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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 9070: YANG Data Model for MPLS LDP</title>
<meta content="Kamran Raza" name="author">
<meta content="Rajiv Asati" name="author">
<meta content="Xufeng Liu" name="author">
<meta content="Santosh Easale" name="author">
<meta content="Xia Chen" name="author">
<meta content="Himanshu Shah" name="author">
<meta content="
       This document describes a YANG data model for the Multiprotocol Label Switching (MPLS)
     Label Distribution Protocol (LDP). The model also serves as the base model
     to define the Multipoint LDP (mLDP) model.  
        The YANG modules in this document conform to the Network Management
   Datastore Architecture (NMDA).
       
    " name="description">
<meta content="xml2rfc 3.12.2" name="generator">
<meta content="MPLS" name="keyword">
<meta content="LDP" name="keyword">
<meta content="YANG" name="keyword">
<meta content="9070" name="rfc.number">
<!-- Generator version information:
  xml2rfc 3.12.2
    Python 3.6.15
    appdirs 1.4.4
    ConfigArgParse 1.4.1
    google-i18n-address 2.4.0
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    setuptools 40.5.0
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    WeasyPrint 52.5
-->
<link href="rfc9070.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,
  this can be consolidated so that style settings occur only in one place, but
  for now the contents of this file consists first of the initial CSS work as
  provided to the RFC Formatter (xml2rfc) work, followed by itemized and
  commented changes found necssary during the development of the v3
  formatters.

*/

/* fonts */
@import url('https://fonts.googleapis.com/css?family=Noto+Sans'); /* Sans-serif */
@import url('https://fonts.googleapis.com/css?family=Noto+Serif'); /* Serif (print) */
@import url('https://fonts.googleapis.com/css?family=Roboto+Mono'); /* Monospace */

@viewport {
  zoom: 1.0;
  width: extend-to-zoom;
}
@-ms-viewport {
  width: extend-to-zoom;
  zoom: 1.0;
}
/* general and mobile first */
html {
}
body {
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  margin: 1.5em auto;
  color: #222;
  background-color: #fff;
  font-size: 14px;
  font-family: 'Noto Sans', Arial, Helvetica, sans-serif;
  line-height: 1.6;
  scroll-behavior: smooth;
}
.ears {
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}

/* headings */
#title, h1, h2, h3, h4, h5, h6 {
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  font-weight: bold;
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}
#title {
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.author {
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h2 {
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h3 {
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h4 {
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h5, h6 {
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#n-copyright-notice {
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div {
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svg {
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.alignCenter.art-text pre {
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.alignCenter {
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/* lists */
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ol ol, ul ul, ol ul, ul ol {
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ul.ulBare, li.ulBare {
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ul.compact, .ulCompact,
ol.compact, .olCompact {
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/* definition lists */
dl {
}
dl > dt {
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/* 
dl.nohang > dt {
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}
*/
dl > dd {
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dl.compact > dd, .dlCompact > dd {
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dl > dd > dl {
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  margin-bottom: 0em;
}

/* links */
a {
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a[href] {
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}
a[href]:hover {
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figcaption a[href],
a[href].selfRef {
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/* XXX probably not this:
a.selfRef:hover {
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} */

/* Figures */
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pre {
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img {
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figure {
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figure blockquote {
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figcaption {
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@media screen {
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/* aside, blockquote */
aside, blockquote {
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blockquote {
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cite {
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}

/* tables */
table {
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th, td {
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th {
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table caption {
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/* pilcrow */
a.pilcrow {
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/* misc */
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.role {
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#identifiers dt {
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/* Fix PDF info block run off issue */
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}
#identifiers .authors .author {
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}
#identifiers .authors .org {
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}

/* The prepared/rendered info at the very bottom of the page */
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}
.docInfo .prepared {
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}

/* table of contents */
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}
nav.toc ul {
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}
nav.toc li {
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  padding-left: 1.2em;
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}
/* references */
.references dt {
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  font-weight: bold;
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}
.references dd {
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.refInstance {
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}

.references .ascii {
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}

/* index */
.index ul {
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}
.index ul ul {
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}
.index li {
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}
.indexIndex {
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}
.index a {
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}
/* make the index two-column on all but the smallest screens */
@media (min-width: 600px) {
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  .index ul ul {
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}

/* authors */
address.vcard {
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}

address.vcard .nameRole {
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address.vcard .label {
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}
address.vcard .type {
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.alternative-contact {
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}
hr.addr {
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}

/* temporary notes */
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  padding: 0.2em;
  content: "The RFC Editor will remove this note";
  color: #9e2a00; /* Arlen: WCAG 2019 */
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}
.rfcEditorRemove {
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  background-color: #ffd; /* Arlen: WCAG 2019 */
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}
.cref {
  background-color: #ffd; /* Arlen: WCAG 2019 */
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}
.crefSource {
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}
/* alternative layout for smaller screens */
@media screen and (max-width: 1023px) {
  body {
    padding-top: 2em;
  }
  #title {
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  }
  h1 {
    font-size: 24px;
  }
  h2 {
    font-size: 20px;
    margin-top: -18px;  /* provide offset for in-page anchors */
    padding-top: 38px;
  }
  #identifiers dd {
    max-width: 60%;
  }
  #toc {
    position: fixed;
    z-index: 2;
    top: 0;
    right: 0;
    padding: 0;
    margin: 0;
    background-color: inherit;
    border-bottom: 1px solid #ccc;
  }
  #toc h2 {
    margin: -1px 0 0 0;
    padding: 4px 0 4px 6px;
    padding-right: 1em;
    min-width: 190px;
    font-size: 1.1em;
    text-align: right;
    background-color: #444;
    color: white;
    cursor: pointer;
  }
  #toc h2::before { /* css hamburger */
    float: right;
    position: relative;
    width: 1em;
    height: 1px;
    left: -164px;
    margin: 6px 0 0 0;
    background: white none repeat scroll 0 0;
    box-shadow: 0 4px 0 0 white, 0 8px 0 0 white;
    content: "";
  }
  #toc nav {
    display: none;
    padding: 0.5em 1em 1em;
    overflow: auto;
    height: calc(100vh - 48px);
    border-left: 1px solid #ddd;
  }
}

/* alternative layout for wide screens */
@media screen and (min-width: 1024px) {
  body {
    max-width: 724px;
    margin: 42px auto;
    padding-left: 1.5em;
    padding-right: 29em;
  }
  #toc {
    position: fixed;
    top: 42px;
    right: 42px;
    width: 25%;
    margin: 0;
    padding: 0 1em;
    z-index: 1;
  }
  #toc h2 {
    border-top: none;
    border-bottom: 1px solid #ddd;
    font-size: 1em;
    font-weight: normal;
    margin: 0;
    padding: 0.25em 1em 1em 0;
  }
  #toc nav {
    display: block;
    height: calc(90vh - 84px);
    bottom: 0;
    padding: 0.5em 0 0;
    overflow: auto;
  }
  img { /* future proofing */
    max-width: 100%;
    height: auto;
  }
}

/* pagination */
@media print {
  body {

    width: 100%;
  }
  p {
    orphans: 3;
    widows: 3;
  }
  #n-copyright-notice {
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  }
  #toc, #n-introduction {
    page-break-before: always;
  }
  #toc {
    border-top: none;
    padding-top: 0;
  }
  figure, pre {
    page-break-inside: avoid;
  }
  figure {
    overflow: scroll;
  }
  h1, h2, h3, h4, h5, h6 {
    page-break-after: avoid;
  }
  h2+*, h3+*, h4+*, h5+*, h6+* {
    page-break-before: avoid;
  }
  pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    font-size: 10pt;
  }
  table {
    border: 1px solid #ddd;
  }
  td {
    border-top: 1px solid #ddd;
  }
}

/* This is commented out here, as the string-set: doesn't
   pass W3C validation currently */
/*
.ears thead .left {
  string-set: ears-top-left content();
}

.ears thead .center {
  string-set: ears-top-center content();
}

.ears thead .right {
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}

.ears tfoot .left {
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}

.ears tfoot .center {
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}

.ears tfoot .right {
  string-set: ears-bottom-right content();
}
*/

@page :first {
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  @top-center {
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    border: none;
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  @top-right {
    content: normal;
    border: none;
  }
}

@page {
  size: A4;
  margin-bottom: 45mm;
  padding-top: 20px;
  /* The follwing is commented out here, but set appropriately by in code, as
     the content depends on the document */
  /*
  @top-left {
    content: 'Internet-Draft';
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-left {
    content: string(ears-top-left);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-center {
    content: string(ears-top-center);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
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  @top-right {
    content: string(ears-top-right);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @bottom-left {
    content: string(ears-bottom-left);
    vertical-align: top;
    border-top: solid 1px #ccc;
  }
  @bottom-center {
    content: string(ears-bottom-center);
    vertical-align: top;
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  @bottom-right {
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      vertical-align: top;
      border-top: solid 1px #ccc;
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  */

}

/* Changes introduced to fix issues found during implementation */
/* Make sure links are clickable even if overlapped by following H* */
a {
  z-index: 2;
}
/* Separate body from document info even without intervening H1 */
section {
  clear: both;
}


/* Top align author divs, to avoid names without organization dropping level with org names */
.author {
  vertical-align: top;
}

/* Leave room in document info to show Internet-Draft on one line */
#identifiers dt {
  width: 8em;
}

/* Don't waste quite as much whitespace between label and value in doc info */
#identifiers dd {
  margin-left: 1em;
}

/* Give floating toc a background color (needed when it's a div inside section */
#toc {
  background-color: white;
}

/* Make the collapsed ToC header render white on gray also when it's a link */
@media screen and (max-width: 1023px) {
  #toc h2 a,
  #toc h2 a:link,
  #toc h2 a:focus,
  #toc h2 a:hover,
  #toc a.toplink,
  #toc a.toplink:hover {
    color: white;
    background-color: #444;
    text-decoration: none;
  }
}

/* Give the bottom of the ToC some whitespace */
@media screen and (min-width: 1024px) {
  #toc {
    padding: 0 0 1em 1em;
  }
}

/* Style section numbers with more space between number and title */
.section-number {
  padding-right: 0.5em;
}

/* prevent monospace from becoming overly large */
tt, code, pre, code {
  font-size: 95%;
}

/* Fix the height/width aspect for ascii art*/
pre.sourcecode,
.art-text pre {
  line-height: 1.12;
}


/* Add styling for a link in the ToC that points to the top of the document */
a.toplink {
  float: right;
  margin-right: 0.5em;
}

/* Fix the dl styling to match the RFC 7992 attributes */
dl > dt,
dl.dlParallel > dt {
  float: left;
  margin-right: 1em;
}
dl.dlNewline > dt {
  float: none;
}

/* Provide styling for table cell text alignment */
table td.text-left,
table th.text-left {
  text-align: left;
}
table td.text-center,
table th.text-center {
  text-align: center;
}
table td.text-right,
table th.text-right {
  text-align: right;
}

/* Make the alternative author contact informatio look less like just another
   author, and group it closer with the primary author contact information */
.alternative-contact {
  margin: 0.5em 0 0.25em 0;
}
address .non-ascii {
  margin: 0 0 0 2em;
}

/* With it being possible to set tables with alignment
  left, center, and right, { width: 100%; } does not make sense */
table {
  width: auto;
}

/* Avoid reference text that sits in a block with very wide left margin,
   because of a long floating dt label.*/
.references dd {
  overflow: visible;
}

/* Control caption placement */
caption {
  caption-side: bottom;
}

/* Limit the width of the author address vcard, so names in right-to-left
   script don't end up on the other side of the page. */

address.vcard {
  max-width: 30em;
  margin-right: auto;
}

/* For address alignment dependent on LTR or RTL scripts */
address div.left {
  text-align: left;
}
address div.right {
  text-align: right;
}

/* Provide table alignment support.  We can't use the alignX classes above
   since they do unwanted things with caption and other styling. */
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] {
  color: #222;
}

@media print {
  .toplink {
    display: none;
  }

  /* avoid overwriting the top border line with the ToC header */
  #toc {
    padding-top: 1px;
  }

  /* Avoid page breaks inside dl and author address entries */
  .vcard {
    page-break-inside: avoid;
  }

}
/* Tweak the bcp14 keyword presentation */
.bcp14 {
  font-variant: small-caps;
  font-weight: bold;
  font-size: 0.9em;
}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  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 */
@media screen {
  .artwork a.pilcrow {
    display: block;
    line-height: 0.7;
    margin-top: 0.15em;
  }
}
/* Make pilcrows on dd visible */
@media screen {
  dd:hover > a.pilcrow {
    visibility: visible;
  }
}
/* Make the placement of figcaption match that of a table's caption
   by removing the figure's added bottom margin */
.alignLeft.art-text,
.alignCenter.art-text,
.alignRight.art-text {
   margin-bottom: 0;
}
.alignLeft,
.alignCenter,
.alignRight {
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<link href="https://dx.doi.org/10.17487/rfc9070" rel="alternate">
  <link href="urn:issn:2070-1721" rel="alternate">
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<table class="ears">
<thead><tr>
<td class="left">RFC 9070</td>
<td class="center">YANG Data Model for MPLS LDP</td>
<td class="right">March 2022</td>
</tr></thead>
<tfoot><tr>
<td class="left">Raza, 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/rfc9070" class="eref">9070</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="2022-03" class="published">March 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">K. Raza, <span class="editor">Ed.</span>
</div>
<div class="org">Cisco Systems</div>
</div>
<div class="author">
      <div class="author-name">R. Asati</div>
<div class="org">Cisco Systems</div>
</div>
<div class="author">
      <div class="author-name">X. Liu</div>
<div class="org">IBM Corporation</div>
</div>
<div class="author">
      <div class="author-name">S. Easale</div>
<div class="org">Juniper Networks</div>
</div>
<div class="author">
      <div class="author-name">X. Chen</div>
<div class="org">Huawei Technologies</div>
</div>
<div class="author">
      <div class="author-name">H. Shah</div>
<div class="org">Ciena Corporation</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 9070</h1>
<h1 id="title">YANG Data Model for MPLS LDP</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document describes a YANG data model for the Multiprotocol Label Switching (MPLS)
     Label Distribution Protocol (LDP). The model also serves as the base model
     to define the Multipoint LDP (mLDP) model.<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).<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/rfc9070">https://www.rfc-editor.org/info/rfc9070</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-base-and-extended" class="xref">Base and Extended</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" class="keepWithNext"><a href="#section-2" class="xref">2</a>.  <a href="#name-specification-of-requiremen" class="xref">Specification of Requirements</a></p>
</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-overview" class="xref">Overview</a></p>
</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-the-complete-tree" class="xref">The Complete Tree</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-configuration" class="xref">Configuration</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1">
                <p id="section-toc.1-1.5.2.1.1"><a href="#section-5.1" class="xref">5.1</a>.  <a href="#name-configuration-hierarchy" class="xref">Configuration Hierarchy</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.1">
                    <p id="section-toc.1-1.5.2.1.2.1.1"><a href="#section-5.1.1" class="xref">5.1.1</a>.  <a href="#name-global-parameters" class="xref">Global Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.2">
                    <p id="section-toc.1-1.5.2.1.2.2.1"><a href="#section-5.1.2" class="xref">5.1.2</a>.  <a href="#name-capabilities-parameters" class="xref">Capabilities Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.3">
                    <p id="section-toc.1-1.5.2.1.2.3.1"><a href="#section-5.1.3" class="xref">5.1.3</a>.  <a href="#name-per-address-family-paramete" class="xref">Per-Address-Family Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.4">
                    <p id="section-toc.1-1.5.2.1.2.4.1"><a href="#section-5.1.4" class="xref">5.1.4</a>.  <a href="#name-hello-discovery-parameters" class="xref">Hello Discovery Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.5">
                    <p id="section-toc.1-1.5.2.1.2.5.1"><a href="#section-5.1.5" class="xref">5.1.5</a>.  <a href="#name-peer-parameters" class="xref">Peer Parameters</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5.2.1.2.6">
                    <p id="section-toc.1-1.5.2.1.2.6.1"><a href="#section-5.1.6" class="xref">5.1.6</a>.  <a href="#name-forwarding-parameters" class="xref">Forwarding Parameters</a></p>
</li>
                </ul>
</li>
            </ul>
</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-operational-state" class="xref">Operational State</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-adjacency-state" class="xref">Adjacency State</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-peer-state" class="xref">Peer State</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6.2.3">
                <p id="section-toc.1-1.6.2.3.1"><a href="#section-6.3" class="xref">6.3</a>.  <a href="#name-bindings-state" class="xref">Bindings State</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6.2.4">
                <p id="section-toc.1-1.6.2.4.1"><a href="#section-6.4" class="xref">6.4</a>.  <a href="#name-capabilities-state" class="xref">Capabilities State</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="#section-7" class="xref">7</a>.  <a href="#name-notifications" class="xref">Notifications</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8">
            <p id="section-toc.1-1.8.1"><a href="#section-8" class="xref">8</a>.  <a href="#name-action" class="xref">Action</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="#section-9" class="xref">9</a>.  <a href="#name-yang-specification" class="xref">YANG Specification</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9.2.1">
                <p id="section-toc.1-1.9.2.1.1"><a href="#section-9.1" class="xref">9.1</a>.  <a href="#name-base" class="xref">Base</a></p>
</li>
              <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9.2.2">
                <p id="section-toc.1-1.9.2.2.1"><a href="#section-9.2" class="xref">9.2</a>.  <a href="#name-extended" class="xref">Extended</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10">
            <p id="section-toc.1-1.10.1"><a href="#section-10" class="xref">10</a>. <a href="#name-security-considerations" class="xref">Security Considerations</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1">
                <p id="section-toc.1-1.10.2.1.1"><a href="#section-10.1" class="xref">10.1</a>.  <a href="#name-yang-data-model" class="xref">YANG Data Model</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1.2.1">
                    <p id="section-toc.1-1.10.2.1.2.1.1"><a href="#section-10.1.1" class="xref">10.1.1</a>.  <a href="#name-writable-nodes" class="xref">Writable Nodes</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1.2.2">
                    <p id="section-toc.1-1.10.2.1.2.2.1"><a href="#section-10.1.2" class="xref">10.1.2</a>.  <a href="#name-readable-nodes" class="xref">Readable Nodes</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1.2.3">
                    <p id="section-toc.1-1.10.2.1.2.3.1"><a href="#section-10.1.3" class="xref">10.1.3</a>.  <a href="#name-rpc-operations" class="xref">RPC Operations</a></p>
</li>
                  <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1.2.4">
                    <p id="section-toc.1-1.10.2.1.2.4.1"><a href="#section-10.1.4" class="xref">10.1.4</a>.  <a href="#name-notifications-2" class="xref">Notifications</a></p>
</li>
                </ul>
</li>
            </ul>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.11">
            <p id="section-toc.1-1.11.1"><a href="#section-11" class="xref">11</a>. <a href="#name-iana-considerations" class="xref">IANA Considerations</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#section-12" class="xref">12</a>. <a href="#name-normative-references" class="xref">Normative References</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#section-13" class="xref">13</a>. <a href="#name-informative-references" class="xref">Informative References</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.14">
            <p id="section-toc.1-1.14.1"><a href="#appendix-A" class="xref">Appendix A</a>.  <a href="#name-data-tree-example" class="xref">Data Tree Example</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.15">
            <p id="section-toc.1-1.15.1"><a href="#appendix-B" class="xref"></a><a href="#name-acknowledgments" class="xref">Acknowledgments</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.16">
            <p id="section-toc.1-1.16.1"><a href="#appendix-C" class="xref"></a><a href="#name-contributors" class="xref">Contributors</a></p>
</li>
          <li class="compact toc ulBare ulEmpty" id="section-toc.1-1.17">
            <p id="section-toc.1-1.17.1"><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">The Network Configuration Protocol (NETCONF) <span>[<a href="#RFC6241" class="xref">RFC6241</a>]</span>
      is one of the network management protocols that defines mechanisms to
      manage network devices. YANG <span>[<a href="#RFC6020" class="xref">RFC6020</a>]</span> <span>[<a href="#RFC7950" class="xref">RFC7950</a>]</span> is a modular language that represents data structures
      in an XML tree format and is used as a data modeling language for
      NETCONF.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2"> This document introduces a YANG data model for the MPLS Label
      Distribution Protocol (LDP) <span>[<a href="#RFC5036" class="xref">RFC5036</a>]</span>. This model also
      covers LDP IPv6 <span>[<a href="#RFC7552" class="xref">RFC7552</a>]</span> and LDP capability <span>[<a href="#RFC5561" class="xref">RFC5561</a>]</span> specifications.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3"> The data model is defined for the following constructs that are used for managing the protocol:<a href="#section-1-3" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-1-4.1"> Configuration<a href="#section-1-4.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-1-4.2"> Operational State<a href="#section-1-4.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-1-4.3"> Executables (Actions)<a href="#section-1-4.3" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-1-4.4"> Notifications<a href="#section-1-4.4" class="pilcrow">¶</a>
</li>
      </ul>
<p id="section-1-5"> This document is organized to define the data model for each of the above constructs
in the sequence as listed above.<a href="#section-1-5" class="pilcrow">¶</a></p>
<section id="section-1.1">
        <h3 id="name-base-and-extended">
<a href="#section-1.1" class="section-number selfRef">1.1. </a><a href="#name-base-and-extended" class="section-name selfRef">Base and Extended</a>
        </h3>
<p id="section-1.1-1"> The configuration and state items are divided into the following two broad categories:<a href="#section-1.1-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-1.1-2.1"> Base<a href="#section-1.1-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-1.1-2.2"> Extended<a href="#section-1.1-2.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-1.1-3"> The "base" category contains the basic and fundamental features that are
covered in LDP base specification <span>[<a href="#RFC5036" class="xref">RFC5036</a>]</span> and constitute the
minimum requirements for a typical base LDP deployment, whereas the "extended"
category contains other non-base features. All the items in a base category
are mandatory and, hence, no "if-feature" is allowed under the "base" category.
The base and extended categories are defined in their own modules as described
later.<a href="#section-1.1-3" class="pilcrow">¶</a></p>
<p id="section-1.1-4"> The examples of a base feature include the configuration of LDP lsr-id,
enabling LDP interfaces, setting passwords for LDP sessions, etc., whereas the
examples of an extended feature include inbound/outbound label policies, IGP
Sync <span>[<a href="#RFC5443" class="xref">RFC5443</a>]</span>, downstream on demand, etc. It is worth
highlighting that LDP IPv6 <span>[<a href="#RFC7552" class="xref">RFC7552</a>]</span> is also categorized as an
extended feature.<a href="#section-1.1-4" class="pilcrow">¶</a></p>
<p id="section-1.1-5"> While "base" model support will suffice for small deployments, it is expected that large deployments will require both "base" and "extended" model support from the vendors.<a href="#section-1.1-5" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-2">
      <h2 id="name-specification-of-requiremen">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-specification-of-requiremen" class="section-name selfRef">Specification of Requirements</a>
      </h2>
<p id="section-2-1"> In this document, the word "IP" is used to refer to both IPv4 and
      IPv6 unless otherwise explicitly stated. For example, "IP address
      family" should be read as "IPv4 and/or IPv6 address family".<a href="#section-2-1" class="pilcrow">¶</a></p>
</section>
<section id="section-3">
      <h2 id="name-overview">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-overview" class="section-name selfRef">Overview</a>
      </h2>
<p id="section-3-1"> This document defines two new modules for LDP YANG support:<a href="#section-3-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-3-2">
        <dt id="section-3-2.1">"ietf-mpls-ldp"
</dt>
        <dd style="margin-left: 1.5em" id="section-3-2.2">A module that specifies the base LDP features and augments
/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol defined in
<span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>. We define the new identity 'mpls-ldp' for LDP; the
model allows only a single instance of 'mpls-ldp'.<a href="#section-3-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-2.3">"ietf-mpls-ldp-extended"
</dt>
        <dd style="margin-left: 1.5em" id="section-3-2.4">A module that specifies the extended LDP features and augments the base
LDP module.<a href="#section-3-2.4" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-3-3"> It is to be noted that the mLDP YANG data model <span>[<a href="#I-D.ietf-mpls-mldp-yang" class="xref">MPLS-MLDP-YANG</a>]</span> augments LDP base and extended
 modules to specify the mLDP-specific base and extended features.<a href="#section-3-3" class="pilcrow">¶</a></p>
<p id="section-3-4">
   There are four types of containers in our module(s):<a href="#section-3-4" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-3-5.1"> Read-write parameters for configuration (<a href="#section_ldp_cfg" class="xref">Section 5</a>)<a href="#section-3-5.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-5.2"> Read-only parameters for operational state (<a href="#section_ldp_oper" class="xref">Section 6</a>)<a href="#section-3-5.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-5.3"> Notifications for events (<a href="#section_ldp_notif" class="xref">Section 7</a>)<a href="#section-3-5.3" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-5.4"> RPCs for executing commands to perform some action (<a href="#section_ldp_action" class="xref">Section 8</a>)<a href="#section-3-5.4" class="pilcrow">¶</a>
</li>
      </ul>
<p id="section-3-6">
   The modules in this document conform to the Network Management
   Datastore Architecture (NMDA) defined in <span>[<a href="#RFC8342" class="xref">RFC8342</a>]</span>.
   The operational state data is combined with the associated
   configuration data in the same hierarchy <span>[<a href="#RFC8407" class="xref">RFC8407</a>]</span>.
   When protocol states are retrieved from the NMDA operational state
   datastore, the returned states cover all "config true" (rw) and
   "config false" (ro) nodes defined in the schema.<a href="#section-3-6" class="pilcrow">¶</a></p>
<p id="section-3-7">The following diagram depicts high-level LDP YANG tree organization and hierarchy:<a href="#section-3-7" class="pilcrow">¶</a></p>
<span id="name-ldp-yang-tree-organization"></span><div id="LDPYangTreeHL">
<figure id="figure-1">
        <div id="section-3-8.1">
<pre class="lang-yangtree sourcecode">
         +-- rw routing
            +-- rw control-plane-protocols
             +-- rw control-plane-protocol
              +-- rw mpls-ldp
                  +-- rw ...
                      +-- rw ...                 // base
                      |   +-- rw ...
                      |   +-- ro ...
                      |   +--
                      +-- ro ...
                      |   +-- ro ...
                      |   +-- ro ...
                      |   +--
                      +-- rw ldp-ext: ....       // extended
                      |   +-- rw ...
                      |   +-- ro ...
                      |   +--
                      +-- ro ...
                          +-- ro ...
                          +-- ro ...


