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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 9050: Path Computation Element Communication Protocol (PCEP) Procedures and Extensions for Using the PCE as a Central Controller (PCECC) of LSPs</title>
<meta content="Zhenbin Li" name="author">
<meta content="Shuping Peng" name="author">
<meta content="Mahendra Singh Negi" name="author">
<meta content="Quintin Zhao" name="author">
<meta content="Chao Zhou" name="author">
<meta content="
       The Path Computation Element (PCE) is a core component of Software-Defined Networking (SDN) systems. 
       A PCE as a Central Controller (PCECC) can
   simplify the processing of a distributed control plane by blending it
   with elements of SDN and without necessarily completely replacing it. 
   Thus, the Label Switched Path (LSP) can be
   calculated/set up/initiated and the label-forwarding entries can also be
   downloaded through a centralized PCE server to each network device
   along the path while leveraging the existing PCE technologies as
   much as possible. 
       This document specifies the procedures and Path Computation Element Communication Protocol (PCEP) extensions for
   using the PCE as the central controller for provisioning labels along the path of the static LSP.
       
    " name="description">
<meta content="xml2rfc 3.9.1" name="generator">
<meta content="SDN" name="keyword">
<meta content="CCI" name="keyword">
<meta content="Central Control" name="keyword">
<meta content="9050" name="rfc.number">
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<link href="https://dx.doi.org/10.17487/rfc9050" rel="alternate">
  <link href="urn:issn:2070-1721" rel="alternate">
  <link href="https://datatracker.ietf.org/doc/draft-ietf-pce-pcep-extension-for-pce-controller-14" rel="prev">
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<table class="ears">
<thead><tr>
<td class="left">RFC 9050</td>
<td class="center">PCECC</td>
<td class="right">July 2021</td>
</tr></thead>
<tfoot><tr>
<td class="left">Li, 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/rfc9050" class="eref">9050</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="2021-07" class="published">July 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">Z. Li</div>
<div class="org">Huawei Technologies</div>
</div>
<div class="author">
      <div class="author-name">S. Peng</div>
<div class="org">Huawei Technologies</div>
</div>
<div class="author">
      <div class="author-name">M. Negi</div>
<div class="org">RtBrick Inc</div>
</div>
<div class="author">
      <div class="author-name">Q. Zhao</div>
<div class="org">Etheric Networks</div>
</div>
<div class="author">
      <div class="author-name">C. Zhou</div>
<div class="org">HPE</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 9050</h1>
<h1 id="title">Path Computation Element Communication Protocol (PCEP) Procedures and Extensions for Using the PCE as a Central Controller (PCECC) of LSPs</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">The Path Computation Element (PCE) is a core component of Software-Defined Networking (SDN) systems.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
<p id="section-abstract-2">A PCE as a Central Controller (PCECC) can
   simplify the processing of a distributed control plane by blending it
   with elements of SDN and without necessarily completely replacing it. 
   Thus, the Label Switched Path (LSP) can be
   calculated/set up/initiated and the label-forwarding entries can also be
   downloaded through a centralized PCE server to each network device
   along the path while leveraging the existing PCE technologies as
   much as possible.<a href="#section-abstract-2" class="pilcrow">¶</a></p>
<p id="section-abstract-3">This document specifies the procedures and Path Computation Element Communication Protocol (PCEP) extensions for
   using the PCE as the central controller for provisioning labels along the path of the static LSP.<a href="#section-abstract-3" 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/rfc9050">https://www.rfc-editor.org/info/rfc9050</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>
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            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
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            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="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact 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>
</li>
          <li class="ulEmpty ulBare compact 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>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" 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-requirements-language" class="xref">Requirements Language</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact 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-basic-pcecc-mode" class="xref">Basic PCECC Mode</a></p>
</li>
          <li class="ulEmpty ulBare compact 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-pcep-requirements" class="xref">PCEP Requirements</a></p>
</li>
          <li class="ulEmpty ulBare compact 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-procedures-for-using-the-pc" class="xref">Procedures for Using the PCE as a Central Controller (PCECC)</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact 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-stateful-pce-model" class="xref">Stateful PCE Model</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.2">
                <p id="section-toc.1-1.5.2.2.1"><a href="#section-5.2" class="xref">5.2</a>.  <a href="#name-new-lsp-functions" class="xref">New LSP Functions</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.3">
                <p id="section-toc.1-1.5.2.3.1"><a href="#section-5.3" class="xref">5.3</a>.  <a href="#name-new-pcep-object" class="xref">New PCEP Object</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.4">
                <p id="section-toc.1-1.5.2.4.1"><a href="#section-5.4" class="xref">5.4</a>.  <a href="#name-pcecc-capability-advertisem" class="xref">PCECC Capability Advertisement</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5">
                <p id="section-toc.1-1.5.2.5.1"><a href="#section-5.5" class="xref">5.5</a>.  <a href="#name-lsp-operations" class="xref">LSP Operations</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.1">
                    <p id="section-toc.1-1.5.2.5.2.1.1"><a href="#section-5.5.1" class="xref">5.5.1</a>.  <a href="#name-pce-initiated-pcecc-lsp" class="xref">PCE-Initiated PCECC LSP</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.2">
                    <p id="section-toc.1-1.5.2.5.2.2.1"><a href="#section-5.5.2" class="xref">5.5.2</a>.  <a href="#name-pcc-initiated-pcecc-lsp" class="xref">PCC-Initiated PCECC LSP</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.3">
                    <p id="section-toc.1-1.5.2.5.2.3.1"><a href="#section-5.5.3" class="xref">5.5.3</a>.  <a href="#name-central-controller-instruct" class="xref">Central Controller Instructions</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.3.2.1">
                        <p id="section-toc.1-1.5.2.5.2.3.2.1.1"><a href="#section-5.5.3.1" class="xref">5.5.3.1</a>.  <a href="#name-label-download-cci" class="xref">Label Download CCI</a></p>
</li>
                      <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.3.2.2">
                        <p id="section-toc.1-1.5.2.5.2.3.2.2.1"><a href="#section-5.5.3.2" class="xref">5.5.3.2</a>.  <a href="#name-label-cleanup-cci" class="xref">Label Cleanup CCI</a></p>
</li>
                    </ul>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.4">
                    <p id="section-toc.1-1.5.2.5.2.4.1"><a href="#section-5.5.4" class="xref">5.5.4</a>.  <a href="#name-pcecc-lsp-update" class="xref">PCECC LSP Update</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.5">
                    <p id="section-toc.1-1.5.2.5.2.5.1"><a href="#section-5.5.5" class="xref">5.5.5</a>.  <a href="#name-re-delegation-and-cleanup" class="xref">Re-delegation and Cleanup</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.6">
                    <p id="section-toc.1-1.5.2.5.2.6.1"><a href="#section-5.5.6" class="xref">5.5.6</a>.  <a href="#name-synchronization-of-central-" class="xref">Synchronization of Central Controller Instructions</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.7">
                    <p id="section-toc.1-1.5.2.5.2.7.1"><a href="#section-5.5.7" class="xref">5.5.7</a>.  <a href="#name-pcecc-lsp-state-report" class="xref">PCECC LSP State Report</a></p>
</li>
                  <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.5.2.5.2.8">
                    <p id="section-toc.1-1.5.2.5.2.8.1"><a href="#section-5.5.8" class="xref">5.5.8</a>.  <a href="#name-pcc-based-allocations" class="xref">PCC-Based Allocations</a></p>
</li>
                </ul>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact 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-pcep-messages" class="xref">PCEP Messages</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.6.2.1">
                <p id="section-toc.1-1.6.2.1.1"><a href="#section-6.1" class="xref">6.1</a>.  <a href="#name-the-pcinitiate-message" class="xref">The PCInitiate Message</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.6.2.2">
                <p id="section-toc.1-1.6.2.2.1"><a href="#section-6.2" class="xref">6.2</a>.  <a href="#name-the-pcrpt-message" class="xref">The PCRpt Message</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact 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-pcep-objects" class="xref">PCEP Objects</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact 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-open-object" class="xref">OPEN Object</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.7.2.1.2.1">
                    <p id="section-toc.1-1.7.2.1.2.1.1"><a href="#section-7.1.1" class="xref">7.1.1</a>.  <a href="#name-pcecc-capability-sub-tlv" class="xref">PCECC Capability Sub-TLV</a></p>
</li>
                </ul>
</li>
              <li class="ulEmpty ulBare compact 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-path-setup-type-tlv" class="xref">PATH-SETUP-TYPE TLV</a></p>
</li>
              <li class="ulEmpty ulBare compact 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-cci-object" class="xref">CCI Object</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.7.2.3.2.1">
                    <p id="section-toc.1-1.7.2.3.2.1.1"><a href="#section-7.3.1" class="xref">7.3.1</a>.  <a href="#name-address-tlvs" class="xref">Address TLVs</a></p>
</li>
                </ul>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact 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-security-considerations" class="xref">Security Considerations</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact 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-malicious-pce" class="xref">Malicious PCE</a></p>
</li>
              <li class="ulEmpty ulBare compact 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-malicious-pcc" class="xref">Malicious PCC</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact 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-manageability-consideration" class="xref">Manageability Considerations</a></p>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact 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-control-of-function-and-pol" class="xref">Control of Function and Policy</a></p>
</li>
              <li class="ulEmpty ulBare compact 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-information-and-data-models" class="xref">Information and Data Models</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.9.2.3">
                <p id="section-toc.1-1.9.2.3.1"><a href="#section-9.3" class="xref">9.3</a>.  <a href="#name-liveness-detection-and-moni" class="xref">Liveness Detection and Monitoring</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.9.2.4">
                <p id="section-toc.1-1.9.2.4.1"><a href="#section-9.4" class="xref">9.4</a>.  <a href="#name-verify-correct-operations" class="xref">Verify Correct Operations</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.9.2.5">
                <p id="section-toc.1-1.9.2.5.1"><a href="#section-9.5" class="xref">9.5</a>.  <a href="#name-requirements-on-other-proto" class="xref">Requirements on Other Protocols</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.9.2.6">
                <p id="section-toc.1-1.9.2.6.1"><a href="#section-9.6" class="xref">9.6</a>.  <a href="#name-impact-on-network-operation" class="xref">Impact on Network Operations</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact toc" 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>
<ul class="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.1">
                <p id="section-toc.1-1.10.2.1.1"><a href="#section-10.1" class="xref">10.1</a>.  <a href="#name-path-setup-type-capability-" class="xref">PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.2">
                <p id="section-toc.1-1.10.2.2.1"><a href="#section-10.2" class="xref">10.2</a>.  <a href="#name-pcecc-capability-sub-tlvs-f" class="xref">PCECC-CAPABILITY Sub-TLV's Flag Field</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.3">
                <p id="section-toc.1-1.10.2.3.1"><a href="#section-10.3" class="xref">10.3</a>.  <a href="#name-pcep-path-setup-type-regist" class="xref">PCEP Path Setup Type Registry</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.4">
                <p id="section-toc.1-1.10.2.4.1"><a href="#section-10.4" class="xref">10.4</a>.  <a href="#name-pcep-object" class="xref">PCEP Object</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.5">
                <p id="section-toc.1-1.10.2.5.1"><a href="#section-10.5" class="xref">10.5</a>.  <a href="#name-cci-object-flag-field" class="xref">CCI Object Flag Field</a></p>
</li>
              <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.10.2.6">
                <p id="section-toc.1-1.10.2.6.1"><a href="#section-10.6" class="xref">10.6</a>.  <a href="#name-pcep-error-object" class="xref">PCEP-Error Object</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty ulBare compact toc" 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="ulEmpty ulBare compact toc">
<li class="ulEmpty ulBare compact toc" 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="ulEmpty ulBare compact toc" 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="ulEmpty ulBare compact toc" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#appendix-A" class="xref"></a><a href="#name-acknowledgments" class="xref">Acknowledgments</a></p>
</li>
          <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#appendix-B" class="xref"></a><a href="#name-contributors" class="xref">Contributors</a></p>
</li>
          <li class="ulEmpty ulBare compact toc" id="section-toc.1-1.14">
            <p id="section-toc.1-1.14.1"><a href="#appendix-C" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1">The Path Computation Element (PCE) <span>[<a href="#RFC4655" class="xref">RFC4655</a>]</span> was developed to offload the
   path computation function from routers in an MPLS traffic-engineered (TE)
   network.  It can compute optimal paths for
   traffic across a network and can also update the paths to reflect
   changes in the network or traffic demands. Since then, the role and function of the PCE have grown to
   cover a number of other uses (such as GMPLS <span>[<a href="#RFC7025" class="xref">RFC7025</a>]</span>) and to allow
   delegated control <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> and PCE-initiated use of network
   resources <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">According to <span>[<a href="#RFC7399" class="xref">RFC7399</a>]</span>, Software-Defined Networking (SDN) refers to a
   separation between the control elements and the forwarding components
   so that software running in a centralized system, called a
   controller, can act to program the devices in the network to behave
   in specific ways.  A required element in an SDN architecture is a
   component that plans how the network resources will be used and how
   the devices will be programmed.  It is possible to view this
   component as performing specific computations to place traffic flows
   within the network given knowledge of the availability of network
   resources, how other forwarding devices are programmed, and the way
   that other flows are routed.  This is the function and purpose of a
   PCE, and the way that a PCE integrates into a wider network control
   system (including an SDN system) is presented in <span>[<a href="#RFC7491" class="xref">RFC7491</a>]</span>.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">In early PCE implementations, where the PCE was used to derive paths
   for MPLS Label Switched Paths (LSPs), paths were requested by network
   elements (known as Path Computation Clients (PCCs)), and the results
   of the path computations were supplied to network elements using the
   Path Computation Element Communication Protocol (PCEP) <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.
