ip-address;
            description
              "IP address of the peer.";
          }
          uses bfd-types:common-cfg-parms;
          leaf tx-ttl {
            type bfd-types:hops;
            default "255";
            description
              "Hop count of outgoing BFD control packets.";
          }
          leaf rx-ttl {
            type bfd-types:hops;
            mandatory true;
            description
              "Minimum allowed hop count value for incoming BFD
               control packets.  Control packets whose hop count is
               lower than this value are dropped.";
          }
          list sessions {
            config false;
            description
              "The multiple BFD sessions between a source and a
               destination.";
            uses bfd-types:all-session;
          }
        }
      }
    }
  }

  /*
   * Notifications
   */

  notification multihop-notification {
    description
      "Notification for BFD multihop session state change.  An
       implementation may rate-limit notifications, e.g., when a
       session is continuously changing state.";
    uses bfd-types:notification-parms;
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.14-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="bfd-over-lag-module">
<section id="section-2.15">
        <h3 id="name-bfd-over-lag-yang-module">
<a href="#section-2.15" class="section-number selfRef">2.15. </a><a href="#name-bfd-over-lag-yang-module" class="section-name selfRef">BFD-over-LAG YANG Module</a>
        </h3>
<p id="section-2.15-1">This YANG module imports "interface-ref" from <span>[<a href="#RFC8343" class="xref">RFC8343</a>]</span> and typedefs from <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>.  It also imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>. Additionally, it references
        <span>[<a href="#RFC7130" class="xref">RFC7130</a>]</span>.<a href="#section-2.15-1" class="pilcrow">¶</a></p>
<div id="section-2.15-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd-lag@2022-09-22.yang"

module ietf-bfd-lag {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-lag";
  prefix bfd-lag;

  import ietf-bfd-types {
    prefix bfd-types;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-bfd {
    prefix bfd;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains the YANG definition for BFD-over-LAG
     interfaces as per RFC 7130.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 7130: Bidirectional Forwarding Detection (BFD) on
     Link Aggregation Group (LAG) Interfaces
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "Updating reference to RFC 9314.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Augments
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/bfd:bfd" {
    description
      "BFD augmentation for a LAG.";
    container lag {
      description
        "BFD-over-LAG top-level container.";
      container micro-bfd-ipv4-session-statistics {
        description
          "Micro-BFD IPv4 session counters.";
        uses bfd-types:session-statistics-summary;
      }
      container micro-bfd-ipv6-session-statistics {
        description
          "Micro-BFD IPv6 session counters.";
        uses bfd-types:session-statistics-summary;
      }
      container sessions {
        description
          "BFD-over-LAG sessions.";
        list session {
          key "lag-name";
          description
            "List of BFD-over-LAG sessions.";
          leaf lag-name {
            type if:interface-ref;
            description
              "Name of the LAG.";
          }
          leaf ipv4-dest-addr {
            type inet:ipv4-address;
            description
              "IPv4 address of the peer, for IPv4 micro-BFD.";
          }
          leaf ipv6-dest-addr {
            type inet:ipv6-address;
            description
              "IPv6 address of the peer, for IPv6 micro-BFD.";
          }
          uses bfd-types:common-cfg-parms;
          leaf use-ipv4 {
            type boolean;
            description
              "Using IPv4 micro-BFD.";
          }
          leaf use-ipv6 {
            type boolean;
            description
              "Using IPv6 micro-BFD.";
          }
          list member-links {
            key "member-link";
            config false;
            description
              "Micro-BFD over a LAG.  This represents one
               member link.";
            leaf member-link {
              type if:interface-ref;
              description
                "Member link on which micro-BFD is running.";
            }
            container micro-bfd-ipv4 {
              when "../../use-ipv4 = 'true'" {
                description
                  "Needed only if IPv4 is used.";
              }
              description
                "Micro-BFD IPv4 session state on a member link.";
              uses bfd-types:all-session;
            }
            container micro-bfd-ipv6 {
              when "../../use-ipv6 = 'true'" {
                description
                  "Needed only if IPv6 is used.";
              }
              description
                "Micro-BFD IPv6 session state on a member link.";
              uses bfd-types:all-session;
            }
          }
        }
      }
    }
  }

  /*
   * Notifications
   */

  notification lag-notification {
    description
      "Notification for BFD-over-LAG session state change.
       An implementation may rate-limit notifications, e.g., when a
       session is continuously changing state.";
    uses bfd-types:notification-parms;
    leaf lag-name {
      type if:interface-ref;
      description
        "LAG interface name.";
    }
    leaf member-link {
      type if:interface-ref;
      description
        "Member link on which BFD is running.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.15-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="bfd-over-mpls-module">
<section id="section-2.16">
        <h3 id="name-bfd-over-mpls-yang-module">
<a href="#section-2.16" class="section-number selfRef">2.16. </a><a href="#name-bfd-over-mpls-yang-module" class="section-name selfRef">BFD-over-MPLS YANG Module</a>
        </h3>
<p id="section-2.16-1">This YANG module imports typedefs from <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>. It also imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>.
        Additionally, it references <span>[<a href="#RFC5586" class="xref">RFC5586</a>]</span> and
        <span>[<a href="#RFC5884" class="xref">RFC5884</a>]</span>.<a href="#section-2.16-1" class="pilcrow">¶</a></p>
<div id="section-2.16-2">
<pre class="breakable lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-bfd-mpls@2022-09-22.yang"

module ietf-bfd-mpls {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-mpls";
  prefix bfd-mpls;

  import ietf-bfd-types {
    prefix bfd-types;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-bfd {
    prefix bfd;
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }
  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }
  import ietf-routing {
    prefix rt;
    reference
      "RFC 8349: A YANG Data Model for Routing Management
       (NMDA Version)";
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains the YANG definition for BFD parameters for
     MPLS LSPs as per RFC 5884.

