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<!DOCTYPE html>
<html lang="en" class="RFC">
<head>
<meta charset="utf-8">
<meta content="Common,Han,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>RFC 9005: Path Computation Element Communication Protocol (PCEP) Extension for Associating Policies and Label Switched Paths (LSPs)</title>
<meta content="Stephane Litkowski" name="author">
<meta content="Siva Sivabalan" name="author">
<meta content="Jeff Tantsura" name="author">
<meta content="Jonathan Hardwick" name="author">
<meta content="李呈 (Cheng Li)" name="author">
<meta content="
       This document introduces a simple mechanism to associate policies with
      a group of Label Switched Paths (LSPs) via an extension to the Path
      Computation Element Communication Protocol (PCEP). The extension
      allows a PCEP speaker to advertise to a PCEP peer that a particular LSP
      belongs to a particular Policy Association Group (PAG). 
    " name="description">
<meta content="xml2rfc 3.6.0" name="generator">
<meta content="Association" name="keyword">
<meta content="Policy" name="keyword">
<meta content="9005" name="rfc.number">
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<link href="rfc9005.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*

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

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

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}
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/* This is commented out here, as the string-set: doesn't
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/* Changes introduced to fix issues found during implementation */
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/* Fix the dl styling to match the RFC 7992 attributes */
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dl.dlNewline > dt {
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/* Provide styling for table cell text alignment */
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table td.text-center,
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table td.text-right,
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/* Make the alternative author contact informatio look less like just another
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/* For address alignment dependent on LTR or RTL scripts */
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address div.right {
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/* Provide table alignment support.  We can't use the alignX classes above
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table.right {
 margin-left: auto;
 margin-right: 0;
}
table.center {
 margin-left: auto;
 margin-right: auto;
}
table.left {
 margin-left: 0;
 margin-right: auto;
}

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

@media print {
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  /* avoid overwriting the top border line with the ToC header */
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  /* Avoid page breaks inside dl and author address entries */
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}
/* Tweak the bcp14 keyword presentation */
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}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
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  padding-top: 31px;
 }
 h3 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
 h4 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
/* Float artwork pilcrow to the right */
@media screen {
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    line-height: 0.7;
    margin-top: 0.15em;
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}
/* Make pilcrows on dd visible */
@media screen {
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}
/* Make the placement of figcaption match that of a table's caption
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.alignRight {
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/* In print, the pilcrow won't show on hover, so prevent it from taking up space,
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}
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<table class="ears">
<thead><tr>
<td class="left">RFC 9005</td>
<td class="center">PCEP Extensions for Policy Association</td>
<td class="right">March 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/rfc9005" class="eref">9005</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="2021-03" class="published">March 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, Inc.</div>
</div>
<div class="author">
      <div class="author-name">S. Sivabalan</div>
<div class="org">Ciena</div>
</div>
<div class="author">
      <div class="author-name">J. Tantsura</div>
<div class="org">Juniper Networks</div>
</div>
<div class="author">
      <div class="author-name">J. Hardwick</div>
<div class="org">Metaswitch Networks</div>
</div>
<div class="author">
      <div class="author-name">
<span class="non-ascii">李呈</span> (<span class="ascii">C. Li</span>)</div>
<div class="org">
<span class="non-ascii">华为技术有限公司</span> (<span class="ascii">Huawei Technologies</span>)</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 9005</h1>
<h1 id="title">Path Computation Element Communication Protocol (PCEP) Extension for Associating Policies and Label Switched Paths (LSPs)</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document introduces a simple mechanism to associate policies with
      a group of Label Switched Paths (LSPs) via an extension to the Path
      Computation Element Communication Protocol (PCEP). The extension
      allows a PCEP speaker to advertise to a PCEP peer that a particular LSP
      belongs to a particular Policy Association Group (PAG).<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/rfc9005">https://www.rfc-editor.org/info/rfc9005</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="compact ulEmpty toc">
<li class="compact ulEmpty toc" id="section-toc.1-1.1">
            <p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="xref">1</a>.  <a href="#name-introduction" class="xref">Introduction</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" id="section-toc.1-1.1.2.1">
                <p id="section-toc.1-1.1.2.1.1" class="keepWithNext"><a href="#section-1.1" class="xref">1.1</a>.  <a href="#name-requirements-language" class="xref">Requirements Language</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1" class="keepWithNext"><a href="#section-2" class="xref">2</a>.  <a href="#name-terminology" class="xref">Terminology</a></p>
</li>
          <li class="compact ulEmpty toc" 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-motivation" class="xref">Motivation</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" id="section-toc.1-1.3.2.1">
                <p id="section-toc.1-1.3.2.1.1"><a href="#section-3.1" class="xref">3.1</a>.  <a href="#name-policy-based-constraints" class="xref">Policy-Based Constraints</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" 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-overview" class="xref">Overview</a></p>
</li>
          <li class="compact ulEmpty toc" 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-policy-association-group" class="xref">Policy Association Group</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" 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-policy-parameters-tlv" class="xref">POLICY-PARAMETERS-TLV</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" 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-security-considerations" class="xref">Security Considerations</a></p>
</li>
          <li class="compact ulEmpty toc" 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-iana-considerations" class="xref">IANA Considerations</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" id="section-toc.1-1.7.2.1">
                <p id="section-toc.1-1.7.2.1.1"><a href="#section-7.1" class="xref">7.1</a>.  <a href="#name-association-object-type-ind" class="xref">ASSOCIATION Object Type Indicators</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.7.2.2">
                <p id="section-toc.1-1.7.2.2.1"><a href="#section-7.2" class="xref">7.2</a>.  <a href="#name-pcep-tlv-type-indicators" class="xref">PCEP TLV Type Indicators</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.7.2.3">
                <p id="section-toc.1-1.7.2.3.1"><a href="#section-7.3" class="xref">7.3</a>.  <a href="#name-pcep-errors" class="xref">PCEP Errors</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" 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-manageability-consideration" class="xref">Manageability Considerations</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" 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-control-of-function-and-pol" class="xref">Control of Function and Policy</a></p>
</li>
              <li class="compact ulEmpty toc" 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-information-and-data-models" class="xref">Information and Data Models</a></p>
</li>
              <li class="compact ulEmpty toc" 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-liveness-detection-and-moni" class="xref">Liveness Detection and Monitoring</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.8.2.4">
                <p id="section-toc.1-1.8.2.4.1"><a href="#section-8.4" class="xref">8.4</a>.  <a href="#name-verifying-correct-operation" class="xref">Verifying Correct Operations</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.8.2.5">
                <p id="section-toc.1-1.8.2.5.1"><a href="#section-8.5" class="xref">8.5</a>.  <a href="#name-requirements-on-other-proto" class="xref">Requirements on Other Protocols</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.8.2.6">