   This protocol was later extended to allow a PCE to send unsolicited
   requests to the network for LSP establishment <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">The PCE was developed to derive paths for MPLS LSPs, which are supplied to the head end of the LSP using the PCEP. But SDN has a broader 
   applicability than signaled MPLS and GMPLS TE networks, and the PCE may be used to determine paths in a range
   of use cases. PCEP has been proposed as a control protocol for
   use in these environments to allow the PCE to be fully enabled as a
   central controller.<a href="#section-1-4" class="pilcrow">¶</a></p>
<p id="section-1-5"><span>[<a href="#RFC8283" class="xref">RFC8283</a>]</span> introduces the architecture for the PCE as a central
   controller as an extension to the architecture described in <span>[<a href="#RFC4655" class="xref">RFC4655</a>]</span>
   and assumes the continued use of PCEP as the protocol used between the PCE and PCC. <span>[<a href="#RFC8283" class="xref">RFC8283</a>]</span>  further examines the motivations and applicability
   for PCEP as a Southbound Interface (SBI) and introduces the implications for the
   protocol.  <span>[<a href="#I-D.ietf-teas-pcecc-use-cases" class="xref">PCECC</a>]</span> describes the use cases for
   the PCECC architecture.<a href="#section-1-5" class="pilcrow">¶</a></p>
<p id="section-1-6">A PCECC can
   simplify the processing of a distributed control plane by blending it
   with elements of SDN and without necessarily completely replacing it. 
   Thus, the LSP can be
   calculated/set up/initiated and the label-forwarding entries can also be
   downloaded through a centralized PCE server to each network device
   along the path while leveraging the existing PCE technologies as
   much as possible.<a href="#section-1-6" class="pilcrow">¶</a></p>
<p id="section-1-7">This document specifies the procedures and PCEP extensions for
   using the PCE as the central controller for static LSPs, where 
   LSPs can be provisioned as explicit label instructions at each
   hop on the end-to-end path.  Each router along the path must be
   told what label-forwarding instructions to program and what resources
   to reserve.  The PCE-based controller keeps a view of the network and
   determines the paths of the end-to-end LSPs, and the controller uses PCEP to
   communicate with each router along the path of the end-to-end LSP.<a href="#section-1-7" class="pilcrow">¶</a></p>
<p id="section-1-8">While this document is focused on the procedures for the static LSPs (referred to as the basic PCECC mode in <a href="#SEC_M" class="xref">Section 3</a>), the mechanisms and protocol encodings are specified in such a way that extensions for other use cases are easy to achieve. For example, the extensions for the PCECC for Segment Routing (SR) are specified in <span>[<a href="#I-D.ietf-pce-pcep-extension-pce-controller-sr" class="xref">PCECC-SR</a>]</span> and <span>[<a href="#I-D.dhody-pce-pcep-extension-pce-controller-srv6" class="xref">PCECC-SRv6</a>]</span>.<a href="#section-1-8" class="pilcrow">¶</a></p>
</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 terminology used in this document is the same as that described in the 
       <span>[<a href="#RFC8283" class="xref">RFC8283</a>]</span>.<a href="#section-2-1" class="pilcrow">¶</a></p>
<section id="section-2.1">
        <h3 id="name-requirements-language">
<a href="#section-2.1" class="section-number selfRef">2.1. </a><a href="#name-requirements-language" class="section-name selfRef">Requirements Language</a>
        </h3>
<p id="section-2.1-1">
    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-2.1-1" class="pilcrow">¶</a></p>
</section>
</section>
<div id="SEC_M">
<section id="section-3">
      <h2 id="name-basic-pcecc-mode">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-basic-pcecc-mode" class="section-name selfRef">Basic PCECC Mode</a>
      </h2>
<p id="section-3-1">In this mode, LSPs are provisioned as explicit label instructions at each
   hop on the end-to-end path. Each router along the path must be
   told what label-forwarding instructions to program and what resources
   to reserve. The controller uses PCEP to communicate with each router
   along the path of the end-to-end LSP.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2"><span>[<a href="#RFC8283" class="xref">RFC8283</a>]</span> examines the motivations and applicability for the
   PCECC and use of PCEP as an SBI. <span><a href="https://www.rfc-editor.org/rfc/rfc8283#section-3.1.2" class="relref">Section 3.1.2</a> of [<a href="#RFC8283" class="xref">RFC8283</a>]</span> 
   highlights the use of the PCECC for label allocation along the static LSPs, and 
   it simplifies the processing of a distributed
   control plane by blending it with elements of SDN and without
   necessarily completely replacing it. This allows the operator to introduce 
   the advantages of SDN (such as programmability) into the network. Further, <span><a href="https://datatracker.ietf.org/doc/html/draft-ietf-teas-pcecc-use-cases-07#section-3.3" class="relref">Section 3.3</a> of [<a href="#I-D.ietf-teas-pcecc-use-cases" class="xref">PCECC</a>]</span> describes some of the scenarios where the PCECC technique could be useful. <span><a href="https://www.rfc-editor.org/rfc/rfc8283#section-4" class="relref">Section 4</a> of [<a href="#RFC8283" class="xref">RFC8283</a>]</span> 
   also describes the implications on the protocol when used as an SDN SBI. The operator needs to evaluate the advantages offered by the PCECC against the operational and scalability needs of the PCECC.<a href="#section-3-2" class="pilcrow">¶</a></p>
<p id="section-3-3">As per <span><a href="https://www.rfc-editor.org/rfc/rfc8283#section-3.1.2" class="relref">Section 3.1.2</a> of [<a href="#RFC8283" class="xref">RFC8283</a>]</span>, the PCE-based controller will take responsibility for
   managing some part of the MPLS label space for each of the routers
   that it controls and may take wider responsibility for partitioning
   the label space for each router and allocating different parts for
   different uses. The PCC <span class="bcp14">MUST NOT</span> make allocations from the label space set aside for the PCE to avoid overlap and collisions of label allocations. It is <span class="bcp14">RECOMMENDED</span> that the PCE makes allocations (from the label space set aside for the PCE) for all nodes along the path. For the purpose
   of this document, it is assumed that the exclusive label range to be used by a PCE
   is known and set on both PCEP peers. A future extension could add the capability to
   advertise this range via a possible PCEP extension as well (see <span>[<a href="#I-D.li-pce-controlled-id-space" class="xref">PCE-ID</a>]</span>). 
   The rest of the processing is similar
   to the existing stateful PCE mechanism.<a href="#section-3-3" class="pilcrow">¶</a></p>
<p id="section-3-4">This document also allows a case where the label space is maintained by the PCC and the labels are  
     allocated by it. In this case, the PCE should request the allocation from the 
     PCC, as described in <a href="#PCC" class="xref">Section 5.5.8</a>.<a href="#section-3-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="SEC_R">
<section id="section-4">
      <h2 id="name-pcep-requirements">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-pcep-requirements" class="section-name selfRef">PCEP Requirements</a>
      </h2>
<p id="section-4-1">The following key requirements should be considered when
   designing the PCECC-based solution:<a href="#section-4-1" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-4-2">
 <li id="section-4-2.1">A PCEP speaker supporting this document needs to have the capability to
       advertise its PCECC capability to its peers.<a href="#section-4-2.1" class="pilcrow">¶</a>
</li>
        <li id="section-4-2.2">A PCEP speaker needs means to identify PCECC-based LSPs in the
       PCEP messages.<a href="#section-4-2.2" class="pilcrow">¶</a>
</li>
        <li id="section-4-2.3">PCEP procedures need to allow for PCC-based label allocations.<a href="#section-4-2.3" class="pilcrow">¶</a>
</li>
        <li id="section-4-2.4">PCEP procedures need to provide a means to update (or clean up) label entries downloaded to the PCC.<a href="#section-4-2.4" class="pilcrow">¶</a>
</li>
        <li id="section-4-2.5">PCEP procedures need to provide a means to synchronize the labels between
       the PCE and the PCC via PCEP messages.<a href="#section-4-2.5" class="pilcrow">¶</a>
</li>
      </ol>
</section>
</div>
<div id="Procedures">
<section id="section-5">
      <h2 id="name-procedures-for-using-the-pc">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-procedures-for-using-the-pc" class="section-name selfRef">Procedures for Using the PCE as a Central Controller (PCECC)</a>
      </h2>
<section id="section-5.1">
        <h3 id="name-stateful-pce-model">
<a href="#section-5.1" class="section-number selfRef">5.1. </a><a href="#name-stateful-pce-model" class="section-name selfRef">Stateful PCE Model</a>
        </h3>
<p id="section-5.1-1">Active stateful PCE is described in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>. A PCE
    as a Central Controller (PCECC) reuses the existing active stateful PCE
    mechanism as much as possible to control LSPs.<a href="#section-5.1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-5.2">
        <h3 id="name-new-lsp-functions">
<a href="#section-5.2" class="section-number selfRef">5.2. </a><a href="#name-new-lsp-functions" class="section-name selfRef">New LSP Functions</a>
        </h3>
<p id="section-5.2-1">Several new functions are required in PCEP to support the PCECC. This document extends the
   existing messages to support the new functions required by the PCECC:<a href="#section-5.2-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2-2">
          <dt id="section-5.2-2.1">PCInitiate:</dt>
          <dd style="margin-left: 1.5em" id="section-5.2-2.2">A PCEP message described in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.
          A PCInitiate message is used to set up a PCE-initiated LSP based on a PCECC mechanism. 
