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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 9020: YANG Data Model for Segment Routing</title>
<meta content="Stephane Litkowski" name="author">
<meta content="Yingzhen Qu" name="author">
<meta content="Acee Lindem" name="author">
<meta content="Pushpasis Sarkar" name="author">
<meta content="Jeff Tantsura" name="author">
<meta content="
       
   This document defines three YANG data models.  The first is for
   Segment Routing (SR) configuration and operation, which is to be
   augmented by different Segment Routing data planes.  The next is a
   YANG data model that defines a collection of generic types and groupings
   for SR.  The third module defines the configuration and operational states
   for the Segment Routing MPLS data plane.

       
    " name="description">
<meta content="xml2rfc 3.8.0" name="generator">
<meta content="mpls" name="keyword">
<meta content="9020" name="rfc.number">
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<table class="ears">
<thead><tr>
<td class="left">RFC 9020</td>
<td class="center">SR YANG Data Model</td>
<td class="right">May 2021</td>
</tr></thead>
<tfoot><tr>
<td class="left">Litkowski, 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/rfc9020" class="eref">9020</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="2021-05" class="published">May 2021</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">S. Litkowski</div>
<div class="org">Cisco Systems</div>
</div>
<div class="author">
      <div class="author-name">Y. Qu</div>
<div class="org">Futurewei</div>
</div>
<div class="author">
      <div class="author-name">A. Lindem</div>
<div class="org">Cisco Systems</div>
</div>
<div class="author">
      <div class="author-name">P. Sarkar</div>
<div class="org">VMware, Inc</div>
</div>
<div class="author">
      <div class="author-name">J. Tantsura</div>
<div class="org">Juniper Networks</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 9020</h1>
<h1 id="title">YANG Data Model for Segment Routing</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">
   This document defines three YANG data models.  The first is for
   Segment Routing (SR) configuration and operation, which is to be
   augmented by different Segment Routing data planes.  The next is a
   YANG data model that defines a collection of generic types and groupings
   for SR.  The third module defines the configuration and operational states
   for the Segment Routing MPLS data plane.<a href="#section-abstract-1" 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/rfc9020">https://www.rfc-editor.org/info/rfc9020</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) 2021 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 Simplified BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Simplified 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="toc ulEmpty compact">
<li class="toc ulEmpty compact" 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>
</li>
          <li class="toc ulEmpty compact" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1"><a href="#section-2" class="xref">2</a>.  <a href="#name-terminology-and-notation" class="xref">Terminology and Notation</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" id="section-toc.1-1.2.2.1">
                <p id="section-toc.1-1.2.2.1.1" class="keepWithNext"><a href="#section-2.1" class="xref">2.1</a>.  <a href="#name-tree-diagram" class="xref">Tree Diagram</a></p>
</li>
              <li class="toc ulEmpty compact" id="section-toc.1-1.2.2.2">
                <p id="section-toc.1-1.2.2.2.1" class="keepWithNext"><a href="#section-2.2" class="xref">2.2</a>.  <a href="#name-prefixes-in-data-node-names" class="xref">Prefixes in Data Node Names</a></p>
</li>
            </ul>
</li>
          <li class="toc ulEmpty compact" 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-design-of-the-data-model" class="xref">Design of the Data Model</a></p>
</li>
          <li class="toc ulEmpty compact" 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-configuration" class="xref">Configuration</a></p>
</li>
          <li class="toc ulEmpty compact" 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-igp-control-plane-configura" class="xref">IGP Control-Plane Configuration</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" 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-igp-interface-configuration" class="xref">IGP Interface Configuration</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" 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-adjacency-sid-adj-sid-prope" class="xref">Adjacency SID (Adj-SID) Properties</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" id="section-toc.1-1.5.2.1.2.1.2.1">
                        <p id="section-toc.1-1.5.2.1.2.1.2.1.1"><a href="#section-5.1.1.1" class="xref">5.1.1.1</a>.  <a href="#name-bundling" class="xref">Bundling</a></p>
</li>
                      <li class="toc ulEmpty compact" id="section-toc.1-1.5.2.1.2.1.2.2">
                        <p id="section-toc.1-1.5.2.1.2.1.2.2.1"><a href="#section-5.1.1.2" class="xref">5.1.1.2</a>.  <a href="#name-protection" class="xref">Protection</a></p>
</li>
                    </ul>
</li>
                </ul>
</li>
            </ul>
</li>
          <li class="toc ulEmpty compact" 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-state-data" class="xref">State Data</a></p>
</li>
          <li class="toc ulEmpty compact" 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="toc ulEmpty compact" 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-yang-modules" class="xref">YANG Modules</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" id="section-toc.1-1.8.2.1">
                <p id="section-toc.1-1.8.2.1.1"><a href="#section-8.1" class="xref">8.1</a>.  <a href="#name-yang-module-for-segment-rou" class="xref">YANG Module for Segment Routing</a></p>
</li>
              <li class="toc ulEmpty compact" id="section-toc.1-1.8.2.2">
                <p id="section-toc.1-1.8.2.2.1"><a href="#section-8.2" class="xref">8.2</a>.  <a href="#name-yang-module-for-segment-rout" class="xref">YANG Module for Segment Routing Common Types</a></p>
</li>
              <li class="toc ulEmpty compact" id="section-toc.1-1.8.2.3">
                <p id="section-toc.1-1.8.2.3.1"><a href="#section-8.3" class="xref">8.3</a>.  <a href="#name-yang-module-for-segment-routi" class="xref">YANG Module for Segment Routing MPLS</a></p>
</li>
            </ul>
</li>
          <li class="toc ulEmpty compact" 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-security-considerations" class="xref">Security Considerations</a></p>
</li>
          <li class="toc ulEmpty compact" 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-iana-considerations" class="xref">IANA Considerations</a></p>
</li>
          <li class="toc ulEmpty compact" 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-references" class="xref">References</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" id="section-toc.1-1.11.2.1">
                <p id="section-toc.1-1.11.2.1.1"><a href="#section-11.1" class="xref">11.1</a>.  <a href="#name-normative-references" class="xref">Normative References</a></p>
</li>
              <li class="toc ulEmpty compact" id="section-toc.1-1.11.2.2">
                <p id="section-toc.1-1.11.2.2.1"><a href="#section-11.2" class="xref">11.2</a>.  <a href="#name-informative-references" class="xref">Informative References</a></p>
</li>
            </ul>
</li>
          <li class="toc ulEmpty compact" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#section-appendix.a" class="xref">Appendix A</a>.  <a href="#name-configuration-examples" class="xref">Configuration Examples</a></p>
<ul class="toc ulEmpty compact">
<li class="toc ulEmpty compact" id="section-toc.1-1.12.2.1">
                <p id="section-toc.1-1.12.2.1.1"><a href="#section-a.1" class="xref">A.1</a>.  <a href="#name-sr-mpls-with-ipv4" class="xref">SR-MPLS with IPv4</a></p>
</li>
              <li class="toc ulEmpty compact" id="section-toc.1-1.12.2.2">
                <p id="section-toc.1-1.12.2.2.1"><a href="#section-a.2" class="xref">A.2</a>.  <a href="#name-sr-mpls-with-ipv6" class="xref">SR-MPLS with IPv6</a></p>
</li>
            </ul>
</li>
          <li class="toc ulEmpty compact" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-acknowledgements" class="xref">Acknowledgements</a></p>
</li>
          <li class="toc ulEmpty compact" id="section-toc.1-1.14">
            <p id="section-toc.1-1.14.1"><a href="#section-appendix.c" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<div id="introduction">
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1">
          This document defines three YANG data models
          <span>[<a href="#RFC7950" class="xref">RFC7950</a>]</span>.  The first one is for
          Segment Routing (SR) <span>[<a href="#RFC8402" class="xref">RFC8402</a>]</span>
          configuration and operation. 
          This document does not define the IGP extensions to support SR, but the second 
   module defines generic
          groupings to be reused by IGP extension modules. The reason for this design choice
   is to not require implementations to support all IGP extensions. For example, an implementation
   may support the IS-IS extension but not the OSPF extension.
   The third YANG data model
          defines a module that is intended to be used on network
          elements to configure or operate the SR MPLS data
          plane <span>[<a href="#RFC8660" class="xref">RFC8660</a>]</span>.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">The YANG modules in this document conform to the Network Management
        Datastore Architecture (NMDA) <span>[<a href="#RFC8342" class="xref">RFC8342</a>]</span>.<a href="#section-1-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="term">
<section id="section-2">
      <h2 id="name-terminology-and-notation">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-terminology-and-notation" class="section-name selfRef">Terminology and Notation</a>
      </h2>
<p id="section-2-1">The key words "<span class="bcp14">MUST</span>", "<span class="bcp14">MUST NOT</span>", "<span class="bcp14">REQUIRED</span>", "<span class="bcp14">SHALL</span>", "<span class="bcp14">SHALL NOT</span>", "<span class="bcp14">SHOULD</span>", "<span class="bcp14">SHOULD NOT</span>", "<span class="bcp14">RECOMMENDED</span>", "<span class="bcp14">NOT RECOMMENDED</span>",
        "<span class="bcp14">MAY</span>", and "<span class="bcp14">OPTIONAL</span>" in this document are to be interpreted as
        described in BCP 14 <span>[<a href="#RFC2119" class="xref">RFC2119</a>]</span> <span>[<a href="#RFC8174" class="xref">RFC8174</a>]</span>
        when, and only when, they appear in all capitals, as shown here.<a href="#section-2-1" class="pilcrow">¶</a></p>
<div id="tree-info">
<section id="section-2.1">
        <h3 id="name-tree-diagram">
<a href="#section-2.1" class="section-number selfRef">2.1. </a><a href="#name-tree-diagram" class="section-name selfRef">Tree Diagram</a>
        </h3>
<p id="section-2.1-1">Tree diagrams used in this document follow the notation defined in
      <span>[<a href="#RFC8340" class="xref">RFC8340</a>]</span>.<a href="#section-2.1-1" class="pilcrow">¶</a></p>
</section>
</div>
<div id="sec.prefixes">
<section id="section-2.2">
        <h3 id="name-prefixes-in-data-node-names">
<a href="#section-2.2" class="section-number selfRef">2.2. </a><a href="#name-prefixes-in-data-node-names" class="section-name selfRef">Prefixes in Data Node Names</a>
        </h3>
<p id="section-2.2-1">In this document, names of data nodes, actions, and other
        data model objects are often used without a prefix, as long as
        it is clear from the context in which YANG module each name is
        defined. Otherwise, names are prefixed using the standard prefix
        associated with the corresponding YANG module, as shown in <a href="#tab.prefixes" class="xref">Table 1</a>.<a href="#section-2.2-1" class="pilcrow">¶</a></p>
<span id="name-prefixes-and-corresponding-"></span><div id="tab.prefixes">
<table class="center" id="table-1">
          <caption>
<a href="#table-1" class="selfRef">Table 1</a>:
<a href="#name-prefixes-and-corresponding-" class="selfRef">Prefixes and Corresponding YANG Modules</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Prefix</th>
              <th class="text-left" rowspan="1" colspan="1">YANG module</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">if</td>
              <td class="text-left" rowspan="1" colspan="1">ietf-interfaces</td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC8343" class="xref">RFC8343</a>]</span>
</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">rt</td>
              <td class="text-left" rowspan="1" colspan="1">ietf-routing</td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span>
</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">rt-types</td>
              <td class="text-left" rowspan="1" colspan="1">ietf-routing-types</td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC8294" class="xref">RFC8294</a>]</span>
</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">yang</td>
              <td class="text-left" rowspan="1" colspan="1">ietf-yang-types</td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>
</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">inet</td>
              <td class="text-left" rowspan="1" colspan="1">ietf-inet-types</td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>
</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
</div>
</section>
</div>
<div id="design">
<section id="section-3">
      <h2 id="name-design-of-the-data-model">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-design-of-the-data-model" class="section-name selfRef">Design of the Data Model</a>
      </h2>
<p id="section-3-1">The ietf-segment-routing YANG module augments the routing container in the
        ietf-routing model <span>[<a href="#RFC8349" class="xref">RFC8349</a>]</span> and defines generic
        SR configuration and operational state. This module is
        augmented by modules supporting different data planes.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">Module ietf-segment-routing-mpls augments ietf-segment-routing and
        supports SR-MPLS data plane configuration and operational state.<a href="#section-3-2" class="pilcrow">¶</a></p>
<p id="section-3-3">Module ietf-segment-routing-common defines generic types and groupings 
        that <span class="bcp14">SHOULD</span> be reused by IGP extension modules.<a href="#section-3-3" class="pilcrow">¶</a></p>
<div id="section-3-4">
<pre class="sourcecode lang-yangtree">
module: ietf-segment-routing
  augment /rt:routing:
    +--rw segment-routing