    rpcs:
       +-- x mpls-ldp-some_action
       +-- x . . . . .

    notifications:
       +--- n mpls-ldp-some_event
       +--- n ...
</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-ldp-yang-tree-organization" class="selfRef">LDP YANG Tree Organization</a>
        </figcaption></figure>
</div>
<p id="section-3-9"> Before going into data model details, it is important to take
   note of the following points:<a href="#section-3-9" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-3-10.1"> This model aims to address only the core LDP parameters as
     per RFC specification, as well as well-known and widely deployed
     manageability controls (such as label filtering policies to apply
     filtering rules on the assignment, advertisement, and acceptance
     for label bindings).  Any vendor-specific feature should be
     defined in a vendor-specific augmentation of this model.<a href="#section-3-10.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.2"> Multi-topology LDP <span>[<a href="#RFC7307" class="xref">RFC7307</a>]</span> is beyond the scope of this document.<a href="#section-3-10.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.3"> This model does not cover any applications running on top of
     LDP, nor does it cover any Operations, Administration, and
     Maintenance (OAM) procedures for LDP.<a href="#section-3-10.3" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.4">This model is a VRF-centric model. It is important to note
     that <span>[<a href="#RFC4364" class="xref">RFC4364</a>]</span> defines VPN Routing and Forwarding
     (VRF) tables and default forwarding tables as different; however,
     from a YANG modeling perspective, this introduces unnecessary
     complications; hence, we are treating the default forwarding table
     as just another VRF.<a href="#section-3-10.4" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.5"> A "network-instance", as defined in <span>[<a href="#RFC8529" class="xref">RFC8529</a>]</span>,
     refers to a VRF instance (both default and non-default) within the
     scope of this model.<a href="#section-3-10.5" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.6"> This model supports two address families, namely, "ipv4" and "ipv6".<a href="#section-3-10.6" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.7"> This model assumes platform-wide label space (i.e., label
     space Id of zero). However, when upstream label assignment <span>[<a href="#RFC6389" class="xref">RFC6389</a>]</span> is in use, an upstream assigned label is looked
     up in a Context-Specific Label Space as defined in <span>[<a href="#RFC5331" class="xref">RFC5331</a>]</span>.<a href="#section-3-10.7" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.8"> The label and peer policies (including filters) are defined
     using prefix-set and neighbor-set, respectively, as defined in the
     routing-policy model <span>[<a href="#RFC9067" class="xref">RFC9067</a>]</span>.<a href="#section-3-10.8" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-3-10.9">
          <p id="section-3-10.9.1"> This model uses the terms LDP "neighbor/adjacency",
     "session", and "peer" with the following semantics:<a href="#section-3-10.9.1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-3-10.9.2">
            <dt id="section-3-10.9.2.1">Neighbor/Adjacency:
</dt>
            <dd style="margin-left: 1.5em" id="section-3-10.9.2.2">An LDP-enabled Label Switching Router (LSR) that is discovered through LDP
discovery mechanisms.<a href="#section-3-10.9.2.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-3-10.9.2.3">Session:
</dt>
            <dd style="margin-left: 1.5em" id="section-3-10.9.2.4">An LDP neighbor with whom a TCP connection has been established.<a href="#section-3-10.9.2.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-3-10.9.2.5">Peer:
</dt>
            <dd style="margin-left: 1.5em" id="section-3-10.9.2.6">An LDP session that has successfully progressed beyond its initialization
phase and is either already exchanging the bindings or is ready to do so.<a href="#section-3-10.9.2.6" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
<p id="section-3-10.9.3">
            It is to be noted that LDP Graceful Restart (GR) mechanisms
            defined in <span>[<a href="#RFC3478" class="xref">RFC3478</a>]</span> allow keeping the exchanged
            bindings for some time after a session goes down with a peer. We
            refer to such a state as belonging to a "stale" peer, i.e., keeping peer
            bindings from a peer with whom currently there is either no
            connection established or connection is established but the GR session
            is in recovery state.
     