          It is also extended for Central Controller Instructions (CCI) (download or clean up the label-forwarding instructions in the context of this document) on all nodes along the path, as described in <a href="#SEC_PCInitiate" class="xref">Section 6.1</a>.<a href="#section-5.2-2.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-5.2-2.3">PCRpt:</dt>
          <dd style="margin-left: 1.5em" id="section-5.2-2.4">A PCEP message described in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.
          A PCRpt message is used to send the PCECC LSP Reports. It is also extended to report the set of CCI (label-forwarding instructions in the context of this document) received 
          from the PCE, as described in <a href="#SEC_PCRpt" class="xref">Section 6.2</a>. <a href="#sec_label_db_sync" class="xref">Section 5.5.6</a> describes the use of a PCRpt message during synchronization.<a href="#section-5.2-2.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-5.2-2.5">PCUpd:</dt>
          <dd style="margin-left: 1.5em" id="section-5.2-2.6">A PCEP message described in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.
          A PCUpd message is used to send the PCECC LSP Updates.<a href="#section-5.2-2.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<p id="section-5.2-3">The new functions defined in this document are mapped onto the PCEP messages, as
    shown in <a href="#SEC_FIG1" class="xref">Table 1</a>.<a href="#section-5.2-3" class="pilcrow">¶</a></p>
<span id="name-functions-mapped-to-the-pce"></span><div id="SEC_FIG1">
<table class="center" id="table-1">
          <caption>
<a href="#table-1" class="selfRef">Table 1</a>:
<a href="#name-functions-mapped-to-the-pce" class="selfRef">Functions Mapped to the PCEP Messages</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Function</th>
              <th class="text-left" rowspan="1" colspan="1">Message</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC Capability advertisement </td>
              <td class="text-left" rowspan="1" colspan="1">Open </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">Label entry Add </td>
              <td class="text-left" rowspan="1" colspan="1">PCInitiate </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">Label entry Clean up </td>
              <td class="text-left" rowspan="1" colspan="1">PCInitiate </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC-Initiated LSP </td>
              <td class="text-left" rowspan="1" colspan="1">PCInitiate </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC LSP Update </td>
              <td class="text-left" rowspan="1" colspan="1">PCUpd </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC LSP State Report </td>
              <td class="text-left" rowspan="1" colspan="1">PCRpt </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC LSP Delegation </td>
              <td class="text-left" rowspan="1" colspan="1">PCRpt </td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">PCECC Label Report </td>
              <td class="text-left" rowspan="1" colspan="1">PCRpt </td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-5.3">
        <h3 id="name-new-pcep-object">
<a href="#section-5.3" class="section-number selfRef">5.3. </a><a href="#name-new-pcep-object" class="section-name selfRef">New PCEP Object</a>
        </h3>
<p id="section-5.3-1">This document defines a new PCEP object called CCI (<a href="#SEC_CCI" class="xref">Section 7.3</a>) to specify the Central Controller Instructions. In the scope of this document, this is limited to label-forwarding instructions. Future documents can create new CCI object-types for other types of Central Controller Instructions. The CC-ID is the unique identifier for the CCI in PCEP. The PCEP messages are extended in this document to handle the PCECC operations.<a href="#section-5.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-5.4">
        <h3 id="name-pcecc-capability-advertisem">
<a href="#section-5.4" class="section-number selfRef">5.4. </a><a href="#name-pcecc-capability-advertisem" class="section-name selfRef">PCECC Capability Advertisement</a>
        </h3>
<p id="section-5.4-1">During the PCEP initialization phase, PCEP speakers (PCE or PCC) advertise their support of and willingness to use PCEP extensions for the PCECC using these elements in the OPEN message:<a href="#section-5.4-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.4-2.1">a new Path Setup Type (PST) (<a href="#SEC_PATH" class="xref">Section 7.2</a>) in the PATH-SETUP-TYPE-CAPABILITY TLV to indicate support for PCEP extensions for the PCECC - 2 (Traffic engineering path is set up using PCECC mode)<a href="#section-5.4-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-2.2">a new PCECC-CAPABILITY sub-TLV (<a href="#SEC_PCECC_CAP_TLV" class="xref">Section 7.1.1</a>) with the L bit set to '1' inside the PATH-SETUP-TYPE-CAPABILITY TLV to indicate a willingness to use PCEP extensions for the PCECC-based Central Controller Instructions for label download<a href="#section-5.4-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-2.3">the STATEFUL-PCE-CAPABILITY TLV <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> (with the I flag set <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>)<a href="#section-5.4-2.3" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-5.4-3">The new PST is to be listed in the PATH-SETUP-TYPE-CAPABILITY TLV by all PCEP speakers that support the PCEP extensions for the PCECC in this document.<a href="#section-5.4-3" class="pilcrow">¶</a></p>
<p id="section-5.4-4">The new PCECC-CAPABILITY sub-TLV is included in the PATH-SETUP-TYPE-CAPABILITY TLV in the OPEN object to indicate a willingness to use the PCEP extensions for the PCECC during the established PCEP session. Using the L bit in this TLV, the PCE shows the intention to function as a PCECC server, and the PCC shows a willingness to act as a PCECC client for label download instructions (see <a href="#SEC_PCECC_CAP_TLV" class="xref">Section 7.1.1</a>).<a href="#section-5.4-4" class="pilcrow">¶</a></p>
<p id="section-5.4-5">If the PCECC-CAPABILITY sub-TLV is advertised and the STATEFUL-PCE-CAPABILITY TLV is not advertised, or is advertised without the I flag set, in the OPEN object, the receiver <span class="bcp14">MUST</span>:<a href="#section-5.4-5" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.4-6.1">send a PCErr message with Error-Type=19 (Invalid Operation) and Error-value=17 (Stateful PCE capability was not advertised) and<a href="#section-5.4-6.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-6.2">terminate the session.<a href="#section-5.4-6.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-5.4-7">If a PCEP speaker receives the PATH-SETUP-TYPE-CAPABILITY TLV with the PCECC PST but without the PCECC-CAPABILITY sub-TLV, it <span class="bcp14">MUST</span>:<a href="#section-5.4-7" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.4-8.1">send a PCErr message with Error-Type=10 (Reception of an invalid object) and Error-value=33 (Missing PCECC Capability sub-TLV) and<a href="#section-5.4-8.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-8.2">terminate the PCEP session.<a href="#section-5.4-8.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-5.4-9">The PCECC-CAPABILITY sub-TLV <span class="bcp14">MUST NOT</span> be used without the corresponding PST being listed in the PATH-SETUP-TYPE-CAPABILITY TLV. If it is present without the corresponding PST listed in the PATH-SETUP-TYPE-CAPABILITY TLV, it <span class="bcp14">MUST</span> be ignored.<a href="#section-5.4-9" class="pilcrow">¶</a></p>
<p id="section-5.4-10">If one or both speakers (PCE and PCC) have not indicated support and willingness to use the PCEP extensions for the PCECC, the PCEP extensions for the PCECC <span class="bcp14">MUST NOT</span> be used. If a PCECC operation is attempted when both speakers have not agreed in the OPEN messages, the receiver of the message <span class="bcp14">MUST</span>:<a href="#section-5.4-10" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.4-11.1">send a PCErr message with Error-Type=19 (Invalid Operation) and Error-value=16 (Attempted PCECC operations when PCECC capability was not advertised) and<a href="#section-5.4-11.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-11.2">terminate the PCEP session.<a href="#section-5.4-11.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-5.4-12">A legacy PCEP speaker (that does not recognize the PCECC Capability sub-TLV) will ignore the sub-TLV in accordance with <span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span> and <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>. As per <span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span>, the legacy PCEP speaker, on receipt of an unsupported PST in a Request Parameter (RP) / Stateful PCE Request Parameter (SRP) object, will:<a href="#section-5.4-12" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-5.4-13.1">send a PCErr message with Error-Type=21 (Invalid traffic engineering path setup type) and Error-value=1 (Unsupported path setup type) and<a href="#section-5.4-13.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-5.4-13.2">terminate the PCEP session.<a href="#section-5.4-13.2" class="pilcrow">¶</a>
</li>
        </ul>
</section>
<section id="section-5.5">
        <h3 id="name-lsp-operations">
<a href="#section-5.5" class="section-number selfRef">5.5. </a><a href="#name-lsp-operations" class="section-name selfRef">LSP Operations</a>
        </h3>
<p id="section-5.5-1"> The PCEP messages pertaining to a PCECC <span class="bcp14">MUST</span> include the PATH-SETUP-TYPE
   TLV <span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span> in the SRP object <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> with the PST set to '2'
   to clearly identify that the PCECC LSP is intended.<a href="#section-5.5-1" class="pilcrow">¶</a></p>
<div id="PCE-I">
<section id="section-5.5.1">
          <h4 id="name-pce-initiated-pcecc-lsp">
<a href="#section-5.5.1" class="section-number selfRef">5.5.1. </a><a href="#name-pce-initiated-pcecc-lsp" class="section-name selfRef">PCE-Initiated PCECC LSP</a>
          </h4>
<p id="section-5.5.1-1">The LSP instantiation operation is defined in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>. In order to set up a PCE-initiated LSP based on the PCECC mechanism, a PCE
    sends a PCInitiate message with the PST set to '2' for the PCECC
    (see <a href="#SEC_PATH" class="xref">Section 7.2</a>) to the ingress PCC.<a href="#section-5.5.1-1" class="pilcrow">¶</a></p>
<p id="section-5.5.1-2">The label-forwarding instructions (see <a href="#CCI" class="xref">Section 5.5.3</a>) from the PCECC are sent after the initial PCInitiate and PCRpt message exchange with the ingress PCC, as per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> (see <a href="#SEC_FIG4" class="xref">Figure 1</a>). This is done so that the PCEP-specific identifier for the LSP (PLSP-ID) and other LSP identifiers can be obtained from the ingress and can be included in the label-forwarding instruction in the next set of PCInitiate messages along the path, as described below.<a href="#section-5.5.1-2" class="pilcrow">¶</a></p>
<p id="section-5.5.1-3">An LSP-IDENTIFIERS TLV <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> <span class="bcp14">MUST</span> be included for the PCECC LSPs; it uniquely identifies the LSP in the network. Note that the fields in the LSP-IDENTIFIERS TLV are described for the RSVP-signaled LSPs but are applicable to the PCECC LSP as well. The LSP object is included in the CCI (label download <a href="#SEC_CCI" class="xref">Section 7.3</a>) to identify the PCECC LSP for  this instruction. The PLSP-ID is the original identifier used by the ingress PCC, so a transit/egress Label Switching Router (LSR) could have multiple Central Controller Instructions that have the same PLSP-ID. The PLSP-ID in combination with the source (in the LSP-IDENTIFIERS TLV) <span class="bcp14">MUST</span> be unique. The PLSP-ID is included for maintainability reasons to ease debugging. As per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>, the LSP object could also include the SPEAKER-ENTITY-ID TLV to identify the PCE that initiated these instructions. Also, the CC-ID is unique in each PCEP session, as described in <a href="#SEC_CCI" class="xref">Section 7.3</a>.<a href="#section-5.5.1-3" class="pilcrow">¶</a></p>
<p id="section-5.5.1-4">On receipt of a PCInitiate message for the PCECC LSP, the PCC responds with a PCRpt message with the status set to 'Going-up' and carrying the assigned PLSP-ID (see <a href="#SEC_FIG4" class="xref">Figure 1</a>). The ingress PCC also sets the D (Delegate) flag (see <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>) and C (Create) flag (see <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>) in the LSP object. When the PCE receives this PCRpt message with the PLSP-ID, it assigns labels along the path and sets up the path by sending a PCInitiate message to each node along the path of the LSP, as per the PCECC technique. The CC-ID uniquely identifies the Central Controller Instructions within a PCEP session. Each node along the path (PCC) responds with a PCRpt message to acknowledge the CCI with the PCRpt messages including the CCI and LSP objects.<a href="#section-5.5.1-4" class="pilcrow">¶</a></p>
<p id="section-5.5.1-5">The ingress node would receive one CCI object with the O bit (out-label) set. The transit node(s) would receive two CCI objects with the in-label CCI without the O bit set and the out-label CCI with the O bit set. The egress node would receive one CCI object without the O bit set (see <a href="#SEC_FIG4" class="xref">Figure 1</a>). A node can determine its role based on the setting of the O bit in the CCI object(s) and the LSP-IDENTIFIERS TLV in the LSP object.<a href="#section-5.5.1-5" class="pilcrow">¶</a></p>
<p id="section-5.5.1-6">The LSP deletion operation for the PCE-initiated PCECC LSP is the same as defined
    in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>. The PCE should further
    perform the label entry cleanup operation, as described in
   <a href="#SEC_CLEANUP" class="xref">Section 5.5.3.2</a>, for the corresponding LSP.<a href="#section-5.5.1-6" class="pilcrow">¶</a></p>
<span id="name-pce-initiated-pcecc-lsp-2"></span><div id="SEC_FIG4">
<figure id="figure-1">
            <div class="artwork art-text alignLeft" id="section-5.5.1-7.1">
<pre>
              +-------+                              +-------+
              |PCC    |                              |  PCE  |
              |ingress|                              +-------+
       +------|       |                                  |
       | PCC  +-------+                                  |
       | transit| |                                      |
+------|        | |&lt;--PCInitiate,PLSP-ID=0,PST=2---------| PCECC LSP
|PCC   +--------+ |                                      | Initiate
|egress  |  |     |----PCRpt,PLSP-ID=2,D=1,C=1----------&gt;| PCECC LSP
+--------+  |     |       (GOING-UP)                     |
    |       |     |                                      |
    |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=2----------------| Label
    |       |     |                                      | download
    |--------PCRpt,CC-ID=X,PLSP-ID=2--------------------&gt;| CCI
    |       |     |                                      |
    |       |&lt;------PCInitiate,CC-ID=Y1,Y2,PLSP-ID=2-----| Label
    |       |     |                                      | download
    |       |-------PCRpt,CC-ID=Y1,Y2,PLSP-ID=2---------&gt;| CCI
    |       |     |                                      |
    |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=2-----| Label
    |       |     |                                      | download
    |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=2---------&gt;| CCI
    |       |     |                                      |
    |       |     |&lt;---PCUpd,PLSP-ID=2,PST=2,D=1---------| PCECC LSP
    |       |     |      (UP)                            | Update
    |       |     |----PCRpt,PLSP-ID=2,D=1,C=1----------&gt;|
    |       |     |      (UP)                            |
</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-pce-initiated-pcecc-lsp-2" class="selfRef">PCE-Initiated PCECC LSP</a>
            </figcaption></figure>
</div>
<p id="section-5.5.1-8">Once the label operations are completed, the PCE <span class="bcp14">MUST</span> send a PCUpd message to the
    ingress PCC. As per <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, the PCUpd message is with the D flag set.<a href="#section-5.5.1-8" class="pilcrow">¶</a></p>
<p id="section-5.5.1-9">The PCECC LSPs are considered to be 'up' by default (on receipt of a PCUpd message from the PCE).