module: ietf-segment-routing-mpls
  augment /rt:routing/sr:segment-routing:
    +--rw sr-mpls
       +--rw bindings
       |  +--rw mapping-server {mapping-server}?
       |  |  +--rw policy* [name]
       |  |     +--rw name       string
       |  |     +--rw entries
       |  |        +--rw mapping-entry* [prefix algorithm]
       |  |           +--rw prefix        inet:ip-prefix
       |  |           +--rw value-type?   enumeration
       |  |           +--rw start-sid     uint32
       |  |           +--rw range?        uint32
       |  |           +--rw algorithm     identityref
       |  +--rw connected-prefix-sid-map
       |  |  +--rw connected-prefix-sid* [prefix algorithm]
       |  |     +--rw prefix               inet:ip-prefix
       |  |     +--rw value-type?          enumeration
       |  |     +--rw start-sid            uint32
       |  |     +--rw range?               uint32
       |  |     +--rw algorithm            identityref
       |  |     +--rw last-hop-behavior?   enumeration
       |  +--rw local-prefix-sid
       |     +--rw local-prefix-sid* [prefix algorithm]
       |        +--rw prefix        inet:ip-prefix
       |        +--rw value-type?   enumeration
       |        +--rw start-sid     uint32
       |        +--rw range?        uint32
       |        +--rw algorithm     identityref
       +--rw srgb
       |  +--rw srgb* [lower-bound upper-bound]
       |     +--rw lower-bound    uint32
       |     +--rw upper-bound    uint32
       +--rw srlb
       |  +--rw srlb* [lower-bound upper-bound]
       |     +--rw lower-bound    uint32
       |     +--rw upper-bound    uint32
       +--ro label-blocks* []
       |  +--ro lower-bound?   uint32
       |  +--ro upper-bound?   uint32
       |  +--ro size?          uint32
       |  +--ro free?          uint32
       |  +--ro used?          uint32
       |  +--ro scope?         enumeration
       +--ro sid-db
          +--ro sid* [target sid source source-protocol binding-type]
             +--ro target             string
             +--ro sid                uint32
             +--ro algorithm?         uint8
             +--ro source             inet:ip-address
             +--ro used?              boolean
             +--ro source-protocol    -&gt; /rt:routing
                                         /control-plane-protocols
                                         /control-plane-protocol/name
             +--ro binding-type       enumeration
             +--ro scope?             enumeration