     When used in this document, the above terms will refer strictly to
     the semantics and definitions defined for them.<a href="#section-3-10.9.3" class="pilcrow">¶</a></p>
</li>
      </ul>
<p id="section-3-11">
   A simplified graphical tree representation of base and extended LDP
   YANG data models is presented in <a href="#ConsolidatedTree" class="xref">Figure 2</a>.
   The meaning of the symbols in these tree diagrams is defined in
   <span>[<a href="#RFC8340" class="xref">RFC8340</a>]</span>.<a href="#section-3-11" class="pilcrow">¶</a></p>
<p id="section-3-12">  
   The actual YANG specification for base and extended modules is
   captured in <a href="#YANG" class="xref">Section 9</a>.<a href="#section-3-12" class="pilcrow">¶</a></p>
<p id="section-3-13">
     While presenting the YANG tree view and actual specification, this
     document assumes readers are familiar with the concepts of YANG
     modeling, its presentation, and its compilation.<a href="#section-3-13" class="pilcrow">¶</a></p>
</section>
<section id="section-4">
      <h2 id="name-the-complete-tree">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-the-complete-tree" class="section-name selfRef">The Complete Tree</a>
      </h2>
<p id="section-4-1">The following is a complete tree representation of configuration,
 state, notification, and RPC items under LDP base and extended
 modules.<a href="#section-4-1" class="pilcrow">¶</a></p>
<span id="name-complete-tree"></span><div id="ConsolidatedTree">
<figure id="figure-2">
        <div id="section-4-2.1">
<pre class="lang-yangtree sourcecode">
module: ietf-mpls-ldp
  augment /rt:routing/rt:control-plane-protocols
            /rt:control-plane-protocol:
    +--rw mpls-ldp
       +--rw global
       |  +--rw capability
       |  |  +--rw ldp-ext:end-of-lib {capability-end-of-lib}?
       |  |  |  +--rw ldp-ext:enabled?   boolean
       |  |  +--rw ldp-ext:typed-wildcard-fec
       |  |  |       {capability-typed-wildcard-fec}?
       |  |  |  +--rw ldp-ext:enabled?   boolean
       |  |  +--rw ldp-ext:upstream-label-assignment
       |  |          {capability-upstream-label-assignment}?
       |  |     +--rw ldp-ext:enabled?   boolean
       |  +--rw graceful-restart
       |  |  +--rw enabled?                  boolean
       |  |  +--rw reconnect-time?           uint16
       |  |  +--rw recovery-time?            uint16
       |  |  +--rw forwarding-holdtime?      uint16
       |  |  +--rw ldp-ext:helper-enabled?   boolean
       |  |          {graceful-restart-helper-mode}?
       |  +--rw lsr-id?
       |  |       rt-types:router-id
       |  +--rw address-families
       |  |  +--rw ipv4!
       |  |  |  +--rw enabled?                           boolean
       |  |  |  +--ro label-distribution-control-mode?   enumeration
       |  |  |  +--ro bindings
       |  |  |  |  +--ro address* [address]
       |  |  |  |  |  +--ro address               inet:ipv4-address
       |  |  |  |  |  +--ro advertisement-type?   advertised-received
       |  |  |  |  |  +--ro peer
       |  |  |  |  |     +--ro lsr-id?           leafref
       |  |  |  |  |     +--ro label-space-id?   leafref
       |  |  |  |  +--ro fec-label* [fec]
       |  |  |  |     +--ro fec     inet:ipv4-prefix
       |  |  |  |     +--ro peer*
       |  |  |  |          [lsr-id label-space-id advertisement-type]
       |  |  |  |        +--ro lsr-id                leafref
       |  |  |  |        +--ro label-space-id        leafref
       |  |  |  |        +--ro advertisement-type
       |  |  |  |        |       advertised-received
       |  |  |  |        +--ro label?
       |  |  |  |        |       rt-types:mpls-label
       |  |  |  |        +--ro used-in-forwarding?   boolean
       |  |  |  +--rw ldp-ext:label-policy
       |  |  |  |  +--rw ldp-ext:advertise
       |  |  |  |  |  +--rw ldp-ext:egress-explicit-null
       |  |  |  |  |  |  +--rw ldp-ext:enabled?   boolean
       |  |  |  |  |  +--rw ldp-ext:prefix-list?
       |  |  |  |  |          prefix-list-ref
       |  |  |  |  +--rw ldp-ext:accept
       |  |  |  |  |  +--rw ldp-ext:prefix-list?   prefix-list-ref
       |  |  |  |  +--rw ldp-ext:assign
       |  |  |  |          {policy-label-assignment-config}?
       |  |  |  |     +--rw ldp-ext:independent-mode
       |  |  |  |     |  +--rw ldp-ext:prefix-list?   prefix-list-ref
       |  |  |  |     +--rw ldp-ext:ordered-mode
       |  |  |  |             {policy-ordered-label-config}?
       |  |  |  |        +--rw ldp-ext:egress-prefix-list?
       |  |  |  |                prefix-list-ref
       |  |  |  +--rw ldp-ext:transport-address?
       |  |  |          inet:ipv4-address
       |  |  +--rw ldp-ext:ipv6!
       |  |     +--rw ldp-ext:enabled?
       |  |     |       boolean
       |  |     +--rw ldp-ext:label-policy
       |  |     |  +--rw ldp-ext:advertise
       |  |     |  |  +--rw ldp-ext:egress-explicit-null
       |  |     |  |  |  +--rw ldp-ext:enabled?   boolean
       |  |     |  |  +--rw ldp-ext:prefix-list?
       |  |     |  |          prefix-list-ref
       |  |     |  +--rw ldp-ext:accept
       |  |     |  |  +--rw ldp-ext:prefix-list?   prefix-list-ref
       |  |     |  +--rw ldp-ext:assign
       |  |     |          {policy-label-assignment-config}?
       |  |     |     +--rw ldp-ext:independent-mode
       |  |     |     |  +--rw ldp-ext:prefix-list?   prefix-list-ref
       |  |     |     +--rw ldp-ext:ordered-mode
       |  |     |             {policy-ordered-label-config}?
       |  |     |        +--rw ldp-ext:egress-prefix-list?
       |  |     |                prefix-list-ref
       |  |     +--rw ldp-ext:transport-address
       |  |     |       inet:ipv6-address
       |  |     +--ro ldp-ext:label-distribution-control-mode?
       |  |     |       enumeration
       |  |     +--ro ldp-ext:bindings
       |  |        +--ro ldp-ext:address* [address]
       |  |        |  +--ro ldp-ext:address
       |  |        |  |       inet:ipv6-address
       |  |        |  +--ro ldp-ext:advertisement-type?
       |  |        |  |       advertised-received
       |  |        |  +--ro ldp-ext:peer
       |  |        |     +--ro ldp-ext:lsr-id?           leafref
       |  |        |     +--ro ldp-ext:label-space-id?   leafref
       |  |        +--ro ldp-ext:fec-label* [fec]
       |  |           +--ro ldp-ext:fec     inet:ipv6-prefix
       |  |           +--ro ldp-ext:peer*
       |  |                [lsr-id label-space-id advertisement-type]
       |  |              +--ro ldp-ext:lsr-id                leafref
       |  |              +--ro ldp-ext:label-space-id        leafref
       |  |              +--ro ldp-ext:advertisement-type
       |  |              |       advertised-received
       |  |              +--ro ldp-ext:label?
       |  |              |       rt-types:mpls-label
       |  |              +--ro ldp-ext:used-in-forwarding?   boolean
       |  +--rw ldp-ext:forwarding-nexthop
       |  |       {forwarding-nexthop-config}?
       |  |  +--rw ldp-ext:interfaces
       |  |     +--rw ldp-ext:interface* [name]
       |  |        +--rw ldp-ext:name              if:interface-ref
       |  |        +--rw ldp-ext:address-family* [afi]
       |  |           +--rw ldp-ext:afi            identityref
       |  |           +--rw ldp-ext:ldp-disable?   boolean
       |  +--rw ldp-ext:igp-synchronization-delay?   uint16
       +--rw discovery
       |  +--rw interfaces
       |  |  +--rw hello-holdtime?   uint16
       |  |  +--rw hello-interval?   uint16
       |  |  +--rw interface* [name]
       |  |     +--rw name
       |  |     |       if:interface-ref
       |  |     +--ro next-hello?                          uint16
       |  |     +--rw address-families
       |  |     |  +--rw ipv4!
       |  |     |  |  +--rw enabled?                     boolean
       |  |     |  |  +--ro hello-adjacencies
       |  |     |  |  |  +--ro hello-adjacency* [adjacent-address]
       |  |     |  |  |     +--ro adjacent-address
       |  |     |  |  |     |       inet:ipv4-address
       |  |     |  |  |     +--ro flag*               identityref
       |  |     |  |  |     +--ro hello-holdtime
       |  |     |  |  |     |  +--ro adjacent?     uint16
       |  |     |  |  |     |  +--ro negotiated?   uint16
       |  |     |  |  |     |  +--ro remaining?    uint16
       |  |     |  |  |     +--ro next-hello?         uint16
       |  |     |  |  |     +--ro statistics
       |  |     |  |  |     |  +--ro discontinuity-time
       |  |     |  |  |     |  |       yang:date-and-time
       |  |     |  |  |     |  +--ro hello-received?
       |  |     |  |  |     |  |       yang:counter64
       |  |     |  |  |     |  +--ro hello-dropped?
       |  |     |  |  |     |          yang:counter64
       |  |     |  |  |     +--ro peer
       |  |     |  |  |        +--ro lsr-id?           leafref
       |  |     |  |  |        +--ro label-space-id?   leafref
       |  |     |  |  +--rw ldp-ext:transport-address?   union
       |  |     |  +--rw ldp-ext:ipv6!
       |  |     |     +--rw ldp-ext:enabled?             boolean
       |  |     |     +--ro ldp-ext:hello-adjacencies
       |  |     |     |  +--ro ldp-ext:hello-adjacency*
       |  |     |     |          [adjacent-address]
       |  |     |     |     +--ro ldp-ext:adjacent-address
       |  |     |     |     |       inet:ipv6-address
       |  |     |     |     +--ro ldp-ext:flag*
       |  |     |     |     |       identityref
       |  |     |     |     +--ro ldp-ext:hello-holdtime
       |  |     |     |     |  +--ro ldp-ext:adjacent?     uint16
       |  |     |     |     |  +--ro ldp-ext:negotiated?   uint16
       |  |     |     |     |  +--ro ldp-ext:remaining?    uint16
       |  |     |     |     +--ro ldp-ext:next-hello?         uint16
       |  |     |     |     +--ro ldp-ext:statistics
       |  |     |     |     |  +--ro ldp-ext:discontinuity-time
       |  |     |     |     |  |       yang:date-and-time
       |  |     |     |     |  +--ro ldp-ext:hello-received?
       |  |     |     |     |  |       yang:counter64
       |  |     |     |     |  +--ro ldp-ext:hello-dropped?
       |  |     |     |     |          yang:counter64
       |  |     |     |     +--ro ldp-ext:peer
       |  |     |     |        +--ro ldp-ext:lsr-id?          leafref
       |  |     |     |        +--ro ldp-ext:label-space-id?  leafref
       |  |     |     +--rw ldp-ext:transport-address?   union
       |  |     +--rw ldp-ext:hello-holdtime?              uint16
       |  |     |       {per-interface-timer-config}?
       |  |     +--rw ldp-ext:hello-interval?              uint16
       |  |     |       {per-interface-timer-config}?
       |  |     +--rw ldp-ext:igp-synchronization-delay?   uint16
       |  |             {per-interface-timer-config}?
       |  +--rw targeted
       |     +--rw hello-holdtime?     uint16
       |     +--rw hello-interval?     uint16
       |     +--rw hello-accept
       |     |  +--rw enabled?                 boolean
       |     |  +--rw ldp-ext:neighbor-list?   neighbor-list-ref
       |     |          {policy-targeted-discovery-config}?
       |     +--rw address-families
       |        +--rw ipv4!
       |        |  +--ro hello-adjacencies
       |        |  |  +--ro hello-adjacency*
       |        |  |          [local-address adjacent-address]
       |        |  |     +--ro local-address       inet:ipv4-address
       |        |  |     +--ro adjacent-address    inet:ipv4-address
       |        |  |     +--ro flag*               identityref
       |        |  |     +--ro hello-holdtime
       |        |  |     |  +--ro adjacent?     uint16
       |        |  |     |  +--ro negotiated?   uint16
       |        |  |     |  +--ro remaining?    uint16
       |        |  |     +--ro next-hello?         uint16
       |        |  |     +--ro statistics
       |        |  |     |  +--ro discontinuity-time
       |        |  |     |  |       yang:date-and-time
       |        |  |     |  +--ro hello-received?
       |        |  |     |  |       yang:counter64
       |        |  |     |  +--ro hello-dropped?
       |        |  |     |          yang:counter64
       |        |  |     +--ro peer
       |        |  |        +--ro lsr-id?           leafref
       |        |  |        +--ro label-space-id?   leafref
       |        |  +--rw target* [adjacent-address]
       |        |     +--rw adjacent-address    inet:ipv4-address
       |        |     +--rw enabled?            boolean
       |        |     +--rw local-address?      inet:ipv4-address
       |        +--rw ldp-ext:ipv6!
       |           +--ro ldp-ext:hello-adjacencies
       |           |  +--ro ldp-ext:hello-adjacency*
       |           |          [local-address adjacent-address]
       |           |     +--ro ldp-ext:local-address
       |           |     |       inet:ipv6-address
       |           |     +--ro ldp-ext:adjacent-address
       |           |     |       inet:ipv6-address
       |           |     +--ro ldp-ext:flag*
       |           |     |       identityref
       |           |     +--ro ldp-ext:hello-holdtime
       |           |     |  +--ro ldp-ext:adjacent?     uint16
       |           |     |  +--ro ldp-ext:negotiated?   uint16
       |           |     |  +--ro ldp-ext:remaining?    uint16
       |           |     +--ro ldp-ext:next-hello?         uint16
       |           |     +--ro ldp-ext:statistics
       |           |     |  +--ro ldp-ext:discontinuity-time
       |           |     |  |       yang:date-and-time
       |           |     |  +--ro ldp-ext:hello-received?
       |           |     |  |       yang:counter64
       |           |     |  +--ro ldp-ext:hello-dropped?
       |           |     |          yang:counter64
       |           |     +--ro ldp-ext:peer
       |           |        +--ro ldp-ext:lsr-id?           leafref
       |           |        +--ro ldp-ext:label-space-id?   leafref
       |           +--rw ldp-ext:target* [adjacent-address]
       |              +--rw ldp-ext:adjacent-address
       |              |       inet:ipv6-address
       |              +--rw ldp-ext:enabled?            boolean
       |              +--rw ldp-ext:local-address?
       |                      inet:ipv6-address
       +--rw peers
          +--rw authentication
          |  +--rw (authentication-type)?
          |     +--:(password)
          |     |  +--rw key?                 string
          |     |  +--rw crypto-algorithm?    identityref
          |     +--:(ldp-ext:key-chain) {key-chain}?
          |        +--rw ldp-ext:key-chain?   key-chain:key-chain-ref
          +--rw session-ka-holdtime?                       uint16
          +--rw session-ka-interval?                       uint16
          +--rw peer* [lsr-id label-space-id]
          |  +--rw lsr-id                         rt-types:router-id
          |  +--rw label-space-id                 uint16
          |  +--rw authentication
          |  |  +--rw (authentication-type)?
          |  |     +--:(password)
          |  |     |  +--rw key?                 string
          |  |     |  +--rw crypto-algorithm?    identityref
          |  |     +--:(ldp-ext:key-chain) {key-chain}?
          |  |        +--rw ldp-ext:key-chain?
          |  |                key-chain:key-chain-ref
          |  +--rw address-families
          |  |  +--rw ipv4!
          |  |  |  +--ro hello-adjacencies
          |  |  |  |  +--ro hello-adjacency*
          |  |  |  |          [local-address adjacent-address]
          |  |  |  |     +--ro local-address       inet:ipv4-address
          |  |  |  |     +--ro adjacent-address    inet:ipv4-address
          |  |  |  |     +--ro flag*               identityref
          |  |  |  |     +--ro hello-holdtime
          |  |  |  |     |  +--ro adjacent?     uint16
          |  |  |  |     |  +--ro negotiated?   uint16
          |  |  |  |     |  +--ro remaining?    uint16
          |  |  |  |     +--ro next-hello?         uint16
          |  |  |  |     +--ro statistics
          |  |  |  |     |  +--ro discontinuity-time
          |  |  |  |     |  |       yang:date-and-time
          |  |  |  |     |  +--ro hello-received?
          |  |  |  |     |  |       yang:counter64
          |  |  |  |     |  +--ro hello-dropped?
          |  |  |  |     |          yang:counter64
          |  |  |  |     +--ro interface?          if:interface-ref
          |  |  |  +--rw ldp-ext:label-policy
          |  |  |     +--rw ldp-ext:advertise
          |  |  |     |  +--rw ldp-ext:prefix-list?   prefix-list-ref
          |  |  |     +--rw ldp-ext:accept
          |  |  |        +--rw ldp-ext:prefix-list?   prefix-list-ref
          |  |  +--rw ldp-ext:ipv6!
          |  |     +--ro ldp-ext:hello-adjacencies
          |  |     |  +--ro ldp-ext:hello-adjacency*
          |  |     |          [local-address adjacent-address]
          |  |     |     +--ro ldp-ext:local-address
          |  |     |     |       inet:ipv6-address
          |  |     |     +--ro ldp-ext:adjacent-address
          |  |     |     |       inet:ipv6-address
          |  |     |     +--ro ldp-ext:flag*
          |  |     |     |       identityref
          |  |     |     +--ro ldp-ext:hello-holdtime
          |  |     |     |  +--ro ldp-ext:adjacent?     uint16
          |  |     |     |  +--ro ldp-ext:negotiated?   uint16
          |  |     |     |  +--ro ldp-ext:remaining?    uint16
          |  |     |     +--ro ldp-ext:next-hello?         uint16
          |  |     |     +--ro ldp-ext:statistics
          |  |     |     |  +--ro ldp-ext:discontinuity-time
          |  |     |     |  |       yang:date-and-time
          |  |     |     |  +--ro ldp-ext:hello-received?
          |  |     |     |  |       yang:counter64
          |  |     |     |  +--ro ldp-ext:hello-dropped?
          |  |     |     |          yang:counter64
          |  |     |     +--ro ldp-ext:interface?
          |  |     |             if:interface-ref
          |  |     +--rw ldp-ext:label-policy
          |  |        +--rw ldp-ext:advertise
          |  |        |  +--rw ldp-ext:prefix-list?   prefix-list-ref
          |  |        +--rw ldp-ext:accept
          |  |           +--rw ldp-ext:prefix-list?   prefix-list-ref
          |  +--ro label-advertisement-mode
          |  |  +--ro local?        label-adv-mode
          |  |  +--ro peer?         label-adv-mode
          |  |  +--ro negotiated?   label-adv-mode
          |  +--ro next-keep-alive?               uint16
          |  +--ro received-peer-state
          |  |  +--ro graceful-restart
          |  |  |  +--ro enabled?          boolean
          |  |  |  +--ro reconnect-time?   uint16
          |  |  |  +--ro recovery-time?    uint16
          |  |  +--ro capability
          |  |     +--ro end-of-lib
          |  |     |  +--ro enabled?   boolean
          |  |     +--ro typed-wildcard-fec
          |  |     |  +--ro enabled?   boolean
          |  |     +--ro upstream-label-assignment
          |  |        +--ro enabled?   boolean
          |  +--ro session-holdtime
          |  |  +--ro peer?         uint16
          |  |  +--ro negotiated?   uint16
          |  |  +--ro remaining?    uint16
          |  +--ro session-state?                 enumeration
          |  +--ro tcp-connection
          |  |  +--ro local-address?    inet:ip-address
          |  |  +--ro local-port?       inet:port-number
          |  |  +--ro remote-address?   inet:ip-address
          |  |  +--ro remote-port?      inet:port-number
          |  +--ro up-time?
          |  |       rt-types:timeticks64
          |  +--ro statistics
          |  |  +--ro discontinuity-time          yang:date-and-time
          |  |  +--ro received
          |  |  |  +--ro total-octets?          yang:counter64
          |  |  |  +--ro total-messages?        yang:counter64
          |  |  |  +--ro address?               yang:counter64
          |  |  |  +--ro address-withdraw?      yang:counter64
          |  |  |  +--ro initialization?        yang:counter64
          |  |  |  +--ro keepalive?             yang:counter64
          |  |  |  +--ro label-abort-request?   yang:counter64
          |  |  |  +--ro label-mapping?         yang:counter64
          |  |  |  +--ro label-release?         yang:counter64
          |  |  |  +--ro label-request?         yang:counter64
          |  |  |  +--ro label-withdraw?        yang:counter64
          |  |  |  +--ro notification?          yang:counter64
          |  |  +--ro sent
          |  |  |  +--ro total-octets?          yang:counter64
          |  |  |  +--ro total-messages?        yang:counter64
          |  |  |  +--ro address?               yang:counter64
          |  |  |  +--ro address-withdraw?      yang:counter64
          |  |  |  +--ro initialization?        yang:counter64
          |  |  |  +--ro keepalive?             yang:counter64
          |  |  |  +--ro label-abort-request?   yang:counter64
          |  |  |  +--ro label-mapping?         yang:counter64
          |  |  |  +--ro label-release?         yang:counter64
          |  |  |  +--ro label-request?         yang:counter64
          |  |  |  +--ro label-withdraw?        yang:counter64
          |  |  |  +--ro notification?          yang:counter64
          |  |  +--ro total-addresses?            uint32
          |  |  +--ro total-labels?               uint32
          |  |  +--ro total-fec-label-bindings?   uint32
          |  +--rw ldp-ext:admin-down?            boolean
          |  |       {per-peer-admin-down}?
          |  +--rw ldp-ext:graceful-restart
          |  |       {per-peer-graceful-restart-config}?
          |  |  +--rw ldp-ext:enabled?          boolean
          |  |  +--rw ldp-ext:reconnect-time?   uint16
          |  |  +--rw ldp-ext:recovery-time?    uint16
          |  +--rw ldp-ext:session-ka-holdtime?   uint16
          |  |       {per-peer-session-attributes-config}?
          |  +--rw ldp-ext:session-ka-interval?   uint16
          |          {per-peer-session-attributes-config}?
          +--rw ldp-ext:session-downstream-on-demand
          |       {session-downstream-on-demand-config}?
          |  +--rw ldp-ext:enabled?     boolean
          |  +--rw ldp-ext:peer-list?   peer-list-ref
          +--rw ldp-ext:dual-stack-transport-preference
                  {peers-dual-stack-transport-preference}?
             +--rw ldp-ext:max-wait?      uint16
             +--rw ldp-ext:prefer-ipv4!
                +--rw ldp-ext:peer-list?   peer-list-ref

  rpcs:
    +---x mpls-ldp-clear-peer
    |   +---w input
    |       +---w protocol-name?    leafref
    |       +---w lsr-id?           leafref
    |       +---w label-space-id?   leafref
    +---x mpls-ldp-clear-hello-adjacency
    |   +---w input
    |       +---w hello-adjacency
    |           +---w protocol-name?    leafref
    |           +---w (hello-adjacency-type)?
    |               +--:(targeted)
    |               |  +---w targeted!
    |               |      +---w target-address?   inet:ip-address
    |               +--:(link)
    |                  +---w link!
    |                      +---w next-hop-interface?  leafref
    |                      +---w next-hop-address?    inet:ip-address
    +---x mpls-ldp-clear-peer-statistics
        +---w input
            +---w protocol-name?    leafref
            +---w lsr-id?           leafref
            +---w label-space-id?   leafref

  notifications:
    +---n mpls-ldp-peer-event
    |   +--ro event-type?   oper-status-event-type
    |   +--ro peer
    |      +--ro protocol-name?    leafref
    |      +--ro lsr-id?           leafref
    |      +--ro label-space-id?   leafref
    +---n mpls-ldp-hello-adjacency-event
    |   +--ro event-type?       oper-status-event-type
    |   +--ro protocol-name?    leafref
    |   +--ro (hello-adjacency-type)?
    |      +--:(targeted)
    |      |  +--ro targeted
    |      |     +--ro target-address?   inet:ip-address
    |      +--:(link)
    |         +--ro link
    |            +--ro next-hop-interface?   if:interface-ref
    |            +--ro next-hop-address?     inet:ip-address
    +---n mpls-ldp-fec-event
        +--ro event-type?      oper-status-event-type
        +--ro protocol-name?   leafref
        +--ro fec?             inet:ip-prefix
</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-complete-tree" class="selfRef">Complete Tree</a>
        </figcaption></figure>
</div>
</section>
<div id="section_ldp_cfg">
<section id="section-5">
      <h2 id="name-configuration">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-configuration" class="section-name selfRef">Configuration</a>
      </h2>
<p id="section-5-1"> This specification defines the configuration parameters for base
 LDP as specified in <span>[<a href="#RFC5036" class="xref">RFC5036</a>]</span> and LDP IPv6 <span>[<a href="#RFC7552" class="xref">RFC7552</a>]</span>. Moreover, it incorporates provisions to enable LDP
 Capabilities <span>[<a href="#RFC5561" class="xref">RFC5561</a>]</span> and defines some of the most
 significant and commonly used capabilities such as Typed Wildcard
 FEC <span>[<a href="#RFC5918" class="xref">RFC5918</a>]</span>, End-of-LIB
 <span>[<a href="#RFC5919" class="xref">RFC5919</a>]</span>, and LDP Upstream
 Label Assignment <span>[<a href="#RFC6389" class="xref">RFC6389</a>]</span>.<a href="#section-5-1" class="pilcrow">¶</a></p>
<p id="section-5-2"> This model augments
 /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol,
 which is defined in <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span> and follows NMDA as
 mentioned earlier.<a href="#section-5-2" class="pilcrow">¶</a></p>
<p id="section-5-3">The following is the high-level configuration organization for the
 base LDP module:<a href="#section-5-3" class="pilcrow">¶</a></p>
<span id="name-base-configuration-organiza"></span><div id="LDPCfgOrgHL">
<figure id="figure-3">
        <div id="section-5-4.1">
<pre class="lang-yangtree sourcecode">
        augment /rt:routing/rt:control-plane-protocols:
                  /rt:control-plane-protocol:
          +-- mpls-ldp
              +-- global
              |   +-- ...
              |   +-- ...
              |   +-- address-families
              |   |   +-- ipv4
              |   |       +-- . . .
              |   |       +-- . . .
              |   +-- capability
              |       +-- ...
              |       +-- ...
              +-- discovery
              |   +-- interfaces
              |   |   +-- ...
              |   |   +-- ...
              |   |   +-- interface* [interface]
              |   |       +-- ...
              |   |       +-- address-families
              |   |           +-- ipv4
              |   |               +-- ...
              |   |               +-- ...
              |   +-- targeted
              |       +-- ...
              |       +-- address-families
              |           +-- ipv4
              |               +-- target* [adjacent-address]
              |                   +-- ...
              |                   +-- ...
              +-- peers
                  +-- ...
                  +-- ...
                  +-- peer* [lsr-id label-space-id]
                      +-- ...
                      +-- ...
</pre>
</div>
<figcaption><a href="#figure-3" class="selfRef">Figure 3</a>:
<a href="#name-base-configuration-organiza" class="selfRef">Base Configuration Organization</a>
        </figcaption></figure>
</div>
<p id="section-5-5">The following is the high-level configuration organization for the
 extended LDP module:<a href="#section-5-5" class="pilcrow">¶</a></p>
<span id="name-extended-configuration-orga"></span><div id="LDPCfgExtOrgHL">
<figure id="figure-4">
        <div id="section-5-6.1">
<pre class="lang-yangtree sourcecode">
augment /rt:routing/rt:control-plane-protocols
          /rt:control-plane-protocol
  +-- mpls-ldp
      +-- global
      |   +-- ...
      |   +-- ...
      |   +-- address-families
      |   |   +-- ipv4
      |   |   |   +-- . . .
      |   |   |   +-- . . .
      |   |   |   +-- label-policy
      |   |   |       +-- ...
      |   |   |       +-- ...
      |   |   +-- ipv6
      |   |       +-- . . .
      |   |       +-- . . .
      |   |       +-- label-policy
      |   |           +-- ...
      |   |           +-- ...
      |   +-- capability
      |   |   +-- ...
      |   |   +-- ...
      |   +-- discovery
      |       +-- interfaces
      |       |   +-- ...
      |       |   +-- ...
      |       |   +-- interface* [interface]
      |       |       +-- ...
      |       |       +-- address-families
      |       |           +-- ipv4
      |       |           |   +-- ...
      |       |           |   +-- ...
      |       |           +-- ipv6
      |       |               +-- ...
      |       |               +-- ...
      |       +-- targeted
      |           +-- ...
      |           +-- address-families
      |               +-- ipv6
      |                   +- target* [adjacent-address]
      |                      +- ...
      |                      +- ...
      +-- forwarding-nexthop
      |   +-- ...
      |   +-- ...
      +-- peers
          +-- ...
          +-- ...
          +-- peer*
              +-- ...
              +-- ...
              +-- label-policy
              |   +-- ..
              +-- address-families
                  +-- ipv4
                  |   +-- ...
                  +-- ipv6
                      +-- ...
</pre>
</div>
<figcaption><a href="#figure-4" class="selfRef">Figure 4</a>:
<a href="#name-extended-configuration-orga" class="selfRef">Extended Configuration Organization</a>
        </figcaption></figure>
</div>
<p id="section-5-7">Given the configuration hierarchy, the model allows inheritance
 such that an item in a child tree is able to derive value from a
 similar or related item in one of the parents. For instance, Hello
 holdtime can be configured per VRF or per VRF interface, thus allowing
 inheritance as well flexibility to override with a different value at
 any child level.<a href="#section-5-7" class="pilcrow">¶</a></p>
<section id="section-5.1">
        <h3 id="name-configuration-hierarchy">
<a href="#section-5.1" class="section-number selfRef">5.1. </a><a href="#name-configuration-hierarchy" class="section-name selfRef">Configuration Hierarchy</a>
        </h3>
<p id="section-5.1-1">The LDP module resides under a network-instance and the scope of
  any LDP configuration defined under this tree is per network-instance
  (per-VRF). This configuration is further divided into sub categories
  as follows:<a href="#section-5.1-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.1-2.1">Global parameters<a href="#section-5.1-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.1-2.2">Per-address-family parameters<a href="#section-5.1-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.1-2.3">LDP Capabilities parameters<a href="#section-5.1-2.3" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.1-2.4">
            <p id="section-5.1-2.4.1">Hello Discovery parameters<a href="#section-5.1-2.4.1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.1-2.4.2.1">
                <p id="section-5.1-2.4.2.1.1">interfaces<a href="#section-5.1-2.4.2.1.1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.1-2.4.2.1.2.1">Global<a href="#section-5.1-2.4.2.1.2.1" class="pilcrow">¶</a>
</li>
                  <li class="normal" id="section-5.1-2.4.2.1.2.2">Per-interface: Global<a href="#section-5.1-2.4.2.1.2.2" class="pilcrow">¶</a>
</li>
                  <li class="normal" id="section-5.1-2.4.2.1.2.3">Per-interface: Per-address-family<a href="#section-5.1-2.4.2.1.2.3" class="pilcrow">¶</a>
</li>
                </ul>
</li>
              <li class="normal" id="section-5.1-2.4.2.2">
                <p id="section-5.1-2.4.2.2.1">targeted<a href="#section-5.1-2.4.2.2.1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.1-2.4.2.2.2.1">Global<a href="#section-5.1-2.4.2.2.2.1" class="pilcrow">¶</a>
</li>
                  <li class="normal" id="section-5.1-2.4.2.2.2.2">Per-address-family: Per-target<a href="#section-5.1-2.4.2.2.2.2" class="pilcrow">¶</a>
</li>
                </ul>
</li>
            </ul>
</li>
          <li class="normal" id="section-5.1-2.5">
            <p id="section-5.1-2.5.1">Peer parameters<a href="#section-5.1-2.5.1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.1-2.5.2.1">Global<a href="#section-5.1-2.5.2.1" class="pilcrow">¶</a>
</li>
              <li class="normal" id="section-5.1-2.5.2.2">Per-peer: Global<a href="#section-5.1-2.5.2.2" class="pilcrow">¶</a>
</li>
              <li class="normal" id="section-5.1-2.5.2.3">Per-peer: Per-address-family<a href="#section-5.1-2.5.2.3" class="pilcrow">¶</a>
</li>
            </ul>
</li>
          <li class="normal" id="section-5.1-2.6">Forwarding parameters<a href="#section-5.1-2.6" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-5.1-3">The following subsections briefly explain these configuration areas.<a href="#section-5.1-3" class="pilcrow">¶</a></p>
<section id="section-5.1.1">
          <h4 id="name-global-parameters">
<a href="#section-5.1.1" class="section-number selfRef">5.1.1. </a><a href="#name-global-parameters" class="section-name selfRef">Global Parameters</a>
          </h4>
<p id="section-5.1.1-1"> There are configuration items that are available directly
       under a VRF instance and do not fall under any other subtree. An
       example of such a parameter is an LDP LSR Id that is typically
       configured per VRF. To keep legacy LDP features and applications
       working in an LDP IPv4 network with this model, this document
       recommends an operator to pick a routable IPv4 unicast address
       (within a routing domain) as an LSR Id.<a href="#section-5.1.1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-5.1.2">
          <h4 id="name-capabilities-parameters">
<a href="#section-5.1.2" class="section-number selfRef">5.1.2. </a><a href="#name-capabilities-parameters" class="section-name selfRef">Capabilities Parameters</a>
          </h4>
<p id="section-5.1.2-1"> This container falls under the global tree and holds the LDP
       capabilities that are to be enabled for certain features.  By
       default, an LDP capability is disabled unless explicitly
       enabled. These capabilities are typically used to negotiate with
       LDP peer(s) the support/non-support related to a feature and its
       parameters. The scope of a capability enabled under this
       container applies to all LDP peers in the given VRF
       instance. There is also a peer-level capability container that
       is provided to override a capability that is enabled/specified
       at VRF level.<a href="#section-5.1.2-1" class="pilcrow">¶</a></p>
</section>
<section id="section-5.1.3">
          <h4 id="name-per-address-family-paramete">
<a href="#section-5.1.3" class="section-number selfRef">5.1.3. </a><a href="#name-per-address-family-paramete" class="section-name selfRef">Per-Address-Family Parameters</a>
          </h4>
<p id="section-5.1.3-1"> Any LDP configuration parameter related to an IP address
       family (AF) whose scope is VRF wide is configured under this
       tree. The examples of per-AF parameters include enabling LDP for
       an address family, prefix-list-based label policies, and LDP
       transport address.<a href="#section-5.1.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-5.1.4">
          <h4 id="name-hello-discovery-parameters">
<a href="#section-5.1.4" class="section-number selfRef">5.1.4. </a><a href="#name-hello-discovery-parameters" class="section-name selfRef">Hello Discovery Parameters</a>
          </h4>
<p id="section-5.1.4-1"> This container is used to hold LDP configuration related to
       the Hello and discovery process for both basic (link) and extended
       (targeted) discovery.<a href="#section-5.1.4-1" class="pilcrow">¶</a></p>
<p id="section-5.1.4-2"> The "interfaces" container is used to configure parameters
       related to VRF interfaces. There are parameters that apply to
       all interfaces (such as Hello timers) as well as parameters
       that can be configured per interface. Hence, an interface list
       is defined under the "interfaces" container. The model defines
       parameters to configure per-interface non-AF-related items as
       well as per-interface per-AF items. The example of the former is
       interface Hello timers, and an example of the latter is enabling
       hellos for a given AF under an interface.<a href="#section-5.1.4-2" class="pilcrow">¶</a></p>
<p id="section-5.1.4-3"> The "targeted" container under a VRF instance allows for the
       configuration of parameters related to LDP targeted
       discovery. Within this container, the "target" list provides a
       means to configure multiple target addresses to perform extended
       discovery to a specific destination target, as well as to
       fine tune the per-target parameters.<a href="#section-5.1.4-3" class="pilcrow">¶</a></p>
</section>
<section id="section-5.1.5">
          <h4 id="name-peer-parameters">
<a href="#section-5.1.5" class="section-number selfRef">5.1.5. </a><a href="#name-peer-parameters" class="section-name selfRef">Peer Parameters</a>
          </h4>
<p id="section-5.1.5-1">