                <p id="section-toc.1-1.8.2.6.1"><a href="#section-8.6" class="xref">8.6</a>.  <a href="#name-impact-on-network-operation" class="xref">Impact on Network Operations</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" 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-references" class="xref">References</a></p>
<ul class="compact ulEmpty toc">
<li class="compact ulEmpty toc" id="section-toc.1-1.9.2.1">
                <p id="section-toc.1-1.9.2.1.1"><a href="#section-9.1" class="xref">9.1</a>.  <a href="#name-normative-references" class="xref">Normative References</a></p>
</li>
              <li class="compact ulEmpty toc" id="section-toc.1-1.9.2.2">
                <p id="section-toc.1-1.9.2.2.1"><a href="#section-9.2" class="xref">9.2</a>.  <a href="#name-informative-references" class="xref">Informative References</a></p>
</li>
            </ul>
</li>
          <li class="compact ulEmpty toc" id="section-toc.1-1.10">
            <p id="section-toc.1-1.10.1"><a href="#section-appendix.a" class="xref">Appendix A</a>.  <a href="#name-example-of-policy-parameter" class="xref">Example of Policy Parameters</a></p>
</li>
          <li class="compact ulEmpty toc" id="section-toc.1-1.11">
            <p id="section-toc.1-1.11.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-acknowledgments" class="xref">Acknowledgments</a></p>
</li>
          <li class="compact ulEmpty toc" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#section-appendix.c" class="xref"></a><a href="#name-contributors" class="xref">Contributors</a></p>
</li>
          <li class="compact ulEmpty toc" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#section-appendix.d" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1"><span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> describes the Path Computation Element
      Communication Protocol (PCEP), which enables the communication between a
      Path Computation Client (PCC) and a Path Control Element (PCE) or
      between two PCEs based on the PCE architecture <span>[<a href="#RFC4655" class="xref">RFC4655</a>]</span>.
      <span>[<a href="#RFC5394" class="xref">RFC5394</a>]</span> provides additional details on policy within
      the PCE architecture and also provides context for the support of PCE
      policy.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">"Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE" (<span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>)
      describes a set of extensions to PCEP to enable active control of
      Multiprotocol Label Switching Traffic Engineering (MPLS-TE) and
      Generalized MPLS (GMPLS) tunnels. <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> describes the
      setup and teardown of PCE-initiated LSPs under the active stateful PCE
      model without the need for local configuration on the PCC, thus
      allowing for a dynamic network. Currently, the LSPs can either be
      signaled via Resource Reservation Protocol Traffic Engineering (RSVP-TE)
      or segment routed as specified in <span>[<a href="#RFC8664" class="xref">RFC8664</a>]</span>.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3"><span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span> introduces a generic mechanism to create a
      grouping of LSPs that can then be used to define associations between a
      set of LSPs and a set of attributes (such as configuration parameters or
      behaviors) and is equally applicable to stateful PCE (active and passive
      modes) and stateless PCE.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">This document specifies a PCEP extension to associate one or more
      LSPs with policies using the generic association mechanism.<a href="#section-1-4" class="pilcrow">¶</a></p>
<p id="section-1-5">A PCEP speaker may want to influence the PCEP peer with respect to
      path selection and other policies. This document describes a PCEP
      extension to associate policies by creating a Policy Association Group
      (PAG) and encoding this association in PCEP messages. The specification
      is applicable to both stateful and stateless PCEP sessions.<a href="#section-1-5" class="pilcrow">¶</a></p>
<p id="section-1-6">Note that the actual policy definition and the associated parameters
      are out of scope of this document.<a href="#section-1-6" class="pilcrow">¶</a></p>
<section id="section-1.1">
        <h3 id="name-requirements-language">
<a href="#section-1.1" class="section-number selfRef">1.1. </a><a href="#name-requirements-language" class="section-name selfRef">Requirements Language</a>
        </h3>
<p id="section-1.1-1">
    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-1.1-1" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-2">
      <h2 id="name-terminology">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-terminology" class="section-name selfRef">Terminology</a>
      </h2>
<p id="section-2-1">The following terminology is used in this document.<a href="#section-2-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-2-2">
        <dt id="section-2-2.1">Association parameters:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.2">As described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>, the combination of the mandatory fields
          Association Type, Association ID, and Association Source in the
          ASSOCIATION object uniquely identifies the association group. If the
          optional TLVs -- Global Association Source or Extended Association ID -- are included, then they are included in combination with mandatory
          fields to uniquely identify the association group.<a href="#section-2-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.3">Association information:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.4">As described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>, the ASSOCIATION object could include other
          optional TLVs based on the Association Types that provide
          "information" related to the association.<a href="#section-2-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.5">LSR:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.6">Label Switching Router<a href="#section-2-2.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.7">MPLS:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.8">Multiprotocol Label Switching<a href="#section-2-2.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.9">PAG:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.10">Policy Association Group<a href="#section-2-2.10" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.11">PAT:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.12">Policy Association Type<a href="#section-2-2.12" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.13">PCC:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.14">Path Computation Client; any client application requesting a
      path computation to be performed by a Path Computation Element.<a href="#section-2-2.14" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.15">PCE:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.16">Path Computation Element; an entity (component,
          application, or network node) that is capable of computing a network
          path or route based on a network graph and applying computational
          constraints.<a href="#section-2-2.16" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-2-2.17">PCEP:</dt>
        <dd style="margin-left: 1.5em" id="section-2-2.18">Path Computation Element Communication
          Protocol<a href="#section-2-2.18" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
</section>
<section id="section-3">
      <h2 id="name-motivation">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-motivation" class="section-name selfRef">Motivation</a>
      </h2>
<p id="section-3-1">Paths computed using PCE can be subjected to various policies at both
      the PCE and the PCC. For example, in a centralized TE scenario, network operators may instantiate LSPs and specify
      policies for traffic accounting, path monitoring, telemetry, etc., for
      some LSPs via the stateful PCE. Similarly, a PCC could request a user-specific
      or service-specific policy to be applied at the PCE, such as a constraints
      relaxation policy, to meet optimal QoS and resiliency levels.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">PCEP speakers can use the generic mechanism of <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span> to associate a set of LSPs with a policy, without the need to know the
   details of such a policy.  This simplifies network operations, avoids
   frequent software upgrades, and provides the ability to
   introduce new policies more quickly.<a href="#section-3-2" class="pilcrow">¶</a></p>
<span id="name-sample-use-cases-for-carryi"></span><div id="fig1">
<figure id="figure-1">
        <div class="artwork art-text alignLeft" id="section-3-3.1">
<pre>
                                                         PAG Y
                                          {Service-Specific Policy
                                                    for constraint
            Monitor LSP                                relaxation}
                 |                                          |
                 | PAG X                    PCReq/PCRpt     |
                 V {Monitor LSP}            {PAG Y}         V
              +-----+                   ----------------&gt; +-----+
   _ _ _ _ _ _| PCE |                  |                  | PCE |
  |           +-----+                  |      ----------&gt; +-----+
  | PCInitiate/PCUpd                   |     |    PCReq/PCRpt
  |{PAG X}                             |     |    {PAG Y}
  |                                    |     |
  |              .-----.               |     |         .-----.