  notifications:
    +---n segment-routing-srgb-collision
    |  +--ro srgb-collisions* []
    |     +--ro lower-bound?          uint32
    |     +--ro upper-bound?          uint32
    |     +--ro routing-protocol?     -&gt; /rt:routing
    |                                    /control-plane-protocols
    |                                    /control-plane-protocol/name
    |     +--ro originating-rtr-id?   router-or-system-id
    +---n segment-routing-global-sid-collision
    |  +--ro received-target?       string
    |  +--ro new-sid-rtr-id?        router-or-system-id
    |  +--ro original-target?       string
    |  +--ro original-sid-rtr-id?   router-or-system-id
    |  +--ro index?                 uint32
    |  +--ro routing-protocol?      -&gt; /rt:routing
    |                                  /control-plane-protocols
    |                                  /control-plane-protocol/name
    +---n segment-routing-index-out-of-range
       +--ro received-target?    string
       +--ro received-index?     uint32
       +--ro routing-protocol?   -&gt; /rt:routing
                                    /control-plane-protocols
                                    /control-plane-protocol/name
</pre><a href="#section-3-4" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="how">
<section id="section-4">
      <h2 id="name-configuration">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-configuration" class="section-name selfRef">Configuration</a>
      </h2>
<p id="section-4-1">
        The module ietf-segment-routing-mpls augments the "/rt:routing/sr:segment-routing:"
        with an sr-mpls container. This container defines all the configuration
        parameters related to the SR MPLS data plane.<a href="#section-4-1" class="pilcrow">¶</a></p>
<p id="section-4-2">
        The sr-mpls configuration is split into global configuration and interface configuration.<a href="#section-4-2" class="pilcrow">¶</a></p>
<p id="section-4-3">The global configuration includes:<a href="#section-4-3" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-4-4">
        <dt id="section-4-4.1">Bindings:</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.2">
          <p id="section-4-4.2.1">Defines Prefix to Segment Identifier (Prefix-SID) mappings. 
   The operator can control
          advertisement of Prefix-SIDs independently for IPv4 and IPv6. Two
          types of mappings are available:<a href="#section-4-4.2.1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-4-4.2.2">
            <dt id="section-4-4.2.2.1">Mapping-server:</dt>
            <dd style="margin-left: 1.5em" id="section-4-4.2.2.2">Maps prefixes that are not local to a SID. Configuration of bindings does not
           automatically allow advertisement of those
      bindings.  Advertisement must be controlled by each
      routing-protocol instance (see <a href="#cp" class="xref">Section 5</a>). Multiple mapping policies
          may be defined.<a href="#section-4-4.2.2.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-4-4.2.2.3">Connected prefixes:</dt>
            <dd style="margin-left: 1.5em" id="section-4-4.2.2.4">Maps connected prefixes to a SID. Advertisement of the mapping
          will be done by IGP when enabled for SR (see <a href="#cp" class="xref">Section 5</a>). The SID value can be expressed as an index (default) or an absolute
          value.  The "last-hop-behavior" configuration dictates the MPLS Penultimate Hop Popping (PHP)
   behavior: "explicit-null", "php", or "non-php".<a href="#section-4-4.2.2.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.3">Segment Routing Global Block (SRGB):</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.4">Defines a list of label
      blocks represented by a pair of lower-bound/upper-bound labels.
      The SRGB is also agnostic to the control plane used. So, all local
      routing-protocol instances will have to advertise the same SRGB.<a href="#section-4-4.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-4-4.5">Segment Routing Local Block (SRLB):</dt>
        <dd style="margin-left: 1.5em" id="section-4-4.6">Defines a list of label
      blocks represented by a pair of lower-bound/upper-bound labels reserved for local SIDs.<a href="#section-4-4.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
</div>
<div id="cp">
<section id="section-5">
      <h2 id="name-igp-control-plane-configura">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-igp-control-plane-configura" class="section-name selfRef">IGP Control-Plane Configuration</a>
      </h2>
<p id="section-5-1">
    Support of SR extensions for a particular IGP control plane is achieved by augmenting routing-protocol configuration with SR extensions.
        This augmentation <span class="bcp14">SHOULD</span> be part of the routing-protocol YANG modules as not to create any dependency for implementations to support SR extensions for all routing protocols.<a href="#section-5-1" class="pilcrow">¶</a></p>
<p id="section-5-2">
        This module defines groupings that <span class="bcp14">SHOULD</span> be used by IGP SR modules.<a href="#section-5-2" class="pilcrow">¶</a></p>
<p id="section-5-3">The "sr-control-plane" grouping defines the generic global configuration for the IGP.<a href="#section-5-3" class="pilcrow">¶</a></p>
<p id="section-5-4">The "enabled" leaf enables SR extensions for the
   routing-protocol instance.<a href="#section-5-4" class="pilcrow">¶</a></p>
<p id="section-5-5">The "bindings" container controls the routing-protocol instance's
   advertisement of local bindings and the processing of received
   bindings.<a href="#section-5-5" class="pilcrow">¶</a></p>
<div id="igp-interface">
<section id="section-5.1">
        <h3 id="name-igp-interface-configuration">
<a href="#section-5.1" class="section-number selfRef">5.1. </a><a href="#name-igp-interface-configuration" class="section-name selfRef">IGP Interface Configuration</a>
        </h3>
<p id="section-5.1-1">The interface configuration is part of the "igp-interface" grouping and includes Adjacency SID (Adj-SID) properties.<a href="#section-5.1-1" class="pilcrow">¶</a></p>
<div id="adj-cfg">
<section id="section-5.1.1">
          <h4 id="name-adjacency-sid-adj-sid-prope">
<a href="#section-5.1.1" class="section-number selfRef">5.1.1. </a><a href="#name-adjacency-sid-adj-sid-prope" class="section-name selfRef">Adjacency SID (Adj-SID) Properties</a>
          </h4>
<div id="adj-cfg-bundling">
<section id="section-5.1.1.1">
            <h5 id="name-bundling">
<a href="#section-5.1.1.1" class="section-number selfRef">5.1.1.1. </a><a href="#name-bundling" class="section-name selfRef">Bundling</a>
            </h5>
<p id="section-5.1.1.1-1">
              In case of parallel IP links between routers, an additional Adj-SID <span>[<a href="#RFC8402" class="xref">RFC8402</a>]</span> may be advertised representing more than one adjacency (i.e.,
              a bundle of adjacencies). The "advertise-adj-group-sid" configuration
              controls for which group(s) an additional Adj-SID is advertised.<a href="#section-5.1.1.1-1" class="pilcrow">¶</a></p>
<p id="section-5.1.1.1-2">The "advertise-adj-group-sid" is a list of group IDs. Each group ID will identify interfaces that are bundled together.<a href="#section-5.1.1.1-2" class="pilcrow">¶</a></p>
<div class="artwork art-text alignLeft" id="section-5.1.1.1-3">
<pre>
        +-------+                 +------+
        |       | ------- L1 ---- |      |
        |   R1  | ------- L2 ---- |  R2  |
        |       | ------- L3 ---- |      |
        |       | ------- L4 ---- |      |
        +-------+                 +------+
</pre><a href="#section-5.1.1.1-3" class="pilcrow">¶</a>
</div>
<p id="section-5.1.1.1-4">
              In the figure above, R1 and R2 are interconnected by four links. A routing protocol adjacency is established on each link.
              The operator would like to create Adj-SIDs that represent bundles of links. We can imagine two different bundles: L1/L2 and L3/L4.
              To achieve this behavior, the operator will configure a "group-id" X for interfaces L1 and L2 and a "group-id" Y for interfaces L3 and L4.
              This will result in R1 advertising an additional Adj-SID for each adjacency. For example, an Adj-SID with a value of 400 will be added to L1 and L2, and
              an Adj-SID with a value of 500 will be added to L3 and L4. As L1/L2 and L3/L4 do not share the same "group-id", a different SID value will be allocated.<a href="#section-5.1.1.1-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="adj-cfg-protection">
<section id="section-5.1.1.2">
            <h5 id="name-protection">
<a href="#section-5.1.1.2" class="section-number selfRef">5.1.1.2. </a><a href="#name-protection" class="section-name selfRef">Protection</a>
            </h5>
<p id="section-5.1.1.2-1">
                                The "advertise-protection" defines how protection for an interface
                   is advertised.  It does not control the activation or deactivation of
                   protection.  If the "single" option is used, a single Adj-SID will be
                   advertised for the interface.  If the interface is protected, the
                   B-Flag for the Adj-SID advertisement will be set. If the "dual"
                   option is used and if the interface is protected, two Adj-SIDs will
                   be advertised for the interface adjacencies. One Adj-SID will always
                   have the B-Flag set, and the other will have the B-Flag clear.
    This
                   option is intended to be used in the case of traffic engineering
                   where a path must use either protected segments or unprotected
                   segments.<a href="#section-5.1.1.2-1" class="pilcrow">¶</a></p>
</section>
</div>
</section>
</div>
</section>
</div>
</section>
</div>
<div id="states">
<section id="section-6">
      <h2 id="name-state-data">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-state-data" class="section-name selfRef">State Data</a>
      </h2>
<p id="section-6-1">
        The operational state contains information reflecting the usage of
   allocated SRGB labels.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">It also includes a list of all global SIDs, their associated
   bindings, and other information, such as the associated source protocol and
   algorithm.<a href="#section-6-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="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">
        The model defines the following notifications for SR.<a href="#section-7-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-7-2">
        <dt id="section-7-2.1">segment-routing-srgb-collision:</dt>
        <dd style="margin-left: 1.5em" id="section-7-2.2">Raised when  control-plane-advertised SRGB blocks have conflicts<a href="#section-7-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-7-2.3">segment-routing-global-sid-collision:</dt>
        <dd style="margin-left: 1.5em" id="section-7-2.4">Raised when a control-plane-advertised index is already associated with another target (in
      this version, the only defined targets are IPv4 and IPv6 prefixes)<a href="#section-7-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-7-2.5">segment-routing-index-out-of-range:</dt>
        <dd style="margin-left: 1.5em" id="section-7-2.6">Raised when a control-plane-advertised index falls outside the range of SRGBs configured for
      the network device<a href="#section-7-2.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
</div>
<div id="yang">
<section id="section-8">
      <h2 id="name-yang-modules">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-yang-modules" class="section-name selfRef">YANG Modules</a>
      </h2>
<p id="section-8-1">There are three YANG modules included in this document.<a href="#section-8-1" class="pilcrow">¶</a></p>
<p id="section-8-2">The following RFCs are not referenced in the document text but
      are referenced in the ietf-segment-routing.yang, ietf-segment-routing-common.yang,
      and/or ietf-segment-routing-mpls.yang modules:
      <span>[<a href="#RFC6991" class="xref">RFC6991</a>]</span>, <span>[<a href="#RFC8294" class="xref">RFC8294</a>]</span>, 
      <span>[<a href="#RFC8661" class="xref">RFC8661</a>]</span>, <span>[<a href="#RFC8665" class="xref">RFC8665</a>]</span>,
      <span>[<a href="#RFC8667" class="xref">RFC8667</a>]</span>, <span>[<a href="#RFC8669" class="xref">RFC8669</a>]</span>, 
      and <span>[<a href="#RFC8814" class="xref">RFC8814</a>]</span>.<a href="#section-8-2" class="pilcrow">¶</a></p>
<div id="sr-yang">
<section id="section-8.1">
        <h3 id="name-yang-module-for-segment-rou">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-yang-module-for-segment-rou" class="section-name selfRef">YANG Module for Segment Routing</a>
        </h3>
<span class="break"></span><dl class="dlParallel" id="section-8.1-1">
          <dt id="section-8.1-1.1">ietf-segment-routing.yang:</dt>
          <dd style="margin-left: 1.5em" id="section-8.1-1.2">This module defines a generic framework
            for Segment Routing (SR), and it is to be augmented by models for different
            SR data planes.<a href="#section-8.1-1.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<div id="section-8.1-2">
<pre class="sourcecode lang-yang">&lt;CODE BEGINS&gt; file "ietf-segment-routing@2021-05-26.yang"

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

  import ietf-routing {
    prefix rt;
    reference "RFC 8349: A YANG Data Model for Routing
                         Management (NMDA Version)";
  }

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

     Author:    Stephane Litkowski
               &lt;mailto:slitkows.ietf@gmail.com&gt;
     Author:    Yingzhen Qu
               &lt;mailto:yingzhen.qu@futurewei.com&gt;
     Author:    Acee Lindem
               &lt;mailto:acee@cisco.com&gt;
     Author:    Pushpasis Sarkar
               &lt;mailto:pushpasis.ietf@gmail.com&gt;
     Author:    Jeff Tantsura
               &lt;jefftant.ietf@gmail.com&gt;

    ";
  description
    "This YANG module defines a generic framework for Segment
     Routing (SR).  It is to be augmented by models for different
     SR data planes.

     This YANG module conforms to the Network Management
     Datastore Architecture (NMDA), as described in RFC 8242.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.