  This container is used to hold LDP configuration related to LDP sessions and
  peers under a VRF instance.

This container allows for the configuration of parameters that either apply to
all or a subset (peer-list) of peers in a given VRF.


       The example of such parameters includes authentication
       passwords, session KeepAlive (KA) timers, etc. Moreover, the
       model also allows per-peer parameter tuning by specifying a
       "peer" list under the "peers" container. A peer is uniquely
       identified by its LSR Id.<a href="#section-5.1.5-1" class="pilcrow">¶</a></p>
<p id="section-5.1.5-2"> Like per-interface parameters, some per-peer parameters are
       AF agnostic (i.e., either non-AF related or apply to both IP
       address families), and some belong to an AF. The example of
       the former is per-peer session password configuration, whereas
       the example of the latter is prefix-lis-based label policies
       (inbound and outbound) that apply to a given peer.<a href="#section-5.1.5-2" class="pilcrow">¶</a></p>
</section>
<section id="section-5.1.6">
          <h4 id="name-forwarding-parameters">
<a href="#section-5.1.6" class="section-number selfRef">5.1.6. </a><a href="#name-forwarding-parameters" class="section-name selfRef">Forwarding Parameters</a>
          </h4>
<p id="section-5.1.6-1"> This container is used to hold configuration used to control LDP
forwarding behavior under a VRF instance.

One example of a configuration under this container is when a user wishes to
enable LDP neighbor discovery on an interface but wishes to disable use of the
same interface for forwarding MPLS packets.  

       This example configuration makes sense only when there are more
       than one LDP-enabled interfaces towards a neighbor.<a href="#section-5.1.6-1" class="pilcrow">¶</a></p>
</section>
</section>
</section>
</div>
<div id="section_ldp_oper">
<section id="section-6">
      <h2 id="name-operational-state">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-operational-state" class="section-name selfRef">Operational State</a>
      </h2>
<p id="section-6-1">The operational state of LDP can be queried and obtained from
 read-only state containers that fall under the same tree
 (/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol) as
 the configuration.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">The following are main areas for which LDP operational state is defined:<a href="#section-6-2" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-6-3.1"> Neighbor Adjacencies<a href="#section-6-3.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-6-3.2"> Peer<a href="#section-6-3.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-6-3.3"> Bindings (FEC-Label and address)<a href="#section-6-3.3" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-6-3.4"> Capabilities<a href="#section-6-3.4" class="pilcrow">¶</a>
</li>
      </ul>
<section id="section-6.1">
        <h3 id="name-adjacency-state">
<a href="#section-6.1" class="section-number selfRef">6.1. </a><a href="#name-adjacency-state" class="section-name selfRef">Adjacency State</a>
        </h3>
<p id="section-6.1-1"> Neighbor adjacencies are per-address-family Hello adjacencies
     that are formed with neighbors as a result of LDP basic or
     extended discovery. In terms of organization, there is a source of
     discovery (e.g., interface or target address) along with its
     associated parameters and one or more discovered neighbors along
     with neighbor-discovery-related parameters. For the basic
     discovery, there could be more than one discovered neighbor for a
     given source (interface), whereas there is at most one discovered
     neighbor for an extended discovery source (local-address and
     target-address).  It is also to be noted that the reason for a
     targeted neighbor adjacency could be either an active source
     (locally configured targeted) or passive source (to allow any
     incoming extended/targeted hellos). A neighbor/adjacency record
     also contains session state that helps highlight whether a given
     adjacency has progressed to the subsequent session level or
     eventual peer level.<a href="#section-6.1-1" class="pilcrow">¶</a></p>
<p id="section-6.1-2">The following captures high-level tree hierarchy for neighbor
     adjacency state. The tree is shown for ipv4 address-family only; a
     similar tree exists for ipv6 address-family as well.<a href="#section-6.1-2" class="pilcrow">¶</a></p>
<span id="name-adjacency-state-2"></span><div id="LDPAdjState">
<figure id="figure-5">
          <div id="section-6.1-3.1">
<pre class="lang-yangtree sourcecode">
+--rw mpls-ldp!
   +--rw discovery
      +--rw interfaces
      |  +--rw interface* [interface]
      |     +--rw address-families
      |        +--rw ipv4
      |           +--ro hello-adjacencies
      |              +--ro hello-adjacencies* [adjacent-address]
      |                 +--ro adjacent-address
      |                    . . . .
      |                    . . . .
      +--rw targeted
         +--rw address-families
            +--rw ipv4
               +--ro hello-adjacencies
                  +--ro hello-adjacencies*
                  |                  [local-address adjacent-address]
                  +--ro local-address
                     +--ro adjacent-address
                        . . . .
                        . . . .
</pre>
</div>
<figcaption><a href="#figure-5" class="selfRef">Figure 5</a>:
<a href="#name-adjacency-state-2" class="selfRef">Adjacency State</a>
          </figcaption></figure>
</div>
</section>
<section id="section-6.2">
        <h3 id="name-peer-state">
<a href="#section-6.2" class="section-number selfRef">6.2. </a><a href="#name-peer-state" class="section-name selfRef">Peer State</a>
        </h3>
<p id="section-6.2-1">Peer-related state is presented under a peers tree. This is one
     of the core states that provides info on the session-related
     parameters (mode, authentication, KA timeout, etc.), TCP connection
     info, Hello adjacencies for the peer, statistics related to
     messages and bindings, and capabilities exchange info.<a href="#section-6.2-1" class="pilcrow">¶</a></p>
<p id="section-6.2-2">The following captures high-level tree hierarchy for peer
     state. The peer's Hello adjacencies tree is shown for ipv4
     address-family only; a similar tree exists for ipv6 address-family
     as well.<a href="#section-6.2-2" class="pilcrow">¶</a></p>
<span id="name-peer-state-2"></span><div id="LDPPeerState">
<figure id="figure-6">
          <div id="section-6.2-3.1">
<pre class="lang-yangtree sourcecode">
+--rw mpls-ldp!
   +--rw peers
      +--rw peer* [lsr-id label-space-id]
         +--rw lsr-id
         +--rw label-space-id
         +--ro label-advertisement-mode
         +--ro session-state
         +--ro tcp-connection
         +--ro session-holdtime?
         +--ro up-time
         +-- . . . .
         +--ro address-families
         |  +--ro ipv4
         |     +--ro hello-adjacencies
         |        +--ro hello-adjacencies*
         |                        [local-address adjacent-address]
         |           . . . .
         |           . . . .
         +--ro received-peer-state
         |  +--ro . . . .
         |  +--ro capability
         |     +--ro . . . .
         +--ro statistics
            +-- . . . .
            +-- received
            |   +-- ...
            +-- sent
                +-- ...
</pre>
</div>
<figcaption><a href="#figure-6" class="selfRef">Figure 6</a>:
<a href="#name-peer-state-2" class="selfRef">Peer State</a>
          </figcaption></figure>
</div>
</section>
<section id="section-6.3">
        <h3 id="name-bindings-state">
<a href="#section-6.3" class="section-number selfRef">6.3. </a><a href="#name-bindings-state" class="section-name selfRef">Bindings State</a>
        </h3>
<p id="section-6.3-1"> Bindings state provides information on LDP FEC-Label bindings
     as well as address bindings for both inbound (received) as well as
     outbound (advertised) direction. FEC-Label bindings are presented
     in a FEC-centric view, and address bindings are presented in an
     address-centric view:<a href="#section-6.3-1" class="pilcrow">¶</a></p>
<span id="name-example-bindings"></span><div id="ExampleBndg">
<figure id="figure-7">
          <div id="section-6.3-2.1">
<pre class="sourcecode">
     FEC-Label bindings:
         FEC 203.0.113.1/32:
           advertised: local-label 16000
             peer 192.0.2.1:0
             peer 192.0.2.2:0
             peer 192.0.2.3:0
           received:
             peer 192.0.2.1:0, label 16002, used-in-forwarding=Yes
             peer 192.0.2.2:0, label 17002, used-in-forwarding=No
         FEC 203.0.113.2/32:
            . . . .
         FEC 198.51.100.0/24:
            . . . .
         FEC 2001:db8:0:2::
            . . . .
         FEC 2001:db8:0:3::
            . . . .

     Address bindings:
         Addr 192.0.2.10:
            advertised
         Addr 2001:db8:0:10::
            advertised

         Addr 192.0.2.1:
           received, peer 192.0.2.1:0
         Addr 192.0.2.2:
           received, peer 192.0.2.2:0
         Addr 192.0.2.3:
           received, peer 192.0.2.3:0
         Addr 2001:db8:0:2::
           received, peer 192.0.2.2:0
         Addr 2001:db8:0:3::
           received, peer 192.0.2.3:0
</pre>
</div>
<figcaption><a href="#figure-7" class="selfRef">Figure 7</a>:
<a href="#name-example-bindings" class="selfRef">Example Bindings</a>
          </figcaption></figure>
</div>
<p id="section-6.3-3"> Note that all local addresses are advertised to all peers;
     hence, there is no need to provide per-peer information for local address
     advertisement. Furthermore, note that it is easy to derive a
     peer-centric view for the bindings from the information already
     provided in this model.<a href="#section-6.3-3" class="pilcrow">¶</a></p>
<p id="section-6.3-4">The following captures high-level tree hierarchy for bindings
     state. The tree shown below is for ipv4 address-family only; a
     similar tree exists for ipv6 address-family as well.<a href="#section-6.3-4" class="pilcrow">¶</a></p>
<span id="name-bindings-state-2"></span><div id="LDPBndgState">
<figure id="figure-8">
          <div id="section-6.3-5.1">
<pre class="lang-yangtree sourcecode">
+--rw mpls-ldp!
   +--rw global
      +--rw address-families
         +--rw ipv4
            +--ro bindings
               +--ro address* [address]
               |  +--ro address (ipv4-address or ipv6-address)
               |  +--ro advertisement-type?   advertised-received
               |  +--ro peer?        leafref
               +--ro fec-label* [fec]
                  +--ro fec     (ipv4-prefix or ipv6-prefix)
                  +--ro peer* [peer advertisement-type]
                     +--ro peer                  leafref
                     +--ro advertisement-type? advertised-received
                     +--ro label?                mpls:mpls-label
                     +--ro used-in-forwarding?   boolean
</pre>
</div>
<figcaption><a href="#figure-8" class="selfRef">Figure 8</a>:
<a href="#name-bindings-state-2" class="selfRef">Bindings State</a>
          </figcaption></figure>
</div>
</section>
<section id="section-6.4">
        <h3 id="name-capabilities-state">
<a href="#section-6.4" class="section-number selfRef">6.4. </a><a href="#name-capabilities-state" class="section-name selfRef">Capabilities State</a>
        </h3>
<p id="section-6.4-1"> LDP capabilities state comprises two types of information:
     global information (such as timer, etc.) and per-peer
     information.<a href="#section-6.4-1" class="pilcrow">¶</a></p>
<p id="section-6.4-2">The following captures high-level tree hierarchy for LDP capabilities state.<a href="#section-6.4-2" class="pilcrow">¶</a></p>
<span id="name-capabilities-state-2"></span><div id="LDPCapState">
<figure id="figure-9">
          <div id="section-6.4-3.1">
<pre class="lang-yangtree sourcecode">
   +--rw mpls-ldp!
      +--rw peers
         +--rw peer* [lsr-id label-space-id]
            +--rw lsr-id    yang:dotted-quad
            +--rw label-space-id
            +--ro received-peer-state
               +--ro capability
                  +--ro . . . .
                  +--ro . . . .
</pre>
</div>
<figcaption><a href="#figure-9" class="selfRef">Figure 9</a>:
<a href="#name-capabilities-state-2" class="selfRef">Capabilities State</a>
          </figcaption></figure>
</div>
</section>
</section>
</div>
<div id="section_ldp_notif">
<section id="section-7">
      <h2 id="name-notifications">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-notifications" class="section-name selfRef">Notifications</a>
      </h2>
<p id="section-7-1"> This model defines a list of notifications to inform the client of
 important events detected during the protocol operation.  These events
 include events related to changes in the operational state of an LDP
 peer, Hello adjacency, and FEC, etc. It is to be noted that an LDP FEC
 is treated as operational (up) as long as it has at least one Next Hop
 Label Forwarding Entry (NHLFE) with an outgoing label.<a href="#section-7-1" class="pilcrow">¶</a></p>
<p id="section-7-2"> A simplified graphical representation of the data model for LDP notifications is shown in <a href="#ConsolidatedTree" class="xref">Figure 2</a>.<a href="#section-7-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="section_ldp_action">
<section id="section-8">
      <h2 id="name-action">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-action" class="section-name selfRef">Action</a>
      </h2>
<p id="section-8-1"> This model defines a list of rpcs that allow performing an action
 or executing a command on the protocol. For example, it allows for the
 clearing (resetting) of LDP peers, hello-adjacencies, and
 statistics. The model makes an effort to provide a different level of
 control so that a user is able to either clear all, clear all for a
 given type, or clear a specific entity.<a href="#section-8-1" class="pilcrow">¶</a></p>
<p id="section-8-2"> A simplified graphical representation of the data model for LDP actions is shown in <a href="#ConsolidatedTree" class="xref">Figure 2</a>.<a href="#section-8-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="YANG">
<section id="section-9">
      <h2 id="name-yang-specification">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-yang-specification" class="section-name selfRef">YANG Specification</a>
      </h2>
<p id="section-9-1">The following sections specify the actual YANG (module) specification
 for LDP constructs defined earlier in the document.<a href="#section-9-1" class="pilcrow">¶</a></p>
<div id="base_yang">
<section id="section-9.1">
        <h3 id="name-base">
<a href="#section-9.1" class="section-number selfRef">9.1. </a><a href="#name-base" class="section-name selfRef">Base</a>
        </h3>
<p id="section-9.1-1">
     This YANG module imports types defined in <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>, <span>[<a href="#RFC8177" class="xref">RFC8177</a>]</span>, <span>[<a href="#RFC8294" class="xref">RFC8294</a>]</span>, <span>[<a href="#RFC8343" class="xref">RFC8343</a>]</span>, <span>[<a href="#RFC8344" class="xref">RFC8344</a>]</span>, <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, and <span>[<a href="#RFC9067" class="xref">RFC9067</a>]</span>.<a href="#section-9.1-1" class="pilcrow">¶</a></p>
<span id="name-ldp-base-module"></span><div id="BASE-YANG-FILE">
<figure id="figure-10">
          <div id="section-9.1-2.1">
<pre class="lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-mpls-ldp@2022-03-14.yang"

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

  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-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the Routing Area";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ietf-ip {
    prefix ip;
    reference
      "RFC 8344: A YANG Data Model for IP Management";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }

  organization
    "IETF MPLS Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/mpls/&gt;
     WG List:  &lt;mailto:mpls@ietf.org&gt;

     Editor:   Kamran Raza
               &lt;mailto:skraza@cisco.com&gt;

     Author:   Rajiv Asati
               &lt;mailto:rajiva@cisco.com&gt;

     Author:   Xufeng Liu
               &lt;mailto:xufeng.liu.ietf@gmail.com&gt;

     Author:   Santosh Easale
               &lt;mailto:santosh_easale@berkeley.edu&gt;

     Author:   Xia Chen
               &lt;mailto:jescia.chenxia@huawei.com&gt;

     Author:   Himanshu Shah
               &lt;mailto:hshah@ciena.com&gt;";
  description
    "This YANG module defines the essential components for the
     management of Multiprotocol Label Switching (MPLS) Label
     Distribution Protocol (LDP).  It is also the base model to
     be augmented for Multipoint LDP (mLDP).