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

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

     This version of this YANG module is part of RFC 9314; see the
     RFC itself for full legal notices.";
  reference
    "RFC 5884: Bidirectional Forwarding Detection (BFD)
     for MPLS Label Switched Paths (LSPs)
     RFC 9314: YANG Data Model for Bidirectional Forwarding
     Detection (BFD)";

  revision 2022-09-22 {
    description
      "Updates to use base-cfg-parms instead of client-cfg-parms,
       and add the enabled flag.";
    reference
      "RFC 9314: YANG Data Model for Bidirectional Forwarding
       Detection (BFD).";
  }
  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Identity definitions
   */

  identity encap-gach {
    base bfd-types:encap-type;
    description
      "BFD with Generic Associated Channel (G-ACh) encapsulation
       as per RFC 5586.";
    reference
      "RFC 5586: MPLS Generic Associated Channel";
  }

  identity encap-ip-gach {
    base bfd-types:encap-type;
    description
      "BFD with IP and G-ACh encapsulation as per RFC 5586.";
  }

  /*
   * Groupings
   */

  grouping encap-cfg {
    description
      "Configuration for BFD encapsulation.";
    leaf encap {
      type identityref {
        base bfd-types:encap-type;
      }
      default "bfd-types:encap-ip";
      description
        "BFD encapsulation.";
    }
  }

  grouping mpls-dest-address {
    description
      "Destination address as per RFC 5884.";
    reference
      "RFC 5884: Bidirectional Forwarding Detection (BFD)
       for MPLS Label Switched Paths (LSPs)";
    leaf mpls-dest-address {
      type inet:ip-address;
      config false;
      description
        "Destination address as per RFC 5884.
         Needed if IP encapsulation is used.";
    }
  }

  /*
   * Augments
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/bfd:bfd" {
    description
      "BFD augmentation for MPLS.";
    container mpls {
      description
        "BFD MPLS top-level container.";
      uses bfd-types:session-statistics-summary;
      container egress {
        description
          "Egress configuration.";
        leaf enabled {
          type boolean;
          default "false";
          description
            "Indicates whether BFD over MPLS is enabled.";
        }
        uses bfd-types:base-cfg-parms;
        uses bfd-types:auth-parms;
      }
      container session-groups {
        description
          "BFD-over-MPLS session groups.";
        list session-group {
          key "mpls-fec";
          description
            "Group of BFD MPLS sessions (for ECMP).  A group of
             sessions is for one FEC.  Each session has a different
             field in the UDP/IP header for ECMP.";
          leaf mpls-fec {
            type inet:ip-prefix;
            description
              "MPLS FEC.";
          }
          uses bfd-types:common-cfg-parms;
          list sessions {
            config false;
            description
              "The BFD sessions for an MPLS FEC.  The local
               discriminator is unique for each session in the
               group.";
            uses bfd-types:all-session;
            uses bfd-mpls:mpls-dest-address;
          }
        }
      }
    }
  }