        The ingress could further choose to deploy a data-plane check
        mechanism and report the status back to the PCE via a PCRpt message to make sure that the correct label instructions are made along the path of the PCECC LSP (and it is ready to carry traffic). The exact mechanism is out of scope of this document.<a href="#section-5.5.1-9" class="pilcrow">¶</a></p>
<p id="section-5.5.1-10">In the case where the label allocations are made by the PCC itself (see <a href="#PCC" class="xref">Section 5.5.8</a>), the PCE could request an allocation to be made by the PCC; then, the PCC would send a PCRpt message with the allocated label encoded in  
     the CC-ID object (as shown in <a href="#SEC_FIG4b" class="xref">Figure 2</a>) in the configuration sequence from the egress towards the ingress along the path.<a href="#section-5.5.1-10" class="pilcrow">¶</a></p>
<span id="name-pce-initiated-pcecc-lsp-pcc"></span><div id="SEC_FIG4b">
<figure id="figure-2">
            <div class="artwork art-text alignLeft" id="section-5.5.1-11.1">
<pre>
              +-------+                              +-------+
              |PCC    |                              |  PCE  |
              |ingress|                              +-------+
       +------|       |                                  |
       | PCC  +-------+                                  |
       | transit| |                                      |
+------|        | |&lt;--PCInitiate,PLSP-ID=0,PST=2,--------| PCECC LSP
|PCC   +--------+ |                                      | Initiate
|egress  |  |     |----PCRpt,PLSP-ID=2,D=1,C=1----------&gt;| PCECC LSP
+--------+  |     |       (GOING-UP)                     |
    |       |     |                                      |
    |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=2----------------| Label
    |       |     |     C=1,O=0                          | download
    |--------PCRpt,CC-ID=X,PLSP-ID=2--------------------&gt;| CCI
    |       |     |     Label=L1                         |
    |       |&lt;------PCInitiate,PLSP-ID=2,----------------| Labels
    |       |     |            CC-ID=Y1,C=1,O=0          | download
    |       |     |            CC-ID=Y2,C=0,O=1,L1       | CCI
    |       |-------PCRpt,PLSP-ID=2---------------------&gt;|
    |       |     |       CC-ID=Y1,O=0,Label=L2          |
    |       |     |       CC-ID=Y2,O=1                   |
    |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=2-----| Label
    |       |     |                C=0,O=1,L2            | download
    |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=2---------&gt;| CCI
    |       |     |                                      |
    |       |     |&lt;---PCUpd,PLSP-ID=2,PST=2,D=1---------| PCECC LSP
    |       |     |      (UP)                            | Update
</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-pce-initiated-pcecc-lsp-pcc" class="selfRef">PCE-Initiated PCECC LSP (PCC Allocation)</a>
            </figcaption></figure>
</div>
<p id="section-5.5.1-12">In this example, it should be noted that the request is made to the  
     egress node with the C bit set in the CCI object to indicate that the  
     label allocation needs to be done by the egress, and the egress responds with the 
     allocated label to the PCE.  The PCE further informs the  
     transit PCC without setting the C bit to '1' in the CCI object for the out-label, but the C bit is set to '1' for the in-label, so the transit node makes the label allocation (for the in-label) and reports to the PCE. Similarly, the C bit is unset towards the ingress to complete all the label allocations for the PCECC LSP.<a href="#section-5.5.1-12" class="pilcrow">¶</a></p>
</section>
</div>
<div id="SEC_BASIC_SETUP">
<section id="section-5.5.2">
          <h4 id="name-pcc-initiated-pcecc-lsp">
<a href="#section-5.5.2" class="section-number selfRef">5.5.2. </a><a href="#name-pcc-initiated-pcecc-lsp" class="section-name selfRef">PCC-Initiated PCECC LSP</a>
          </h4>
<p id="section-5.5.2-1">In order to set up an LSP based on the PCECC mechanism where the LSP is configured at the PCC, a PCC <span class="bcp14">MUST</span> delegate the LSP by
    sending a PCRpt message with the PST set for the PCECC (see <a href="#SEC_PATH" class="xref">Section 7.2</a>) and D (Delegate)
    flag (see <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>) set in the LSP object (see <a href="#SEC_FIG2" class="xref">Figure 3</a>).<a href="#section-5.5.2-1" class="pilcrow">¶</a></p>
<p id="section-5.5.2-2">When a PCE receives the initial PCRpt message with the D flag and PST set to '2', it <span class="bcp14">SHOULD</span> calculate the path and assign labels along the path in addition to setting up the path by sending a PCInitiate message to each node along the path of the LSP, as per the PCECC technique (see <a href="#SEC_FIG2" class="xref">Figure 3</a>). The CC-ID uniquely identifies the CCI within a PCEP session. Each PCC further responds with the PCRpt messages, including the CCI and LSP objects.<a href="#section-5.5.2-2" class="pilcrow">¶</a></p>
<p id="section-5.5.2-3">Once the CCI (label operations) are completed, the PCE <span class="bcp14">MUST</span> send the PCUpd message to the
    ingress PCC. As per <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, this PCUpd message should include the path information calculated by the PCE.<a href="#section-5.5.2-3" class="pilcrow">¶</a></p>
<p id="section-5.5.2-4">Note that the PCECC LSPs <span class="bcp14">MUST</span> be delegated to a PCE at all times.<a href="#section-5.5.2-4" class="pilcrow">¶</a></p>
<p id="section-5.5.2-5">The LSP deletion operation for the PCECC LSPs
    is the same as defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>. If the PCE receives
    a PCRpt message for LSP deletion, then it does label the cleanup operation, as
    described in <a href="#SEC_CLEANUP" class="xref">Section 5.5.3.2</a>, for the corresponding LSP.<a href="#section-5.5.2-5" class="pilcrow">¶</a></p>
<p id="section-5.5.2-6">The basic PCECC LSP setup sequence is as shown in <a href="#SEC_FIG2" class="xref">Figure 3</a>.<a href="#section-5.5.2-6" class="pilcrow">¶</a></p>
<span id="name-pcc-initiated-pcecc-lsp-2"></span><div id="SEC_FIG2">
<figure id="figure-3">
            <div class="artwork art-text alignLeft" id="section-5.5.2-7.1">
<pre>
               +-------+                             +-------+
               |PCC    |                             |  PCE  |
               |ingress|                             +-------+
        +------|       |                                 |
        | PCC  +-------+                                 |
        | transit| |                                     |
 +------|        | |---PCRpt,PLSP-ID=1,PST=2,D=1--------&gt;| PCECC LSP
 |PCC   +--------+ |                                     |
 |egress  |  |     |                                     |
 +--------+  |     |                                     |
     |       |     |                                     |
     |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=1---------------| Label
     |       |     |     L1,O=0                          | download
     |--------PCRpt,CC-ID=X,PLSP-ID=1-------------------&gt;| CCI
     |       |     |                                     |
     |       |&lt;------PCInitiate,PLSP-ID=1,---------------| Labels
     |       |     |            CC-ID=Y1,O=0,L2          | download
     |       |     |            CC-ID=Y2,O=1,L1          | CCI
     |       |-------PCRpt,CC-ID=Y1,Y2,PLSP-ID=1--------&gt;|
     |       |     |                                     |
     |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=1----| Label
     |       |     |                L2,O=1               | download
     |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=1--------&gt;| CCI
     |       |     |                                     |
     |       |     |&lt;---PCUpd,PLSP-ID=1,PST=2,D=1--------| PCECC LSP
     |       |     |                                     | Update
     |       |     |                                     |
</pre>
</div>
<figcaption><a href="#figure-3" class="selfRef">Figure 3</a>:
<a href="#name-pcc-initiated-pcecc-lsp-2" class="selfRef">PCC-Initiated PCECC LSP</a>
            </figcaption></figure>
</div>
<p id="section-5.5.2-8">In the case where the label allocations are made by the PCC itself (see <a href="#PCC" class="xref">Section 5.5.8</a>), the PCE could request an allocation to be made by the PCC; then, 
     the PCC would send a PCRpt message with the allocated label encoded in 
     the CC-ID object, as shown in <a href="#SEC_FIG2b" class="xref">Figure 4</a>.<a href="#section-5.5.2-8" class="pilcrow">¶</a></p>
<span id="name-pcc-initiated-pcecc-lsp-pcc"></span><div id="SEC_FIG2b">
<figure id="figure-4">
            <div class="artwork art-text alignLeft" id="section-5.5.2-9.1">
<pre>
               +-------+                             +-------+
               |PCC    |                             |  PCE  |
               |ingress|                             +-------+
        +------|       |                                 |
        | PCC  +-------+                                 |
        | transit| |                                     |
 +------|        | |---PCRpt,PLSP-ID=1,PST=2,D=1--------&gt;| PCECC LSP
 |PCC   +--------+ |                                     |
 |egress  |  |     |                                     |
 +--------+  |     |                                     |
     |       |     |                                     |
     |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=1---------------| Label
     |       |     |     C=1                             | download
     |--------PCRpt,CC-ID=X,PLSP-ID=1-------------------&gt;| CCI
     |       |     |     Label=L1                        |
     |       |&lt;------PCInitiate,PLSP-ID=1,---------------| Labels
     |       |     |            CC-ID=Y1,C=1             | download
     |       |     |            CC-ID=Y2,C=0,L1          | CCI
     |       |-------PCRpt,PLSP-ID=1--------------------&gt;|
     |       |     |       CC-ID=Y1,Label=L2             |
     |       |     |       CC-ID=Y2                      |
     |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=1----| Label
     |       |     |                C=0,L2               | download
     |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=1--------&gt;| CCI
     |       |     |                                     |
     |       |     |&lt;---PCUpd,PLSP-ID=1,PST=2,D=1--------| PCECC LSP
     |       |     |                                     | Update
     |       |     |                                     |
</pre>
</div>
<figcaption><a href="#figure-4" class="selfRef">Figure 4</a>:
<a href="#name-pcc-initiated-pcecc-lsp-pcc" class="selfRef">PCC-Initiated PCECC LSP (PCC Allocation)</a>
            </figcaption></figure>
</div>
<aside id="section-5.5.2-10">
            <p id="section-5.5.2-10.1">Note:<a href="#section-5.5.2-10.1" class="pilcrow">¶</a></p>
<p id="section-5.5.2-10.2">The O bit is set as before (and thus not included).<a href="#section-5.5.2-10.2" class="pilcrow">¶</a></p>
</aside>