  |             (       )              |  +----+      (       )
  |         .--(         )--.          |  |PCC1|--.--(         )--.
  V        (                 )         |  +----+ (                 )
+---+     (                   )        |        (                   )
|PCC|----(   (G)MPLS network    )   +----+     ( (G)MPLS network   )
+---+     (                   )     |PCC2|------(                   )
PAG X      (                 )      +----+       (                 )
{Monitor    '--(         )--'                     '--(         )--'
LSP}            (       )                             (       )
                 '-----'                               '-----'

Case 1: Policy requested by PCE        Case 2: Policy requested by
        and enforced by PCC                    PCC and enforced by
                                               PCE
</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-sample-use-cases-for-carryi" class="selfRef">Sample Use Cases for Carrying Policies over PCEP</a>
        </figcaption></figure>
</div>
<section id="section-3.1">
        <h3 id="name-policy-based-constraints">
<a href="#section-3.1" class="section-number selfRef">3.1. </a><a href="#name-policy-based-constraints" class="section-name selfRef">Policy-Based Constraints</a>
        </h3>
<p id="section-3.1-1">In the context of a policy-enabled path computation framework <span>[<a href="#RFC5394" class="xref">RFC5394</a>]</span>, path computation policies may be applied at a PCC, a PCE, or both.
        A Label Switching Router (LSR) with a policy-enabled PCC can receive:<a href="#section-3.1-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-3.1-2.1">A service request via signaling, including
        over a Network-Network Interface (NNI) or User-Network Interface (UNI)
        reference point.<a href="#section-3.1-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-3.1-2.2">A configuration request over a management
        interface to establish a service.<a href="#section-3.1-2.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-3.1-3">The PCC may apply user-specific or
        service-specific policies to decide how the path selection process
        should be constrained -- that is, which constraints, diversities,
        optimization criteria, and constraint-relaxation strategies should be
        applied to increase the likelihood that the service LSP(s) will be successfully established and will provide the necessary QoS and resilience
        against network failures. The user-specific or service-specific policies are applied to the PCC and are then passed to the PCE along with the path
        computation request in the form of constraints <span>[<a href="#RFC5394" class="xref">RFC5394</a>]</span>.<a href="#section-3.1-3" class="pilcrow">¶</a></p>
<p id="section-3.1-4">The PCEP speaker can use the generic mechanism as per <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span> to associate a set of LSPs with user-specific or service-specific policies. This would simplify the path
        computation message exchanges in PCEP.<a href="#section-3.1-4" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-4">
      <h2 id="name-overview">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-overview" class="section-name selfRef">Overview</a>
      </h2>
<p id="section-4-1">As per <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>, LSPs are associated with other LSPs
      with which they interact by adding them to a common association group.
      Grouping can also be used to define the association between LSPs and the policies associated with them. As described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>,
      the association group is uniquely identified by the combination of the
      following fields in the ASSOCIATION object: Association Type,
      Association ID, Association Source, and (if present) Global Association
      Source or Extended Association ID. This document defines a new
      Association Type called "Policy Association" with value 3 based on the
      generic ASSOCIATION object. This new Association Type is called
"Policy Association Type" (PAT).<a href="#section-4-1" class="pilcrow">¶</a></p>
<p id="section-4-2"><span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span> specifies the mechanism for the capability
      advertisement of the Association Types supported by a PCEP speaker by
      defining an ASSOC-Type-List TLV to be carried within an OPEN object. This
      capability exchange for the PAT <span class="bcp14">MUST</span> be done before using the
      Policy Association. Thus, the PCEP speaker <span class="bcp14">MUST</span> include the PAT in
      the ASSOC-Type-List TLV and <span class="bcp14">MUST</span> receive the same from the PCEP peer
      before using the PAG in PCEP messages.<a href="#section-4-2" class="pilcrow">¶</a></p>
<p id="section-4-3">The Policy Association Type (3) is operator configured (as specified in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>),
      i.e., the association is created by the operator manually on the PCEP
      peers, and an LSP belonging to this association is conveyed via PCEP
      messages to the PCEP peer. There is no need to convey an explicit
      Operator-configured Association Range, which could only serve to
      artificially limit the available Association IDs. Thus, for the Policy Association Type, the Operator-configured Association Range <span class="bcp14">MUST NOT</span> be set and <span class="bcp14">MUST</span> be ignored if received.<a href="#section-4-3" class="pilcrow">¶</a></p>
<p id="section-4-4">A PAG can have one or more LSPs. The association parameters including
      Association Identifier, Policy Association Type (PAT), as well as the
      Association Source IP address are manually configured by the operator and
      are used to identify the PAG as described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>.