  /*
   * Notifications
   */

  notification mpls-notification {
    description
      "Notification for BFD-over-MPLS FEC session state change.
       An implementation may rate-limit notifications, e.g., when a
       session is continuously changing state.";
    uses bfd-types:notification-parms;
    leaf mpls-dest-address {
      type inet:ip-address;
      description
        "Destination address as per RFC 5884.
         Needed if IP encapsulation is used.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-2.16-2" class="pilcrow">¶</a>
</div>
</section>
</div>
</section>
</div>
<section id="section-3">
      <h2 id="name-data-model-examples">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-data-model-examples" class="section-name selfRef">Data Model Examples</a>
      </h2>
<p id="section-3-1">This section presents some simple and illustrative examples of how to
      configure BFD.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">The examples are represented in XML <span>[<a href="#W3C.REC-xml-20081126" class="xref">W3C.REC-xml-20081126</a>]</span>.<a href="#section-3-2" class="pilcrow">¶</a></p>
<section id="section-3.1">
        <h3 id="name-ip-single-hop">
<a href="#section-3.1" class="section-number selfRef">3.1. </a><a href="#name-ip-single-hop" class="section-name selfRef">IP Single-Hop</a>
        </h3>
<p id="section-3.1-1">The following is an example configuration for a BFD IP single-hop
        session. The desired transmit interval and the required receive
        interval are both set to 10 ms.<a href="#section-3.1-1" class="pilcrow">¶</a></p>
<div id="section-3.1-2">
<pre class="lang-xml sourcecode">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"&gt;
  &lt;interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"&gt;
    &lt;interface&gt;
      &lt;name&gt;eth0&lt;/name&gt;
      &lt;type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"&gt;
        ianaift:ethernetCsmacd
      &lt;/type&gt;
    &lt;/interface&gt;
  &lt;/interfaces&gt;
  &lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
    &lt;control-plane-protocols&gt;
      &lt;control-plane-protocol&gt;
        &lt;type xmlns:bfd-types=
            "urn:ietf:params:xml:ns:yang:ietf-bfd-types"&gt;
          bfd-types:bfdv1
        &lt;/type&gt;
        &lt;name&gt;name:BFD&lt;/name&gt;
        &lt;bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"&gt;
          &lt;ip-sh xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh"&gt;
            &lt;sessions&gt;
              &lt;session&gt;
                &lt;interface&gt;eth0&lt;/interface&gt;
                &lt;dest-addr&gt;2001:db8:0:113::101&lt;/dest-addr&gt;
                &lt;desired-min-tx-interval&gt;
                  10000
                &lt;/desired-min-tx-interval&gt;
                &lt;required-min-rx-interval&gt;
                  10000
                &lt;/required-min-rx-interval&gt;
              &lt;/session&gt;
            &lt;/sessions&gt;
          &lt;/ip-sh&gt;
        &lt;/bfd&gt;
      &lt;/control-plane-protocol&gt;
    &lt;/control-plane-protocols&gt;
  &lt;/routing&gt;
&lt;/config&gt;
</pre><a href="#section-3.1-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-3.2">
        <h3 id="name-ip-multihop">
<a href="#section-3.2" class="section-number selfRef">3.2. </a><a href="#name-ip-multihop" class="section-name selfRef">IP Multihop</a>
        </h3>
<p id="section-3.2-1">The following is an example configuration for a BFD IP multihop
        session group. The desired transmit interval and the required receive
        interval are both set to 150 ms.<a href="#section-3.2-1" class="pilcrow">¶</a></p>
<div id="section-3.2-2">
<pre class="lang-xml sourcecode">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"&gt;
  &lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
    &lt;control-plane-protocols&gt;
      &lt;control-plane-protocol&gt;
        &lt;type xmlns:bfd-types=
            "urn:ietf:params:xml:ns:yang:ietf-bfd-types"&gt;
          bfd-types:bfdv1
        &lt;/type&gt;
        &lt;name&gt;name:BFD&lt;/name&gt;
        &lt;bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"&gt;
          &lt;ip-mh xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh"&gt;
            &lt;session-groups&gt;
              &lt;session-group&gt;
                &lt;source-addr&gt;2001:db8:0:113::103&lt;/source-addr&gt;
                &lt;dest-addr&gt;2001:db8:0:114::100&lt;/dest-addr&gt;
                &lt;desired-min-tx-interval&gt;
                  150000
                &lt;/desired-min-tx-interval&gt;
                &lt;required-min-rx-interval&gt;
                  150000
                &lt;/required-min-rx-interval&gt;
                &lt;rx-ttl&gt;240&lt;/rx-ttl&gt;
              &lt;/session-group&gt;
            &lt;/session-groups&gt;
          &lt;/ip-mh&gt;
        &lt;/bfd&gt;
      &lt;/control-plane-protocol&gt;
    &lt;/control-plane-protocols&gt;
  &lt;/routing&gt;
&lt;/config&gt;
</pre><a href="#section-3.2-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-3.3">
        <h3 id="name-lag">
<a href="#section-3.3" class="section-number selfRef">3.3. </a><a href="#name-lag" class="section-name selfRef">LAG</a>
        </h3>
<p id="section-3.3-1">The following is an example of BFD configuration for a LAG session.
        In this case, an interface named "Bundle-Ether1" of interface type
        "ieee8023adLag" has a desired transmit interval and required receive interval
        set to 10 ms.<a href="#section-3.3-1" class="pilcrow">¶</a></p>
<div id="section-3.3-2">
<pre class="lang-xml sourcecode">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"&gt;
  &lt;interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"&gt;
    &lt;interface&gt;
      &lt;name&gt;Bundle-Ether1&lt;/name&gt;
      &lt;type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"&gt;
        ianaift:ieee8023adLag
      &lt;/type&gt;
    &lt;/interface&gt;
  &lt;/interfaces&gt;
  &lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
    &lt;control-plane-protocols&gt;
      &lt;control-plane-protocol&gt;
        &lt;type xmlns:bfd-types=
            "urn:ietf:params:xml:ns:yang:ietf-bfd-types"&gt;
          bfd-types:bfdv1
        &lt;/type&gt;
        &lt;name&gt;name:BFD&lt;/name&gt;
        &lt;bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"&gt;
          &lt;lag xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-lag"&gt;
            &lt;sessions&gt;
              &lt;session&gt;
                &lt;lag-name&gt;Bundle-Ether1&lt;/lag-name&gt;
                &lt;ipv6-dest-addr&gt;2001:db8:112::16&lt;/ipv6-dest-addr&gt;
                &lt;desired-min-tx-interval&gt;
                  10000
                &lt;/desired-min-tx-interval&gt;
                &lt;required-min-rx-interval&gt;
                  10000
                &lt;/required-min-rx-interval&gt;
                &lt;use-ipv6&gt;true&lt;/use-ipv6&gt;
              &lt;/session&gt;
            &lt;/sessions&gt;
          &lt;/lag&gt;
        &lt;/bfd&gt;
      &lt;/control-plane-protocol&gt;
    &lt;/control-plane-protocols&gt;
  &lt;/routing&gt;
&lt;/config&gt;
</pre><a href="#section-3.3-2" class="pilcrow">¶</a>
</div>
</section>
<section id="section-3.4">
        <h3 id="name-mpls">
<a href="#section-3.4" class="section-number selfRef">3.4. </a><a href="#name-mpls" class="section-name selfRef">MPLS</a>
        </h3>
<p id="section-3.4-1">The following is an example of BFD configured for an MPLS LSP. In
        this case, the desired transmit interval and required receive interval
        are both set to 250 ms.<a href="#section-3.4-1" class="pilcrow">¶</a></p>
<div id="section-3.4-2">
<pre class="lang-xml sourcecode">
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"&gt;
  &lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
    &lt;control-plane-protocols&gt;
      &lt;control-plane-protocol&gt;
        &lt;type xmlns:bfd-types=
            "urn:ietf:params:xml:ns:yang:ietf-bfd-types"&gt;
          bfd-types:bfdv1
        &lt;/type&gt;
        &lt;name&gt;name:BFD&lt;/name&gt;
        &lt;bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd"&gt;
          &lt;mpls xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-mpls"&gt;
            &lt;session-groups&gt;
              &lt;session-group&gt;
                &lt;mpls-fec&gt;2001:db8:114::/116&lt;/mpls-fec&gt;
                &lt;desired-min-tx-interval&gt;
                  250000
                &lt;/desired-min-tx-interval&gt;
                &lt;required-min-rx-interval&gt;
                  250000
                &lt;/required-min-rx-interval&gt;
              &lt;/session-group&gt;
            &lt;/session-groups&gt;
          &lt;/mpls&gt;
        &lt;/bfd&gt;
      &lt;/control-plane-protocol&gt;
    &lt;/control-plane-protocols&gt;
  &lt;/routing&gt;
&lt;/config&gt;
</pre><a href="#section-3.4-2" class="pilcrow">¶</a>
</div>
</section>
</section>
<section id="section-4">
      <h2 id="name-security-considerations">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-4-1">The YANG modules specified in this document define a schema for data
that is designed to be accessed via network management protocols such