<p id="section-5.5.2-11">In the case where the label allocations are made by the PCC itself (see <a href="#PCC" class="xref">Section 5.5.8</a>), the procedure remains the same, with just an additional
 constraint on the configuration sequence.<a href="#section-5.5.2-11" class="pilcrow">¶</a></p>
<p id="section-5.5.2-12">The rest of the PCC-initiated PCECC LSP setup operations are the same as those described in <a href="#PCE-I" class="xref">Section 5.5.1</a>.<a href="#section-5.5.2-12" class="pilcrow">¶</a></p>
</section>
</div>
<div id="CCI">
<section id="section-5.5.3">
          <h4 id="name-central-controller-instruct">
<a href="#section-5.5.3" class="section-number selfRef">5.5.3. </a><a href="#name-central-controller-instruct" class="section-name selfRef">Central Controller Instructions</a>
          </h4>
<p id="section-5.5.3-1">The new CCI for the label operations in PCEP are done via the PCInitiate message (<a href="#SEC_PCInitiate" class="xref">Section 6.1</a>) by
   defining a new PCEP object for CCI operations. The local label range of
   each PCC is assumed to be known by both the PCC and the PCE.<a href="#section-5.5.3-1" class="pilcrow">¶</a></p>
<div id="LabelDownloadCCI">
<section id="section-5.5.3.1">
            <h5 id="name-label-download-cci">
<a href="#section-5.5.3.1" class="section-number selfRef">5.5.3.1. </a><a href="#name-label-download-cci" class="section-name selfRef">Label Download CCI</a>
            </h5>
<p id="section-5.5.3.1-1">In order to set up an LSP based on the PCECC, the PCE sends a PCInitiate message
    to each node along the path to download the label instructions, as described in Sections <a href="#PCE-I" class="xref">5.5.1</a> and 
    <a href="#SEC_BASIC_SETUP" class="xref">5.5.2</a>.<a href="#section-5.5.3.1-1" class="pilcrow">¶</a></p>
<p id="section-5.5.3.1-2">The CCI object <span class="bcp14">MUST</span> be included, along with the LSP object in the PCInitiate message. The LSP-IDENTIFIERS TLV <span class="bcp14">MUST</span> be included in the LSP object. The SPEAKER-ENTITY-ID TLV
<span class="bcp14">SHOULD</span> be included in the LSP object.<a href="#section-5.5.3.1-2" class="pilcrow">¶</a></p>
<p id="section-5.5.3.1-3">If a node (PCC) receives a PCInitiate message that includes a label to download (as part of CCI) that is out
     of the range set aside for the PCE, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31
   (PCECC failure) and Error-value=1 (Label out of range) and <span class="bcp14">MUST</span> include the
   SRP object to specify the error is for the corresponding label update via a PCInitiate message.
    If a PCC receives a PCInitiate message but fails to download
   the label entry, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31
   (PCECC failure) and Error-value=2 (Instruction failed) and <span class="bcp14">MUST</span> include the
   SRP object to specify the error is for the corresponding label update via a PCInitiate message.<a href="#section-5.5.3.1-3" class="pilcrow">¶</a></p>
<p id="section-5.5.3.1-4">A new PCEP object for CCI is defined in <a href="#SEC_CCI" class="xref">Section 7.3</a>.<a href="#section-5.5.3.1-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="SEC_CLEANUP">
<section id="section-5.5.3.2">
            <h5 id="name-label-cleanup-cci">
<a href="#section-5.5.3.2" class="section-number selfRef">5.5.3.2. </a><a href="#name-label-cleanup-cci" class="section-name selfRef">Label Cleanup CCI</a>
            </h5>
<p id="section-5.5.3.2-1">In order to delete an LSP based on the PCECC, the PCE sends Central Controller Instructions via a PCInitiate
    message to each node along the path of the LSP to clean up the label-forwarding instruction.<a href="#section-5.5.3.2-1" class="pilcrow">¶</a></p>
<p id="section-5.5.3.2-2">If the PCC receives a PCInitiate message but does not recognize the
   label in the CCI, the PCC <span class="bcp14">MUST</span> generate a PCErr message with Error-Type=19 (Invalid operation) and Error-value=18 (Unknown Label) and 
   <span class="bcp14">MUST</span> include the SRP object to specify the error is for the
   corresponding label cleanup (via a PCInitiate message).<a href="#section-5.5.3.2-2" class="pilcrow">¶</a></p>
<p id="section-5.5.3.2-3">The R flag in the SRP object defined in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> specifies
    the deletion of the label entry in the PCInitiate message.<a href="#section-5.5.3.2-3" class="pilcrow">¶</a></p>
<span id="name-label-cleanup"></span><div id="SEC_FIG3">
<figure id="figure-5">
              <div class="artwork art-text alignLeft" id="section-5.5.3.2-4.1">
<pre>
               +-------+                              +-------+
               |PCC    |                              |  PCE  |
               |ingress|                              +-------+
        +------|       |                                  |
        | PCC  +-------+                                  |
        | transit| |                                      |
 +------|        | |                                      |
 |PCC   +--------+ |                                      |
 |egress  |  |     |                                      |
 +--------+  |     |                                      |
     |       |     |                                      |
     |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=2----------------| Label
     |       |     |                   R=1                | cleanup
     |--------PCRpt,CC-ID=X,PLSP-ID=2--------------------&gt;| CCI
     |       |     |              R=1                     |
     |       |&lt;------PCInitiate,CC-ID=Y1,Y2,PLSP-ID=2-----| Label
     |       |     |                          R=1         | cleanup
     |       |-------PCRpt,CC-ID=Y1,Y2,PLSP-ID=2---------&gt;| CCI
     |       |     |                         R=1          |
     |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=2-----| Label
     |       |     |                              R=1     | cleanup
     |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=2---------&gt;| CCI
     |       |     |                         R=1          |
     |       |     |&lt;--PCInitiate,PLSP-ID=2,PST=2,R=1-----| PCECC LSP
     |       |     |                                      | remove
</pre>
</div>
<figcaption><a href="#figure-5" class="selfRef">Figure 5</a>:
<a href="#name-label-cleanup" class="selfRef">Label Cleanup</a>
              </figcaption></figure>
</div>
<p id="section-5.5.3.2-5">As per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>, following the removal of the label-forwarding instruction, the PCC <span class="bcp14">MUST</span> send a PCRpt message. 
        The SRP object in the PCRpt message <span class="bcp14">MUST</span> include the
   SRP-ID-number from the PCInitiate message that triggered the removal.
   The R flag in the SRP object <span class="bcp14">MUST</span> be set.<a href="#section-5.5.3.2-5" class="pilcrow">¶</a></p>
<p id="section-5.5.3.2-6">In the case where the label allocation is made by the PCC itself (see <a href="#PCC" class="xref">Section 5.5.8</a>), the removal procedure remains the same, adding the sequence constraint.<a href="#section-5.5.3.2-6" class="pilcrow">¶</a></p>
</section>
</div>
</section>
</div>
<section id="section-5.5.4">
          <h4 id="name-pcecc-lsp-update">
<a href="#section-5.5.4" class="section-number selfRef">5.5.4. </a><a href="#name-pcecc-lsp-update" class="section-name selfRef">PCECC LSP Update</a>
          </h4>
<p id="section-5.5.4-1">The update is done as per the make-before-break procedures, i.e., the PCECC first updates new label instructions based on the updated path and then informs the ingress to switch traffic before cleaning up the former instructions. New CC-IDs are used to identify the updated instructions; the identifiers in the LSP object uniquely identify the existing LSP. Once new instructions are downloaded, the PCE further updates the new path at the ingress, which triggers the traffic switch on the updated path. The ingress PCC acknowledges with a PCRpt message, on receipt of the PCRpt message, the PCE does the cleanup operation for the former LSP, as described in <a href="#SEC_CLEANUP" class="xref">Section 5.5.3.2</a>.<a href="#section-5.5.4-1" class="pilcrow">¶</a></p>
<span id="name-pcecc-lsp-update-2"></span><div id="SEC_FIG5">
<figure id="figure-6">
            <div class="artwork art-text alignLeft" id="section-5.5.4-2.1">
<pre>
              +-------+                             +-------+
              |PCC    |                             |  PCE  |
              |ingress|                             +-------+
       +------|       |                                 |
       | PCC  +-------+                                 |
       | transit| |                                     |
+------|        | |                                     |
|PCC   +--------+ |                                     |
|egress  |  |     |                                     |
+--------+  |     |                                     |
    |       |     |                                     | New Path
    |&lt;------ PCInitiate,CC-ID=XX,PLSP-ID=1 -------------| for LSP
    |       |     |                                     | trigger
    |--------PCRpt,CC-ID=XX,PLSP-ID=1------------------&gt;| new CCI
    |       |     |                                     |
    |       |&lt;------PCInitiate,CC-ID=YY1,YY2,PLSP-ID=1--| Label
    |       |     |                                     | download
    |       |-------PCRpt,CC-ID=YY1,YY2,PLSP-ID=1------&gt;| CCI
    |       |     |                                     |
    |       |     |&lt;----PCInitiate,CC-ID=ZZ,PLSP-ID=1---| Label
    |       |     |                                     | download
    |       |     |-----PCRpt,CC-ID=ZZ,PLSP-ID=1-------&gt;| CCI
    |       |     |                                     |
    |       |     |&lt;---PCUpd,PLSP-ID=1,PST=2,D=1--------| PCECC
    |       |     |    SRP=S                            | LSP Update
    |       |     |                                     |
    |       |     |---PCRpt,PLSP-ID=1,PST=2,D=1--------&gt;| Trigger
    |       |     |       (SRP=S)                       | Delete
    |       |     |                                     | former CCI
    |       |     |                                     |
    |&lt;-------PCInitiate,CC-ID=X,PLSP-ID=1---------------| Label
    |       |     |                   R=1               | cleanup
    |--------PCRpt,CC-ID=X,PLSP-ID=1-------------------&gt;| CCI
    |       |     |              R=1                    |
    |       |&lt;------PCInitiate,CC-ID=Y1,Y2,PLSP-ID=1----| Label
    |       |     |                              R=1    | cleanup
    |       |-------PCRpt,CC-ID=Y1,Y2,PLSP-ID=1--------&gt;| CCI
    |       |     |                         R=1         |
    |       |     |&lt;----PCInitiate,CC-ID=Z,PLSP-ID=1----| Label
    |       |     |                              R=1    | cleanup
    |       |     |-----PCRpt,CC-ID=Z,PLSP-ID=1--------&gt;| CCI
    |       |     |                         R=1         |
</pre>
</div>
<figcaption><a href="#figure-6" class="selfRef">Figure 6</a>:
<a href="#name-pcecc-lsp-update-2" class="selfRef">PCECC LSP Update</a>
            </figcaption></figure>
</div>
<p id="section-5.5.4-3">The modified PCECC LSPs are considered to be 'up' by default.