     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 9070; see the
     RFC itself for full legal notices.";

  revision 2022-03-14 {
    description
      "Initial revision.";
    reference
      "RFC 9070: YANG Data Model for MPLS LDP";
  }

  /*
   * Typedefs
   */

  typedef advertised-received {
    type enumeration {
      enum advertised {
        description
          "Advertised information.";
      }
      enum received {
        description
          "Received information.";
      }
    }
    description
      "Received or advertised.";
  }

  typedef downstream-upstream {
    type enumeration {
      enum downstream {
        description
          "Downstream information.";
      }
      enum upstream {
        description
          "Upstream information.";
      }
    }
    description
      "Downstream or upstream.";
  }

  typedef label-adv-mode {
    type enumeration {
      enum downstream-unsolicited {
        description
          "Downstream Unsolicited.";
      }
      enum downstream-on-demand {
        description
          "Downstream on Demand.";
      }
    }
    description
      "Label Advertisement Mode.";
  }

  typedef oper-status-event-type {
    type enumeration {
      enum up {
        value 1;
        description
          "Operational status changed to up.";
      }
      enum down {
        value 2;
        description
          "Operational status changed to down.";
      }
    }
    description
      "Operational status event type for notifications.";
  }

  /*
   * Identities
   */

  identity mpls-ldp {
    base rt:control-plane-protocol;
    description
      "LDP protocol.";
    reference
      "RFC 5036: LDP Specification";
  }

  identity adjacency-flag-base {
    description
      "Base type for adjacency flags.";
  }

  identity adjacency-flag-active {
    base adjacency-flag-base;
    description
      "This adjacency is configured and actively created.";
  }

  identity adjacency-flag-passive {
    base adjacency-flag-base;
    description
      "This adjacency is not configured and passively accepted.";
  }

  /*
   * Groupings
   */

  grouping adjacency-state-attributes {
    description
      "The operational state attributes of an LDP Hello adjacency,
       which can used for basic and extended discoveries, in IPv4 and
       IPv6 address families.";
    leaf-list flag {
      type identityref {
        base adjacency-flag-base;
      }
      description
        "One or more flags to indicate whether the adjacency is
         actively created, passively accepted, or both.";
    }
    container hello-holdtime {
      description
        "Containing Hello holdtime state information.";
      leaf adjacent {
        type uint16;
        units "seconds";
        description
          "The holdtime value learned from the adjacent LSR.";
      }
      leaf negotiated {
        type uint16;
        units "seconds";
        description
          "The holdtime negotiated between this LSR and the adjacent
           LSR.";
      }
      leaf remaining {
        type uint16;
        units "seconds";
        description
          "The time remaining until the holdtime timer expires.";
      }
    }
    leaf next-hello {
      type uint16;
      units "seconds";
      description
        "The time when the next Hello message will be sent.";
    }
    container statistics {
      description
        "Statistics objects.";
      leaf discontinuity-time {
        type yang:date-and-time;
        mandatory true;
        description
          "The time on the most recent occasion at which any one or
           more of this interface's counters suffered a
           discontinuity.  If no such discontinuities have occurred
           since the last re-initialization of the local management
           subsystem, then this node contains the time the local
           management subsystem re-initialized itself.";
      }
      leaf hello-received {
        type yang:counter64;
        description
          "The number of Hello messages received.";
      }
      leaf hello-dropped {
        type yang:counter64;
        description
          "The number of Hello messages dropped.";
      }
    } // statistics
  } // adjacency-state-attributes

  grouping basic-discovery-timers {
    description
      "The timer attributes for basic discovery, used in the
       per-interface setting and in the all-interface setting.";
    leaf hello-holdtime {
      type uint16 {
        range "15..3600";
      }
      units "seconds";
      description
        "The time interval for which an LDP link Hello adjacency
         is maintained in the absence of link Hello messages from
         the LDP neighbor.
         This leaf may be configured at the per-interface level or
         the global level, with precedence given to the value at the
         per-interface level.  If the leaf is not configured at
         either level, the default value at the global level is
         used.";
    }
    leaf hello-interval {
      type uint16 {
        range "5..1200";
      }
      units "seconds";
      description
        "The interval between consecutive LDP link Hello messages
         used in basic LDP discovery.
         This leaf may be configured at the per-interface level or
         the global level, with precedence given to the value at the
         per-interface level.  If the leaf is not configured at
         either level, the default value at the global level is
         used.";
    }
  } // basic-discovery-timers

  grouping binding-address-state-attributes {
    description
      "Operational state attributes of an address binding, used in
       IPv4 and IPv6 address families.";
    leaf advertisement-type {
      type advertised-received;
      description
        "Received or advertised.";
    }
    container peer {
      when "../advertisement-type = 'received'" {
        description
          "Applicable for received address.";
      }
      description
        "LDP peer from which this address is received.";
      uses ldp-peer-ref-from-binding;
    }
  } // binding-address-state-attributes

  grouping binding-label-state-attributes {
    description
      "Operational state attributes for a FEC-Label binding, used in
       IPv4 and IPv6 address families.";
    list peer {
      key "lsr-id label-space-id advertisement-type";
      description
        "List of advertised and received peers.";
      uses ldp-peer-ref-from-binding {
        description
          "The LDP peer from which this binding is received, or to
           which this binding is advertised.
           The peer is identified by its LDP ID, which consists of
           the LSR Id and the label space Id.";
      }
      leaf advertisement-type {
        type advertised-received;
        description
          "Received or advertised.";
      }
      leaf label {
        type rt-types:mpls-label;
        description
          "Advertised (outbound) or received (inbound)
           label.";
      }
      leaf used-in-forwarding {
        type boolean;
        description
          "'true' if the label is used in forwarding.";
      }
    } // peer
  } // binding-label-state-attributes

  grouping graceful-restart-attributes-per-peer {
    description
      "Per-peer graceful restart attributes.
       On the local side, these attributes are configuration and
       operational state data.  On the peer side, these attributes
       are operational state data received from the peer.";
    container graceful-restart {
      description
        "Attributes for graceful restart.";
      leaf enabled {
        type boolean;
        description
          "Enable or disable graceful restart.
           This leaf may be configured at the per-peer level or the
           global level, with precedence given to the value at the
           per-peer level.  If the leaf is not configured at either
           level, the default value at the global level is used.";
      }
      leaf reconnect-time {
        type uint16 {
          range "10..1800";
        }
        units "seconds";
        description
          "Specifies the time interval that the remote LDP peer
           must wait for the local LDP peer to reconnect after the
           remote peer detects the LDP communication failure.
           This leaf may be configured at the per-peer level or the
           global level, with precedence given to the value at the
           per-peer level.  If the leaf is not configured at either
           level, the default value at the global level is used.";
      }
      leaf recovery-time {
        type uint16 {
          range "30..3600";
        }
        units "seconds";
        description
          "Specifies the time interval, in seconds, that the remote
           LDP peer preserves its MPLS forwarding state after
           receiving the Initialization message from the restarted
           local LDP peer.
           This leaf may be configured at the per-peer level or the
           global level, with precedence given to the value at the
           per-peer level.  If the leaf is not configured at either
           level, the default value at the global level is used.";
      }
    } // graceful-restart
  } // graceful-restart-attributes-per-peer

  grouping ldp-interface-ref {
    description
      "Defining a reference to an LDP interface.";
    leaf name {
      type if:interface-ref;
      must '(/if:interfaces/if:interface[if:name=current()]/ip:ipv4)'
         + ' or '
         + '(/if:interfaces/if:interface[if:name=current()]/ip:ipv6)'
      {
        description
          "Interface is IPv4 or IPv6.";
      }
      description
        "The name of an LDP interface.";
    }
  }

  grouping ldp-peer-ref-absolute {
    description
      "An absolute reference to an LDP peer, by the LDP ID, which
       consists of the LSR Id and the label space Id.";
    leaf protocol-name {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:name";
      }
      description
        "The name of the LDP protocol instance.";
    }
    leaf lsr-id {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol"
           + "[rt:name=current()/../protocol-name]/"
           + "ldp:mpls-ldp/ldp:peers/ldp:peer/ldp:lsr-id";
      }
      description
        "The LSR Id of the peer, as a portion of the peer LDP ID.";
    }
    leaf label-space-id {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol"
           + "[rt:name=current()/../protocol-name]/"
           + "ldp:mpls-ldp/ldp:peers/"
           + "ldp:peer[ldp:lsr-id=current()/../lsr-id]/"
           + "ldp:label-space-id";
      }
      description
        "The label space Id of the peer, as a portion of the peer
         LDP ID.";
    }
  } // ldp-peer-ref-absolute

  grouping ldp-peer-ref-from-binding {
    description
      "A relative reference to an LDP peer, by the LDP ID, which
       consists of the LSR Id and the label space Id.";
    leaf lsr-id {
      type leafref {
        path "../../../../../../../ldp:peers/ldp:peer/ldp:lsr-id";
      }
      description
        "The LSR Id of the peer, as a portion of the peer LDP ID.";
    }
    leaf label-space-id {
      type leafref {
        path "../../../../../../../ldp:peers/"
           + "ldp:peer[ldp:lsr-id=current()/../lsr-id]/"
           + "ldp:label-space-id";
      }
      description
        "The label space Id of the peer, as a portion of the peer
         LDP ID.";
    }
  } // ldp-peer-ref-from-binding

  grouping ldp-peer-ref-from-interface {
    description
      "A relative reference to an LDP peer, by the LDP ID, which
       consists of the LSR Id and the label space Id.";
    container peer {
      description
        "Reference to an LDP peer, by the LDP ID, which consists of
         the LSR Id and the label space Id.";
      leaf lsr-id {
        type leafref {
          path "../../../../../../../../../ldp:peers/ldp:peer/"
             + "ldp:lsr-id";
        }
        description
          "The LSR Id of the peer, as a portion of the peer LDP ID.";
      }
      leaf label-space-id {
        type leafref {
          path "../../../../../../../../../ldp:peers/"
             + "ldp:peer[ldp:lsr-id=current()/../lsr-id]/"
             + "ldp:label-space-id";
        }
        description
          "The label space Id of the peer, as a portion of the peer
           LDP ID.";
      }
    } // peer
  } // ldp-peer-ref-from-interface

  grouping ldp-peer-ref-from-target {
    description
      "A relative reference to an LDP peer, by the LDP ID, which
       consists of the LSR Id and the label space Id.";
    container peer {
      description
        "Reference to an LDP peer, by the LDP ID, which consists of
         the LSR Id and the label space Id.";
      leaf lsr-id {
        type leafref {
          path "../../../../../../../../ldp:peers/ldp:peer/"
             + "ldp:lsr-id";
        }
        description
          "The LSR Id of the peer, as a portion of the peer LDP ID.";
      }
      leaf label-space-id {
        type leafref {
          path "../../../../../../../../ldp:peers/"
             + "ldp:peer[ldp:lsr-id=current()/../lsr-id]/"
             + "ldp:label-space-id";
        }
        description
          "The label space Id of the peer, as a portion of the peer
           LDP ID.";
      }
    } // peer
  } // ldp-peer-ref-from-target

  grouping peer-attributes {
    description
      "Peer configuration attributes, used in the per-peer setting
       can in the all-peer setting.";
    leaf session-ka-holdtime {
      type uint16 {
        range "45..3600";
      }
      units "seconds";
      description
        "The time interval after which an inactive LDP session
         terminates and the corresponding TCP session closes.
         Inactivity is defined as not receiving LDP packets from the
         peer.
         This leaf may be configured at the per-peer level or the
         global level, with precedence given to the value at the
         per-peer level.  If the leaf is not configured at either
         level, the default value at the global level is used.";
    }
    leaf session-ka-interval {
      type uint16 {
        range "15..1200";
      }
      units "seconds";
      description
        "The interval between successive transmissions of KeepAlive
         packets.  Keepalive packets are only sent in the absence of
         other LDP packets transmitted over the LDP session.
         This leaf may be configured at the per-peer level or the
         global level, with precedence given to the value at the
         per-peer level.  If the leaf is not configured at either
         level, the default value at the global level is used.";
    }
  } // peer-attributes

  grouping peer-authentication {
    description
      "Peer authentication container, used in the per-peer setting
       can in the all-peer setting.";
    container authentication {
      description
        "Containing authentication information.";
      choice authentication-type {
        description
          "Choice of authentication.";
        case password {
          leaf key {
            type string;
            description
              "This leaf specifies the authentication key.  The
               length of the key may be dependent on the
               cryptographic algorithm.";
          }
          leaf crypto-algorithm {
            type identityref {
              base key-chain:crypto-algorithm;
            }
            description
              "Cryptographic algorithm associated with key.";
          }
        }
      }
    }
  } // peer-authentication

  grouping peer-state-derived {
    description
      "The peer state information derived from the LDP protocol
       operations.";
    container label-advertisement-mode {
      config false;
      description
        "Label advertisement mode state.";
      leaf local {
        type label-adv-mode;
        description
          "Local Label Advertisement Mode.";
      }
      leaf peer {
        type label-adv-mode;
        description
          "Peer Label Advertisement Mode.";
      }
      leaf negotiated {
        type label-adv-mode;
        description
          "Negotiated Label Advertisement Mode.";
      }
    }
    leaf next-keep-alive {
      type uint16;
      units "seconds";
      config false;
      description
        "Time duration from now until sending the next KeepAlive
         message.";
    }
    container received-peer-state {
      config false;
      description
        "Operational state information learned from the peer.";
      uses graceful-restart-attributes-per-peer;
      container capability {
        description
          "Peer capability information.";
        container end-of-lib {
          description
            "Peer's end-of-lib capability.";
          leaf enabled {
            type boolean;
            description
              "'true' if peer's end-of-lib capability is enabled.";
          }
        }
        container typed-wildcard-fec {
          description
            "Peer's typed-wildcard-fec capability.";
          leaf enabled {
            type boolean;
            description
              "'true' if peer's typed-wildcard-fec capability is
                enabled.";
          }
        }
        container upstream-label-assignment {
          description
            "Peer's upstream label assignment capability.";
          leaf enabled {
            type boolean;
            description
              "'true' if peer's upstream label assignment is
               enabled.";
          }
        }
      } // capability
    } // received-peer-state
    container session-holdtime {
      config false;
      description
        "Session holdtime state.";
      leaf peer {
        type uint16;
        units "seconds";
        description
          "Peer holdtime.";
      }
      leaf negotiated {
        type uint16;
        units "seconds";
        description
          "Negotiated holdtime.";
      }
      leaf remaining {
        type uint16;
        units "seconds";
        description
          "Remaining holdtime.";
      }
    } // session-holdtime
    leaf session-state {
      type enumeration {
        enum non-existent {
          description
            "NON EXISTENT state.  Transport disconnected.";
        }
        enum initialized {
          description
            "INITIALIZED state.";
        }
        enum openrec {
          description
            "OPENREC state.";
        }
        enum opensent {
          description
            "OPENSENT state.";
        }
        enum operational {
          description
            "OPERATIONAL state.";
        }
      }
      config false;
      description
        "Representing the operational status of the LDP session.";
      reference
        "RFC 5036: LDP Specification, Sec. 2.5.4.";
    }
    container tcp-connection {
      config false;
      description
        "TCP connection state.";
      leaf local-address {
        type inet:ip-address;
        description
          "Local address.";
      }
      leaf local-port {
        type inet:port-number;
        description
          "Local port number.";
      }
      leaf remote-address {
        type inet:ip-address;
        description
          "Remote address.";
      }
      leaf remote-port {
        type inet:port-number;
        description
          "Remote port number.";
      }
    } // tcp-connection
    leaf up-time {
      type rt-types:timeticks64;
      config false;
      description
        "The number of time ticks (hundredths of a second) since the
         state of the session with the peer changed to
         OPERATIONAL.";
    }
    container statistics {
      config false;
      description
        "Statistics objects.";
      leaf discontinuity-time {
        type yang:date-and-time;
        mandatory true;
        description
          "The time on the most recent occasion at which any one or
           more of this interface's counters suffered a
           discontinuity.  If no such discontinuities have occurred
           since the last re-initialization of the local management
           subsystem, then this node contains the time the local
           management subsystem re-initialized itself.";
      }
      container received {
        description
          "Inbound statistics.";
        uses statistics-peer-received-sent;
      }
      container sent {
        description
          "Outbound statistics.";
        uses statistics-peer-received-sent;
      }
      leaf total-addresses {
        type uint32;
        description
          "The number of learned addresses.";
      }
      leaf total-labels {
        type uint32;
        description
          "The number of learned labels.";
      }
      leaf total-fec-label-bindings {
        type uint32;
        description
          "The number of learned label-address bindings.";
      }
    } // statistics
  } // peer-state-derived

  grouping statistics-peer-received-sent {
    description
      "Inbound and outbound statistic counters.";
    leaf total-octets {
      type yang:counter64;
      description
        "The total number of octets sent or received.";
    }
    leaf total-messages {
      type yang:counter64;
      description
        "The number of messages sent or received.";
    }
    leaf address {
      type yang:counter64;
      description
        "The number of Address messages sent or received.";
    }
    leaf address-withdraw {
      type yang:counter64;
      description
        "The number of address-withdraw messages sent or received.";
    }
    leaf initialization {
      type yang:counter64;
      description
        "The number of Initialization messages sent or received.";
    }
    leaf keepalive {
      type yang:counter64;
      description
        "The number of KeepAlive messages sent or received.";
    }
    leaf label-abort-request {
      type yang:counter64;
      description
        "The number of label-abort-request messages sent or
         received.";
    }
    leaf label-mapping {
      type yang:counter64;
      description
        "The number of label-mapping messages sent or received.";
    }
    leaf label-release {
      type yang:counter64;
      description
        "The number of label-release messages sent or received.";
    }
    leaf label-request {
      type yang:counter64;
      description
        "The number of label-request messages sent or received.";
    }
    leaf label-withdraw {
      type yang:counter64;
      description
        "The number of label-withdraw messages sent or received.";
    }
    leaf notification {
      type yang:counter64;
      description
        "The number of notification messages sent or received.";
    }
  } // statistics-peer-received-sent