as NETCONF <span>[<a href="#RFC6241" class="xref">RFC6241</a>]</span> or RESTCONF <span>[<a href="#RFC8040" class="xref">RFC8040</a>]</span>.
The lowest NETCONF layer is the secure transport layer, and the
mandatory-to-implement secure transport is Secure Shell (SSH)
<span>[<a href="#RFC6242" class="xref">RFC6242</a>]</span>. The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS <span>[<a href="#RFC8446" class="xref">RFC8446</a>]</span>.<a href="#section-4-1" class="pilcrow">¶</a></p>
<p id="section-4-2">The Network Configuration Access Control Model (NACM) <span>[<a href="#RFC8341" class="xref">RFC8341</a>]</span>
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.<a href="#section-4-2" class="pilcrow">¶</a></p>
<p id="section-4-3">There are a number of data nodes defined in these YANG modules that are
writable/creatable/deletable (i.e., config true, which is the default). These
data nodes may be considered sensitive or vulnerable in some network
environments. Write operations (e.g., edit-config) to these data nodes without
proper protection can have a negative effect on network operations. These are
      the subtrees and data nodes and their sensitivity/vulnerability from a write access perspective:<a href="#section-4-3" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-4-4">
        <dt id="section-4-4.1">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh/sessions:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.2">
          <p id="section-4-4.2.1">This list specifies the IP single-hop BFD sessions.<a href="#section-4-4.2.1" class="pilcrow">¶</a></p>
<p id="section-4-4.2.2">Data nodes "local-multiplier", "desired-min-tx-interval",
      "required-min-rx-interval", and "min-interval" all impact the
      BFD IP single-hop session. The "source-addr" and "dest-addr" data nodes can be used to
      send BFD packets to unwitting recipients. <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span> describes how BFD mitigates such
      threats. Authentication data nodes "key-chain" and "meticulous" impact the
      security of the BFD IP single-hop session.<a href="#section-4-4.2.2" class="pilcrow">¶</a></p>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.3">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/session-group:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.4">
          <p id="section-4-4.4.1">This list specifies the IP multihop BFD session groups.<a href="#section-4-4.4.1" class="pilcrow">¶</a></p>
<p id="section-4-4.4.2">Data nodes "local-multiplier", "desired-min-tx-interval",
      "required-min-rx-interval", and "min-interval" all impact the
      BFD IP multihop session. The "source-addr" and "dest-addr" data nodes can be used to
      send BFD packets to unwitting recipients. <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span> describes how BFD mitigates such
      threats. Authentication data nodes "key-chain" and "meticulous" impact the
      security of the BFD IP multihop session.<a href="#section-4-4.4.2" class="pilcrow">¶</a></p>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.5">/routing/control-plane-protocols/control-plane-protocol/bfd/lag/sessions:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.6">
          <p id="section-4-4.6.1">This list specifies the BFD sessions over a LAG.<a href="#section-4-4.6.1" class="pilcrow">¶</a></p>
<p id="section-4-4.6.2">Data nodes "local-multiplier", "desired-min-tx-interval",
      "required-min-rx-interval", and "min-interval" all impact the BFD-over-LAG
      session. The "ipv4-dest-addr" and "ipv6-dest-addr" data nodes can be used to
      send BFD packets to unwitting recipients. <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span> describes how BFD mitigates such
      threats. Authentication data nodes "key-chain" and "meticulous" impact the
      security of the BFD-over-LAG session.<a href="#section-4-4.6.2" class="pilcrow">¶</a></p>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.7">/routing/control-plane-protocols/control-plane-protocol/bfd/mpls/session-group:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.8">
          <p id="section-4-4.8.1">This list specifies the session groups for BFD over MPLS.<a href="#section-4-4.8.1" class="pilcrow">¶</a></p>
<p id="section-4-4.8.2">Data nodes "local-multiplier", "desired-min-tx-interval",
      "required-min-rx-interval", and "min-interval" all impact the
      BFD-over-MPLS-LSPs session. Authentication data nodes "key-chain" and "meticulous" impact
      the security of the BFD-over-MPLS-LSPs session.<a href="#section-4-4.8.2" class="pilcrow">¶</a></p>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.9">/routing/control-plane-protocols/control-plane-protocol/bfd/mpls/egress:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.10">Data nodes "local-multiplier", "desired-min-tx-interval",
      "required-min-rx-interval", and "min-interval" all impact the
      BFD-over-MPLS-LSPs sessions for which this device is an MPLS LSP egress
      node. Authentication data nodes "key-chain" and "meticulous" impact the
      security of the BFD-over-MPLS-LSPs sessions for which this device is an
      MPLS LSP egress node.<a href="#section-4-4.10" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-4-5">The YANG modules have writable data nodes that can be used for the
      creation of BFD sessions and the modification of BFD session parameters. The
      system should "police" the creation of BFD sessions to prevent new sessions
      from causing existing BFD sessions to fail. In the case of BFD session
      modification, the BFD protocol has mechanisms in place that allow for
      in-service modification.<a href="#section-4-5" class="pilcrow">¶</a></p>
<p id="section-4-6">When BFD clients are used to modify BFD configuration (as described
      in <a href="#CFG-MODEL" class="xref">Section 2.1</a>), the BFD clients need to
      be included in an analysis of the security properties of the system that
      uses BFD (e.g., when considering the authentication and authorization of
      control actions). In many cases, BFD is not the most vulnerable portion
      of such a composite system, since BFD is limited to generating
      well-defined traffic at a fixed rate on a given path; in the case of an
      IGP acting as a BFD client, attacking the IGP could cause more broad-scale
      disruption than would (de)configuring a BFD session.<a href="#section-4-6" class="pilcrow">¶</a></p>
<p id="section-4-7">Some of the readable data nodes in these YANG modules 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 from a read access perspective:<a href="#section-4-7" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-4-8">
        <dt id="section-4-8.1">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh/summary:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.2">Access to this information discloses the number of BFD IP single-hop
      sessions that are in the "up", "down", or "admin-down" state. The counters include BFD
      sessions for which the user does not have read access.<a href="#section-4-8.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.3">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-sh/sessions/session/:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.4">Access to data nodes "local-discriminator" and "remote-discriminator"
      (combined with the data nodes in the authentication container) provides the
      ability to spoof BFD IP single-hop packets.<a href="#section-4-8.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.5">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/summary:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.6">Access to this information discloses the number of BFD IP multihop
      sessions that are in the "up", "down", or "admin-down" state. The counters include BFD
      sessions for which the user does not have read access.<a href="#section-4-8.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.7">/routing/control-plane-protocols/control-plane-protocol/bfd/ip-mh/session-groups/session-group/sessions:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.8">Access to data nodes "local-discriminator" and "remote-discriminator"
      (combined with the data nodes in the session group's authentication container) provides the
      ability to spoof BFD IP multihop packets.<a href="#section-4-8.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.9">/routing/control-plane-protocols/control-plane-protocol/bfd/lag/micro-bfd-ipv4-session-statistics/summary:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.10">Access to this information discloses the number of micro-BFD IPv4 LAG
      sessions that are in the "up", "down", or "admin-down" state. The counters include BFD
      sessions for which the user does not have read access.<a href="#section-4-8.10" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.11">/routing/control-plane-protocols/control-plane-protocol/bfd/lag/sessions/session/member-links/member-link/micro-bfd-ipv4:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.12">Access to data nodes "local-discriminator" and "remote-discriminator"