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

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified 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 9020;
     see the RFC itself for full legal notices.";

  reference
    "RFC 9020: YANG Data Model for Segment Routing.";

  revision 2021-05-26 {
    description
      "Initial version";
    reference
      "RFC 9020: YANG Data Model for Segment Routing.";
  }

  augment "/rt:routing" {
    description
      "This module augments the routing data model (RFC 8349)
       with Segment Routing (SR).";
    container segment-routing {
      description
        "Segment Routing configuration.  This container
         is to be augmented by models for different SR
         data planes.";
      reference
        "RFC 8402: Segment Routing Architecture.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-8.1-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="sr-cmn-yang">
<section id="section-8.2">
        <h3 id="name-yang-module-for-segment-rout">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-yang-module-for-segment-rout" class="section-name selfRef">YANG Module for Segment Routing Common Types</a>
        </h3>
<span class="break"></span><dl class="dlParallel" id="section-8.2-1">
          <dt id="section-8.2-1.1">ietf-segment-routing-common.yang:</dt>
          <dd style="margin-left: 1.5em" id="section-8.2-1.2">This module defines a collection of generic types and 
   groupings for SR, as defined in <span>[<a href="#RFC8402" class="xref">RFC8402</a>]</span>.<a href="#section-8.2-1.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<div id="section-8.2-2">
<pre class="sourcecode lang-yang">&lt;CODE BEGINS&gt; file "ietf-segment-routing-common@2021-05-26.yang"

module ietf-segment-routing-common {
  yang-version 1.1;
  namespace
   "urn:ietf:params:xml:ns:yang:ietf-segment-routing-common";
  prefix sr-cmn;

  import ietf-inet-types {
    prefix inet;
    reference
      "RFC 6991: Common YANG Data Types";
  }

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

     Author:    Stephane Litkowski
               &lt;mailto:slitkows.ietf@gmail.com&gt;
     Author:    Yingzhen Qu
               &lt;mailto:yingzhen.qu@futurewei.com&gt;
     Author:    Acee Lindem
               &lt;mailto:acee@cisco.com&gt;
     Author:    Pushpasis Sarkar
               &lt;mailto:pushpasis.ietf@gmail.com&gt;
     Author:    Jeff Tantsura
               &lt;jefftant.ietf@gmail.com&gt;

    ";
  description
    "This YANG module defines a collection of generic types and
     groupings for Segment Routing (SR), as described in RFC 8402.

     This YANG module conforms to the Network Management
     Datastore Architecture (NMDA), as described in RFC 8242.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.

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

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified 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 9020;
     see the RFC itself for full legal notices.";
  reference
    "RFC 9020: YANG Data Model for Segment Routing";

  revision 2021-05-26 {
    description
      "Initial version";
    reference
      "RFC 9020: YANG Data Model for Segment Routing";
  }

  feature sid-last-hop-behavior {
    description
      "Configurable last-hop behavior.";
    reference
      "RFC 8660: Segment Routing with the MPLS Data Plane";
  }

  identity prefix-sid-algorithm {
    description
      "Base identity for prefix-sid algorithm.";
    reference
      "RFC 8402: Segment Routing Architecture";
  }

  identity prefix-sid-algorithm-shortest-path {
    base prefix-sid-algorithm;
    description
      "Shortest Path First (SPF) Prefix-SID algorithm.  This
       is the default algorithm.";
  }

  identity prefix-sid-algorithm-strict-spf {
    base prefix-sid-algorithm;
    description
      "This algorithm mandates that the packet is forwarded
       according to the ECMP-aware SPF algorithm.";
  }

  grouping srlr {
    description
      "Grouping for SR Label Range configuration.";
    leaf lower-bound {
      type uint32;
      description
        "Lower value in the label range.";
    }
    leaf upper-bound {
      type uint32;
      must '../lower-bound &lt; ../upper-bound' {
        error-message
          "The upper-bound must be greater than the lower-bound.";
        description
          "The value must be greater than lower-bound.";
      }
      description
        "Upper value in the label range.";
    }
  }

  grouping srgb {
    description
      "Grouping for SR Global Label Range.";
    list srgb {
      key "lower-bound upper-bound";
      ordered-by user;
      description
        "List of global blocks to be advertised.";
      uses srlr;
    }
  }

  grouping srlb {
    description
      "Grouping for SR Local Block Range.";
    list srlb {
      key "lower-bound upper-bound";
      ordered-by user;
      description
        "List of SRLBs.";
      uses srlr;
    }
  }

  grouping sid-value-type {
    description
      "Defines how the SID value is expressed.";
    leaf value-type {
      type enumeration {
        enum index {
          description
            "The value will be interpreted as an index.";
        }
        enum absolute {
          description
            "The value will become interpreted as an absolute
             value.";
        }
      }
      default "index";
      description
        "This leaf defines how the value must be interpreted.";
    }
  }

  grouping prefix-sid {
    description
      "This grouping defines configuration of a Prefix-SID.";
    leaf prefix {
      type inet:ip-prefix;
      description
        "Connected Prefix-SID.";
    }
    uses prefix-sid-attributes;
  }

  grouping ipv4-sid {
    description
      "Grouping for an IPv4 Prefix-SID.";
    leaf prefix {
      type inet:ipv4-prefix;
      description
        "Connected IPv4 Prefix-SID.";
    }
    uses prefix-sid-attributes;
  }

  grouping ipv6-sid {
    description
      "Grouping for an IPv6 Prefix-SID.";
    leaf prefix {
      type inet:ipv6-prefix;
      description
        "Connected IPv6 Prefix-SID.";
    }
    uses prefix-sid-attributes;
  }

  grouping last-hop-behavior {
    description
      "Defines last-hop behavior.";
    leaf last-hop-behavior {
      if-feature "sid-last-hop-behavior";
      type enumeration {
        enum explicit-null {
          description
            "Use explicit-null for the SID.";
        }
        enum no-php {
          description
            "Do not use MPLS Penultimate Hop Popping (PHP)
             for the SID.";
        }
        enum php {
          description
            "Use MPLS PHP for the SID.";
        }
      }
      description
        "Configure last-hop behavior.";
    }
  }

  grouping prefix-sid-attributes {
    description
      "Grouping for Segment Routing (SR) prefix attributes.";
    uses sid-value-type;
    leaf start-sid {
      type uint32;
      mandatory true;
      description
        "Value associated with prefix.  The value must be
         interpreted in the context of sid-value-type.";
    }
    leaf range {
      type uint32;
      description
        "Indicates how many SIDs can be allocated.";
    }
    leaf algorithm {
      type identityref {
        base prefix-sid-algorithm;
      }
      description
        "Prefix-SID algorithm.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-8.2-2" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="sr-mpls-yang">
<section id="section-8.3">
        <h3 id="name-yang-module-for-segment-routi">
<a href="#section-8.3" class="section-number selfRef">8.3. </a><a href="#name-yang-module-for-segment-routi" class="section-name selfRef">YANG Module for Segment Routing MPLS</a>
        </h3>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-8.3-1">
          <dt id="section-8.3-1.1">ietf-segment-routing-mpls.yang:</dt>
          <dd style="margin-left: 1.5em" id="section-8.3-1.2">This module defines the configuration
            and operational states for the Segment Routing MPLS data plane.<a href="#section-8.3-1.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<div id="section-8.3-2">
<pre class="sourcecode lang-yang">&lt;CODE BEGINS&gt; file "ietf-segment-routing-mpls@2021-05-26.yang"

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

  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-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the
                 Routing Area";
  }
  import ietf-segment-routing {
    prefix sr;
    reference
      "RFC 9020: YANG Data Model for Segment Routing";
  }
  import ietf-segment-routing-common {
    prefix sr-cmn;
    reference
      "RFC 9020: YANG Data Model for Segment Routing";
  }

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

     Author:    Stephane Litkowski
               &lt;mailto:slitkows.ietf@gmail.com&gt;
     Author:    Yingzhen Qu
               &lt;mailto:yingzhen.qu@futurewei.com&gt;
     Author:    Acee Lindem
               &lt;mailto:acee@cisco.com&gt;
     Author:    Pushpasis Sarkar
               &lt;mailto:pushpasis.ietf@gmail.com&gt;
     Author:    Jeff Tantsura
               &lt;jefftant.ietf@gmail.com&gt;

    ";
  description
    "This YANG module defines a generic configuration model for
     the Segment Routing MPLS data plane.

     This YANG module conforms to the Network Management
     Datastore Architecture (NMDA), as described in RFC 8242.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.