      The Global Association Source and Extended Association ID <span class="bcp14">MAY</span> also be
      included.<a href="#section-4-4" class="pilcrow">¶</a></p>
<p id="section-4-5">As per the processing rules specified in <span><a href="https://www.rfc-editor.org/rfc/rfc8697#section-6.4" class="relref">Section 6.4</a> of [<a href="#RFC8697" class="xref">RFC8697</a>]</span>, if a PCEP speaker does not support this Policy
      Association Type, it would return a PCEP error (PCErr) message with Error-Type 26
      "Association Error" and Error-value 1 "Association type is not
      supported". The PAG and the policy
      <span class="bcp14">MUST</span> be configured on the PCEP peers as per the operator-configured
      association procedures. All further processing is as per <span><a href="https://www.rfc-editor.org/rfc/rfc8697#section-6.4" class="relref">Section 6.4</a> of [<a href="#RFC8697" class="xref">RFC8697</a>]</span>. If a PCE speaker receives a PAG in a PCEP
      message and the Policy Association information is not configured, it
      <span class="bcp14">MUST</span> return a PCErr message with Error-Type 26 "Association Error" and
      Error-value 4 "Association unknown".<a href="#section-4-5" class="pilcrow">¶</a></p>
<p id="section-4-6">Associating a particular LSP with multiple policy groups is allowed
      from a protocol perspective; however, there is no assurance that the
      PCEP speaker will be able to apply multiple policies. If a PCEP speaker
      does not support handling of multiple policies for an LSP, it <span class="bcp14">MUST NOT</span>
      add the LSP into the association group and <span class="bcp14">MUST</span> return a PCErr with
      Error-Type 26 "Association Error" and Error-value 7 "Cannot join the
      association group".<a href="#section-4-6" class="pilcrow">¶</a></p>
</section>
<section id="section-5">
      <h2 id="name-policy-association-group">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-policy-association-group" class="section-name selfRef">Policy Association Group</a>
      </h2>
<p id="section-5-1">Association groups and their memberships are defined using the
      ASSOCIATION object defined in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>. Two object types
      for IPv4 and IPv6 are defined. The ASSOCIATION object includes
      "Association type" indicating the type of the association group. This
      document adds a new Association Type, Policy Association Type (PAT).<a href="#section-5-1" class="pilcrow">¶</a></p>
<p id="section-5-2">PAG may carry optional TLVs including but not limited to:<a href="#section-5-2" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlNewline" id="section-5-3">
        <dt id="section-5-3.1">POLICY-PARAMETERS-TLV:</dt>
        <dd style="margin-left: 1.5em" id="section-5-3.2">Used to communicate opaque information useful to applying the policy, described in <a href="#policy-tlv" class="xref">Section 5.1</a>.<a href="#section-5-3.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-5-3.3">VENDOR-INFORMATION-TLV:</dt>
        <dd style="margin-left: 1.5em" id="section-5-3.4">Used to communicate arbitrary vendor-specific behavioral information, described in <span>[<a href="#RFC7470" class="xref">RFC7470</a>]</span>.<a href="#section-5-3.4" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<div id="policy-tlv">
<section id="section-5.1">
        <h3 id="name-policy-parameters-tlv">
<a href="#section-5.1" class="section-number selfRef">5.1. </a><a href="#name-policy-parameters-tlv" class="section-name selfRef">POLICY-PARAMETERS-TLV</a>
        </h3>
<p id="section-5.1-1">
   The ASSOCIATION object (for PAT) can carry an optional  
   POLICY-PARAMETERS-TLV with opaque information that is needed to apply 
   the policy at the PCEP peer. In some cases, to apply a PCE policy
        successfully, it is required to also associate some policy parameters
        that need to be evaluated. This TLV is used to carry those policy
        parameters. The TLV could include one or more policy-related
        parameters. The encoding format and the order <span class="bcp14">MUST</span> be known to the
        PCEP peers; this could be done during the configuration of the policy
        (and its association parameters) for the PAG. The TLV format is as per
        the format of the PCEP TLVs, as defined in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>
        and shown in <a href="#fig-policy-tlv" class="xref">Figure 2</a>. Only one
        POLICY-PARAMETERS-TLV can be carried, and only the first occurrence is
        processed. Any others <span class="bcp14">MUST</span> be ignored.<a href="#section-5.1-1" class="pilcrow">¶</a></p>
<span id="name-the-policy-parameters-tlv-f"></span><div id="fig-policy-tlv">
<figure id="figure-2">
          <div class="artwork art-text alignLeft" id="section-5.1-2.1">
<pre>
    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Type=48               |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                     Policy Parameters                       //
   |                                                               |
   +---------------------------------------------------------------+
</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-the-policy-parameters-tlv-f" class="selfRef">The POLICY-PARAMETERS-TLV Format</a>
          </figcaption></figure>
</div>
<p id="section-5.1-3">The POLICY-PARAMETERS-TLV type is 48, and it has a variable
        length. The Value field is variable and padded to a 4-byte alignment;
        padding is not included in the Length field. The PCEP peer
        implementation needs to be aware of the encoding format, order, and
        meaning of the policy parameters well in advance based on the
        policy. Note that from the protocol point of view, this data is opaque
        and can be used to carry parameters in any format understood by the
        PCEP peers and associated with the policy. The exact use of this TLV is
        beyond the scope of this document. Examples are included for
        illustration purposes in <a href="#example" class="xref">Appendix A</a>.<a href="#section-5.1-3" class="pilcrow">¶</a></p>
<p id="section-5.1-4">If the PCEP peer is unaware of the policy parameters associated
        with the policy and it receives the POLICY-PARAMETERS-TLV, it <span class="bcp14">MUST</span>
        reject the PCEP message and send a PCErr message with Error-Type 26
        "Association Error" and Error-value 12 "Not expecting policy
        parameters". Further, if at least one parameter in the
        POLICY-PARAMETERS-TLV received by the PCEP speaker is considered unacceptable in the context of the associated policy (e.g., out of
        range value, badly encoded value, etc.), the PCEP speaker <span class="bcp14">MUST</span> reject the
        PCEP message and send a PCErr message with Error-Type 26 "Association
        Error" and Error-value 13 "Unacceptable policy parameters".<a href="#section-5.1-4" class="pilcrow">¶</a></p>
<p id="section-5.1-5">Note that the vendor-specific behavioral information is encoded in the VENDOR-INFORMATION-TLV, which can be used along with this TLV.<a href="#section-5.1-5" class="pilcrow">¶</a></p>
</section>
</div>
</section>
<section id="section-6">
      <h2 id="name-security-considerations">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-6-1">The security considerations described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>, 
   <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, <span>[<a href="#RFC5394" class="xref">RFC5394</a>]</span>, and <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> apply to the 
   extensions described in this document as well. In particular,
   a malicious PCEP speaker could be spoofed and used as an attack vector
   by creating spurious Policy Associations as described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>. 