      (combined with the data nodes in the session's authentication container) provides the
      ability to spoof BFD IPv4 LAG packets.<a href="#section-4-8.12" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.13">/routing/control-plane-protocols/control-plane-protocol/bfd/lag/micro-bfd-ipv6-session-statistics/summary:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.14">Access to this information discloses the number of micro-BFD IPv6 LAG
      sessions that are in the "up", "down", or "admin-down" state. The counters include BFD
      sessions for which the user does not have read access.<a href="#section-4-8.14" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.15">/routing/control-plane-protocols/control-plane-protocol/bfd/lag/sessions/session/member-links/member-link/micro-bfd-ipv6:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.16">Access to data nodes "local-discriminator" and "remote-discriminator"
      (combined with the data nodes in the session's authentication container) provides the
      ability to spoof BFD IPv6 LAG packets.<a href="#section-4-8.16" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.17">/routing/control-plane-protocols/control-plane-protocol/bfd/mpls/summary:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.18">Access to this information discloses the number of BFD sessions over
      MPLS LSPs that are in the "up", "down", or "admin-down" state. The counters include BFD
      sessions for which the user does not have read access.<a href="#section-4-8.18" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-8.19">/routing/control-plane-protocols/control-plane-protocol/bfd/mpls/session-groups/session-group/sessions:</dt>
        <dd style="margin-left: 1.5em" id="section-4-8.20">Access to data nodes "local-discriminator" and "remote-discriminator"
      (combined with the data nodes in the session group's authentication container) provides the
      ability to spoof BFD-over-MPLS-LSPs packets.<a href="#section-4-8.20" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-4-9">This document does not define any RPC operations.<a href="#section-4-9" class="pilcrow">¶</a></p>
</section>
<section id="section-5">
      <h2 id="name-iana-considerations">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-5-1">This document registers the following namespace URIs in the "IETF XML Registry" <span>[<a href="#RFC3688" class="xref">RFC3688</a>]</span>:<a href="#section-5-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-2">
        <dt id="section-5-2.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-2.2">urn:ietf:params:xml:ns:yang:ietf-bfd-types<a href="#section-5-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-2.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-2.4">The IESG.<a href="#section-5-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-2.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-2.6">N/A; the requested URI is an XML namespace.<a href="#section-5-2.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-3">
        <dt id="section-5-3.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-3.2">urn:ietf:params:xml:ns:yang:ietf-bfd<a href="#section-5-3.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-3.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-3.4">The IESG.<a href="#section-5-3.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-3.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-3.6">N/A; the requested URI is an XML namespace.<a href="#section-5-3.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-4">
        <dt id="section-5-4.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-4.2">urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh<a href="#section-5-4.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-4.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-4.4">The IESG.<a href="#section-5-4.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-4.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-4.6">N/A; the requested URI is an XML namespace.<a href="#section-5-4.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-5">
        <dt id="section-5-5.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-5.2">urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh<a href="#section-5-5.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-5.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-5.4">The IESG.<a href="#section-5-5.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-5.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-5.6">N/A; the requested URI is an XML namespace.<a href="#section-5-5.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-6">
        <dt id="section-5-6.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-6.2">urn:ietf:params:xml:ns:yang:ietf-bfd-lag<a href="#section-5-6.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-6.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-6.4">The IESG.<a href="#section-5-6.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-6.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-6.6">N/A; the requested URI is an XML namespace.<a href="#section-5-6.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-7">
        <dt id="section-5-7.1">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-5-7.2">urn:ietf:params:xml:ns:yang:ietf-bfd-mpls<a href="#section-5-7.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-7.3">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-5-7.4">The IESG.<a href="#section-5-7.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-7.5">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-5-7.6">N/A; the requested URI is an XML namespace.<a href="#section-5-7.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-5-8">This document registers the following YANG modules in the "YANG Module Names"
      registry <span>[<a href="#RFC6020" class="xref">RFC6020</a>]</span>:<a href="#section-5-8" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-9">
        <dt id="section-5-9.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-9.2">ietf-bfd-types<a href="#section-5-9.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-9.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-9.4">urn:ietf:params:xml:ns:yang:ietf-bfd-types<a href="#section-5-9.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-9.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-9.6">bfd-types<a href="#section-5-9.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-9.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-9.8">RFC 9314<a href="#section-5-9.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-10">
        <dt id="section-5-10.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-10.2">ietf-bfd<a href="#section-5-10.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-10.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-10.4">urn:ietf:params:xml:ns:yang:ietf-bfd<a href="#section-5-10.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-10.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-10.6">bfd<a href="#section-5-10.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-10.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-10.8">RFC 9314<a href="#section-5-10.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-11">
        <dt id="section-5-11.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-11.2">ietf-bfd-ip-sh<a href="#section-5-11.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-11.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-11.4">urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh<a href="#section-5-11.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-11.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-11.6">bfd-ip-sh<a href="#section-5-11.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-11.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-11.8">RFC 9314<a href="#section-5-11.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-12">
        <dt id="section-5-12.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-12.2">ietf-bfd-ip-mh<a href="#section-5-12.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-12.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-12.4">urn:ietf:params:xml:ns:yang:ietf-bfd-ip-mh<a href="#section-5-12.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-12.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-12.6">bfd-ip-mh<a href="#section-5-12.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-12.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-12.8">RFC 9314<a href="#section-5-12.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-13">
        <dt id="section-5-13.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-13.2">ietf-bfd-lag<a href="#section-5-13.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-13.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-13.4">urn:ietf:params:xml:ns:yang:ietf-bfd-lag<a href="#section-5-13.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-13.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-13.6">bfd-lag<a href="#section-5-13.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-13.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-13.8">RFC 9314<a href="#section-5-13.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-5-14">