  /*
   * Configuration data and operational state data nodes
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol" {
    when "derived-from-or-self(rt:type, 'ldp:mpls-ldp')" {
      description
        "This augmentation is only valid for a control plane
         protocol instance of LDP (type 'mpls-ldp').";
    }
    description
      "LDP augmentation to routing control plane protocol
       configuration and state.";
    container mpls-ldp {
      must "not (../../rt:control-plane-protocol"
         + "[derived-from-or-self(rt:type, 'ldp:mpls-ldp')]"
         + "[rt:name!=current()/../rt:name])" {
        description
          "Only one LDP instance is allowed.";
      }
      description
        "Containing configuration and operational data for the LDP
         protocol.";
      container global {
        description
          "Global attributes for LDP.";
        container capability {
          description
            "Containing the LDP capability data.  The container is
             used for augmentations.";
          reference
            "RFC 5036: LDP Specification, Sec. 1.5.";
        }
        container graceful-restart {
          description
            "Attributes for graceful restart.";
          leaf enabled {
            type boolean;
            default "false";
            description
              "Enable or disable graceful restart.";
          }
          leaf reconnect-time {
            type uint16 {
              range "10..1800";
            }
            units "seconds";
            default "120";
            description
              "Specifies the time interval that the remote LDP peer
               must wait for the local LDP peer to reconnect after
               the remote peer detects the LDP communication
               failure.";
          }
          leaf recovery-time {
            type uint16 {
              range "30..3600";
            }
            units "seconds";
            default "120";
            description
              "Specifies the time interval, in seconds, that the
               remote LDP peer preserves its MPLS forwarding state
               after receiving the Initialization message from the
               restarted local LDP peer.";
          }
          leaf forwarding-holdtime {
            type uint16 {
              range "30..3600";
            }
            units "seconds";
            default "180";
            description
              "Specifies the time interval, in seconds, before the
               termination of the recovery phase.";
          }
        } // graceful-restart
        leaf lsr-id {
          type rt-types:router-id;
          description
            "Specifies the value to act as the LDP LSR Id.
             If this attribute is not specified, LDP uses the router
             ID as determined by the system.";
        }
        container address-families {
          description
            "Per-address-family configuration and operational state.
             The address family can be either IPv4 or IPv6.";
          container ipv4 {
            presence "Present if IPv4 is enabled, unless the
                      'enabled' leaf is set to 'false'.";
            description
              "Containing data related to the IPv4 address family.";
            leaf enabled {
              type boolean;
              default "true";
              description
                "'false' to disable the address family.";
            }
            leaf label-distribution-control-mode {
              type enumeration {
                enum independent {
                  description
                    "Independent label distribution control.";
                }
                enum ordered {
                  description
                    "Ordered label distribution control.";
                }
              }
              config false;
              description
                "Label distribution control mode.";
              reference
                "RFC 5036: LDP Specification, Sec. 2.6.";
            }
            // ipv4 bindings
            container bindings {
              config false;
              description
                "LDP address and label binding information.";
              list address {
                key "address";
                description
                  "List of address bindings learned by LDP.";
                leaf address {
                  type inet:ipv4-address;
                  description
                    "The IPv4 address learned from an Address
                     message received from or advertised to a peer.";
                }
                uses binding-address-state-attributes;
              }
              list fec-label {
                key "fec";
                description
                  "List of FEC-label bindings learned by LDP.";
                leaf fec {
                  type inet:ipv4-prefix;
                  description
                    "The prefix FEC value in the FEC-Label binding,
                     learned in a Label Mapping message received from
                     or advertised to a peer.";
                }
                uses binding-label-state-attributes;
              }
            } // bindings
          } // ipv4
        } // address-families
      } // global
      container discovery {
        description
          "Neighbor-discovery configuration and operational state.";
        container interfaces {
          description
            "A list of interfaces for LDP Basic Discovery.";
          reference
            "RFC 5036: LDP Specification, Sec. 2.4.1.";
          uses basic-discovery-timers {
            refine "hello-holdtime" {
              default "15";
            }
            refine "hello-interval" {
              default "5";
            }
          }
          list interface {
            key "name";
            description
              "List of LDP interfaces used for LDP Basic Discovery.";
            uses ldp-interface-ref;
            leaf next-hello {
              type uint16;
              units "seconds";
              config false;
              description
                "Time to send the next Hello message.";
            }
            container address-families {
              description
                "Container for address families.";
              container ipv4 {
                presence "Present if IPv4 is enabled, unless the
                          'enabled' leaf is set to 'false'.";
                description
                  "IPv4 address family.";
                leaf enabled {
                  type boolean;
                  default "true";
                  description
                    "Set to false to disable the address family on
                     the interface.";
                }
                container hello-adjacencies {
                  config false;
                  description
                    "Containing a list of Hello adjacencies.";
                  list hello-adjacency {
                    key "adjacent-address";
                    config false;
                    description
                      "List of Hello adjacencies.";
                    leaf adjacent-address {
                      type inet:ipv4-address;
                      description
                        "Neighbor address of the Hello adjacency.";
                    }
                    uses adjacency-state-attributes;
                    uses ldp-peer-ref-from-interface;
                  }
                }
              } // ipv4
            } // address-families
          } // interface
        } // interfaces
        container targeted {
          description
            "A list of targeted neighbors for extended discovery.";
          leaf hello-holdtime {
            type uint16 {
              range "15..3600";
            }
            units "seconds";
            default "45";
            description
              "The time interval for which an LDP targeted Hello
               adjacency is maintained in the absence of targeted
               Hello messages from an LDP neighbor.";
          }
          leaf hello-interval {
            type uint16 {
              range "5..3600";
            }
            units "seconds";
            default "15";
            description
              "The interval between consecutive LDP targeted Hello
               messages used in extended LDP discovery.";
          }
          container hello-accept {
            description
              "LDP policy to control the acceptance of extended
               neighbor-discovery Hello messages.";
            leaf enabled {
              type boolean;
              default "false";
              description
                "'true' to accept; 'false' to deny.";
            }
          }
          container address-families {
            description
              "Container for address families.";
            container ipv4 {
              presence "Present if IPv4 is enabled.";
              description
                "IPv4 address family.";
              container hello-adjacencies {
                config false;
                description
                  "Containing a list of Hello adjacencies.";
                list hello-adjacency {
                  key "local-address adjacent-address";
                  description
                    "List of Hello adjacencies.";
                  leaf local-address {
                    type inet:ipv4-address;
                    description
                      "Local address of the Hello adjacency.";
                  }
                  leaf adjacent-address {
                    type inet:ipv4-address;
                    description
                      "Neighbor address of the Hello adjacency.";
                  }
                  uses adjacency-state-attributes;
                  uses ldp-peer-ref-from-target;
                }
              }
              list target {
                key "adjacent-address";
                description
                  "Targeted discovery params.";
                leaf adjacent-address {
                  type inet:ipv4-address;
                  description
                    "Configures a remote LDP neighbor for the
                     extended LDP discovery.";
                }
                leaf enabled {
                  type boolean;
                  default "true";
                  description
                    "'true' to enable the target.";
                }
                leaf local-address {
                  type inet:ipv4-address;
                  description
                    "The local address used as the source address to
                     send targeted Hello messages.
                     If the value is not specified, the
                     transport address is used as the source
                     address.";
                }
              } // target
            } // ipv4
          } // address-families
        } // targeted
      } // discovery
      container peers {
        description
          "Peers configuration attributes.";
        uses peer-authentication;
        uses peer-attributes {
          refine "session-ka-holdtime" {
            default "180";
          }
          refine "session-ka-interval" {
            default "60";
          }
        }
        list peer {
          key "lsr-id label-space-id";
          description
            "List of peers.";
          leaf lsr-id {
            type rt-types:router-id;
            description
              "The LSR Id of the peer, used to identify the globally
               unique LSR.  This is the first four octets of the LDP
               ID.  This leaf is used together with the leaf
               'label-space-id' to form the LDP ID.";
            reference
              "RFC 5036: LDP Specification, Sec. 2.2.2.";
          }
          leaf label-space-id {
            type uint16;
            description
              "The label space Id of the peer, used to identify a
               specific label space within the LSR.  This is the last
               two octets of the LDP ID.  This leaf is used together
               with the leaf 'lsr-id' to form the LDP ID.";
            reference
              "RFC 5036: LDP Specification, Sec. 2.2.2.";
          }
          uses peer-authentication;
          container address-families {
            description
              "Per-vrf per-af params.";
            container ipv4 {
              presence "Present if IPv4 is enabled.";
              description
                "IPv4 address family.";
              container hello-adjacencies {
                config false;
                description
                  "Containing a list of Hello adjacencies.";
                list hello-adjacency {
                  key "local-address adjacent-address";
                  description
                    "List of Hello adjacencies.";
                  leaf local-address {
                    type inet:ipv4-address;
                    description
                      "Local address of the Hello adjacency.";
                  }
                  leaf adjacent-address {
                    type inet:ipv4-address;
                    description
                      "Neighbor address of the Hello adjacency.";
                  }
                  uses adjacency-state-attributes;
                  leaf interface {
                    type if:interface-ref;
                    description
                      "Interface for this adjacency.";
                  }
                }
              }
            } // ipv4
          } // address-families
          uses peer-state-derived;
        } // list peer
      } // peers
    } // container mpls-ldp
  }

  /*
   * RPCs
   */

  rpc mpls-ldp-clear-peer {
    description
      "Clears the session to the peer.";
    input {
      uses ldp-peer-ref-absolute {
        description
          "The LDP peer to be cleared.  If this is not provided,
           then all peers are cleared.
           The peer is identified by its LDP ID, which consists of
           the LSR Id and the label space Id.";
      }
    }
  }

  rpc mpls-ldp-clear-hello-adjacency {
    description
      "Clears the Hello adjacency.";
    input {
      container hello-adjacency {
        description
          "Link adjacency or targeted adjacency.  If this is not
           provided, then all Hello adjacencies are cleared.";
        leaf protocol-name {
          type leafref {
            path "/rt:routing/rt:control-plane-protocols/"
               + "rt:control-plane-protocol/rt:name";
          }
          description
            "The name of the LDP protocol instance.";
        }
        choice hello-adjacency-type {
          description
            "Adjacency type.";
          case targeted {
            container targeted {
              presence "Present to clear targeted adjacencies.";
              description
                "Clear targeted adjacencies.";
              leaf target-address {
                type inet:ip-address;
                description
                  "The target address.  If this is not provided, then
                   all targeted adjacencies are cleared.";
              }
            }
          }
          case link {
            container link {
              presence "Present to clear link adjacencies.";
              description
                "Clear link adjacencies.";
              leaf next-hop-interface {
                type leafref {
                  path "/rt:routing/rt:control-plane-protocols/"
                     + "rt:control-plane-protocol/mpls-ldp/"
                     + "discovery/interfaces/interface/name";
                }
                description
                  "Interface connecting to a next hop.  If this is
                   not provided, then all link adjacencies are
                   cleared.";
              }
              leaf next-hop-address {
                type inet:ip-address;
                must '../next-hop-interface' {
                  description
                    "Applicable when an interface is specified.";
                }
                description
                  "IP address of a next hop.  If this is not
                   provided, then adjacencies to all next hops on the
                   given interface are cleared.";
              }
            }
          }
        } // hello-adjacency-type
      } // hello-adjacency
    } // input
  } // mpls-ldp-clear-hello-adjacency

  rpc mpls-ldp-clear-peer-statistics {
    description
      "Clears protocol statistics (e.g., sent and received
       counters).";
    input {
      uses ldp-peer-ref-absolute {
        description
          "The LDP peer whose statistics are to be cleared.
           If this is not provided, then all peers' statistics are
           cleared.
           The peer is identified by its LDP ID, which consists of
           the LSR Id and the label space Id.";
      }
    }
  }

  /*
   * Notifications
   */

  notification mpls-ldp-peer-event {
    description
      "Notification event for a change of LDP peer operational
       status.";
    leaf event-type {
      type oper-status-event-type;
      description
        "Event type.";
    }
    container peer {
      description
        "Reference to an LDP peer, by the LDP ID, which consists of
         the LSR Id and the label space Id.";
      uses ldp-peer-ref-absolute;
    }
  }

  notification mpls-ldp-hello-adjacency-event {
    description
      "Notification event for a change of LDP adjacency operational
       status.";
    leaf event-type {
      type oper-status-event-type;
      description
        "Event type.";
    }
    leaf protocol-name {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:name";
      }
      description
        "The name of the LDP protocol instance.";
    }
    choice hello-adjacency-type {
      description
        "Interface or targeted adjacency.";
      case targeted {
        container targeted {
          description
            "Targeted adjacency through LDP extended discovery.";
          leaf target-address {
            type inet:ip-address;
            description
              "The target adjacent-address learned.";
          }
        }
      }
      case link {
        container link {
          description
            "Link adjacency through LDP basic discovery.";
          leaf next-hop-interface {
            type if:interface-ref;
            description
              "The interface connecting to the adjacent next hop.";
          }
          leaf next-hop-address {
            type inet:ip-address;
            must '../next-hop-interface' {
              description
                "Applicable when an interface is specified.";
            }
            description
              "IP address of the next hop. This can be IPv4 or IPv6
               address.";
          }
        }
      }
    } // hello-adjacency-type
  } // mpls-ldp-hello-adjacency-event

  notification mpls-ldp-fec-event {
    description
      "Notification event for a change of FEC status.";
    leaf event-type {
      type oper-status-event-type;
      description
        "Event type.";
    }
    leaf protocol-name {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:name";
      }
      description
        "The name of the LDP protocol instance.";
    }
    leaf fec {
      type inet:ip-prefix;
      description
        "The address prefix element of the FEC whose status
         has changed.";
    }
  }
}


&lt;CODE ENDS&gt;</pre>
</div>
<figcaption><a href="#figure-10" class="selfRef">Figure 10</a>:
<a href="#name-ldp-base-module" class="selfRef">LDP Base Module</a>
          </figcaption></figure>
</div>
</section>
</div>
<section id="section-9.2">
        <h3 id="name-extended">
<a href="#section-9.2" class="section-number selfRef">9.2. </a><a href="#name-extended" class="section-name selfRef">Extended</a>
        </h3>
<p id="section-9.2-1">
     This YANG module imports types defined in <span>[<a href="#RFC5036" class="xref">RFC5036</a>]</span>, <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>, <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>, <span>[<a href="#RFC8177" class="xref">RFC8177</a>]</span>, <span>[<a href="#RFC8343" class="xref">RFC8343</a>]</span>, and <span>[<a href="#RFC9067" class="xref">RFC9067</a>]</span>.<a href="#section-9.2-1" class="pilcrow">¶</a></p>
<span id="name-ldp-extended-module"></span><div id="EXT-YANG-FILE">
<figure id="figure-11">
          <div id="section-9.2-2.1">
<pre class="lang-yang sourcecode">&lt;CODE BEGINS&gt; file "ietf-mpls-ldp-extended@2022-03-14.yang"

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

  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)";
  }
  import ietf-key-chain {
    prefix key-chain;
    reference
      "RFC 8177: YANG Data Model for Key Chains";
  }
  import ietf-mpls-ldp {
    prefix ldp;
    reference
      "RFC 9070: YANG Data Model for MPLS LDP";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model for Interface Management";
  }
  import ietf-routing-policy {
    prefix rt-pol;
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }

  organization
    "IETF MPLS Working Group";
  contact
    "WG Web:   &lt;https://datatracker.ietf.org/wg/mpls/&gt;
     WG List:  &lt;mailto:mpls@ietf.org&gt;

     Editor:   Kamran Raza
               &lt;mailto:skraza@cisco.com&gt;

     Author:   Rajiv Asati
               &lt;mailto:rajiva@cisco.com&gt;

     Author:   Xufeng Liu
               &lt;mailto:xufeng.liu.ietf@gmail.com&gt;

     Author:   Santosh Easale
               &lt;mailto:santosh_easale@berkeley.edu&gt;

     Author:   Xia Chen
               &lt;mailto:jescia.chenxia@huawei.com&gt;

     Author:   Himanshu Shah
               &lt;mailto:hshah@ciena.com&gt;";
  description
    "This YANG module defines the extended components for the
     management of Multiprotocol Label Switching (MPLS) Label
     Distribution Protocol (LDP).  It is also the model to
     be augmented for extended Multipoint LDP (mLDP).

     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 9070; see the
     RFC itself for full legal notices.";

  revision 2022-03-14 {
    description
      "Initial revision.";
    reference
      "RFC 9070: YANG Data Model for MPLS LDP";
  }

  /*
   * Features
   */

  feature capability-end-of-lib {
    description
      "This feature indicates that the system allows for the
       configuration of LDP end-of-lib capability.";
  }

  feature capability-typed-wildcard-fec {
    description
      "This feature indicates that the system allows for the
       configuration of LDP typed-wildcard-fec capability.";
  }

  feature capability-upstream-label-assignment {
    description
      "This feature indicates that the system allows for the
       configuration of LDP upstream label assignment capability.";
  }

  feature forwarding-nexthop-config {
    description
      "This feature indicates that the system allows for controlling
       MPLS forwarding on an LDP interface.";
  }

  feature graceful-restart-helper-mode {
    description
      "This feature indicates that the system supports graceful
       restart helper mode.  We call an LSR to be operating in GR
       helper mode when it advertises 0 as its FT Reconnect Timeout
       in the FT Session TLV.
       Please refer to Section 2 of RFC 3478 for details.";
  }

  feature key-chain {
    description
      "This feature indicates that the system supports key-chain for
       authentication.";
  }

  feature peers-dual-stack-transport-preference {
    description
      "This feature indicates that the system allows for the
       configuration of the transport connection preference in a
       dual-stack setup for peers.";
  }

  feature per-interface-timer-config {
    description
      "This feature indicates that the system allows for the
       configuration of interface Hello timers at the per-interface
       level.";
  }

  feature per-peer-admin-down {
    description
      "This feature indicates that the system allows for the
       administrative disabling of a peer.";
  }

  feature per-peer-graceful-restart-config {
    description
      "This feature indicates that the system allows for the
       configuration of graceful restart at the per-peer level.";
  }

  feature per-peer-session-attributes-config {
    description
      "This feature indicates that the system allows for the
       configuration of session attributes at the per-peer level.";
  }

  feature policy-label-assignment-config {
    description
      "This feature indicates that the system allows for the
       configuration of policies to assign labels according to
       certain prefixes.";
  }

  feature policy-ordered-label-config {
    description
      "This feature indicates that the system allows for the
       configuration of ordered label policies.";
  }

  feature policy-targeted-discovery-config {
    description
      "This feature indicates that the system allows for the
       configuration of policies to control the acceptance of
       targeted neighbor-discovery Hello messages.";
  }

  feature session-downstream-on-demand-config {
    description
      "This feature indicates that the system allows for the
       configuration of session downstream on demand.";
  }

  /*
   * Typedefs
   */

  typedef neighbor-list-ref {
    type leafref {
      path "/rt-pol:routing-policy/rt-pol:defined-sets/"
         + "rt-pol:neighbor-sets/rt-pol:neighbor-set/rt-pol:name";
    }
    description
      "A type for a reference to a neighbor address list.
       The string value is the name identifier for uniquely
       identifying the referenced address list, which contains a list
       of addresses that a routing policy can applied.";
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }

  typedef prefix-list-ref {
    type leafref {
      path "/rt-pol:routing-policy/rt-pol:defined-sets/"
         + "rt-pol:prefix-sets/rt-pol:prefix-set/rt-pol:name";
    }
    description
      "A type for a reference to a prefix list.
       The string value is the name identifier for uniquely
       identifying the referenced prefix set, which contains a list
       of prefixes that a routing policy can applied.";
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }

  typedef peer-list-ref {
    type leafref {
      path "/rt-pol:routing-policy/rt-pol:defined-sets/"
         + "rt-pol:neighbor-sets/rt-pol:neighbor-set/rt-pol:name";
    }
    description
      "A type for a reference to a peer address list.
       The string value is the name identifier for uniquely
       identifying the referenced address list, which contains a list
       of addresses that a routing policy can applied.";
    reference
      "RFC 9067: A YANG Data Model for Routing Policy";
  }

  /*
   * Identities
   */
  /*
   * Groupings
   */

  grouping address-family-ipv4-augment {
    description
      "Augmentation to address family IPv4.";
    uses policy-container;
    leaf transport-address {
      type inet:ipv4-address;
      description
        "The transport address advertised in LDP Hello messages.
         If this value is not specified, the LDP LSR Id is used as
         the transport address.";
      reference
        "RFC 5036: LDP Specification, Sec. 3.5.2.";
    }
  }

  grouping authentication-keychain-augment {
    description
      "Augmentation to authentication to add key-chain.";
    leaf key-chain {
      type key-chain:key-chain-ref;
      description
        "key-chain name.
         If not specified, no key chain is used.";
    }
  }

  grouping capability-augment {
    description
      "Augmentation to capability.";
    container end-of-lib {
      if-feature "capability-end-of-lib";
      description
        "Configure end-of-lib capability.";
      leaf enabled {
        type boolean;
        default "false";
        description
          "'true' to enable end-of-lib capability.";
      }
    }
    container typed-wildcard-fec {
      if-feature "capability-typed-wildcard-fec";
      description
        "Configure typed-wildcard-fec capability.";
      leaf enabled {
        type boolean;
        default "false";
        description
          "'true' to enable typed-wildcard-fec capability.";
      }
    }
    container upstream-label-assignment {
      if-feature "capability-upstream-label-assignment";
      description
        "Configure upstream label assignment capability.";
      leaf enabled {
        type boolean;
        default "false";
        description
          "'true' to enable upstream label assignment.";
      }
    }
  } // capability-augment

  grouping global-augment {
    description
      "Augmentation to global attributes.";
    leaf igp-synchronization-delay {
      type uint16 {
        range "0 | 3..300";
      }
      units "seconds";
      default "0";
      description
        "Sets the interval that the LDP waits before notifying the
         Interior Gateway Protocol (IGP) that label exchange is
         completed so that IGP can start advertising the normal
         metric for the link.
         If the value is not specified, there is no delay.";
    }
  }

  grouping global-forwarding-nexthop-augment {
    description
      "Augmentation at the global level for controlling MPLS
       forwarding on LDP interfaces.";
    container forwarding-nexthop {
      if-feature "forwarding-nexthop-config";
      description
        "Configuration for controlling MPLS forwarding on LDP
         interfaces.";
      container interfaces {
        description
          "Containing a list of interfaces on which forwarding can be
           disabled.";
        list interface {
          key "name";
          description
            "List of LDP interfaces on which forwarding can be
             disabled.";
          uses ldp:ldp-interface-ref;
          list address-family {
            key "afi";
            description
              "Per-vrf per-af params.";
            leaf afi {
              type identityref {
                base rt:address-family;
              }
              description
                "Address family type value.";
            }
            leaf ldp-disable {
              type boolean;
              default "false";
              description
                "'true' to disable LDP forwarding on the interface.";
            }
          }
        } // interface
      } // interfaces
    } // forwarding-nexthop
  } // global-forwarding-nexthop-augment

  grouping graceful-restart-augment {
    description
      "Augmentation to graceful restart.";
    leaf helper-enabled {
      if-feature "graceful-restart-helper-mode";
      type boolean;
      default "false";
      description
        "Enable or disable graceful restart helper mode.";
    }
  }

  grouping interface-address-family-ipv4-augment {
    description
      "Augmentation to interface address family IPv4.";
    leaf transport-address {
      type union {
        type enumeration {
          enum use-global-transport-address {
            description
              "Use the transport address set at the global level
               common for all interfaces for this address family.";
          }
          enum use-interface-address {
            description
              "Use interface address as the transport address.";
          }
        }
        type inet:ipv4-address;
      }
      default "use-global-transport-address";
      description
        "IP address to be advertised as the LDP transport address.";
    }
  }

  grouping interface-address-family-ipv6-augment {
    description
      "Augmentation to interface address family IPv6.";
    leaf transport-address {
      type union {
        type enumeration {
          enum use-global-transport-address {
            description
              "Use the transport address set at the global level
               common for all interfaces for this address family.";
          }
          enum use-interface-address {
            description
              "Use interface address as the transport address.";
          }
        }
        type inet:ipv6-address;
      }
      default "use-global-transport-address";
      description
        "IP address to be advertised as the LDP transport address.";
    }
  }

  grouping interface-augment {
    description
      "Augmentation to interface.";
    uses ldp:basic-discovery-timers {
      if-feature "per-interface-timer-config";
    }
    leaf igp-synchronization-delay {
      if-feature "per-interface-timer-config";
      type uint16 {
        range "0 | 3..300";
      }
      units "seconds";
      description
        "Sets the interval that the LDP waits before notifying the
         Interior Gateway Protocol (IGP) that label exchange is
         completed so that IGP can start advertising the normal
         metric for the link.
         This leaf may be configured at the per-interface level or
         the global level, with precedence given to the value at the
         per-interface level.  If the leaf is not configured at
         either level, the default value at the global level is
         used.";
    }
  }