        The ingress could further choose to deploy a data-plane check
        mechanism and report the status back to the PCE via a PCRpt message. The exact mechanism is out of scope of this document.<a href="#section-5.5.4-3" class="pilcrow">¶</a></p>
<p id="section-5.5.4-4">In the case where the label allocations are made by the PCC itself (see <a href="#PCC" class="xref">Section 5.5.8</a>), the procedure remains the same.<a href="#section-5.5.4-4" class="pilcrow">¶</a></p>
</section>
<section id="section-5.5.5">
          <h4 id="name-re-delegation-and-cleanup">
<a href="#section-5.5.5" class="section-number selfRef">5.5.5. </a><a href="#name-re-delegation-and-cleanup" class="section-name selfRef">Re-delegation and Cleanup</a>
          </h4>
<p id="section-5.5.5-1">As described in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>, a new PCE can gain control over an orphaned LSP. In the case of a PCECC LSP, the new PCE <span class="bcp14">MUST</span> also gain control over the CCI in the same way by sending a PCInitiate
   message that includes the SRP, LSP, and CCI objects and carries the
   CC-ID and PLSP-ID identifying the instructions that it wants to take control of.<a href="#section-5.5.5-1" class="pilcrow">¶</a></p>
<p id="section-5.5.5-2">Further, as described in <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>, the State Timeout Interval timer ensures that a PCE crash does not
   result in automatic and immediate disruption for the services using
   PCE-initiated LSPs. Similarly the Central Controller Instructions are not removed immediately
   upon PCE failure.  Instead, they are cleaned up on the expiration of
   this timer. This allows for network cleanup without manual
   intervention. The PCC <span class="bcp14">MUST</span> support the removal of CCI as
   one of the behaviors applied on expiration of the State Timeout
   Interval timer.<a href="#section-5.5.5-2" class="pilcrow">¶</a></p>
<p id="section-5.5.5-3">In the case of the PCC-initiated PCECC LSP, the control over the orphaned LSP at the ingress PCC is taken over by the mechanism specified in <span>[<a href="#RFC8741" class="xref">RFC8741</a>]</span> to request delegation. The control over the CCI is described above using <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-5.5.5-3" class="pilcrow">¶</a></p>
</section>
<div id="sec_label_db_sync">
<section id="section-5.5.6">
          <h4 id="name-synchronization-of-central-">
<a href="#section-5.5.6" class="section-number selfRef">5.5.6. </a><a href="#name-synchronization-of-central-" class="section-name selfRef">Synchronization of Central Controller Instructions</a>
          </h4>
<p id="section-5.5.6-1">The purpose of CCI synchronization (labels in the context of this document) is to make sure that the
   PCE's view of CCI (labels) matches with the PCC's label allocation. 
   This synchronization is performed as part of the LSP State Synchronization,
   as described in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> and 
   <span>[<a href="#RFC8232" class="xref">RFC8232</a>]</span>.<a href="#section-5.5.6-1" class="pilcrow">¶</a></p>
<p id="section-5.5.6-2">As per LSP State Synchronization <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, a PCC reports the state of
   its LSPs to the PCE using PCRpt messages and, as per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>, the PCE would 
   initiate any missing LSPs and/or remove any LSPs that are not wanted. The same PCEP messages and procedures are 
   also used for the CCI synchronization. The PCRpt message includes the CCI and the LSP object to report the label-forwarding instructions. The PCE would further 
   remove any unwanted instructions or initiate any missing instructions.<a href="#section-5.5.6-2" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-5.5.7">
          <h4 id="name-pcecc-lsp-state-report">
<a href="#section-5.5.7" class="section-number selfRef">5.5.7. </a><a href="#name-pcecc-lsp-state-report" class="section-name selfRef">PCECC LSP State Report</a>
          </h4>
<p id="section-5.5.7-1">As mentioned before, an ingress PCC <span class="bcp14">MAY</span> choose to apply any Operations, Administration, and Maintenance (OAM) mechanism to check the status
    of the LSP in the data plane and <span class="bcp14">MAY</span> further send its status in a PCRpt message to the PCE.<a href="#section-5.5.7-1" class="pilcrow">¶</a></p>
</section>
<div id="PCC">
<section id="section-5.5.8">
          <h4 id="name-pcc-based-allocations">
<a href="#section-5.5.8" class="section-number selfRef">5.5.8. </a><a href="#name-pcc-based-allocations" class="section-name selfRef">PCC-Based Allocations</a>
          </h4>
<p id="section-5.5.8-1">
             The PCE can request the PCC to allocate the label using the 
     PCInitiate message.  The C flag in the  
     CCI object is set to '1' to indicate that the allocation needs to be made by the PCC.  
     The PCC <span class="bcp14">MUST</span> try to allocate the label and <span class="bcp14">MUST</span> report to the PCE via a PCRpt or PCErr message.<a href="#section-5.5.8-1" class="pilcrow">¶</a></p>
<p id="section-5.5.8-2">If the value of the label is 0 and the C flag is set to '1', it  
     indicates that the PCE is requesting the allocation to be made by the PCC.  If the 
     label is 'n' and the C flag is set to '1' in the CCI object, it 
     indicates that the PCE requests a specific value 'n' for the label. 
     If  
     the allocation is successful, the PCC <span class="bcp14">MUST</span> report  
     via the PCRpt message with the CCI object.  If the value of the label in the CCI object is invalid, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31 (PCECC failure) and Error-value=3 (Invalid CCI).  If  
     it is valid but the PCC is unable to  
     allocate it, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31 (PCECC failure) and Error-value=4 (Unable to 
     allocate the specified CCI).<a href="#section-5.5.8-2" class="pilcrow">¶</a></p>
<p id="section-5.5.8-3">If the PCC wishes to withdraw or modify the previously assigned label, it <span class="bcp14">MUST</span> send a PCRpt message without any label
     or with the label containing the new value, respectively, in 
     the CCI object.  The PCE would further trigger the label cleanup of the older label, as per <a href="#SEC_CLEANUP" class="xref">Section 5.5.3.2</a>.<a href="#section-5.5.8-3" class="pilcrow">¶</a></p>
</section>
</div>
</section>
</section>
</div>
<section id="section-6">
      <h2 id="name-pcep-messages">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-pcep-messages" class="section-name selfRef">PCEP Messages</a>
      </h2>
<p id="section-6-1">As defined in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>, a PCEP message consists of a common header
   followed by a variable-length body made of a set of objects that can
   be either mandatory or optional.  An object is said to be mandatory
   in a PCEP message when the object must be included for the message to
   be considered valid.  For each PCEP message type, a set of rules is
   defined, which specifies the set of objects that the message can carry.
   An implementation <span class="bcp14">MUST</span> form the PCEP messages using the object
   ordering specified in this document.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">The LSP-IDENTIFIERS TLV <span class="bcp14">MUST</span> be included in the LSP object for the PCECC
   LSP.<a href="#section-6-2" class="pilcrow">¶</a></p>
<p id="section-6-3">The message formats in this document are specified using Routing
   Backus-Naur Form (RBNF) encoding, as specified in <span>[<a href="#RFC5511" class="xref">RFC5511</a>]</span>.<a href="#section-6-3" class="pilcrow">¶</a></p>
<div id="SEC_PCInitiate">
<section id="section-6.1">
        <h3 id="name-the-pcinitiate-message">
<a href="#section-6.1" class="section-number selfRef">6.1. </a><a href="#name-the-pcinitiate-message" class="section-name selfRef">The PCInitiate Message</a>
        </h3>
<p id="section-6.1-1">The PCInitiate message <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> can be used to download or remove the labels; this document extends the message, as shown below.<a href="#section-6.1-1" class="pilcrow">¶</a></p>
<div id="section-6.1-2">
<pre class="sourcecode">
     &lt;PCInitiate Message&gt; ::= &lt;Common Header&gt;
                              &lt;PCE-initiated-lsp-list&gt;
</pre><a href="#section-6.1-2" class="pilcrow">¶</a>
</div>
<p id="section-6.1-3">Where:<a href="#section-6.1-3" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-6.1-4.1">&lt;Common Header&gt; is defined in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.<a href="#section-6.1-4.1" class="pilcrow">¶</a>
</li>
        </ul>
<div id="section-6.1-5">
<pre class="sourcecode">
     &lt;PCE-initiated-lsp-list&gt; ::= &lt;PCE-initiated-lsp-request&gt;
                                  [&lt;PCE-initiated-lsp-list&gt;]

     &lt;PCE-initiated-lsp-request&gt; ::=
                            (&lt;PCE-initiated-lsp-instantiation&gt;|
                             &lt;PCE-initiated-lsp-deletion&gt;|
                             &lt;PCE-initiated-lsp-central-control&gt;)

     &lt;PCE-initiated-lsp-central-control&gt; ::= &lt;SRP&gt;
                                             &lt;LSP&gt;
                                             &lt;cci-list&gt;

     &lt;cci-list&gt; ::=  &lt;CCI&gt;
                     [&lt;cci-list&gt;]
</pre><a href="#section-6.1-5" class="pilcrow">¶</a>
</div>
<p id="section-6.1-6">Where:<a href="#section-6.1-6" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-6.1-7.1">&lt;PCE-initiated-lsp-instantiation&gt; and 
     &lt;PCE-initiated-lsp-deletion&gt; are as per 
      <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-6.1-7.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-6.1-7.2">The LSP and SRP object is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.<a href="#section-6.1-7.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-6.1-8">When a PCInitiate message is used for the CCI (labels), the SRP, LSP, and CCI objects <span class="bcp14">MUST</span> be present. 
        The SRP object is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>; if the SRP object is missing, the receiving PCC <span class="bcp14">MUST</span> send
    a PCErr message with Error-Type=6 (Mandatory Object missing) and
    Error-value=10 (SRP object missing). The LSP object is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, and if the LSP object is missing, the receiving PCC <span class="bcp14">MUST</span> send
    a PCErr message with Error-Type=6 (Mandatory Object missing) and
    Error-value=8 (LSP object missing). The CCI object is defined in <a href="#SEC_CCI" class="xref">Section 7.3</a>, and if the CCI object is
    missing, the receiving PCC <span class="bcp14">MUST</span> send a PCErr message with Error-Type=6
    (Mandatory Object missing) and Error-value=17 (CCI object missing).