        <dt id="section-5-14.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-5-14.2">ietf-bfd-mpls<a href="#section-5-14.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-14.3">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-5-14.4">urn:ietf:params:xml:ns:yang:ietf-bfd-mpls<a href="#section-5-14.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-14.5">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-5-14.6">bfd-mpls<a href="#section-5-14.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-14.7">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-5-14.8">RFC 9314<a href="#section-5-14.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
<section id="section-6">
      <h2 id="name-references">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-6.1">
        <h3 id="name-normative-references">
<a href="#section-6.1" class="section-number selfRef">6.1. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
        </h3>
<dl class="references">
<dt id="RFC3688">[RFC3688]</dt>
        <dd>
<span class="refAuthor">Mealling, M.</span>, <span class="refTitle">"The IETF XML Registry"</span>, <span class="seriesInfo">BCP 81</span>, <span class="seriesInfo">RFC 3688</span>, <span class="seriesInfo">DOI 10.17487/RFC3688</span>, <time datetime="2004-01" class="refDate">January 2004</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3688">https://www.rfc-editor.org/info/rfc3688</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5586">[RFC5586]</dt>
        <dd>
<span class="refAuthor">Bocci, M., Ed.</span>, <span class="refAuthor">Vigoureux, M., Ed.</span>, and <span class="refAuthor">S. Bryant, Ed.</span>, <span class="refTitle">"MPLS Generic Associated Channel"</span>, <span class="seriesInfo">RFC 5586</span>, <span class="seriesInfo">DOI 10.17487/RFC5586</span>, <time datetime="2009-06" class="refDate">June 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5586">https://www.rfc-editor.org/info/rfc5586</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5880">[RFC5880]</dt>
        <dd>
<span class="refAuthor">Katz, D.</span> and <span class="refAuthor">D. Ward</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD)"</span>, <span class="seriesInfo">RFC 5880</span>, <span class="seriesInfo">DOI 10.17487/RFC5880</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5880">https://www.rfc-editor.org/info/rfc5880</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5881">[RFC5881]</dt>
        <dd>
<span class="refAuthor">Katz, D.</span> and <span class="refAuthor">D. Ward</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)"</span>, <span class="seriesInfo">RFC 5881</span>, <span class="seriesInfo">DOI 10.17487/RFC5881</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5881">https://www.rfc-editor.org/info/rfc5881</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5882">[RFC5882]</dt>
        <dd>
<span class="refAuthor">Katz, D.</span> and <span class="refAuthor">D. Ward</span>, <span class="refTitle">"Generic Application of Bidirectional Forwarding Detection (BFD)"</span>, <span class="seriesInfo">RFC 5882</span>, <span class="seriesInfo">DOI 10.17487/RFC5882</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5882">https://www.rfc-editor.org/info/rfc5882</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5883">[RFC5883]</dt>
        <dd>
<span class="refAuthor">Katz, D.</span> and <span class="refAuthor">D. Ward</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD) for Multihop Paths"</span>, <span class="seriesInfo">RFC 5883</span>, <span class="seriesInfo">DOI 10.17487/RFC5883</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5883">https://www.rfc-editor.org/info/rfc5883</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5884">[RFC5884]</dt>
        <dd>
<span class="refAuthor">Aggarwal, R.</span>, <span class="refAuthor">Kompella, K.</span>, <span class="refAuthor">Nadeau, T.</span>, and <span class="refAuthor">G. Swallow</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)"</span>, <span class="seriesInfo">RFC 5884</span>, <span class="seriesInfo">DOI 10.17487/RFC5884</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5884">https://www.rfc-editor.org/info/rfc5884</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5885">[RFC5885]</dt>
        <dd>
<span class="refAuthor">Nadeau, T., Ed.</span> and <span class="refAuthor">C. Pignataro, Ed.</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)"</span>, <span class="seriesInfo">RFC 5885</span>, <span class="seriesInfo">DOI 10.17487/RFC5885</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5885">https://www.rfc-editor.org/info/rfc5885</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6020">[RFC6020]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M., Ed.</span>, <span class="refTitle">"YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)"</span>, <span class="seriesInfo">RFC 6020</span>, <span class="seriesInfo">DOI 10.17487/RFC6020</span>, <time datetime="2010-10" class="refDate">October 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6020">https://www.rfc-editor.org/info/rfc6020</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6241">[RFC6241]</dt>
        <dd>
<span class="refAuthor">Enns, R., Ed.</span>, <span class="refAuthor">Bjorklund, M., Ed.</span>, <span class="refAuthor">Schoenwaelder, J., Ed.</span>, and <span class="refAuthor">A. Bierman, Ed.</span>, <span class="refTitle">"Network Configuration Protocol (NETCONF)"</span>, <span class="seriesInfo">RFC 6241</span>, <span class="seriesInfo">DOI 10.17487/RFC6241</span>, <time datetime="2011-06" class="refDate">June 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6241">https://www.rfc-editor.org/info/rfc6241</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6242">[RFC6242]</dt>
        <dd>
<span class="refAuthor">Wasserman, M.</span>, <span class="refTitle">"Using the NETCONF Protocol over Secure Shell (SSH)"</span>, <span class="seriesInfo">RFC 6242</span>, <span class="seriesInfo">DOI 10.17487/RFC6242</span>, <time datetime="2011-06" class="refDate">June 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6242">https://www.rfc-editor.org/info/rfc6242</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6991">[RFC6991]</dt>
        <dd>
<span class="refAuthor">Schoenwaelder, J., Ed.</span>, <span class="refTitle">"Common YANG Data Types"</span>, <span class="seriesInfo">RFC 6991</span>, <span class="seriesInfo">DOI 10.17487/RFC6991</span>, <time datetime="2013-07" class="refDate">July 2013</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6991">https://www.rfc-editor.org/info/rfc6991</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7130">[RFC7130]</dt>
        <dd>
<span class="refAuthor">Bhatia, M., Ed.</span>, <span class="refAuthor">Chen, M., Ed.</span>, <span class="refAuthor">Boutros, S., Ed.</span>, <span class="refAuthor">Binderberger, M., Ed.</span>, and <span class="refAuthor">J. Haas, Ed.</span>, <span class="refTitle">"Bidirectional Forwarding Detection (BFD) on Link Aggregation Group (LAG) Interfaces"</span>, <span class="seriesInfo">RFC 7130</span>, <span class="seriesInfo">DOI 10.17487/RFC7130</span>, <time datetime="2014-02" class="refDate">February 2014</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7130">https://www.rfc-editor.org/info/rfc7130</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8040">[RFC8040]</dt>
        <dd>
<span class="refAuthor">Bierman, A.</span>, <span class="refAuthor">Bjorklund, M.</span>, and <span class="refAuthor">K. Watsen</span>, <span class="refTitle">"RESTCONF Protocol"</span>, <span class="seriesInfo">RFC 8040</span>, <span class="seriesInfo">DOI 10.17487/RFC8040</span>, <time datetime="2017-01" class="refDate">January 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8040">https://www.rfc-editor.org/info/rfc8040</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8177">[RFC8177]</dt>
        <dd>
<span class="refAuthor">Lindem, A., Ed.</span>, <span class="refAuthor">Qu, Y.</span>, <span class="refAuthor">Yeung, D.</span>, <span class="refAuthor">Chen, I.</span>, and <span class="refAuthor">J. Zhang</span>, <span class="refTitle">"YANG Data Model for Key Chains"</span>, <span class="seriesInfo">RFC 8177</span>, <span class="seriesInfo">DOI 10.17487/RFC8177</span>, <time datetime="2017-06" class="refDate">June 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8177">https://www.rfc-editor.org/info/rfc8177</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8340">[RFC8340]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M.</span> and <span class="refAuthor">L. Berger, Ed.</span>, <span class="refTitle">"YANG Tree Diagrams"</span>, <span class="seriesInfo">BCP 215</span>, <span class="seriesInfo">RFC 8340</span>, <span class="seriesInfo">DOI 10.17487/RFC8340</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8340">https://www.rfc-editor.org/info/rfc8340</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8341">[RFC8341]</dt>
        <dd>