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

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified 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 9020;
     see the RFC itself for full legal notices.";
  reference
    "RFC 9020: YANG Data Model for Segment Routing";

  revision 2021-05-26 {
    description
      "Initial version";
    reference
      "RFC 9020: YANG Data Model for Segment Routing";
  }

  feature mapping-server {
    description
      "Support for Segment Routing Mapping Server (SRMS).";
    reference
      "RFC 8661: Segment Routing MPLS Interworking
                 with LDP";
  }

  feature protocol-srgb {
    description
      "Support for per-protocol Segment Routing Global Block
       (SRGB) configuration.";
    reference
      "RFC 8660: Segment Routing with the MPLS
                 Data Plane";
  }

  typedef system-id {
    type string {
      pattern '[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}';
    }
    description
      "This type defines an IS-IS system-id using a pattern.
       An example system-id is 0143.0438.AEF0.";
  }

  typedef router-or-system-id {
    type union {
      type rt-types:router-id;
      type system-id;
    }
    description
      "OSPF/BGP router-id or IS-IS system ID.";
  }

  grouping sr-control-plane {
    description
      "Defines protocol configuration.";
    container segment-routing {
      description
        "Segment Routing global configuration.";
      leaf enabled {
        type boolean;
        default "false";
        description
          "Enables Segment Routing control-plane protocol
           extensions.";
      }
      container bindings {
        if-feature "mapping-server";
        description
          "Control of binding advertisement and reception.";
        container advertise {
          description
            "Control advertisement of local mappings
             in binding TLVs.";
          leaf-list policies {
            type leafref {
              path "/rt:routing/sr:segment-routing/sr-mpls:sr-mpls"
                 + "/sr-mpls:bindings/sr-mpls:mapping-server"
                 + "/sr-mpls:policy/sr-mpls:name";
            }
            description
              "List of binding advertisement policies.";
          }
        }
        leaf receive {
          type boolean;
          default "true";
          description
            "Allow the reception and usage of binding TLVs.";
        }
      }
    }
  }

  grouping igp-interface {
    description
      "Grouping for IGP interface configuration.";
    container segment-routing {
      description
        "Container for SR interface configuration.";
      container adjacency-sid {
        description
          "Adjacency SID (Adj-SID) configuration.";
        reference
          "RFC 8660: Segment Routing with the MPLS
                     Data Plane";
        list adj-sids {
          key "value";
          uses sr-cmn:sid-value-type;
          leaf value {
            type uint32;
            description
              "Value of the Adj-SID.";
          }
          leaf protected {
            type boolean;
            default "false";
            description
              "It is used to protect the Adj-SID, e.g., using
               IP Fast Reroute (IPFRR) or MPLS-FRR.";
          }
          leaf weight {
            type uint8;
            description
              "The load-balancing factor over parallel adjacencies.";
            reference
              "RFC 8402: Segment Routing Architecture
               RFC 8665: OSPF Extensions for Segment Routing
               RFC 8667: IS-IS Extensions for Segment
                         Routing";
          }
          description
            "List of Adj-SIDs and their configuration.";
        }
        list advertise-adj-group-sid {
          key "group-id";
          description
            "Control advertisement of S-flag or G-flag.  Enable
             advertisement of a common Adj-SID for parallel
             links.";
          reference
            "RFC 8665: OSPF Extensions for Segment Routing,
                       Section 6.1
             RFC 8667: IS-IS Extensions for Segment
                       Routing, Section 2.2.1";
          leaf group-id {
            type uint32;
            description
              "The value is an internal value to identify a
               group-ID. Interfaces with the same group-ID
               will be bundled together.";
          }
        }
        leaf advertise-protection {
          type enumeration {
            enum single {
              description
                "A single Adj-SID is associated with the
                 adjacency and reflects the protection
                 configuration.";
            }
            enum dual {
              description
                "Two Adj-SIDs will be associated with the adjacency
                 if the interface is protected.  In this case, one
                 Adj-SID will be advertised with the backup-flag
                 set and the other with the backup-flag clear.  In
                 the case where protection is not configured, a
                 single Adj-SID will be advertised with the
                 backup-flag clear.";
            }
          }
          description
            "If set, the Adj-SID refers to a protected adjacency.";
          reference
            "RFC 8665: OSPF Extensions for Segment Routing,
                       Section 6.1
             RFC 8667: IS-IS Extensions for Segment
                       Routing, Section 2.2.1";
        }
      }
    }
  }

  augment "/rt:routing/sr:segment-routing" {
    description
      "This augments the routing data model (RFC 8349)
       with Segment Routing (SR) using the MPLS data plane.";
    container sr-mpls {
      description
        "Segment Routing global configuration and
         operational state.";
      container bindings {
        description
          "List of bindings.";
        container mapping-server {
          if-feature "mapping-server";
          description
            "Configuration of mapping-server local entries.";
          list policy {
            key "name";
            description
              "List mapping-server policies.";
            leaf name {
              type string;
              description
                "Name of the mapping policy.";
            }
            container entries {
              description
                "IPv4/IPv6 mapping entries.";
              list mapping-entry {
                key "prefix algorithm";
                description
                  "Mapping entries.";
                uses sr-cmn:prefix-sid;
              }
            }
          }
        }
        container connected-prefix-sid-map {
          description
            "Prefix-SID configuration.";
          list connected-prefix-sid {
            key "prefix algorithm";
            description
              "List of mappings of Prefix-SIDs to IPv4/IPv6
               local prefixes.";
            uses sr-cmn:prefix-sid;
            uses sr-cmn:last-hop-behavior;
          }
        }
        container local-prefix-sid {
          description
            "Local SID configuration.";
          list local-prefix-sid {
            key "prefix algorithm";
            description
              "List of local IPv4/IPv6 Prefix-SIDs.";
            uses sr-cmn:prefix-sid;
          }
        }
      }
      container srgb {
        description
          "Global SRGB configuration.";
        uses sr-cmn:srgb;
      }
      container srlb {
        description
          "Segment Routing Local Block (SRLB) configuration.";
        uses sr-cmn:srlb;
      }
      list label-blocks {
        config false;
        description
          "List of label blocks currently in use.";
        leaf lower-bound {
          type uint32;
          description
            "Lower bound of the label block.";
        }
        leaf upper-bound {
          type uint32;
          description
            "Upper bound of the label block.";
        }
        leaf size {
          type uint32;
          description
            "Number of indexes in the block.";
        }
        leaf free {
          type uint32;
          description
            "Number of free indexes in the block.";
        }
        leaf used {
          type uint32;
          description
            "Number of indexes in use in the block.";
        }
        leaf scope {
          type enumeration {
            enum global {
              description
                "Global SID.";
            }
            enum local {
              description
                "Local SID.";
            }
          }
          description
            "Scope of this label block.";
        }
      }
      container sid-db {
        config false;
        description
          "List of prefix and SID associations.";
        list sid {
          key "target sid source source-protocol binding-type";
          ordered-by system;
          description
            "SID binding.";
          leaf target {
            type string;
            description
              "Defines the target of the binding.  It can be a
               prefix or something else.";
          }
          leaf sid {
            type uint32;
            description
              "Index associated with the prefix.";
          }
          leaf algorithm {
            type uint8;
            description
              "Algorithm to be used for the Prefix-SID.";
            reference
              "RFC 8665: OSPF Extensions for Segment Routing
               RFC 8667: IS-IS Extensions for Segment
                         Routing
               RFC 8669: Segment Routing Prefix Segment
                         Identifier Extensions to BGP";
          }
          leaf source {
            type inet:ip-address;
            description
              "IP address of the router that owns the binding.";
          }
          leaf used {
            type boolean;
            description
              "Indicates if the binding is installed in the
               forwarding plane.";
          }
          leaf source-protocol {
            type leafref {
              path "/rt:routing/rt:control-plane-protocols/"
                 + "rt:control-plane-protocol/rt:name";
            }
            description
              "Routing protocol that owns the binding.";
          }
          leaf binding-type {
            type enumeration {
              enum prefix-sid {
                description
                  "Binding is learned from a Prefix-SID.";
              }
              enum binding-tlv {
                description
                  "Binding is learned from a binding TLV.";
              }
            }
            description
              "Type of binding.";
          }
          leaf scope {
            type enumeration {
              enum global {
                description
                  "Global SID.";
              }
              enum local {
                description
                  "Local SID.";
              }
            }
            description
              "SID scoping.";
          }
        }
      }
    }
  }

  notification segment-routing-srgb-collision {
    description
      "This notification is sent when SRGB blocks received from
       different routers collide.";
    list srgb-collisions {
      description
        "List of SRGB blocks that collide.";
      leaf lower-bound {
        type uint32;
        description
          "Lower value in the block.";
      }
      leaf upper-bound {
        type uint32;
        description
          "Upper value in the block.";
      }
      leaf routing-protocol {
        type leafref {
          path "/rt:routing/rt:control-plane-protocols/"
             + "rt:control-plane-protocol/rt:name";
        }
        description
          "Routing protocol reference for SRGB collision.";
      }
      leaf originating-rtr-id {
        type router-or-system-id;
        description
          "Originating router ID of this SRGB block.";
      }
    }
  }

  notification segment-routing-global-sid-collision {
    description
      "This notification is sent when a new mapping is learned
       containing a mapping where the SID is already used.
       The notification generation must be throttled with at least
       a 5-second gap between notifications.";
    leaf received-target {
      type string;
      description
        "Target received in the router advertisement that caused
         the SID collision.";
    }
    leaf new-sid-rtr-id {
      type router-or-system-id;
      description
        "Router ID that advertised the colliding SID.";
    }
    leaf original-target {
      type string;
      description
        "Target already available in the database with the same SID
         as the received target.";
    }
    leaf original-sid-rtr-id {
      type router-or-system-id;
      description
        "Router ID for the router that originally advertised the
         colliding SID, i.e., the instance in the database.";
    }
    leaf index {
      type uint32;
      description
        "Value of the index used by two different prefixes.";
    }
    leaf routing-protocol {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:name";
      }
      description
        "Routing protocol reference for colliding SID.";
    }
  }

  notification segment-routing-index-out-of-range {
    description
      "This notification is sent when a binding is received
       containing a segment index that is out of the local
       configured ranges.  The notification generation must be
       throttled with at least a 5-second gap between
       notifications.";
    leaf received-target {
      type string;
      description
        "A human-readable string representing the target
         received in the protocol-specific advertisement
         corresponding to the out-of-range index.";
    }
    leaf received-index {
      type uint32;
      description
        "Value of the index received.";
    }
    leaf routing-protocol {
      type leafref {
        path "/rt:routing/rt:control-plane-protocols/"
           + "rt:control-plane-protocol/rt:name";
      }
      description
        "Routing protocol reference for out-of-range indexed.";
    }
  }
}