   Further, as described in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>, a spurious LSP can have policies that are inconsistent with those of the
   legitimate LSPs of the group and, thus, cause problems in the handling of the policy for the
   legitimate LSPs. It should be noted that Policy Association could provide an adversary with the
   opportunity to eavesdrop on the relationship between the LSPs. <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span> suggests that the implementations and operators use indirect values as a way to hide any sensitive business
   relationships. Thus, securing the PCEP session using Transport Layer Security (TLS)
   <span>[<a href="#RFC8253" class="xref">RFC8253</a>]</span>, as per the recommendations and best current practices in
   BCP 195 <span>[<a href="#RFC7525" class="xref">RFC7525</a>]</span>, is <span class="bcp14">RECOMMENDED</span>.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">Further, extra care needs to be taken by the implementation with respect to the
      POLICY-PARAMETERS-TLV while decoding, verifying, and applying these
      policy variables. This TLV parsing could be exploited by an
      attacker; thus, extra care must be taken while configuring a Policy Association that uses the POLICY-PARAMETERS-TLV and making sure that the data is easy to parse and verify before use. Ensuring agreement among all
relevant PCEP peers as to the format and layout of the policy parameters information is key for 
correct operations. Note that the parser for POLICY-PARAMETERS-TLV is particularly
sensitive since it is opaque to PCEP and can be used to
convey data with many different internal structures/formats. The choice of decoder is dependent on the additional metadata
associated with the policy; thus, additional risk of using a wrong decoder and getting garbage results is incurred. Using standard and well-known policy formats could help
alleviate those risks.<a href="#section-6-2" class="pilcrow">¶</a></p>
<p id="section-6-3"></p>
</section>
<section id="section-7">
      <h2 id="name-iana-considerations">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<section id="section-7.1">
        <h3 id="name-association-object-type-ind">
<a href="#section-7.1" class="section-number selfRef">7.1. </a><a href="#name-association-object-type-ind" class="section-name selfRef">ASSOCIATION Object Type Indicators</a>
        </h3>
<p id="section-7.1-1">This document defines a new Association Type in the subregistry
        "ASSOCIATION Type Field" of the "Path Computation Element Protocol
        (PCEP) Numbers" registry that was originally defined in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>.<a href="#section-7.1-1" class="pilcrow">¶</a></p>
<table class="center" id="table-1">
          <caption><a href="#table-1" class="selfRef">Table 1</a></caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Value</th>
              <th class="text-left" rowspan="1" colspan="1">Name</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">3</td>
              <td class="text-left" rowspan="1" colspan="1">Policy Association</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9005</td>
            </tr>
          </tbody>
        </table>
</section>
<section id="section-7.2">
        <h3 id="name-pcep-tlv-type-indicators">
<a href="#section-7.2" class="section-number selfRef">7.2. </a><a href="#name-pcep-tlv-type-indicators" class="section-name selfRef">PCEP TLV Type Indicators</a>
        </h3>
<p id="section-7.2-1">The following TLV Type Indicator value has been registered within the
        "PCEP TLV Type Indicators" subregistry of the "Path Computation
        Element Protocol (PCEP) Numbers" registry.<a href="#section-7.2-1" class="pilcrow">¶</a></p>
<table class="center" id="table-2">
          <caption><a href="#table-2" class="selfRef">Table 2</a></caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Value</th>
              <th class="text-left" rowspan="1" colspan="1">Description</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">48</td>
              <td class="text-left" rowspan="1" colspan="1">POLICY-PARAMETERS-TLV</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9005</td>
            </tr>
          </tbody>
        </table>
</section>
<section id="section-7.3">
        <h3 id="name-pcep-errors">
<a href="#section-7.3" class="section-number selfRef">7.3. </a><a href="#name-pcep-errors" class="section-name selfRef">PCEP Errors</a>
        </h3>
<p id="section-7.3-1">This document defines new Error-values for Error-Type 26
        "Association Error" defined in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>. IANA has allocated new error values within the "PCEP-ERROR Object
        Error Types and Values" subregistry of the "Path Computation Element Protocol (PCEP) Numbers" registry as
        follows:<a href="#section-7.3-1" class="pilcrow">¶</a></p>
<table class="center" id="table-3">
          <caption><a href="#table-3" class="selfRef">Table 3</a></caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Error-Type</th>
              <th class="text-left" rowspan="1" colspan="1">Meaning</th>
              <th class="text-left" rowspan="1" colspan="1">Error-value</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">26</td>
              <td class="text-left" rowspan="1" colspan="1">Association Error</td>
              <td class="text-left" rowspan="1" colspan="1"></td>
              <td class="text-left" rowspan="1" colspan="1">
                <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>
</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1"></td>
              <td class="text-left" rowspan="1" colspan="1"></td>
              <td class="text-left" rowspan="1" colspan="1">12: Not expecting policy parameters</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9005</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1"></td>
              <td class="text-left" rowspan="1" colspan="1"></td>
              <td class="text-left" rowspan="1" colspan="1">13: Unacceptable policy parameters</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9005</td>
            </tr>
          </tbody>
        </table>
</section>
</section>
<section id="section-8">
      <h2 id="name-manageability-consideration">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-manageability-consideration" class="section-name selfRef">Manageability Considerations</a>
      </h2>
<section id="section-8.1">
        <h3 id="name-control-of-function-and-pol">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-control-of-function-and-pol" class="section-name selfRef">Control of Function and Policy</a>
        </h3>
<p id="section-8.1-1">An operator <span class="bcp14">MUST</span> be allowed to configure the Policy Associations at
        PCEP peers and associate them with the LSPs. They <span class="bcp14">MAY</span> also allow
        configuration to related policy parameters and provide information on 
        the encoding format and order to parse the