<span class="refAuthor">Bierman, A.</span> and <span class="refAuthor">M. Bjorklund</span>, <span class="refTitle">"Network Configuration Access Control Model"</span>, <span class="seriesInfo">STD 91</span>, <span class="seriesInfo">RFC 8341</span>, <span class="seriesInfo">DOI 10.17487/RFC8341</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8341">https://www.rfc-editor.org/info/rfc8341</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8343">[RFC8343]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M.</span>, <span class="refTitle">"A YANG Data Model for Interface Management"</span>, <span class="seriesInfo">RFC 8343</span>, <span class="seriesInfo">DOI 10.17487/RFC8343</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8343">https://www.rfc-editor.org/info/rfc8343</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8344">[RFC8344]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M.</span>, <span class="refTitle">"A YANG Data Model for IP Management"</span>, <span class="seriesInfo">RFC 8344</span>, <span class="seriesInfo">DOI 10.17487/RFC8344</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8344">https://www.rfc-editor.org/info/rfc8344</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8349">[RFC8349]</dt>
        <dd>
<span class="refAuthor">Lhotka, L.</span>, <span class="refAuthor">Lindem, A.</span>, and <span class="refAuthor">Y. Qu</span>, <span class="refTitle">"A YANG Data Model for Routing Management (NMDA Version)"</span>, <span class="seriesInfo">RFC 8349</span>, <span class="seriesInfo">DOI 10.17487/RFC8349</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8349">https://www.rfc-editor.org/info/rfc8349</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8446">[RFC8446]</dt>
        <dd>
<span class="refAuthor">Rescorla, E.</span>, <span class="refTitle">"The Transport Layer Security (TLS) Protocol Version 1.3"</span>, <span class="seriesInfo">RFC 8446</span>, <span class="seriesInfo">DOI 10.17487/RFC8446</span>, <time datetime="2018-08" class="refDate">August 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8446">https://www.rfc-editor.org/info/rfc8446</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8960">[RFC8960]</dt>
        <dd>
<span class="refAuthor">Saad, T.</span>, <span class="refAuthor">Raza, K.</span>, <span class="refAuthor">Gandhi, R.</span>, <span class="refAuthor">Liu, X.</span>, and <span class="refAuthor">V. Beeram</span>, <span class="refTitle">"A YANG Data Model for MPLS Base"</span>, <span class="seriesInfo">RFC 8960</span>, <span class="seriesInfo">DOI 10.17487/RFC8960</span>, <time datetime="2020-12" class="refDate">December 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8960">https://www.rfc-editor.org/info/rfc8960</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC9127">[RFC9127]</dt>
      <dd>
<span class="refAuthor">Rahman, R., Ed.</span>, <span class="refAuthor">Zheng, L., Ed.</span>, <span class="refAuthor">Jethanandani, M., Ed.</span>, <span class="refAuthor">Pallagatti, S.</span>, and <span class="refAuthor">G. Mirsky</span>, <span class="refTitle">"YANG Data Model for Bidirectional Forwarding Detection (BFD)"</span>, <span class="seriesInfo">RFC 9127</span>, <span class="seriesInfo">DOI 10.17487/RFC9127</span>, <time datetime="2021-10" class="refDate">October 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc9127">https://www.rfc-editor.org/info/rfc9127</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-6.2">
        <h3 id="name-informative-references">
<a href="#section-6.2" class="section-number selfRef">6.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="RFC3031">[RFC3031]</dt>
        <dd>
<span class="refAuthor">Rosen, E.</span>, <span class="refAuthor">Viswanathan, A.</span>, and <span class="refAuthor">R. Callon</span>, <span class="refTitle">"Multiprotocol Label Switching Architecture"</span>, <span class="seriesInfo">RFC 3031</span>, <span class="seriesInfo">DOI 10.17487/RFC3031</span>, <time datetime="2001-01" class="refDate">January 2001</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3031">https://www.rfc-editor.org/info/rfc3031</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8342">[RFC8342]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M.</span>, <span class="refAuthor">Schoenwaelder, J.</span>, <span class="refAuthor">Shafer, P.</span>, <span class="refAuthor">Watsen, K.</span>, and <span class="refAuthor">R. Wilton</span>, <span class="refTitle">"Network Management Datastore Architecture (NMDA)"</span>, <span class="seriesInfo">RFC 8342</span>, <span class="seriesInfo">DOI 10.17487/RFC8342</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8342">https://www.rfc-editor.org/info/rfc8342</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8529">[RFC8529]</dt>
        <dd>
<span class="refAuthor">Berger, L.</span>, <span class="refAuthor">Hopps, C.</span>, <span class="refAuthor">Lindem, A.</span>, <span class="refAuthor">Bogdanovic, D.</span>, and <span class="refAuthor">X. Liu</span>, <span class="refTitle">"YANG Data Model for Network Instances"</span>, <span class="seriesInfo">RFC 8529</span>, <span class="seriesInfo">DOI 10.17487/RFC8529</span>, <time datetime="2019-03" class="refDate">March 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8529">https://www.rfc-editor.org/info/rfc8529</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8530">[RFC8530]</dt>
        <dd>
<span class="refAuthor">Berger, L.</span>, <span class="refAuthor">Hopps, C.</span>, <span class="refAuthor">Lindem, A.</span>, <span class="refAuthor">Bogdanovic, D.</span>, and <span class="refAuthor">X. Liu</span>, <span class="refTitle">"YANG Model for Logical Network Elements"</span>, <span class="seriesInfo">RFC 8530</span>, <span class="seriesInfo">DOI 10.17487/RFC8530</span>, <time datetime="2019-03" class="refDate">March 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8530">https://www.rfc-editor.org/info/rfc8530</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8532">[RFC8532]</dt>
        <dd>
<span class="refAuthor">Kumar, D.</span>, <span class="refAuthor">Wang, Z.</span>, <span class="refAuthor">Wu, Q., Ed.</span>, <span class="refAuthor">Rahman, R.</span>, and <span class="refAuthor">S. Raghavan</span>, <span class="refTitle">"Generic YANG Data Model for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications"</span>, <span class="seriesInfo">RFC 8532</span>, <span class="seriesInfo">DOI 10.17487/RFC8532</span>, <time datetime="2019-04" class="refDate">April 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8532">https://www.rfc-editor.org/info/rfc8532</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="W3C.REC-xml-20081126">[W3C.REC-xml-20081126]</dt>
      <dd>
<span class="refAuthor">Bray, T.</span>, <span class="refAuthor">Paoli, J.</span>, <span class="refAuthor">Sperberg-McQueen, M.</span>, <span class="refAuthor">Maler, E.</span>, and <span class="refAuthor">F. Yergeau</span>, <span class="refTitle">"Extensible Markup Language (XML) 1.0 (Fifth Edition)"</span>, <span class="refContent">World Wide Web Consortium Recommendation REC-xml-20081126</span>, <time datetime="2008-11" class="refDate">November 2008</time>, <span>&lt;<a href="https://www.w3.org/TR/2008/REC-xml-20081126">https://www.w3.org/TR/2008/REC-xml-20081126</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<div id="ECHO-CONFIG">
<section id="appendix-A">
      <h2 id="name-echo-function-configuration">
<a href="#appendix-A" class="section-number selfRef">Appendix A. </a><a href="#name-echo-function-configuration" class="section-name selfRef">Echo Function Configuration Example</a>
      </h2>
<p id="appendix-A-1">As mentioned in <a href="#IP-SH-CFG" class="xref">Section 2.1.2</a>, the mechanism to start
      and stop the Echo function, as defined in <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span> and discussed in 
      <span>[<a href="#RFC5881" class="xref">RFC5881</a>]</span>, is implementation specific. In this appendix, we
      provide an example of how the Echo function can be implemented via
      configuration.<a href="#appendix-A-1" class="pilcrow">¶</a></p>
<div id="appendix-A-2">
<pre class="lang-yangtree sourcecode">
module: example-bfd-echo
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh
            /bfd-ip-sh:sessions:
    +--rw echo {bfd-types:echo-mode}?
       +--rw desired-min-echo-tx-interval?    uint32
       +--rw required-min-echo-rx-interval?   uint32
</pre><a href="#appendix-A-2" class="pilcrow">¶</a>
</div>
<section id="appendix-A.1">
        <h3 id="name-example-yang-module-for-bfd">
<a href="#appendix-A.1" class="section-number selfRef">A.1. </a><a href="#name-example-yang-module-for-bfd" class="section-name selfRef">Example YANG Module for BFD Echo Function Configuration</a>
        </h3>
<p id="appendix-A.1-1">This appendix provides an example YANG module for
        configuration of the BFD Echo function.  It imports and augments
        "/routing/control-plane-protocols/control-plane-protocol" from
        <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, and it references <span>[<a href="#RFC5880" class="xref">RFC5880</a>]</span>.<a href="#appendix-A.1-1" class="pilcrow">¶</a></p>
<div id="appendix-A.1-2">
<pre class="breakable lang-yang sourcecode">
module example-bfd-echo {
  namespace "tag:example.com,2021:example-bfd-echo";
  prefix example-bfd-echo;