&lt;CODE ENDS&gt;</pre><a href="#section-8.3-2" class="pilcrow">¶</a>
</div>
</section>
</div>
</section>
</div>
<div id="Security">
<section id="section-9">
      <h2 id="name-security-considerations">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-9-1">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-9-1" class="pilcrow">¶</a></p>
<p id="section-9-2">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-9-2" class="pilcrow">¶</a></p>
<p id="section-9-3">There are a number of data nodes defined in the modules
      that are writable/creatable/deletable (i.e., config true, which is the default).
      These data nodes may be considered sensitive or vulnerable in some network
      environments. Write operations (e.g., edit-config) to these data nodes without
      proper protection can have a negative effect on network operations.
      These are the subtrees and data nodes and their sensitivity/vulnerability:<a href="#section-9-3" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-9-4.1">/segment-routing<a href="#section-9-4.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.2">/segment-routing/mpls<a href="#section-9-4.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.3">/segment-routing/mpls/bindings -- Modification to the local bindings could result
       in a Denial-of-Service (DoS) attack. An attacker may also try to create segment conflicts
       (using the same segment identifier for different purposes) to redirect traffic within the
       trusted domain. However, the traffic will remain within the trusted domain.
       Redirection could be used to route the traffic to compromised nodes within
       the trusted domain or to avoid certain security functions (e.g., firewall). 
       Refer to <span><a href="https://www.rfc-editor.org/rfc/rfc8402#section-8.1" class="relref">Section 8.1</a> of [<a href="#RFC8402" class="xref">RFC8402</a>]</span> for a discussion of the SR-MPLS
       trusted domain.<a href="#section-9-4.3" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.4">/segment-routing/mpls/srgb -- Modification of the Segment Routing Global
       Block (SRGB) could be used to mount a DoS attack. For example, if the SRGB
       size is reduced to a very small value, a lot of existing segments could no longer
       be installed leading to a traffic disruption.<a href="#section-9-4.4" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.5">/segment-routing/mpls/srlb -- Modification of the Segment Routing Local Block (SRLB)
       could be used to mount a DoS attack similar to those applicable to the SRGB.<a href="#section-9-4.5" class="pilcrow">¶</a>
</li>
      </ul>
<p id="section-9-5">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-9-5" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-9-6.1">/segment-routing/mpls/bindings -- Knowledge of these data nodes can be used to
 attack the local router with a Denial-of-Service (DoS) attack.<a href="#section-9-6.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-6.2">/segment-routing/mpls/sid-db -- Knowledge of these data nodes can be used to
 attack the other routers in the SR domain with either a Denial-of-Service (DoS) attack or redirection traffic destined for those routers.<a href="#section-9-6.2" class="pilcrow">¶</a>
</li>
      </ul>
</section>
</div>
<div id="IANA">
<section id="section-10">
      <h2 id="name-iana-considerations">
<a href="#section-10" class="section-number selfRef">10. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-10-1">This document registers a URI in the "IETF XML Registry"
   <span>[<a href="#RFC3688" class="xref">RFC3688</a>]</span>.  Following the format in <span>[<a href="#RFC3688" class="xref">RFC3688</a>]</span>,
   the following registration is requested to be made:<a href="#section-10-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-2">
        <dt id="section-10-2.1">ID:</dt>
        <dd style="margin-left: 1.5em" id="section-10-2.2">yang:ietf-segment-routing-common<a href="#section-10-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-2.3">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-10-2.4">urn:ietf:params:xml:ns:yang:ietf-segment-routing-common<a href="#section-10-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-2.5">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-10-2.6">The IESG.<a href="#section-10-2.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-2.7">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-10-2.8">N/A, the requested URI is an XML namespace.<a href="#section-10-2.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-3">
        <dt id="section-10-3.1">ID:</dt>
        <dd style="margin-left: 1.5em" id="section-10-3.2">yang:ietf-segment-routing<a href="#section-10-3.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-3.3">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-10-3.4">urn:ietf:params:xml:ns:yang:ietf-segment-routing<a href="#section-10-3.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-3.5">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-10-3.6">The IESG.<a href="#section-10-3.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-3.7">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-10-3.8">N/A, the requested URI is an XML namespace.<a href="#section-10-3.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-4">
        <dt id="section-10-4.1">ID:</dt>
        <dd style="margin-left: 1.5em" id="section-10-4.2">yang:ietf-segment-routing-mpls<a href="#section-10-4.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-4.3">URI:</dt>
        <dd style="margin-left: 1.5em" id="section-10-4.4">urn:ietf:params:xml:ns:yang:ietf-segment-routing-mpls<a href="#section-10-4.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-4.5">Registrant Contact:</dt>
        <dd style="margin-left: 1.5em" id="section-10-4.6">The IESG.<a href="#section-10-4.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-4.7">XML:</dt>
        <dd style="margin-left: 1.5em" id="section-10-4.8">N/A, the requested URI is an XML namespace.<a href="#section-10-4.8" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-10-5">This document registers YANG modules in the "YANG Module Names"
      registry <span>[<a href="#RFC6020" class="xref">RFC6020</a>]</span>.<a href="#section-10-5" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-6">
        <dt id="section-10-6.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-10-6.2">ietf-segment-routing-common<a href="#section-10-6.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-6.3">Maintained by IANA:</dt>
        <dd style="margin-left: 1.5em" id="section-10-6.4">N<a href="#section-10-6.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-6.5">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-10-6.6">urn:ietf:params:xml:ns:yang:ietf-segment-routing-common<a href="#section-10-6.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-6.7">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-10-6.8">sr-cmn<a href="#section-10-6.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-6.9">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-10-6.10">RFC 9020<a href="#section-10-6.10" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-7">
        <dt id="section-10-7.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-10-7.2">ietf-segment-routing<a href="#section-10-7.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-7.3">Maintained by IANA:</dt>
        <dd style="margin-left: 1.5em" id="section-10-7.4">N<a href="#section-10-7.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-7.5">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-10-7.6">urn:ietf:params:xml:ns:yang:ietf-segment-routing<a href="#section-10-7.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-7.7">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-10-7.8">sr<a href="#section-10-7.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-7.9">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-10-7.10">RFC 9020<a href="#section-10-7.10" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<span class="break"></span><dl class="dlParallel dlCompact" id="section-10-8">
        <dt id="section-10-8.1">Name:</dt>
        <dd style="margin-left: 1.5em" id="section-10-8.2">ietf-segment-routing-mpls<a href="#section-10-8.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-8.3">Maintained by IANA:</dt>
        <dd style="margin-left: 1.5em" id="section-10-8.4">N<a href="#section-10-8.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-8.5">Namespace:</dt>
        <dd style="margin-left: 1.5em" id="section-10-8.6">urn:ietf:params:xml:ns:yang:ietf-segment-routing-mpls<a href="#section-10-8.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-8.7">Prefix:</dt>
        <dd style="margin-left: 1.5em" id="section-10-8.8">sr-mpls<a href="#section-10-8.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-10-8.9">Reference:</dt>
        <dd style="margin-left: 1.5em" id="section-10-8.10">RFC 9020<a href="#section-10-8.10" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
</div>
<section id="section-11">
      <h2 id="name-references">
<a href="#section-11" class="section-number selfRef">11. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-11.1">
        <h3 id="name-normative-references">
<a href="#section-11.1" class="section-number selfRef">11.1. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
        </h3>
<dl class="references">
<dt id="RFC2119">[RFC2119]</dt>
        <dd>
<span class="refAuthor">Bradner, S.</span>, <span class="refTitle">"Key words for use in RFCs to Indicate Requirement Levels"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 2119</span>, <span class="seriesInfo">DOI 10.17487/RFC2119</span>, <time datetime="1997-03" class="refDate">March 1997</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc2119">https://www.rfc-editor.org/info/rfc2119</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="RFC6020">[RFC6020]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M., Ed.</span>, <span class="refTitle">"YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)"</span>, <span class="seriesInfo">RFC 6020</span>, <span class="seriesInfo">DOI 10.17487/RFC6020</span>, <time datetime="2010-10" class="refDate">October 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6020">https://www.rfc-editor.org/info/rfc6020</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6241">[RFC6241]</dt>