        associated POLICY-PARAMETERS-TLV.<a href="#section-8.1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.2">
        <h3 id="name-information-and-data-models">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-information-and-data-models" class="section-name selfRef">Information and Data Models</a>
        </h3>
<p id="section-8.2-1"><span>[<a href="#RFC7420" class="xref">RFC7420</a>]</span> describes the PCEP MIB; there are no new
        MIB objects for this document.<a href="#section-8.2-1" class="pilcrow">¶</a></p>
<p id="section-8.2-2">The PCEP YANG module is defined in <span>[<a href="#I-D.ietf-pce-pcep-yang" class="xref">PCE-PCEP-YANG</a>]</span>. That module supports associations
        as defined in <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>; thus, it supports the Policy
        Association Groups.<a href="#section-8.2-2" class="pilcrow">¶</a></p>
<p id="section-8.2-3">An implementation <span class="bcp14">SHOULD</span> allow the operator to view the PAG
        configured. Further implementation <span class="bcp14">SHOULD</span> allow one to view associations
        reported by each peer and the current set of LSPs in the PAG.<a href="#section-8.2-3" class="pilcrow">¶</a></p>
</section>
<section id="section-8.3">
        <h3 id="name-liveness-detection-and-moni">
<a href="#section-8.3" class="section-number selfRef">8.3. </a><a href="#name-liveness-detection-and-moni" class="section-name selfRef">Liveness Detection and Monitoring</a>
        </h3>
<p id="section-8.3-1">The mechanisms defined in this document do not imply any new liveness
        detection and monitoring requirements in addition to those already
        listed in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> and <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.<a href="#section-8.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.4">
        <h3 id="name-verifying-correct-operation">
<a href="#section-8.4" class="section-number selfRef">8.4. </a><a href="#name-verifying-correct-operation" class="section-name selfRef">Verifying Correct Operations</a>
        </h3>
<p id="section-8.4-1">Verifying the correct operation of a policy can be
   performed by monitoring various parameters as described in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> and <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>. A PCEP implementation
   <span class="bcp14">SHOULD</span> provide information on failed path computation due to applying policy and log error events, e.g., parsing failure for a POLICY-PARAMETERS-TLV.<a href="#section-8.4-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.5">
        <h3 id="name-requirements-on-other-proto">
<a href="#section-8.5" class="section-number selfRef">8.5. </a><a href="#name-requirements-on-other-proto" class="section-name selfRef">Requirements on Other Protocols</a>
        </h3>
<p id="section-8.5-1">The mechanisms defined in this document do not imply any new
        requirements on other protocols.<a href="#section-8.5-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.6">
        <h3 id="name-impact-on-network-operation">
<a href="#section-8.6" class="section-number selfRef">8.6. </a><a href="#name-impact-on-network-operation" class="section-name selfRef">Impact on Network Operations</a>
        </h3>
<p id="section-8.6-1">The mechanisms defined in this document do not have any impact on
        network operations in addition to those already listed in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>, <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, and <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-8.6-1" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-9">
      <h2 id="name-references">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-9.1">
        <h3 id="name-normative-references">
<a href="#section-9.1" class="section-number selfRef">9.1. </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="RFC5440">[RFC5440]</dt>
        <dd>
<span class="refAuthor">Vasseur, JP., Ed.</span> and <span class="refAuthor">JL. Le Roux, Ed.</span>, <span class="refTitle">"Path Computation Element (PCE) Communication Protocol (PCEP)"</span>, <span class="seriesInfo">RFC 5440</span>, <span class="seriesInfo">DOI 10.17487/RFC5440</span>, <time datetime="2009-03" class="refDate">March 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5440">https://www.rfc-editor.org/info/rfc5440</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="RFC8231">[RFC8231]</dt>
        <dd>
<span class="refAuthor">Crabbe, E.</span>, <span class="refAuthor">Minei, I.</span>, <span class="refAuthor">Medved, J.</span>, and <span class="refAuthor">R. Varga</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE"</span>, <span class="seriesInfo">RFC 8231</span>, <span class="seriesInfo">DOI 10.17487/RFC8231</span>, <time datetime="2017-09" class="refDate">September 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8231">https://www.rfc-editor.org/info/rfc8231</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8253">[RFC8253]</dt>
        <dd>
<span class="refAuthor">Lopez, D.</span>, <span class="refAuthor">Gonzalez de Dios, O.</span>, <span class="refAuthor">Wu, Q.</span>, and <span class="refAuthor">D. Dhody</span>, <span class="refTitle">"PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)"</span>, <span class="seriesInfo">RFC 8253</span>, <span class="seriesInfo">DOI 10.17487/RFC8253</span>, <time datetime="2017-10" class="refDate">October 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8253">https://www.rfc-editor.org/info/rfc8253</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8697">[RFC8697]</dt>
      <dd>
<span class="refAuthor">Minei, I.</span>, <span class="refAuthor">Crabbe, E.</span>, <span class="refAuthor">Sivabalan, S.</span>, <span class="refAuthor">Ananthakrishnan, H.</span>, <span class="refAuthor">Dhody, D.</span>, and <span class="refAuthor">Y. Tanaka</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for Establishing Relationships between Sets of Label Switched Paths (LSPs)"</span>, <span class="seriesInfo">RFC 8697</span>, <span class="seriesInfo">DOI 10.17487/RFC8697</span>, <time datetime="2020-01" class="refDate">January 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8697">https://www.rfc-editor.org/info/rfc8697</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-9.2">
        <h3 id="name-informative-references">
<a href="#section-9.2" class="section-number selfRef">9.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="I-D.ietf-pce-pcep-yang">[PCE-PCEP-YANG]</dt>
        <dd>
<span class="refAuthor">Dhody, D., Ed.</span>, <span class="refAuthor">Hardwick, J.</span>, <span class="refAuthor">Beeram, V.</span>, and <span class="refAuthor">J. Tantsura</span>, <span class="refTitle">"A YANG Data Model for Path Computation Element Communications Protocol (PCEP)"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-pce-pcep-yang-16</span>, <time datetime="2021-02-22" class="refDate">22 February 2021</time>, <span>&lt;<a href="https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-16">https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-16</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC4655">[RFC4655]</dt>