  import ietf-bfd-types {
    prefix bfd-types;
  }
  import ietf-bfd {
    prefix bfd;
  }
  import ietf-bfd-ip-sh {
    prefix bfd-ip-sh;
  }
  import ietf-routing {
    prefix rt;
  }

  organization
    "IETF BFD Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/bfd/&gt;
     WG List:  &lt;mailto:rtg-bfd@ietf.org&gt;

     Editor:   Reshad Rahman
               &lt;mailto:reshad@yahoo.com&gt;

     Editor:   Lianshu Zheng
               &lt;mailto:veronique_cheng@hotmail.com&gt;

     Editor:   Mahesh Jethanandani
               &lt;mailto:mjethanandani@gmail.com&gt;";
  description
    "This module contains an example YANG augmentation for
     configuration of the BFD Echo function.

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

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the 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 9127; see the
     RFC itself for full legal notices.";

  revision 2021-10-21 {
    description
      "Initial revision.";
    reference
      "RFC 9127: YANG Data Model for Bidirectional Forwarding
       Detection (BFD)";
  }

  /*
   * Groupings
   */

  grouping echo-cfg-parms {
    description
      "BFD grouping for Echo configuration parameters.";
    leaf desired-min-echo-tx-interval {
      type uint32;
      units "microseconds";
      default "0";
      description
        "This is the minimum interval that the local system would
         like to use when transmitting BFD Echo packets.  If 0,
         the Echo function as defined in BFD (RFC 5880) is
         disabled.";
    }
    leaf required-min-echo-rx-interval {
      type uint32;
      units "microseconds";
      default "0";
      description
        "This is the Required Min Echo RX Interval as defined in BFD
         (RFC 5880).";
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh/"
        + "bfd-ip-sh:sessions" {
    description
      "Augmentation for the BFD Echo function.";
    container echo {
      if-feature "bfd-types:echo-mode";
      description
        "BFD Echo function container.";
      uses echo-cfg-parms;
    }
  }
}
</pre><a href="#appendix-A.1-2" class="pilcrow">¶</a>
</div>
</section>
</section>
</div>
<div id="updates-since-rfc-9127">
<section id="appendix-B">
      <h2 id="name-updates-since-rfc-9127">
<a href="#appendix-B" class="section-number selfRef">Appendix B. </a><a href="#name-updates-since-rfc-9127" class="section-name selfRef">Updates since RFC 9127</a>
      </h2>
<p id="appendix-B-1">This document updates the 'ietf-bfd-types' module
      to define a new feature called 'client-base-cfg-parms and an
      'if-feature' statement that conditionally includes definitions
      of parameters, such as 'multiplier' or
      'desired-min-tx-interval'. The feature statement allows
      YANG implementations of protocols, such as OSPF, IS-IS, PIM,
      and BGP, to support both a model where such parameters are
      not needed, such as when multiple BFD sessions are supported
      over a given interface, as well as when they need to be
      defined per session. As a result, the BFD MPLS module has to
      use the base-cfg-parms instead of client-cfg-parms to be able
      to include all the parameters unconditionally.<a href="#appendix-B-1" class="pilcrow">¶</a></p>
<p id="appendix-B-2">The
      iana-bfd-types module, created in RFC 9127, was delegated to
      IANA for maintenance. No changes are requested from IANA as
      part of this update.<a href="#appendix-B-2" class="pilcrow">¶</a></p>
</section>
</div>
<section id="appendix-C">
      <h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
      </h2>
<p id="appendix-C-1">We would like to thank <span class="contact-name">Nobo Akiya</span> and
      <span class="contact-name">Jeff Haas</span> for their encouragement on this work.
      We would also like to thank <span class="contact-name">Tom Petch</span> for his
      comments on the document. We would also like to thank
      <span class="contact-name">Acee Lindem</span> for his guidance. Thanks also to
      <span class="contact-name">Jürgen Schönwälder</span>, who was instrumental in improving the YANG
      modules.<a href="#appendix-C-1" class="pilcrow">¶</a></p>
</section>
<div id="authors-addresses">
<section id="appendix-D">
      <h2 id="name-authors-addresses">
<a href="#name-authors-addresses" class="section-name selfRef">Authors' Addresses</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Mahesh Jethanandani (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">Xoriant Corporation</span></div>
<div dir="auto" class="left"><span class="street-address">1248 Reamwood Ave</span></div>
<div dir="auto" class="left">
<span class="locality">Sunnyvale</span>, <span class="region">CA</span> <span class="postal-code">94089</span>
</div>
<div dir="auto" class="left"><span class="country-name">United States of America</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:mjethanandani@gmail.com" class="email">mjethanandani@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Reshad Rahman (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="country-name">Canada</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:reshad@yahoo.com" class="email">reshad@yahoo.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Lianshu Zheng (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:veronique_cheng@hotmail.com" class="email">veronique_cheng@hotmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Santosh Pallagatti</span></div>
<div dir="auto" class="left"><span class="org">VMware</span></div>
<div dir="auto" class="left"><span class="country-name">India</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:santosh.pallagatti@gmail.com" class="email">santosh.pallagatti@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Greg Mirsky</span></div>
<div dir="auto" class="left"><span class="org">Ericsson</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:gregimirsky@gmail.com" class="email">gregimirsky@gmail.com</a>
</div>
</address>
</section>
</div>
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