  grouping peer-af-policy-container {
    description
      "LDP policy attribute container under peer address family.";
    container label-policy {
      description
        "Label policy attributes.";
      container advertise {
        description
          "Label advertising policies.";
        leaf prefix-list {
          type prefix-list-ref;
          description
            "Applies the prefix list to filter outgoing label
             advertisements.
             If the value is not specified, no prefix filter
             is applied.";
        }
      }
      container accept {
        description
          "Label advertisement acceptance policies.";
        leaf prefix-list {
          type prefix-list-ref;
          description
            "Applies the prefix list to filer incoming label
             advertisements.
             If the value is not specified, no prefix filter
             is applied.";
        }
      }
    }
  } // peer-af-policy-container

  grouping peer-augment {
    description
      "Augmentation to each peer list entry.";
    leaf admin-down {
      if-feature "per-peer-admin-down";
      type boolean;
      default "false";
      description
        "'true' to disable the peer.";
    }
    uses ldp:graceful-restart-attributes-per-peer {
      if-feature "per-peer-graceful-restart-config";
    }
    uses ldp:peer-attributes {
      if-feature "per-peer-session-attributes-config";
    }
  }

  grouping peers-augment {
    description
      "Augmentation to peers container.";
    container session-downstream-on-demand {
      if-feature "session-downstream-on-demand-config";
      description
        "Session downstream-on-demand attributes.";
      leaf enabled {
        type boolean;
        default "false";
        description
          "'true' if session downstream on demand is enabled.";
      }
      leaf peer-list {
        type peer-list-ref;
        description
          "The name of a peer ACL, to be applied to the
           downstream-on-demand sessions.
           If this value is not specified, no filter is applied to
           any downstream-on-demand sessions.";
      }
    }
    container dual-stack-transport-preference {
      if-feature "peers-dual-stack-transport-preference";
      description
        "The settings of peers to establish TCP connection in a
         dual-stack setup.";
      leaf max-wait {
        type uint16 {
          range "0..60";
        }
        default "30";
        description
          "The maximum wait time in seconds for preferred transport
           connection establishment.  0 indicates no preference.";
      }
      container prefer-ipv4 {
        presence "Present if IPv4 is preferred for transport
                  connection establishment, subject to the
                  'peer-list' in this container.";
        description
          "Uses IPv4 as the preferred address family for transport
           connection establishment, subject to the 'peer-list' in
           this container.
           If this container is not present, as a default, IPv6 is
           the preferred address family for transport connection
           establishment.";
        leaf peer-list {
          type peer-list-ref;
          description
            "The name of a peer ACL, to be applied to the IPv4
             transport connections.
             If this value is not specified, no filter is applied,
             and the IPv4 is preferred for all peers.";
        }
      }
    }
  } // peers-augment

  grouping policy-container {
    description
      "LDP policy attributes.";
    container label-policy {
      description
        "Label policy attributes.";
      container advertise {
        description
          "Label advertising policies.";
        container egress-explicit-null {
          description
            "Enables an egress router to advertise an
             explicit null label (value 0) in place of an
             implicit null label (value 3) to the
             penultimate hop router.";
          leaf enabled {
            type boolean;
            default "false";
            description
              "'true' to enable explicit null.";
          }
        }
        leaf prefix-list {
          type prefix-list-ref;
          description
            "Applies the prefix list to filter outgoing label
             advertisements.
             If the value is not specified, no prefix filter
             is applied.";
        }
      }
      container accept {
        description
          "Label advertisement acceptance policies.";
        leaf prefix-list {
          type prefix-list-ref;
          description
            "Applies the prefix list to filter incoming label
             advertisements.
             If the value is not specified, no prefix filter
             is applied.";
        }
      }
      container assign {
        if-feature "policy-label-assignment-config";
        description
          "Label assignment policies.";
        container independent-mode {
          description
            "Independent label policy attributes.";
          leaf prefix-list {
            type prefix-list-ref;
            description
              "Assign labels according to certain prefixes.
               If the value is not specified, no prefix filter
               is applied (labels are assigned to all learned
               routes).";
          }
        }
        container ordered-mode {
          if-feature "policy-ordered-label-config";
          description
            "Ordered label policy attributes.";
          leaf egress-prefix-list {
            type prefix-list-ref;
            description
              "Assign labels according to certain prefixes for
               egress LSR.";
          }
        }
      } // assign
    } // label-policy
  } // policy-container

  /*
   * Configuration and state data nodes
   */
  // Forwarding nexthop augmentation to the global tree

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global" {
    description
      "Forwarding nexthop augmentation.";
    uses global-forwarding-nexthop-augment;
  }

  // global/address-families/ipv6

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
        + "ldp:address-families" {
    description
      "Global IPv6 augmentation.";
    container ipv6 {
      presence "Present if IPv6 is enabled, unless the 'enabled'
                leaf is set to 'false'.";
      description
        "Containing data related to the IPv6 address family.";
      leaf enabled {
        type boolean;
        default "true";
        description
          "'false' to disable the address family.";
      }
      uses policy-container;
      leaf transport-address {
        type inet:ipv6-address;
        mandatory true;
        description
          "The transport address advertised in LDP Hello messages.";
      }
      leaf label-distribution-control-mode {
        type enumeration {
          enum independent {
            description
              "Independent label distribution control.";
          }
          enum ordered {
            description
              "Ordered label distribution control.";
          }
        }
        config false;
        description
          "Label distribution control mode.";
        reference
          "RFC 5036: LDP Specification, Sec. 2.6.";
      }
      // ipv6 bindings
      container bindings {
        config false;
        description
          "LDP address and label binding information.";
        list address {
          key "address";
          description
            "List of address bindings learned by LDP.";
          leaf address {
            type inet:ipv6-address;
            description
              "The IPv6 address learned from an Address
               message received from or advertised to a peer.";
          }
          uses ldp:binding-address-state-attributes;
        }
        list fec-label {
          key "fec";
          description
            "List of FEC-label bindings learned by LDP.";
          leaf fec {
            type inet:ipv6-prefix;
            description
              "The prefix FEC value in the FEC-Label binding,
               learned in a Label Mapping message received from
               or advertised to a peer.";
          }
          uses ldp:binding-label-state-attributes;
        }
      } // bindings
    } // ipv6
  }

  // discovery/interfaces/interface/address-families/ipv6

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:interfaces/ldp:interface/"
        + "ldp:address-families" {
    description
      "Interface IPv6 augmentation.";
    container ipv6 {
      presence "Present if IPv6 is enabled, unless the 'enabled'
                leaf is set to 'false'.";
      description
        "IPv6 address family.";
      leaf enabled {
        type boolean;
        default "true";
        description
          "'false' to disable the address family on the interface.";
      }
      container hello-adjacencies {
        config false;
        description
          "Containing a list of Hello adjacencies.";
        list hello-adjacency {
          key "adjacent-address";
          config false;
          description
            "List of Hello adjacencies.";
          leaf adjacent-address {
            type inet:ipv6-address;
            description
              "Neighbor address of the Hello adjacency.";
          }
          uses ldp:adjacency-state-attributes;
          uses ldp:ldp-peer-ref-from-interface;
        }
      }
    } // ipv6
  }

  // discovery/targeted/address-families/ipv6

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:targeted/ldp:address-families" {
    description
      "Targeted discovery IPv6 augmentation.";
    container ipv6 {
      presence "Present if IPv6 is enabled.";
      description
        "IPv6 address family.";
      container hello-adjacencies {
        config false;
        description
          "Containing a list of Hello adjacencies.";
        list hello-adjacency {
          key "local-address adjacent-address";
          config false;
          description
            "List of Hello adjacencies.";
          leaf local-address {
            type inet:ipv6-address;
            description
              "Local address of the Hello adjacency.";
          }
          leaf adjacent-address {
            type inet:ipv6-address;
            description
              "Neighbor address of the Hello adjacency.";
          }
          uses ldp:adjacency-state-attributes;
          uses ldp:ldp-peer-ref-from-target;
        }
      }
      list target {
        key "adjacent-address";
        description
          "Targeted discovery params.";
        leaf adjacent-address {
          type inet:ipv6-address;
          description
            "Configures a remote LDP neighbor for the
             extended LDP discovery.";
        }
        leaf enabled {
          type boolean;
          default "true";
          description
            "'true' to enable the target.";
        }
        leaf local-address {
          type inet:ipv6-address;
          description
            "The local address used as the source address to send
             targeted Hello messages.
             If the value is not specified, the transport address
             is used as the source address.";
        }
      } // target
    } // ipv6
  }

  // /peers/peer/state/address-families/ipv6

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:peer/ldp:address-families" {
    description
      "Peer state IPv6 augmentation.";
    container ipv6 {
      presence "Present if IPv6 is enabled.";
      description
        "IPv6 address family.";
      container hello-adjacencies {
        config false;
        description
          "Containing a list of Hello adjacencies.";
        list hello-adjacency {
          key "local-address adjacent-address";
          description
            "List of Hello adjacencies.";
          leaf local-address {
            type inet:ipv6-address;
            description
              "Local address of the Hello adjacency.";
          }
          leaf adjacent-address {
            type inet:ipv6-address;
            description
              "Neighbor address of the Hello adjacency.";
          }
          uses ldp:adjacency-state-attributes;
          leaf interface {
            type if:interface-ref;
            description
              "Interface for this adjacency.";
          }
        }
      }
    } // ipv6
  }

  /*
   * Configuration data and operational state data nodes
   */

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global" {
    description
      "Graceful restart augmentation.";
    uses global-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
        + "ldp:capability" {
    description
      "Capability augmentation.";
    uses capability-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
        + "ldp:graceful-restart" {
    description
      "Graceful restart augmentation.";
    uses graceful-restart-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:global/"
        + "ldp:address-families/ldp:ipv4" {
    description
      "Address family IPv4 augmentation.";
    uses address-family-ipv4-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:interfaces/ldp:interface" {
    description
      "Interface augmentation.";
    uses interface-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:interfaces/ldp:interface/ldp:address-families/"
        + "ldp:ipv4" {
    description
      "Interface address family IPv4 augmentation.";
    uses interface-address-family-ipv4-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:interfaces/ldp:interface/ldp:address-families/"
        + "ldp-ext:ipv6" {
    description
      "Interface address family IPv6 augmentation.";
    uses interface-address-family-ipv6-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:discovery/"
        + "ldp:targeted/ldp:hello-accept" {
    description
      "Targeted discovery augmentation.";
    leaf neighbor-list {
      if-feature "policy-targeted-discovery-config";
      type neighbor-list-ref;
      description
        "The name of a neighbor ACL, used to accept Hello messages
         from LDP peers as permitted by the neighbor-list policy.
         If this value is not specified, targeted Hello messages
         from any source are accepted.";
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers" {
    description
      "Peers augmentation.";
    uses peers-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:authentication/ldp:authentication-type" {
    if-feature "key-chain";
    description
      "Peers authentication augmentation.";
    case key-chain {
      uses authentication-keychain-augment;
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:peer" {
    description
      "Peer list entry augmentation.";
    uses peer-augment;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:peer/ldp:authentication/ldp:authentication-type" {
    if-feature "key-chain";
    description
      "Peer list entry authentication augmentation.";
    case key-chain {
      uses authentication-keychain-augment;
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:peer/ldp:address-families/ldp:ipv4" {
    description
      "Peer list entry IPv4 augmentation.";
    uses peer-af-policy-container;
  }

  augment "/rt:routing/rt:control-plane-protocols/"
        + "rt:control-plane-protocol/ldp:mpls-ldp/ldp:peers/"
        + "ldp:peer/ldp:address-families/ldp-ext:ipv6" {
    description
      "Peer list entry IPv6 augmentation.";
    uses peer-af-policy-container;
  }
}