        <dd>
<span class="refAuthor">Farrel, A.</span>, <span class="refAuthor">Vasseur, J.-P.</span>, and <span class="refAuthor">J. Ash</span>, <span class="refTitle">"A Path Computation Element (PCE)-Based Architecture"</span>, <span class="seriesInfo">RFC 4655</span>, <span class="seriesInfo">DOI 10.17487/RFC4655</span>, <time datetime="2006-08" class="refDate">August 2006</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc4655">https://www.rfc-editor.org/info/rfc4655</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5394">[RFC5394]</dt>
        <dd>
<span class="refAuthor">Bryskin, I.</span>, <span class="refAuthor">Papadimitriou, D.</span>, <span class="refAuthor">Berger, L.</span>, and <span class="refAuthor">J. Ash</span>, <span class="refTitle">"Policy-Enabled Path Computation Framework"</span>, <span class="seriesInfo">RFC 5394</span>, <span class="seriesInfo">DOI 10.17487/RFC5394</span>, <time datetime="2008-12" class="refDate">December 2008</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5394">https://www.rfc-editor.org/info/rfc5394</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5905">[RFC5905]</dt>
        <dd>
<span class="refAuthor">Mills, D.</span>, <span class="refAuthor">Martin, J., Ed.</span>, <span class="refAuthor">Burbank, J.</span>, and <span class="refAuthor">W. Kasch</span>, <span class="refTitle">"Network Time Protocol Version 4: Protocol and Algorithms Specification"</span>, <span class="seriesInfo">RFC 5905</span>, <span class="seriesInfo">DOI 10.17487/RFC5905</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5905">https://www.rfc-editor.org/info/rfc5905</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7420">[RFC7420]</dt>
        <dd>
<span class="refAuthor">Koushik, A.</span>, <span class="refAuthor">Stephan, E.</span>, <span class="refAuthor">Zhao, Q.</span>, <span class="refAuthor">King, D.</span>, and <span class="refAuthor">J. Hardwick</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Management Information Base (MIB) Module"</span>, <span class="seriesInfo">RFC 7420</span>, <span class="seriesInfo">DOI 10.17487/RFC7420</span>, <time datetime="2014-12" class="refDate">December 2014</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7420">https://www.rfc-editor.org/info/rfc7420</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7470">[RFC7470]</dt>
        <dd>
<span class="refAuthor">Zhang, F.</span> and <span class="refAuthor">A. Farrel</span>, <span class="refTitle">"Conveying Vendor-Specific Constraints in the Path Computation Element Communication Protocol"</span>, <span class="seriesInfo">RFC 7470</span>, <span class="seriesInfo">DOI 10.17487/RFC7470</span>, <time datetime="2015-03" class="refDate">March 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7470">https://www.rfc-editor.org/info/rfc7470</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7525">[RFC7525]</dt>
        <dd>
<span class="refAuthor">Sheffer, Y.</span>, <span class="refAuthor">Holz, R.</span>, and <span class="refAuthor">P. Saint-Andre</span>, <span class="refTitle">"Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)"</span>, <span class="seriesInfo">BCP 195</span>, <span class="seriesInfo">RFC 7525</span>, <span class="seriesInfo">DOI 10.17487/RFC7525</span>, <time datetime="2015-05" class="refDate">May 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7525">https://www.rfc-editor.org/info/rfc7525</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8281">[RFC8281]</dt>
        <dd>
<span class="refAuthor">Crabbe, E.</span>, <span class="refAuthor">Minei, I.</span>, <span class="refAuthor">Sivabalan, S.</span>, and <span class="refAuthor">R. Varga</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model"</span>, <span class="seriesInfo">RFC 8281</span>, <span class="seriesInfo">DOI 10.17487/RFC8281</span>, <time datetime="2017-12" class="refDate">December 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8281">https://www.rfc-editor.org/info/rfc8281</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8664">[RFC8664]</dt>
      <dd>
<span class="refAuthor">Sivabalan, S.</span>, <span class="refAuthor">Filsfils, C.</span>, <span class="refAuthor">Tantsura, J.</span>, <span class="refAuthor">Henderickx, W.</span>, and <span class="refAuthor">J. Hardwick</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing"</span>, <span class="seriesInfo">RFC 8664</span>, <span class="seriesInfo">DOI 10.17487/RFC8664</span>, <time datetime="2019-12" class="refDate">December 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8664">https://www.rfc-editor.org/info/rfc8664</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<div id="example">
<section id="section-appendix.a">
      <h2 id="name-example-of-policy-parameter">
<a href="#section-appendix.a" class="section-number selfRef">Appendix A. </a><a href="#name-example-of-policy-parameter" class="section-name selfRef">Example of Policy Parameters</a>
      </h2>
<p id="section-appendix.a-1">An example could be a monitoring and telemetry policy, P1, that is
      dependent on a profile (GOLD/SILVER/BRONZE) as set by the operator. The
      PCEP peers need to be aware of policy P1 (and its associated
      characteristics) in advance as well the fact that the policy parameter
      will encode the profile of a type string in the POLICY-PARAMETERS-TLV. As
      an example, LSP1 could encode the PAG with the POLICY-PARAMETERS-TLV
      using the string "GOLD".<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
<p id="section-appendix.a-2">The following is another example where the path computation at the PCE could be dependent
      on when the LSP was configured at the PCC. For such a policy, P2, the
      timestamp can be encoded in the POLICY-PARAMETERS-TLV, and the exact
      encoding could be the 64-bit timestamp format as defined in <span>[<a href="#RFC5905" class="xref">RFC5905</a>]</span>.<a href="#section-appendix.a-2" class="pilcrow">¶</a></p>
<p id="section-appendix.a-3">While the above example has a single field in the
      POLICY-PARAMETERS-TLV, it is possible to include multiple fields, but
      the exact order, encoding format, and meanings need to be known in
      advance at the PCEP peers.<a href="#section-appendix.a-3" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-appendix.b">
      <h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
      </h2>
<p id="section-appendix.b-1">We would like to acknowledge and thank <span class="contact-name">Santiago Alvarez</span>, <span class="contact-name">Zafar Ali</span>, <span class="contact-name">Luis Tomotaki</span>, <span class="contact-name">Victor Lopez</span>, <span class="contact-name">Rob Shakir</span>, and <span class="contact-name">Clarence Filsfils</span> for working on earlier draft versions with similar motivation.<a href="#section-appendix.b-1" class="pilcrow">¶</a></p>