        <dd>
<span class="refAuthor">Enns, R., Ed.</span>, <span class="refAuthor">Bjorklund, M., Ed.</span>, <span class="refAuthor">Schoenwaelder, J., Ed.</span>, and <span class="refAuthor">A. Bierman, Ed.</span>, <span class="refTitle">"Network Configuration Protocol (NETCONF)"</span>, <span class="seriesInfo">RFC 6241</span>, <span class="seriesInfo">DOI 10.17487/RFC6241</span>, <time datetime="2011-06" class="refDate">June 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6241">https://www.rfc-editor.org/info/rfc6241</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6242">[RFC6242]</dt>
        <dd>
<span class="refAuthor">Wasserman, M.</span>, <span class="refTitle">"Using the NETCONF Protocol over Secure Shell (SSH)"</span>, <span class="seriesInfo">RFC 6242</span>, <span class="seriesInfo">DOI 10.17487/RFC6242</span>, <time datetime="2011-06" class="refDate">June 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6242">https://www.rfc-editor.org/info/rfc6242</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6991">[RFC6991]</dt>
        <dd>
<span class="refAuthor">Schoenwaelder, J., Ed.</span>, <span class="refTitle">"Common YANG Data Types"</span>, <span class="seriesInfo">RFC 6991</span>, <span class="seriesInfo">DOI 10.17487/RFC6991</span>, <time datetime="2013-07" class="refDate">July 2013</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6991">https://www.rfc-editor.org/info/rfc6991</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="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="RFC8174">[RFC8174]</dt>
        <dd>
<span class="refAuthor">Leiba, B.</span>, <span class="refTitle">"Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 8174</span>, <span class="seriesInfo">DOI 10.17487/RFC8174</span>, <time datetime="2017-05" class="refDate">May 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8174">https://www.rfc-editor.org/info/rfc8174</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="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="RFC8402">[RFC8402]</dt>
        <dd>
<span class="refAuthor">Filsfils, C., Ed.</span>, <span class="refAuthor">Previdi, S., Ed.</span>, <span class="refAuthor">Ginsberg, L.</span>, <span class="refAuthor">Decraene, B.</span>, <span class="refAuthor">Litkowski, S.</span>, and <span class="refAuthor">R. Shakir</span>, <span class="refTitle">"Segment Routing Architecture"</span>, <span class="seriesInfo">RFC 8402</span>, <span class="seriesInfo">DOI 10.17487/RFC8402</span>, <time datetime="2018-07" class="refDate">July 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8402">https://www.rfc-editor.org/info/rfc8402</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="RFC8660">[RFC8660]</dt>
        <dd>
<span class="refAuthor">Bashandy, A., Ed.</span>, <span class="refAuthor">Filsfils, C., Ed.</span>, <span class="refAuthor">Previdi, S.</span>, <span class="refAuthor">Decraene, B.</span>, <span class="refAuthor">Litkowski, S.</span>, and <span class="refAuthor">R. Shakir</span>, <span class="refTitle">"Segment Routing with the MPLS Data Plane"</span>, <span class="seriesInfo">RFC 8660</span>, <span class="seriesInfo">DOI 10.17487/RFC8660</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8660">https://www.rfc-editor.org/info/rfc8660</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8661">[RFC8661]</dt>
        <dd>
<span class="refAuthor">Bashandy, A., Ed.</span>, <span class="refAuthor">Filsfils, C., Ed.</span>, <span class="refAuthor">Previdi, S.</span>, <span class="refAuthor">Decraene, B.</span>, and <span class="refAuthor">S. Litkowski</span>, <span class="refTitle">"Segment Routing MPLS Interworking with LDP"</span>, <span class="seriesInfo">RFC 8661</span>, <span class="seriesInfo">DOI 10.17487/RFC8661</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8661">https://www.rfc-editor.org/info/rfc8661</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8665">[RFC8665]</dt>
        <dd>
<span class="refAuthor">Psenak, P., Ed.</span>, <span class="refAuthor">Previdi, S., Ed.</span>, <span class="refAuthor">Filsfils, C.</span>, <span class="refAuthor">Gredler, H.</span>, <span class="refAuthor">Shakir, R.</span>, <span class="refAuthor">Henderickx, W.</span>, and <span class="refAuthor">J. Tantsura</span>, <span class="refTitle">"OSPF Extensions for Segment Routing"</span>, <span class="seriesInfo">RFC 8665</span>, <span class="seriesInfo">DOI 10.17487/RFC8665</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8665">https://www.rfc-editor.org/info/rfc8665</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8667">[RFC8667]</dt>
        <dd>
<span class="refAuthor">Previdi, S., Ed.</span>, <span class="refAuthor">Ginsberg, L., Ed.</span>, <span class="refAuthor">Filsfils, C.</span>, <span class="refAuthor">Bashandy, A.</span>, <span class="refAuthor">Gredler, H.</span>, and <span class="refAuthor">B. Decraene</span>, <span class="refTitle">"IS-IS Extensions for Segment Routing"</span>, <span class="seriesInfo">RFC 8667</span>, <span class="seriesInfo">DOI 10.17487/RFC8667</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8667">https://www.rfc-editor.org/info/rfc8667</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8669">[RFC8669]</dt>
        <dd>
<span class="refAuthor">Previdi, S.</span>, <span class="refAuthor">Filsfils, C.</span>, <span class="refAuthor">Lindem, A., Ed.</span>, <span class="refAuthor">Sreekantiah, A.</span>, and <span class="refAuthor">H. Gredler</span>, <span class="refTitle">"Segment Routing Prefix Segment Identifier Extensions for BGP"</span>, <span class="seriesInfo">RFC 8669</span>, <span class="seriesInfo">DOI 10.17487/RFC8669</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8669">https://www.rfc-editor.org/info/rfc8669</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8814">[RFC8814]</dt>
        <dd>
<span class="refAuthor">Tantsura, J.</span>, <span class="refAuthor">Chunduri, U.</span>, <span class="refAuthor">Talaulikar, K.</span>, <span class="refAuthor">Mirsky, G.</span>, and <span class="refAuthor">N. Triantafillis</span>, <span class="refTitle">"Signaling Maximum SID Depth (MSD) Using the Border Gateway Protocol - Link State"</span>, <span class="seriesInfo">RFC 8814</span>, <span class="seriesInfo">DOI 10.17487/RFC8814</span>, <time datetime="2020-08" class="refDate">August 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8814">https://www.rfc-editor.org/info/rfc8814</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="W3C.REC-xml11-20060816">[W3C.REC-xml11-20060816]</dt>
      <dd>
<span class="refAuthor">Bray, T.</span>, <span class="refAuthor">Paoli, J.</span>, <span class="refAuthor">Sperberg-McQueen, M.</span>, <span class="refAuthor">Maler, E.</span>, <span class="refAuthor">Yergeau, F.</span>, and <span class="refAuthor">J. Cowan</span>, <span class="refTitle">"Extensible Markup Language (XML) 1.1 (Second Edition)"</span>, <span class="seriesInfo">World Wide Web Consortium Recommendation REC-xml11-20060816</span>, <time datetime="2006-08-16" class="refDate">16 August 2006</time>, <span>&lt;<a href="https://www.w3.org/TR/2006/REC-xml11-20060816">https://www.w3.org/TR/2006/REC-xml11-20060816</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-11.2">
        <h3 id="name-informative-references">
<a href="#section-11.2" class="section-number selfRef">11.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="RFC8340">[RFC8340]</dt>
        <dd>
<span class="refAuthor">Bjorklund, M.</span> and <span class="refAuthor">L. Berger, Ed.</span>, <span class="refTitle">"YANG Tree Diagrams"</span>, <span class="seriesInfo">BCP 215</span>, <span class="seriesInfo">RFC 8340</span>, <span class="seriesInfo">DOI 10.17487/RFC8340</span>, <time datetime="2018-03" class="refDate">March 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8340">https://www.rfc-editor.org/info/rfc8340</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8792">[RFC8792]</dt>
      <dd>
<span class="refAuthor">Watsen, K.</span>, <span class="refAuthor">Auerswald, E.</span>, <span class="refAuthor">Farrel, A.</span>, and <span class="refAuthor">Q. Wu</span>, <span class="refTitle">"Handling Long Lines in Content of Internet-Drafts and RFCs"</span>, <span class="seriesInfo">RFC 8792</span>, <span class="seriesInfo">DOI 10.17487/RFC8792</span>, <time datetime="2020-06" class="refDate">June 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8792">https://www.rfc-editor.org/info/rfc8792</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<div id="examples">
<section id="section-appendix.a">
      <h2 id="name-configuration-examples">
<a href="#section-appendix.a" class="section-number selfRef">Appendix A. </a><a href="#name-configuration-examples" class="section-name selfRef">Configuration Examples</a>
      </h2>
<p id="section-appendix.a-1">Note: '\' line wrapping per <span>[<a href="#RFC8792" class="xref">RFC8792</a>]</span>.<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
<div id="ipv4">
<section id="section-a.1">
        <h2 id="name-sr-mpls-with-ipv4">
<a href="#section-a.1" class="section-number selfRef">A.1. </a><a href="#name-sr-mpls-with-ipv4" class="section-name selfRef">SR-MPLS with IPv4</a>
        </h2>
<p id="section-a.1-1">The following is an XML <span>[<a href="#W3C.REC-xml11-20060816" class="xref">W3C.REC-xml11-20060816</a>]</span> example using the SR-MPLS YANG modules with IPv4 addresses.<a href="#section-a.1-1" class="pilcrow">¶</a></p>
<div id="section-a.1-2">
<pre class="sourcecode lang-xml">
&lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
  &lt;segment-routing