&lt;CODE ENDS&gt;</pre>
</div>
<figcaption><a href="#figure-11" class="selfRef">Figure 11</a>:
<a href="#name-ldp-extended-module" class="selfRef">LDP Extended Module</a>
          </figcaption></figure>
</div>
</section>
</section>
</div>
<section id="section-10">
      <h2 id="name-security-considerations">
<a href="#section-10" class="section-number selfRef">10. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-10-1"> This specification inherits the security
 considerations captured in <span>[<a href="#RFC5920" class="xref">RFC5920</a>]</span> and the LDP protocol specification documents, namely base LDP
 <span>[<a href="#RFC5036" class="xref">RFC5036</a>]</span>, LDP IPv6 <span>[<a href="#RFC7552" class="xref">RFC7552</a>]</span>, LDP Capabilities
 <span>[<a href="#RFC5561" class="xref">RFC5561</a>]</span>, Typed Wildcard FEC <span>[<a href="#RFC5918" class="xref">RFC5918</a>]</span>, LDP End-of-LIB
 <span>[<a href="#RFC5919" class="xref">RFC5919</a>]</span>, and LDP Upstream Label Assignment
 <span>[<a href="#RFC6389" class="xref">RFC6389</a>]</span>.<a href="#section-10-1" class="pilcrow">¶</a></p>
<section id="section-10.1">
        <h3 id="name-yang-data-model">
<a href="#section-10.1" class="section-number selfRef">10.1. </a><a href="#name-yang-data-model" class="section-name selfRef">YANG Data Model</a>
        </h3>
<p id="section-10.1-1"> 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-10.1-1" class="pilcrow">¶</a></p>
<p id="section-10.1-2"> 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-10.1-2" class="pilcrow">¶</a></p>
<section id="section-10.1.1">
          <h4 id="name-writable-nodes">
<a href="#section-10.1.1" class="section-number selfRef">10.1.1. </a><a href="#name-writable-nodes" class="section-name selfRef">Writable Nodes</a>
          </h4>
<p id="section-10.1.1-1"> 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.<a href="#section-10.1.1-1" class="pilcrow">¶</a></p>
<p id="section-10.1.1-2"> For LDP, the ability to modify MPLS LDP configuration may allow the entire MPLS LDP domain to be compromised including forming LDP adjacencies and/or peer sessions with unauthorized
routers to mount a massive Denial-of-Service (DoS) attack. In particular, the following are the subtrees and data nodes that are sensitive and vulnerable:<a href="#section-10.1.1-2" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-10.1.1-3">
            <dt id="section-10.1.1-3.1">/mpls-ldp/discovery/interfaces/interface:
            </dt>
            <dd style="margin-left: 1.5em" id="section-10.1.1-3.2">Adding LDP on any unprotected interface could allow an LDP Hello adjacency
  to be formed with an unauthorized and malicious neighbor. Once a Hello
  adjacency is formed, a peer session could progress with this neighbor.<a href="#section-10.1.1-3.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-10.1.1-3.3">/mpls-ldp/discovery/targeted/hello-accept:
            </dt>
            <dd style="margin-left: 1.5em" id="section-10.1.1-3.4"> Allowing acceptance of targeted-hellos could open LDP to DoS attacks
  related to incoming targeted hellos from malicious sources.<a href="#section-10.1.1-3.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-10.1.1-3.5">/mpls-ldp/peers/authentication:
            </dt>
            <dd style="margin-left: 1.5em" id="section-10.1.1-3.6">Allowing a peer session establishment is typically controlled via LDP
  authentication where a proper and secure authentication password/key
  management is warranted.<a href="#section-10.1.1-3.6" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-10.1.1-3.7">/mpls-ldp/peers/peer/authentication:
            </dt>
            <dd style="margin-left: 1.5em" id="section-10.1.1-3.8">Same as above.<a href="#section-10.1.1-3.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
<section id="section-10.1.2">
          <h4 id="name-readable-nodes">
<a href="#section-10.1.2" class="section-number selfRef">10.1.2. </a><a href="#name-readable-nodes" class="section-name selfRef">Readable Nodes</a>
          </h4>
<p id="section-10.1.2-1"> 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:<a href="#section-10.1.2-1" class="pilcrow">¶</a></p>
<p id="section-10.1.2-2">The exposure of LDP databases (such as Hello adjacencies, peers, address bindings, and FEC-Label bindings) beyond the scope of the LDP admin domain may be undesirable. The relevant subtrees and data nodes are as follows:<a href="#section-10.1.2-2" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-10.1.2-3.1"> /mpls-ldp/global/address-families/ipv4/bindings/address<a href="#section-10.1.2-3.1" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.2"> /mpls-ldp/global/address-families/ipv6/bindings/address<a href="#section-10.1.2-3.2" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.3"> /mpls-ldp/global/address-families/ipv4/bindings/fec-label<a href="#section-10.1.2-3.3" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.4"> /mpls-ldp/global/address-families/ipv6/bindings/fec-label<a href="#section-10.1.2-3.4" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.5"> /mpls-ldp/discovery/interfaces/interface/address-families/ipv4/hello-adjacencies<a href="#section-10.1.2-3.5" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.6"> /mpls-ldp/discovery/interfaces/interface/address-families/ipv6/hello-adjacencies<a href="#section-10.1.2-3.6" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.7"> /mpls-ldp/discovery/targeted/address-families/ipv4/hello-adjacencies<a href="#section-10.1.2-3.7" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.8"> /mpls-ldp/discovery/targeted/address-families/ipv6/hello-adjacencies<a href="#section-10.1.2-3.8" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-3.9"> /mpls-ldp/peers<a href="#section-10.1.2-3.9" class="pilcrow">¶</a>
</li>
          </ul>
<p id="section-10.1.2-4"> The configuration for LDP peer authentication is supported via the
key-chain specification <span>[<a href="#RFC8177" class="xref">RFC8177</a>]</span> or via direct
specification of a key associated with a crypto algorithm (such as MD5).
The relevant subtrees and data nodes are as follows:<a href="#section-10.1.2-4" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-10.1.2-5.1"> /mpls-ldp/peers/authentication<a href="#section-10.1.2-5.1" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.2-5.2"> /mpls-ldp/peers/peer/authentication<a href="#section-10.1.2-5.2" class="pilcrow">¶</a>
</li>
          </ul>
<p id="section-10.1.2-6"> The actual authentication key data (whether locally specified or part of a
key-chain) is sensitive and needs to be kept secret from unauthorized parties.
For key-chain-based authentication, this model inherits the security
considerations of <span>[<a href="#RFC8040" class="xref">RFC8040</a>]</span> (that includes the considerations
with respect to the local storage and handling of authentication keys). A
similar procedure for storage and access to direct keys is warranted.<a href="#section-10.1.2-6" class="pilcrow">¶</a></p>
</section>
<section id="section-10.1.3">
          <h4 id="name-rpc-operations">
<a href="#section-10.1.3" class="section-number selfRef">10.1.3. </a><a href="#name-rpc-operations" class="section-name selfRef">RPC Operations</a>
          </h4>
<p id="section-10.1.3-1">Some of the RPC operations in these YANG modules may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations; otherwise, control plane flaps, network outages, and DoS attacks are possible. The RPC operations are:<a href="#section-10.1.3-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-10.1.3-2.1"> mpls-ldp-clear-peer<a href="#section-10.1.3-2.1" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-10.1.3-2.2"> mpls-ldp-clear-hello-adjacency<a href="#section-10.1.3-2.2" class="pilcrow">¶</a>
</li>
          </ul>
</section>
<section id="section-10.1.4">
          <h4 id="name-notifications-2">
<a href="#section-10.1.4" class="section-number selfRef">10.1.4. </a><a href="#name-notifications-2" class="section-name selfRef">Notifications</a>
          </h4>
<p id="section-10.1.4-1"> The model describes several notifications. The implementations must rate-limit the generation of these notifications to avoid creating
  significant notification load and possible side effects on the system stability.<a href="#section-10.1.4-1" class="pilcrow">¶</a></p>
</section>
</section>
</section>
<section id="section-11">
      <h2 id="name-iana-considerations">
<a href="#section-11" class="section-number selfRef">11. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-11-1">Per this document, the following URIs have been registered in the IETF "XML
      Registry" <span>[<a href="#RFC3688" class="xref">RFC3688</a>]</span>:<a href="#section-11-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-11-2">
        <dt id="section-11-2.1">URI:
</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.2">urn:ietf:params:xml:ns:yang:ietf-mpls-ldp<a href="#section-11-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-2.3">Registrant: 
</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.4">The IESG<a href="#section-11-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-2.5">XML:
</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.6">N/A<a href="#section-11-2.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-11-3">
        <dt id="section-11-3.1">URI:
</dt>
        <dd style="margin-left: 1.5em" id="section-11-3.2">urn:ietf:params:xml:ns:yang:ietf-mpls-ldp-extended<a href="#section-11-3.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-3.3">Registrant: 
</dt>
        <dd style="margin-left: 1.5em" id="section-11-3.4">The IESG<a href="#section-11-3.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-3.5">XML:
</dt>
        <dd style="margin-left: 1.5em" id="section-11-3.6">N/A<a href="#section-11-3.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-11-4">Per this document, the following YANG modules have been registered in the
      "YANG Module Names" registry <span>[<a href="#RFC6020" class="xref">RFC6020</a>]</span>:<a href="#section-11-4" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-11-5">
        <dt id="section-11-5.1">Name:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-5.2">ietf-mpls-ldp<a href="#section-11-5.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-5.3">Namespace:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-5.4">urn:ietf:params:xml:ns:yang:ietf-mpls-ldp<a href="#section-11-5.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-5.5">Prefix:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-5.6">ldp<a href="#section-11-5.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-5.7">Reference:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-5.8">RFC 9070<a href="#section-11-5.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlCompact dlParallel" id="section-11-6">
        <dt id="section-11-6.1">Name:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-6.2">ietf-mpls-ldp-extended<a href="#section-11-6.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-6.3">Namespace:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-6.4">urn:ietf:params:xml:ns:yang:ietf-mpls-ldp-extended<a href="#section-11-6.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-6.5">Prefix:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-6.6">ldp-ext<a href="#section-11-6.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-6.7">Reference:
        </dt>
        <dd style="margin-left: 1.5em" id="section-11-6.8">RFC 9070<a href="#section-11-6.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
<section id="section-12">
      <h2 id="name-normative-references">
<a href="#section-12" class="section-number selfRef">12. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
      </h2>
<dl class="references">
<dt id="RFC3478">[RFC3478]</dt>
      <dd>
<span class="refAuthor">Leelanivas, M.</span>, <span class="refAuthor">Rekhter, Y.</span>, and <span class="refAuthor">R. Aggarwal</span>, <span class="refTitle">"Graceful Restart Mechanism for Label Distribution Protocol"</span>, <span class="seriesInfo">RFC 3478</span>, <span class="seriesInfo">DOI 10.17487/RFC3478</span>, <time datetime="2003-02" class="refDate">February 2003</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3478">https://www.rfc-editor.org/info/rfc3478</a>&gt;</span>. </dd>
<dd class="break"></dd>
<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="RFC5036">[RFC5036]</dt>
      <dd>
<span class="refAuthor">Andersson, L., Ed.</span>, <span class="refAuthor">Minei, I., Ed.</span>, and <span class="refAuthor">B. Thomas, Ed.</span>, <span class="refTitle">"LDP Specification"</span>, <span class="seriesInfo">RFC 5036</span>, <span class="seriesInfo">DOI 10.17487/RFC5036</span>, <time datetime="2007-10" class="refDate">October 2007</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5036">https://www.rfc-editor.org/info/rfc5036</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5331">[RFC5331]</dt>
      <dd>
<span class="refAuthor">Aggarwal, R.</span>, <span class="refAuthor">Rekhter, Y.</span>, and <span class="refAuthor">E. Rosen</span>, <span class="refTitle">"MPLS Upstream Label Assignment and Context-Specific Label Space"</span>, <span class="seriesInfo">RFC 5331</span>, <span class="seriesInfo">DOI 10.17487/RFC5331</span>, <time datetime="2008-08" class="refDate">August 2008</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5331">https://www.rfc-editor.org/info/rfc5331</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5443">[RFC5443]</dt>
      <dd>
<span class="refAuthor">Jork, M.</span>, <span class="refAuthor">Atlas, A.</span>, and <span class="refAuthor">L. Fang</span>, <span class="refTitle">"LDP IGP Synchronization"</span>, <span class="seriesInfo">RFC 5443</span>, <span class="seriesInfo">DOI 10.17487/RFC5443</span>, <time datetime="2009-03" class="refDate">March 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5443">https://www.rfc-editor.org/info/rfc5443</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5561">[RFC5561]</dt>
      <dd>
<span class="refAuthor">Thomas, B.</span>, <span class="refAuthor">Raza, K.</span>, <span class="refAuthor">Aggarwal, S.</span>, <span class="refAuthor">Aggarwal, R.</span>, and <span class="refAuthor">JL. Le Roux</span>, <span class="refTitle">"LDP Capabilities"</span>, <span class="seriesInfo">RFC 5561</span>, <span class="seriesInfo">DOI 10.17487/RFC5561</span>, <time datetime="2009-07" class="refDate">July 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5561">https://www.rfc-editor.org/info/rfc5561</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5918">[RFC5918]</dt>
      <dd>
<span class="refAuthor">Asati, R.</span>, <span class="refAuthor">Minei, I.</span>, and <span class="refAuthor">B. Thomas</span>, <span class="refTitle">"Label Distribution Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class (FEC)"</span>, <span class="seriesInfo">RFC 5918</span>, <span class="seriesInfo">DOI 10.17487/RFC5918</span>, <time datetime="2010-08" class="refDate">August 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5918">https://www.rfc-editor.org/info/rfc5918</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5919">[RFC5919]</dt>
      <dd>
<span class="refAuthor">Asati, R.</span>, <span class="refAuthor">Mohapatra, P.</span>, <span class="refAuthor">Chen, E.</span>, and <span class="refAuthor">B. Thomas</span>, <span class="refTitle">"Signaling LDP Label Advertisement Completion"</span>, <span class="seriesInfo">RFC 5919</span>, <span class="seriesInfo">DOI 10.17487/RFC5919</span>, <time datetime="2010-08" class="refDate">August 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5919">https://www.rfc-editor.org/info/rfc5919</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5920">[RFC5920]</dt>
      <dd>
<span class="refAuthor">Fang, L., Ed.</span>, <span class="refTitle">"Security Framework for MPLS and GMPLS Networks"</span>, <span class="seriesInfo">RFC 5920</span>, <span class="seriesInfo">DOI 10.17487/RFC5920</span>, <time datetime="2010-07" class="refDate">July 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5920">https://www.rfc-editor.org/info/rfc5920</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="RFC6389">[RFC6389]</dt>
      <dd>
<span class="refAuthor">Aggarwal, R.</span> and <span class="refAuthor">JL. Le Roux</span>, <span class="refTitle">"MPLS Upstream Label Assignment for LDP"</span>, <span class="seriesInfo">RFC 6389</span>, <span class="seriesInfo">DOI 10.17487/RFC6389</span>, <time datetime="2011-11" class="refDate">November 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6389">https://www.rfc-editor.org/info/rfc6389</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="RFC7552">[RFC7552]</dt>
      <dd>
<span class="refAuthor">Asati, R.</span>, <span class="refAuthor">Pignataro, C.</span>, <span class="refAuthor">Raza, K.</span>, <span class="refAuthor">Manral, V.</span>, and <span class="refAuthor">R. Papneja</span>, <span class="refTitle">"Updates to LDP for IPv6"</span>, <span class="seriesInfo">RFC 7552</span>, <span class="seriesInfo">DOI 10.17487/RFC7552</span>, <time datetime="2015-06" class="refDate">June 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7552">https://www.rfc-editor.org/info/rfc7552</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7950">[RFC7950]</dt>
      <dd>
<span class="refAuthor">Bjorklund, M., Ed.</span>, <span class="refTitle">"The YANG 1.1 Data Modeling Language"</span>, <span class="seriesInfo">RFC 7950</span>, <span class="seriesInfo">DOI 10.17487/RFC7950</span>, <time datetime="2016-08" class="refDate">August 2016</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7950">https://www.rfc-editor.org/info/rfc7950</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="RFC8294">[RFC8294]</dt>
      <dd>
<span class="refAuthor">Liu, X.</span>, <span class="refAuthor">Qu, Y.</span>, <span class="refAuthor">Lindem, A.</span>, <span class="refAuthor">Hopps, C.</span>, and <span class="refAuthor">L. Berger</span>, <span class="refTitle">"Common YANG Data Types for the Routing Area"</span>, <span class="seriesInfo">RFC 8294</span>, <span class="seriesInfo">DOI 10.17487/RFC8294</span>, <time datetime="2017-12" class="refDate">December 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8294">https://www.rfc-editor.org/info/rfc8294</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="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="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="RFC8407">[RFC8407]</dt>
      <dd>
<span class="refAuthor">Bierman, A.</span>, <span class="refTitle">"Guidelines for Authors and Reviewers of Documents Containing YANG Data Models"</span>, <span class="seriesInfo">BCP 216</span>, <span class="seriesInfo">RFC 8407</span>, <span class="seriesInfo">DOI 10.17487/RFC8407</span>, <time datetime="2018-10" class="refDate">October 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8407">https://www.rfc-editor.org/info/rfc8407</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="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="RFC9067">[RFC9067]</dt>
    <dd>
<span class="refAuthor">Qu, Y.</span>, <span class="refAuthor">Tantsura, J.</span>, <span class="refAuthor">Lindem, A.</span>, and <span class="refAuthor">X. Liu</span>, <span class="refTitle">"A YANG Data Model for Routing Policy"</span>, <span class="seriesInfo">RFC 9067</span>, <span class="seriesInfo">DOI 10.17487/RFC9067</span>, <time datetime="2021-10" class="refDate">October 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc9067">https://www.rfc-editor.org/info/rfc9067</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-13">
      <h2 id="name-informative-references">
<a href="#section-13" class="section-number selfRef">13. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
      </h2>
<dl class="references">
<dt id="I-D.ietf-mpls-mldp-yang">[MPLS-MLDP-YANG]</dt>
      <dd>
<span class="refAuthor">Raza, K., Ed.</span>, <span class="refAuthor">Liu, X.</span>, <span class="refAuthor">Esale, S.</span>, <span class="refAuthor">Andersson, L.</span>, <span class="refAuthor">Tantsura, J.</span>, and <span class="refAuthor">S. Krishnaswamy</span>, <span class="refTitle">"YANG Data Model for MPLS mLDP"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-mpls-mldp-yang-10</span>, <time datetime="2021-11-11" class="refDate">11 November 2021</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mldp-yang-10">https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mldp-yang-10</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC4364">[RFC4364]</dt>
      <dd>
<span class="refAuthor">Rosen, E.</span> and <span class="refAuthor">Y. Rekhter</span>, <span class="refTitle">"BGP/MPLS IP Virtual Private Networks (VPNs)"</span>, <span class="seriesInfo">RFC 4364</span>, <span class="seriesInfo">DOI 10.17487/RFC4364</span>, <time datetime="2006-02" class="refDate">February 2006</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc4364">https://www.rfc-editor.org/info/rfc4364</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7307">[RFC7307]</dt>
      <dd>
<span class="refAuthor">Zhao, Q.</span>, <span class="refAuthor">Raza, K.</span>, <span class="refAuthor">Zhou, C.</span>, <span class="refAuthor">Fang, L.</span>, <span class="refAuthor">Li, L.</span>, and <span class="refAuthor">D. King</span>, <span class="refTitle">"LDP Extensions for Multi-Topology"</span>, <span class="seriesInfo">RFC 7307</span>, <span class="seriesInfo">DOI 10.17487/RFC7307</span>, <time datetime="2014-07" class="refDate">July 2014</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7307">https://www.rfc-editor.org/info/rfc7307</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7951">[RFC7951]</dt>
      <dd>
<span class="refAuthor">Lhotka, L.</span>, <span class="refTitle">"JSON Encoding of Data Modeled with YANG"</span>, <span class="seriesInfo">RFC 7951</span>, <span class="seriesInfo">DOI 10.17487/RFC7951</span>, <time datetime="2016-08" class="refDate">August 2016</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7951">https://www.rfc-editor.org/info/rfc7951</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>
</dl>
</section>
<section id="appendix-A">
      <h2 id="name-data-tree-example">
<a href="#appendix-A" class="section-number selfRef">Appendix A. </a><a href="#name-data-tree-example" class="section-name selfRef">Data Tree Example</a>
      </h2>
<p id="appendix-A-1">
   This section contains an example of an instance data tree in the JSON
   encoding <span>[<a href="#RFC7951" class="xref">RFC7951</a>]</span>, containing both configuration and
   state data.<a href="#appendix-A-1" class="pilcrow">¶</a></p>
<span id="name-example-topology"></span><div id="ex_top">
<figure id="figure-12">
        <div class="alignLeft art-text artwork" id="appendix-A-2.1">
<pre>
                  +---------------------+
                  |                     |
                  | Router 203.0.113.1  |
                  |                     |
                  +----------+----------+
                             |eth1
                             |2001:db8:0:1::1/64
                             |
                             |
                             |2001:db8:0:1::2/64
                  +----------+----------+
                  |                     |         |
                  |   Another Router    +---------| 2001:db8:0:2::/64
                  |                     |         |
                  +---------------------+
</pre>
</div>
<figcaption><a href="#figure-12" class="selfRef">Figure 12</a>:
<a href="#name-example-topology" class="selfRef">Example Topology</a>
        </figcaption></figure>
</div>
<p id="appendix-A-3">
   The configuration instance data tree for Router 203.0.113.1 in <a href="#ex_top" class="xref">Figure 12</a> could be as follows:<a href="#appendix-A-3" class="pilcrow">¶</a></p>
<span id="name-example-configuration-data-"></span><figure id="figure-13">
        <div id="appendix-A-4.1">
<pre class="lang-json sourcecode">

{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth1",
        "description": "An interface with LDP enabled.",
        "type": "iana-if-type:ethernetCsmacd",
        "ietf-ip:ipv6": {
          "address": [
            {
              "ip": "2001:db8:0:1::1",
              "prefix-length": 64
            }
          ],
          "forwarding": true
        }
      }
    ]
  },
  "ietf-routing:routing": {
    "router-id": "203.0.113.1",
    "control-plane-protocols": {
      "control-plane-protocol": [
        {
          "type": "ietf-mpls-ldp:mpls-ldp",
          "name": "ldp-1",
          "ietf-mpls-ldp:mpls-ldp": {
            "global": {
              "address-families": {
                "ietf-mpls-ldp-extended:ipv6": {
                  "enabled": true,
                  "transport-address": "2001:db8:0:1::1"
                }
              }
            },
            "discovery": {
              "interfaces": {
                "interface": [
                  {
                    "name": "eth1",
                    "address-families": {
                      "ietf-mpls-ldp-extended:ipv6": {
                        "enabled": true
                      }
                    }
                  }
                ]
              }
            }
          }
        }
      ]
    }
  }
}

</pre>
</div>
<figcaption><a href="#figure-13" class="selfRef">Figure 13</a>:
<a href="#name-example-configuration-data-" class="selfRef">Example Configuration Data in JSON</a>
        </figcaption></figure>
<p id="appendix-A-5">
   The corresponding operational state data for Router 203.0.113.1
   could be as follows:<a href="#appendix-A-5" class="pilcrow">¶</a></p>
<span id="name-example-operational-data-in"></span><figure id="figure-14">
        <div id="appendix-A-6.1">
<pre class="lang-json sourcecode">
{
  "ietf-interfaces:interfaces": {
    "interface": [
      {
        "name": "eth1",
        "description": "An interface with LDP enabled.",
        "type": "iana-if-type:ethernetCsmacd",
        "phys-address": "00:00:5e:00:53:01",
        "oper-status": "up",
        "statistics": {
          "discontinuity-time": "2018-09-10T15:16:27-05:00"
        },
        "ietf-ip:ipv6": {
          "forwarding": true,
          "mtu": 1500,
          "address": [
            {
              "ip": "2001:db8:0:1::1",
              "prefix-length": 64,
              "origin": "static",
              "status": "preferred"
            },
            {
              "ip": "fe80::200:5eff:fe00:5301",
              "prefix-length": 64,
              "origin": "link-layer",
              "status": "preferred"
            }
          ],
          "neighbor": [
            {
              "ip": "2001:db8:0:1::2",
              "link-layer-address": "00:00:5e:00:53:02",
              "origin": "dynamic",
              "is-router": [null],
              "state": "reachable"
            },
            {
              "ip": "fe80::200:5eff:fe00:5302",
              "link-layer-address": "00:00:5e:00:53:02",
              "origin": "dynamic",
              "is-router": [null],
              "state": "reachable"
            }
          ]
        }
      }
    ]
  },
  "ietf-routing:routing": {
    "router-id": "203.0.113.1",
    "interfaces": {
      "interface": [
        "eth1"
      ]
    },
    "control-plane-protocols": {
      "control-plane-protocol": [
        {
          "type": "ietf-mpls-ldp:mpls-ldp",
          "name": "ldp-1",
          "ietf-mpls-ldp:mpls-ldp": {
            "global": {
              "address-families": {
                "ietf-mpls-ldp-extended:ipv6": {
                  "enabled": true,
                  "transport-address": "2001:db8:0:1::1"
                }
              }
            },
            "discovery": {
              "interfaces": {
                "interface": [
                  {
                    "name": "eth1",
                    "address-families": {
                      "ietf-mpls-ldp-extended:ipv6": {
                        "enabled": true,
                        "hello-adjacencies": {
                          "hello-adjacency": [
                            {
                              "adjacent-address":
                              "fe80::200:5eff:fe00:5302",
                              "flag": ["adjacency-flag-active"],
                              "hello-holdtime": {
                                "adjacent": 15,
                                "negotiated": 15,
                                "remaining": 9
                              },
                              "next-hello": 3,
                              "statistics": {
                                "discontinuity-time":
                                "2018-09-10T15:16:27-05:00"
                              },
                              "peer": {
                                "lsr-id": "203.0.113.2",
                                "label-space-id": 0
                              }
                            }
                          ]
                        }
                      }
                    }
                  }
                ]
              }
            },
            "peers": {
              "peer": [
                {
                  "lsr-id": "203.0.113.2",
                  "label-space-id": 0,
                  "label-advertisement-mode": {
                    "local": "downstream-unsolicited",
                    "peer": "downstream-unsolicited",
                    "negotiated": "downstream-unsolicited"
                  },
                  "next-keep-alive": 5,
                  "session-holdtime": {
                    "peer": 180,
                    "negotiated": 180,
                    "remaining": 78
                  },
                  "session-state": "operational",
                  "tcp-connection": {
                    "local-address": "fe80::200:5eff:fe00:5301",
                    "local-port": 646,
                    "remote-address": "fe80::200:5eff:fe00:5302",
                    "remote-port": 646
                  },
                  "up-time": 3438100,
                  "statistics": {
                    "discontinuity-time": "2018-09-10T15:16:27-05:00"
                  }
                }
              ]
            }
          }
        }
      ]
    }
  }
}
</pre>
</div>
<figcaption><a href="#figure-14" class="selfRef">Figure 14</a>:
<a href="#name-example-operational-data-in" class="selfRef">Example Operational Data in JSON</a>
        </figcaption></figure>
</section>
<section id="appendix-B">
      <h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
      </h2>
<p id="appendix-B-1">The authors would like to acknowledge <span class="contact-name">Eddie Chami</span>, <span class="contact-name">Nagendra  Kumar</span>, <span class="contact-name">Mannan Venkatesan</span>, and <span class="contact-name">Pavan Beeram</span> for their contribution to this
 document.<a href="#appendix-B-1" class="pilcrow">¶</a></p>
<p id="appendix-B-2"> We also acknowledge <span class="contact-name">Ladislav Lhotka</span>,
 <span class="contact-name">Jan Lindblad</span>, <span class="contact-name">Tom  Petch</span>, <span class="contact-name">Yingzhen Qu</span>, and <span class="contact-name">Benjamin Kaduk</span> for their detailed review of the
 model during WG and IESG processes.<a href="#appendix-B-2" class="pilcrow">¶</a></p>
</section>
<section id="appendix-C">
      <h2 id="name-contributors">
<a href="#name-contributors" class="section-name selfRef">Contributors</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Danial Johari</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:dajohari@cisco.com" class="email">dajohari@cisco.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Loa Andersson</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:loa@pi.nu" class="email">loa@pi.nu</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Jeff Tantsura</span></div>
<div dir="auto" class="left"><span class="org">Apstra</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:jefftant.ietf@gmail.com" class="email">jefftant.ietf@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Matthew Bocci</span></div>
<div dir="auto" class="left"><span class="org">Nokia</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:matthew.bocci@nokia.com" class="email">matthew.bocci@nokia.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Reshad Rahman</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">Stephane Litkowski</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:slitkows@cisco.com" class="email">slitkows@cisco.com</a>
</div>
</address>
</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">Kamran Raza (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</span></div>
<div dir="auto" class="left"><span class="country-name">Canada</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:skraza@cisco.com" class="email">skraza@cisco.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Rajiv Asati</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</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:rajiva@cisco.com" class="email">rajiva@cisco.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Xufeng Liu</span></div>
<div dir="auto" class="left"><span class="org">IBM Corporation</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:xufeng.liu.ietf@gmail.com" class="email">xufeng.liu.ietf@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Santosh Easale</span></div>
<div dir="auto" class="left"><span class="org">Juniper Networks</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:santosh_easale@berkeley.edu" class="email">santosh_easale@berkeley.edu</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Xia Chen</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:jescia.chenxia@huawei.com" class="email">jescia.chenxia@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Himanshu Shah</span></div>
<div dir="auto" class="left"><span class="org">Ciena Corporation</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:hshah@ciena.com" class="email">hshah@ciena.com</a>
</div>
</address>
</section>
</div>
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