<p id="section-appendix.b-2">Special thanks to the authors of <span>[<a href="#RFC8697" class="xref">RFC8697</a>]</span>. This
      document borrowed some of its text. The authors would like to
      thank <span class="contact-name">Aijun Wang</span>, <span class="contact-name">Peng Shuping</span>, and <span class="contact-name">Gyan Mishra</span> for their useful
      comments.<a href="#section-appendix.b-2" class="pilcrow">¶</a></p>
<p id="section-appendix.b-3">Thanks to <span class="contact-name">Hariharan Ananthakrishnan</span> for shepherding this document. Thanks to <span class="contact-name">Deborah Brungard</span> for providing comments and being the responsible AD for this document.<a href="#section-appendix.b-3" class="pilcrow">¶</a></p>
<p id="section-appendix.b-4">Thanks to <span class="contact-name">Nic Leymann</span> for the RTGDIR review.<a href="#section-appendix.b-4" class="pilcrow">¶</a></p>
<p id="section-appendix.b-5">Thanks to <span class="contact-name">Benjamin Kaduk</span> and <span class="contact-name">Murray Kucherawy</span> for their comments during the IESG review.<a href="#section-appendix.b-5" class="pilcrow">¶</a></p>
</section>
<section id="section-appendix.c">
      <h2 id="name-contributors">
<a href="#name-contributors" class="section-name selfRef">Contributors</a>
      </h2>
<p id="section-appendix.c-1">
The following individuals have contributed extensively:<a href="#section-appendix.c-1" class="pilcrow">¶</a></p>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Mahendra Singh Negi</span></div>
<div dir="auto" class="left"><span class="org">RtBrick Inc</span></div>
<div dir="auto" class="left"><span class="street-address">N-17L, 18th Cross Rd, HSR Layout</span></div>
<div dir="auto" class="left">
<span class="locality">Bangalore</span> <span class="postal-code">560102</span>
</div>
<div dir="auto" class="left"><span class="region">Karnataka</span></div>
<div dir="auto" class="left"><span class="country-name">India</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:mahend.ietf@gmail.com" class="email">mahend.ietf@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Dhruv Dhody</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">Divyashree Techno Park, Whitefield</span></div>
<div dir="auto" class="left">
<span class="locality">Bangalore</span> <span class="postal-code">560066</span>
</div>
<div dir="auto" class="left"><span class="region">Karnataka</span></div>
<div dir="auto" class="left"><span class="country-name">India</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:dhruv.ietf@gmail.com" class="email">dhruv.ietf@gmail.com</a>
</div>
</address>
<p id="section-appendix.c-2">
The following individuals have contributed text that was incorporated:<a href="#section-appendix.c-2" class="pilcrow">¶</a></p>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Qin Wu</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">101 Software Avenue, Yuhua District</span></div>
<div dir="auto" class="left"><span class="locality">Nanjing</span></div>
<div dir="auto" class="left">
<span class="region">Jiangsu</span>, <span class="postal-code">210012</span>
</div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:sunseawq@huawei.com" class="email">sunseawq@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Xian Zhang</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">Bantian, Longgang District</span></div>
<div dir="auto" class="left"><span class="locality">Shenzhen</span></div>
<div dir="auto" class="left"><span class="postal-code">518129</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:zhang.xian@huawei.com" class="email">zhang.xian@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Udayasree Palle</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:udayasreereddy@gmail.com" class="email">udayasreereddy@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Mike Koldychev</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems, Inc.</span></div>
<div dir="auto" class="left"><span class="country-name">Canada</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:mkoldych@cisco.com" class="email">mkoldych@cisco.com</a>
</div>
</address>
</section>
<div id="authors-addresses">
<section id="section-appendix.d">
      <h2 id="name-authors-addresses">
<a href="#name-authors-addresses" class="section-name selfRef">Authors' Addresses</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Stephane Litkowski</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems, Inc.</span></div>
<div dir="auto" class="left"><span class="street-address">11 Rue Camille Desmoulins</span></div>
<div dir="auto" class="left">
<span class="postal-code">92130</span> <span class="locality">Issy-les-Moulineaux</span>
</div>
<div dir="auto" class="left"><span class="country-name">France</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:slitkows@cisco.com" class="email">slitkows@cisco.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Siva Sivabalan</span></div>
<div dir="auto" class="left"><span class="org">Ciena</span></div>
<div dir="auto" class="left"><span class="street-address">385 Terry Fox Drive</span></div>
<div dir="auto" class="left">
<span class="locality">Kanata</span> <span class="region">Ontario</span> <span class="postal-code">K2K 0L1</span>
</div>
<div dir="auto" class="left"><span class="country-name">Canada</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:msiva282@gmail.com" class="email">msiva282@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>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Jonathan Hardwick</span></div>
<div dir="auto" class="left"><span class="org">Metaswitch Networks</span></div>
<div dir="auto" class="left"><span class="street-address">33 Genotin Road</span></div>
<div dir="auto" class="left"><span class="locality">Enfield</span></div>
<div dir="auto" class="left"><span class="country-name">United Kingdom</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:Jonathan.Hardwick@metaswitch.com" class="email">Jonathan.Hardwick@metaswitch.com</a>
</div>
</address>
<address class="vcard">
        <div class="ascii">
<div dir="auto" class="left"><span class="fn nameRole">Cheng Li</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">Huawei Campus, No. 156 Beiqing Rd.</span></div>
<div dir="auto" class="left"><span class="locality">Beijing</span></div>
<div dir="auto" class="left"><span class="postal-code">100095</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:c.l@huawei.com" class="email">c.l@huawei.com</a>
</div>
</div>
<div class="alternative-contact">Additional contact information:</div>
<div class="non-ascii">
<div dir="auto" class="left"><span class="fn nameRole">李呈</span></div>
<div dir="auto" class="left"><span class="country-name">中国</span></div>
<div dir="auto" class="left"><span class="postal-code">100095</span></div>
<div dir="auto" class="left">
<span class="locality">北京</span> </div>
<div dir="auto" class="left"><span class="street-address">华为北研所</span></div>
<div dir="auto" class="left"><span class="org">华为技术有限公司</span></div>
</div>
</address>
</section>
</div>
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