    More than one CCI object <span class="bcp14">MAY</span> be included in the PCInitiate message
    for a transit LSR.<a href="#section-6.1-8" class="pilcrow">¶</a></p>
<p id="section-6.1-9">To clean up entries, the R (remove) bit <span class="bcp14">MUST</span> be set in the SRP object to be encoded along with the LSP and CCI objects.<a href="#section-6.1-9" class="pilcrow">¶</a></p>
<p id="section-6.1-10">The CCI object received at the ingress node <span class="bcp14">MUST</span> have the O bit (out-label) set. The CCI object received at the egress <span class="bcp14">MUST</span> have the O bit unset. If this is not the case, the PCC <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31 (PCECC failure) and Error-value=3 (Invalid CCI). Other instances of the CCI object, if present, <span class="bcp14">MUST</span> be ignored.<a href="#section-6.1-10" class="pilcrow">¶</a></p>
<p id="section-6.1-11">For the point-to-point (P2P) LSP setup via the PCECC technique, at the transit LSR, two CCI objects are expected for incoming and outgoing labels associated with the LSP object. If any other CCI object is included in the PCInitiate message, it <span class="bcp14">MUST</span> be ignored. If the transit LSR did not receive two CCI objects, with one of them having the O bit set and another with the O bit unset, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31 (PCECC failure) and Error-value=3 (Invalid CCI).<a href="#section-6.1-11" class="pilcrow">¶</a></p>
<p id="section-6.1-12">Note that, on receipt of the PCInitiate message with CCI object, the ingress, egress, or transit role of the PCC is identified via the ingress and egress IP address encoded in the LSP-IDENTIFIERS TLV.<a href="#section-6.1-12" class="pilcrow">¶</a></p>
</section>
</div>
<div id="SEC_PCRpt">
<section id="section-6.2">
        <h3 id="name-the-pcrpt-message">
<a href="#section-6.2" class="section-number selfRef">6.2. </a><a href="#name-the-pcrpt-message" class="section-name selfRef">The PCRpt Message</a>
        </h3>
<p id="section-6.2-1">The PCRpt message can be used to report the labels that were allocated by the PCE to be used during the State Synchronization phase or as an acknowledgment to a PCInitiate message.<a href="#section-6.2-1" class="pilcrow">¶</a></p>
<div id="section-6.2-2">
<pre class="sourcecode">
      &lt;PCRpt Message&gt; ::= &lt;Common Header&gt;
                          &lt;state-report-list&gt;
</pre><a href="#section-6.2-2" class="pilcrow">¶</a>
</div>
<p id="section-6.2-3">Where:<a href="#section-6.2-3" class="pilcrow">¶</a></p>
<div id="section-6.2-4">
<pre class="sourcecode">
      &lt;state-report-list&gt; ::= &lt;state-report&gt;[&lt;state-report-list&gt;]

      &lt;state-report&gt; ::= (&lt;lsp-state-report&gt;|
                          &lt;central-control-report&gt;)

      &lt;lsp-state-report&gt; ::= [&lt;SRP&gt;]
                             &lt;LSP&gt;
                             &lt;path&gt;

      &lt;central-control-report&gt; ::= [&lt;SRP&gt;]
                                   &lt;LSP&gt;
                                   &lt;cci-list&gt;

      &lt;cci-list&gt; ::=  &lt;CCI&gt;
                      [&lt;cci-list&gt;]
</pre><a href="#section-6.2-4" class="pilcrow">¶</a>
</div>
<p id="section-6.2-5">Where:<a href="#section-6.2-5" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-6.2-6.1">&lt;path&gt; is as per <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, and the LSP and SRP objects are 
      also defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.<a href="#section-6.2-6.1" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-6.2-7">When a PCRpt message is used to report the CCI (labels), the LSP and CCI objects <span class="bcp14">MUST</span> be present. 
        The LSP object is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, and if the LSP object is missing, the receiving PCE <span class="bcp14">MUST</span> send
    a PCErr message with Error-Type=6 (Mandatory Object missing) and
    Error-value=8 (LSP object missing). The CCI object is defined in <a href="#SEC_CCI" class="xref">Section 7.3</a>, and if the CCI object is
    missing, the receiving PCE <span class="bcp14">MUST</span> send a PCErr message with Error-Type=6
    (Mandatory Object missing) and Error-value=17 (CCI object missing).
    Two CCI objects can be included in the PCRpt message
    for a transit LSR.<a href="#section-6.2-7" class="pilcrow">¶</a></p>
</section>
</div>
</section>
<section id="section-7">
      <h2 id="name-pcep-objects">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-pcep-objects" class="section-name selfRef">PCEP Objects</a>
      </h2>
<p id="section-7-1">The PCEP objects defined in this document are compliant with the PCEP object
    format defined in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.<a href="#section-7-1" class="pilcrow">¶</a></p>
<section id="section-7.1">
        <h3 id="name-open-object">
<a href="#section-7.1" class="section-number selfRef">7.1. </a><a href="#name-open-object" class="section-name selfRef">OPEN Object</a>
        </h3>
<p id="section-7.1-1">This document defines a new PST (2) to be included in the PATH-SETUP-TYPE-CAPABILITY TLV in the OPEN object. Further, a new sub-TLV for the PCECC capability exchange is also defined.<a href="#section-7.1-1" class="pilcrow">¶</a></p>
<div id="SEC_PCECC_CAP_TLV">
<section id="section-7.1.1">
          <h4 id="name-pcecc-capability-sub-tlv">
<a href="#section-7.1.1" class="section-number selfRef">7.1.1. </a><a href="#name-pcecc-capability-sub-tlv" class="section-name selfRef">PCECC Capability Sub-TLV</a>
          </h4>
<p id="section-7.1.1-1">The PCECC-CAPABILITY sub-TLV is an optional TLV for use in the OPEN object in the PATH-SETUP-TYPE-CAPABILITY TLV when the Path Setup Type list includes the PCECC Path Setup Type 2. A PCECC-CAPABILITY sub-TLV <span class="bcp14">MUST</span> be ignored if the PST list does not contain PST=2.<a href="#section-7.1.1-1" class="pilcrow">¶</a></p>
<p id="section-7.1.1-2">Its format is shown in <a href="#SEC_FIG8" class="xref">Figure 7</a>.<a href="#section-7.1.1-2" class="pilcrow">¶</a></p>
<span id="name-pcecc-capability-sub-tlv-2"></span><div id="SEC_FIG8">
<figure id="figure-7">
            <div class="artwork art-text alignLeft" id="section-7.1.1-3.1">
<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=1          |          Length=4             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Flags                           |L|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</pre>
</div>
<figcaption><a href="#figure-7" class="selfRef">Figure 7</a>:
<a href="#name-pcecc-capability-sub-tlv-2" class="selfRef">PCECC Capability Sub-TLV</a>
            </figcaption></figure>
</div>
<p id="section-7.1.1-4">The type of the TLV is 1, and it has a fixed length of 4 octets.<a href="#section-7.1.1-4" class="pilcrow">¶</a></p>
<p id="section-7.1.1-5">The value comprises a single field: Flags (32 bits).
      Currently, the following flag bit is
    defined:<a href="#section-7.1.1-5" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-7.1.1-6">
            <dt id="section-7.1.1-6.1">L bit (Label):</dt>
            <dd style="margin-left: 1.5em" id="section-7.1.1-6.2">If set to '1' by a PCEP speaker, the L flag
      indicates that the PCEP speaker will support and is willing to handle the PCEC-based Central Controller Instructions for label download. The bit <span class="bcp14">MUST</span> be set to '1' by both a PCC and a PCE for the PCECC label download/report on a PCEP session.<a href="#section-7.1.1-6.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
<p id="section-7.1.1-7">Unassigned bits <span class="bcp14">MUST</span> be set to '0' on
    transmission and <span class="bcp14">MUST</span> be ignored on receipt.<a href="#section-7.1.1-7" class="pilcrow">¶</a></p>
</section>
</div>
</section>
<div id="SEC_PATH">
<section id="section-7.2">
        <h3 id="name-path-setup-type-tlv">
<a href="#section-7.2" class="section-number selfRef">7.2. </a><a href="#name-path-setup-type-tlv" class="section-name selfRef">PATH-SETUP-TYPE TLV</a>
        </h3>
<p id="section-7.2-1">The PATH-SETUP-TYPE TLV is defined in <span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span>;
      this document defines a new PST value:<a href="#section-7.2-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-7.2-2">
          <dt id="section-7.2-2.1">PST=2:</dt>
          <dd style="margin-left: 1.5em" id="section-7.2-2.2">Path is set up via the PCECC mode.<a href="#section-7.2-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<p id="section-7.2-3">On a PCRpt/PCUpd/PCInitiate message, the PST=2 in the PATH-SETUP-TYPE TLV
   in the SRP object <span class="bcp14">MUST</span> be included for an LSP set up via the PCECC-based mechanism.<a href="#section-7.2-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="SEC_CCI">
<section id="section-7.3">
        <h3 id="name-cci-object">
<a href="#section-7.3" class="section-number selfRef">7.3. </a><a href="#name-cci-object" class="section-name selfRef">CCI Object</a>
        </h3>
<p id="section-7.3-1">The CCI object is used by the PCE to specify the forwarding instructions (label information in the context of this document) to the PCC and
    <span class="bcp14">MAY</span> be carried within a PCInitiate or PCRpt message for label download/report.<a href="#section-7.3-1" class="pilcrow">¶</a></p>
<p id="section-7.3-2">CCI Object-Class is 44.<a href="#section-7.3-2" class="pilcrow">¶</a></p>
<p id="section-7.3-3">CCI Object-Type is 1 for the MPLS label.<a href="#section-7.3-3" class="pilcrow">¶</a></p>
<span id="name-cci-object-2"></span><div id="SEC_FIG9">
<figure id="figure-8">
          <div class="artwork art-text alignLeft" id="section-7.3-4.1">
<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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            CC-ID                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Reserved1            |             Flags         |C|O|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                 Label                 |     Reserved2         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
//                        Optional TLV                         //
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</pre>
</div>
<figcaption><a href="#figure-8" class="selfRef">Figure 8</a>:
<a href="#name-cci-object-2" class="selfRef">CCI Object</a>
          </figcaption></figure>
</div>
<p id="section-7.3-5">The fields in the CCI object are as follows:<a href="#section-7.3-5" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-7.3-6">
          <dt id="section-7.3-6.1">CC-ID:</dt>
          <dd style="margin-left: 1.5em" id="section-7.3-6.2"> A PCEP-specific identifier for the CCI
   information.  A PCE creates a CC-ID for each instruction; the value is
   unique within the scope of the PCE and is constant for the lifetime
   of a PCEP session.  The values 0 and 0xFFFFFFFF are reserved
   and <span class="bcp14">MUST NOT</span> be used. Note
   that <span>[<a href="#I-D.gont-numeric-ids-sec-considerations" class="xref">SECURITY-ID</a>]</span> gives advice on
   assigning transient numeric identifiers, such as the CC-ID, so as to
   minimize security risks.<a href="#section-7.3-6.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-7.3-6.3">Reserved1 (16 bit):</dt>
          <dd style="margin-left: 1.5em" id="section-7.3-6.4">Set to 'zero' while sending; ignored on receipt.<a href="#section-7.3-6.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-7.3-6.5">Flags (16 bit):</dt>
          <dd style="margin-left: 1.5em" id="section-7.3-6.6">
            <p id="section-7.3-6.6.1"> A field used to carry any additional information
    pertaining to the CCI. Currently, the following flag bits are
    defined:<a href="#section-7.3-6.6.1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-7.3-6.6.2.1">O bit (out-label) : If the bit is set to '1', it specifies the label is
    the out-label, and it is mandatory to encode the next-hop
    information (via Address TLVs (<a href="#AddressTLVs" class="xref">Section 7.3.1</a>) in
    the CCI object). If the bit is not set, it specifies the label is
    the in-label, and it is optional to encode the local interface
    information (via Address TLVs in
    the CCI object).<a href="#section-7.3-6.6.2.1" class="pilcrow">¶</a>
</li>