    xmlns="urn:ietf:params:xml:ns:yang:ietf-segment-routing"&gt;
    &lt;sr-mpls
      xmlns="urn:ietf:params:xml:ns:yang:ietf-segment-routing-mpls"&gt;
      &lt;bindings&gt;
        &lt;mapping-server&gt;
          &lt;policy&gt;
            &lt;name&gt;mapping 1&lt;/name&gt;
            &lt;entries&gt;
              &lt;mapping-entry&gt;
                &lt;prefix&gt;198.51.100.0/24&lt;/prefix&gt;
                &lt;algorithm xmlns:sr-cmn="urn:ietf:params:xml:ns:yang\
                  :ietf-segment-routing-common"&gt;\
                  sr-cmn:prefix-sid-algorithm-shortest-path\
                &lt;/algorithm&gt;
                &lt;start-sid&gt;200&lt;/start-sid&gt;
                &lt;range&gt;100&lt;/range&gt;
              &lt;/mapping-entry&gt;
            &lt;/entries&gt;
          &lt;/policy&gt;
        &lt;/mapping-server&gt;
        &lt;connected-prefix-sid-map&gt;
          &lt;connected-prefix-sid&gt;
            &lt;prefix&gt;192.0.2.0/24&lt;/prefix&gt;
            &lt;algorithm xmlns:sr-cmn="urn:ietf:params:xml:ns:yang:\
              ietf-segment-routing-common"&gt;\
              sr-cmn:prefix-sid-algorithm-strict-spf&lt;/algorithm&gt;
            &lt;start-sid&gt;100&lt;/start-sid&gt;
            &lt;range&gt;1&lt;/range&gt;
            &lt;last-hop-behavior&gt;php&lt;/last-hop-behavior&gt;
          &lt;/connected-prefix-sid&gt;
        &lt;/connected-prefix-sid-map&gt;
      &lt;/bindings&gt;
      &lt;srgb&gt;
        &lt;srgb&gt;
          &lt;lower-bound&gt;45000&lt;/lower-bound&gt;
          &lt;upper-bound&gt;55000&lt;/upper-bound&gt;
        &lt;/srgb&gt;
      &lt;/srgb&gt;
    &lt;/sr-mpls&gt;
  &lt;/segment-routing&gt;
&lt;/routing&gt;
</pre><a href="#section-a.1-2" class="pilcrow">¶</a>
</div>
<p id="section-a.1-3">The following is the same example using JSON format.<a href="#section-a.1-3" class="pilcrow">¶</a></p>
<div id="section-a.1-4">
<pre class="sourcecode lang-json">
{
  "ietf-routing:routing": {
    "ietf-segment-routing:segment-routing": {
      "ietf-segment-routing-mpls:sr-mpls": {
        "bindings": {
          "mapping-server": {
            "policy": [
              {
                "name": "mapping 1",
                "entries": {
                  "mapping-entry": [
                    {
                      "prefix": "198.51.100.0/24",
                      "algorithm": "ietf-segment-routing-common:\
                      prefix-sid-algorithm-shortest-path",
                      "start-sid": 200,
                      "range": 100
                    }
                  ]
                }
              }
            ]
          },
          "connected-prefix-sid-map": {
            "connected-prefix-sid": [
              {
                "prefix": "192.0.2.0/24",
                "algorithm": "ietf-segment-routing-common:\
                prefix-sid-algorithm-strict-spf",
                "start-sid": 100,
                "range": 1,
                "last-hop-behavior": "php"
              }
            ]
          }
        },
        "srgb": {
          "srgb": [
            {
              "lower-bound": 45000,
              "upper-bound": 55000
            }
          ]
        }
      }
    }
  }
}
</pre><a href="#section-a.1-4" class="pilcrow">¶</a>
</div>
</section>
</div>
<div id="ipv6">
<section id="section-a.2">
        <h2 id="name-sr-mpls-with-ipv6">
<a href="#section-a.2" class="section-number selfRef">A.2. </a><a href="#name-sr-mpls-with-ipv6" class="section-name selfRef">SR-MPLS with IPv6</a>
        </h2>
<p id="section-a.2-1">The following is an XML  <span>[<a href="#W3C.REC-xml11-20060816" class="xref">W3C.REC-xml11-20060816</a>]</span> example using the SR-MPLS YANG modules with IPv6 addresses.<a href="#section-a.2-1" class="pilcrow">¶</a></p>
<div id="section-a.2-2">
<pre class="sourcecode lang-xml">
&lt;routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"&gt;
  &lt;segment-routing
    xmlns="urn:ietf:params:xml:ns:yang:ietf-segment-routing"&gt;
    &lt;sr-mpls
      xmlns="urn:ietf:params:xml:ns:yang:ietf-segment-routing-mpls"&gt;
      &lt;bindings&gt;
        &lt;mapping-server&gt;
          &lt;policy&gt;
            &lt;name&gt;mapping 1&lt;/name&gt;
            &lt;entries&gt;
              &lt;mapping-entry&gt;
                &lt;prefix&gt;2001:db8:aaaa:bbbb::/64&lt;/prefix&gt;
                &lt;algorithm xmlns:sr-cmn="urn:ietf:params:xml:ns:yang\
                  :ietf-segment-routing-common"&gt;\
                  sr-cmn:prefix-sid-algorithm-shortest-path\
                &lt;/algorithm&gt;
                &lt;start-sid&gt;200&lt;/start-sid&gt;
                &lt;range&gt;100&lt;/range&gt;
              &lt;/mapping-entry&gt;
            &lt;/entries&gt;
          &lt;/policy&gt;
        &lt;/mapping-server&gt;
        &lt;connected-prefix-sid-map&gt;
          &lt;connected-prefix-sid&gt;
            &lt;prefix&gt;2001:db8:aaaa:cccc::/64&lt;/prefix&gt;
            &lt;algorithm xmlns:sr-cmn="urn:ietf:params:xml:ns:yang:\
              ietf-segment-routing-common"&gt;\
              sr-cmn:prefix-sid-algorithm-strict-spf&lt;/algorithm&gt;
            &lt;start-sid&gt;100&lt;/start-sid&gt;
            &lt;range&gt;1&lt;/range&gt;
            &lt;last-hop-behavior&gt;php&lt;/last-hop-behavior&gt;
          &lt;/connected-prefix-sid&gt;
        &lt;/connected-prefix-sid-map&gt;
      &lt;/bindings&gt;
      &lt;srgb&gt;
        &lt;srgb&gt;
          &lt;lower-bound&gt;45000&lt;/lower-bound&gt;
          &lt;upper-bound&gt;55000&lt;/upper-bound&gt;
        &lt;/srgb&gt;
      &lt;/srgb&gt;
    &lt;/sr-mpls&gt;
  &lt;/segment-routing&gt;
&lt;/routing&gt;
</pre><a href="#section-a.2-2" class="pilcrow">¶</a>
</div>
<p id="section-a.2-3">The following is the same example using JSON format.<a href="#section-a.2-3" class="pilcrow">¶</a></p>
<div id="section-a.2-4">
<pre class="sourcecode lang-json">
{
  "ietf-routing:routing": {
    "ietf-segment-routing:segment-routing": {
      "ietf-segment-routing-mpls:sr-mpls": {
        "bindings": {
          "mapping-server": {
            "policy": [
              {
                "name": "mapping 1",
                "entries": {
                  "mapping-entry": [
                    {
                      "prefix": "2001:db8:aaaa:bbbb::/64",
                      "algorithm": "ietf-segment-routing-common:\
                      prefix-sid-algorithm-shortest-path",
                      "start-sid": 200,
                      "range": 100
                    }
                  ]
                }
              }
            ]
          },
          "connected-prefix-sid-map": {
            "connected-prefix-sid": [
              {
                "prefix": "2001:db8:aaaa:cccc::/64",
                "algorithm": "ietf-segment-routing-common:\
                prefix-sid-algorithm-strict-spf",
                "start-sid": 100,
                "range": 1,
                "last-hop-behavior": "php"
              }
            ]
          }
        },
        "srgb": {
          "srgb": [
            {
              "lower-bound": 45000,
              "upper-bound": 55000
            }
          ]
        }
      }
    }
  }
}
</pre><a href="#section-a.2-4" class="pilcrow">¶</a>
</div>
</section>
</div>
</section>
</div>
<div id="Acknowledgements">
<section id="section-appendix.b">
      <h2 id="name-acknowledgements">
<a href="#name-acknowledgements" class="section-name selfRef">Acknowledgements</a>
      </h2>
<p id="section-appendix.b-1">The authors would like to thank <span class="contact-name">Derek Yeung</span>, <span class="contact-name">Greg Hankins</span>, <span class="contact-name">Hannes Gredler</span>, <span class="contact-name">Uma Chunduri</span>,
      <span class="contact-name">Jeffrey Zhang</span>, <span class="contact-name">Shradda Hedge</span>, and <span class="contact-name">Les Ginsberg</span> for their contributions.<a href="#section-appendix.b-1" class="pilcrow">¶</a></p>
<p id="section-appendix.b-2">Thanks to <span class="contact-name">Ladislav Lhotka</span> and <span class="contact-name">Tom Petch</span> for 
      their thorough reviews and helpful comments.<a href="#section-appendix.b-2" class="pilcrow">¶</a></p>
<p id="section-appendix.b-3">The authors would like to thank <span class="contact-name">Benjamin Kaduk</span>, <span class="contact-name">Alvaro Retana</span>, and <span class="contact-name">Roman Danyliw</span> for IESG
         review and comments.<a href="#section-appendix.b-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="authors-addresses">
<section id="section-appendix.c">
      <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">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.ietf@gmail.com" class="email">slitkows.ietf@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Yingzhen Qu</span></div>
<div dir="auto" class="left"><span class="org">Futurewei</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:yingzhen.qu@futurewei.com" class="email">yingzhen.qu@futurewei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Acee Lindem</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</span></div>
<div dir="auto" class="left"><span class="street-address">301 Mindenhall Way</span></div>
<div dir="auto" class="left">
<span class="locality">Cary</span>, <span class="region">NC</span> <span class="postal-code">27513</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:acee@cisco.com" class="email">acee@cisco.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Pushpasis Sarkar</span></div>
<div dir="auto" class="left"><span class="org">VMware, Inc</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:pushpasis.ietf@gmail.com" class="email">pushpasis.ietf@gmail.com</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">Juniper Networks</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:jefftant.ietf@gmail.com" class="email">jefftant.ietf@gmail.com</a>
</div>
</address>
</section>
</div>
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