              <li class="normal" id="section-7.3-6.6.2.2">C Bit (PCC allocation): If the bit is set to '1', it indicates that 
        the label allocation needs to be done by the PCC for the Central 
        Controller Instruction.  A PCE sets this bit to request the PCC to 
        make an allocation from its label space.  A PCC would set 
        this bit to indicate that it has allocated the label and report it  
        to the PCE.<a href="#section-7.3-6.6.2.2" class="pilcrow">¶</a>
</li>
              <li class="normal" id="section-7.3-6.6.2.3">All unassigned bits <span class="bcp14">MUST</span> be set to 'zero' at transmission and ignored at receipt.<a href="#section-7.3-6.6.2.3" class="pilcrow">¶</a>
</li>
            </ul>
</dd>
          <dd class="break"></dd>
<dt id="section-7.3-6.7">Label (20-bit):</dt>
          <dd style="margin-left: 1.5em" id="section-7.3-6.8">The label information.<a href="#section-7.3-6.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-7.3-6.9">Reserved2 (12 bit):</dt>
          <dd style="margin-left: 1.5em" id="section-7.3-6.10">Set to 'zero' while sending; ignored on receive.<a href="#section-7.3-6.10" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<div id="AddressTLVs">
<section id="section-7.3.1">
          <h4 id="name-address-tlvs">
<a href="#section-7.3.1" class="section-number selfRef">7.3.1. </a><a href="#name-address-tlvs" class="section-name selfRef">Address TLVs</a>
          </h4>
<p id="section-7.3.1-1"><span>[<a href="#RFC8779" class="xref">RFC8779</a>]</span> defines the IPV4-ADDRESS, IPV6-ADDRESS, and UNNUMBERED-ENDPOINT TLVs for the use of Generalized Endpoint. The same TLVs can also be used in the CCI object to
    associate the next-hop information in the case of an outgoing label and
    local interface information in the case of an incoming label. The next-hop information encoded in these TLVs needs to be a directly connected IP address/interface information. If the PCC is not able to resolve the next-hop information, it <span class="bcp14">MUST</span> reject the CCI and respond with a PCErr message with Error-Type=31 (PCECC failure) and Error-value=5 (Invalid next-hop information).<a href="#section-7.3.1-1" class="pilcrow">¶</a></p>
</section>
</div>
</section>
</div>
</section>
<section id="section-8">
      <h2 id="name-security-considerations">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-8-1">As per <span>[<a href="#RFC8283" class="xref">RFC8283</a>]</span>, the security considerations for a PCE-based controller are a little
   different from those for any other PCE system.  That is, the
   operation relies heavily on the use and security of PCEP, so
   consideration should be given to the security features discussed in
   <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> and the additional mechanisms described in <span>[<a href="#RFC8253" class="xref">RFC8253</a>]</span>. It further lists the vulnerability of a central controller architecture, such as a central
   point of failure, denial of service, and a focus for
   interception and modification of messages sent to individual Network Elements (NEs).<a href="#section-8-1" class="pilcrow">¶</a></p>
<p id="section-8-2">In the PCECC operations, the PCEP sessions are also required to the internal routers, thus increasing the resources required for the session management at the PCE.<a href="#section-8-2" class="pilcrow">¶</a></p>
<p id="section-8-3">The PCECC extension builds on the existing PCEP messages; thus, the security considerations described 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> continue to apply. <span>[<a href="#RFC8253" class="xref">RFC8253</a>]</span> specifies the support of Transport Layer Security (TLS) in PCEP, as it
   provides support for peer authentication, message encryption, and
   integrity. It further provides mechanisms for
   associating peer identities with different levels of access and/or
   authoritativeness via an attribute in X.509 certificates or a local policy with a specific accept-list of X.509 certificates. This can be used to check the authority for the PCECC operations. 
       Additional considerations are discussed in following sections.<a href="#section-8-3" class="pilcrow">¶</a></p>
<section id="section-8.1">
        <h3 id="name-malicious-pce">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-malicious-pce" class="section-name selfRef">Malicious PCE</a>
        </h3>
<p id="section-8.1-1">In this extension, the PCE has complete control over the PCC to download/remove the labels and can
   cause the LSPs to behave inappropriately and cause a major impact
   to the network. As a general precaution, it is <span class="bcp14">RECOMMENDED</span> that
   this PCEP extension be activated on mutually authenticated and encrypted
   sessions across PCEs and PCCs belonging to the same administrative
   authority, using 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>.<a href="#section-8.1-1" class="pilcrow">¶</a></p>
<p id="section-8.1-2">Further, an attacker may flood the PCC
   with the PCECC-related messages at a rate that exceeds either the PCC's ability
   to process them or the network's ability to send them, by
   either spoofing messages or compromising the PCE itself. <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> provides a mechanism to protect the PCC by imposing a limit. The same can be used for the PCECC operations as well.<a href="#section-8.1-2" class="pilcrow">¶</a></p>
<p id="section-8.1-3">As specified in <a href="#LabelDownloadCCI" class="xref">Section 5.5.3.1</a>, a PCC needs to check if the label in the CCI object is in the range set aside for the PCE; otherwise, it <span class="bcp14">MUST</span> send a PCErr message with Error-Type=31
   (PCECC failure) and Error-value=1 (Label out of range).<a href="#section-8.1-3" class="pilcrow">¶</a></p>
</section>
<section id="section-8.2">
        <h3 id="name-malicious-pcc">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-malicious-pcc" class="section-name selfRef">Malicious PCC</a>
        </h3>
<p id="section-8.2-1">The PCECC mechanism described in this document requires
   the PCE to keep labels (CCI) that it downloads and relies on the
   PCC responding (with either an acknowledgment or an error message) to
   request for LSP instantiation. This is an additional attack surface by
   placing a requirement for the PCE to keep a CCI/label replica for
   each PCC.  It is <span class="bcp14">RECOMMENDED</span> that PCE implementations provide a limit
   on resources (in this case the CCI) a single PCC can occupy. <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> provides a notification mechanism when such threshold is reached.<a href="#section-8.2-1" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-9">
      <h2 id="name-manageability-consideration">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-manageability-consideration" class="section-name selfRef">Manageability Considerations</a>
      </h2>
<section id="section-9.1">
        <h3 id="name-control-of-function-and-pol">
<a href="#section-9.1" class="section-number selfRef">9.1. </a><a href="#name-control-of-function-and-pol" class="section-name selfRef">Control of Function and Policy</a>
        </h3>
<p id="section-9.1-1">A PCE or PCC implementation <span class="bcp14">SHOULD</span> allow the PCECC capability to be enabled/disabled as part of the global configuration. <span><a href="https://www.rfc-editor.org/rfc/rfc8664#section-6.1" class="relref">Section 6.1</a> of [<a href="#RFC8664" class="xref">RFC8664</a>]</span> list various controlling factors regarding the Path Setup Type. They are also applicable to the PCECC Path Setup Types. Further, <span><a href="https://www.rfc-editor.org/rfc/rfc8664#section-6.2" class="relref">Section 6.2</a> of [<a href="#RFC8664" class="xref">RFC8664</a>]</span> describes the migration steps when the Path Setup Type of an existing LSP is changed.<a href="#section-9.1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-9.2">
        <h3 id="name-information-and-data-models">
<a href="#section-9.2" class="section-number selfRef">9.2. </a><a href="#name-information-and-data-models" class="section-name selfRef">Information and Data Models</a>
        </h3>
<p id="section-9.2-1"><span>[<a href="#RFC7420" class="xref">RFC7420</a>]</span> describes the PCEP MIB; this MIB can be extended to get the
           PCECC capability status.<a href="#section-9.2-1" class="pilcrow">¶</a></p>
<p id="section-9.2-2">The PCEP YANG module <span>[<a href="#I-D.ietf-pce-pcep-yang" class="xref">PCEP-YANG</a>]</span> could be extended
           to enable/disable the PCECC capability.<a href="#section-9.2-2" class="pilcrow">¶</a></p>
</section>
<section id="section-9.3">
        <h3 id="name-liveness-detection-and-moni">
<a href="#section-9.3" class="section-number selfRef">9.3. </a><a href="#name-liveness-detection-and-moni" class="section-name selfRef">Liveness Detection and Monitoring</a>
        </h3>
<p id="section-9.3-1">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>.<a href="#section-9.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-9.4">
        <h3 id="name-verify-correct-operations">
<a href="#section-9.4" class="section-number selfRef">9.4. </a><a href="#name-verify-correct-operations" class="section-name selfRef">Verify Correct Operations</a>
        </h3>
<p id="section-9.4-1">The operator needs the following information to verify that PCEP is
   operating correctly with respect to the PCECC Path Setup
   Type.<a href="#section-9.4-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-9.4-2.1">An implementation <span class="bcp14">SHOULD</span> allow the operator to view whether the
      PCEP speaker sent the PCECC PST capability to its peer.<a href="#section-9.4-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-9.4-2.2">An implementation <span class="bcp14">SHOULD</span> allow the operator to view whether the
      peer sent the PCECC PST capability.<a href="#section-9.4-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-9.4-2.3">An implementation <span class="bcp14">SHOULD</span> allow the operator to view whether the
      PCECC PST is enabled on a PCEP session.<a href="#section-9.4-2.3" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-9.4-2.4">If one PCEP speaker advertises the PCECC PST capability,
      but the other does not, then the implementation <span class="bcp14">SHOULD</span> create a
      log to inform the operator of the capability mismatch.<a href="#section-9.4-2.4" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-9.4-2.5">If a PCEP speaker rejects a CCI, then it <span class="bcp14">SHOULD</span>
      create a log to inform the operator, giving the reason for the
      decision (local policy, label issues, etc.).<a href="#section-9.4-2.5" class="pilcrow">¶</a>
</li>
        </ul>
</section>
<section id="section-9.5">
        <h3 id="name-requirements-on-other-proto">
<a href="#section-9.5" class="section-number selfRef">9.5. </a><a href="#name-requirements-on-other-proto" class="section-name selfRef">Requirements on Other Protocols</a>
        </h3>
<p id="section-9.5-1">PCEP extensions defined in this document do not put new requirements
   on other protocols.<a href="#section-9.5-1" class="pilcrow">¶</a></p>
</section>
<section id="section-9.6">
        <h3 id="name-impact-on-network-operation">
<a href="#section-9.6" class="section-number selfRef">9.6. </a><a href="#name-impact-on-network-operation" class="section-name selfRef">Impact on Network Operations</a>
        </h3>
<p id="section-9.6-1">PCEP extensions defined in this document do not put new requirements
   on network operations.<a href="#section-9.6-1" class="pilcrow">¶</a></p>
</section>
</section>
<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>
<section id="section-10.1">
        <h3 id="name-path-setup-type-capability-">
<a href="#section-10.1" class="section-number selfRef">10.1. </a><a href="#name-path-setup-type-capability-" class="section-name selfRef">PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators</a>
        </h3>
<p id="section-10.1-1"><span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span> detailed the creation of the "PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators" subregistry. Further, IANA has allocated the following codepoint:<a href="#section-10.1-1" class="pilcrow">¶</a></p>
<span id="name-path-setup-type-capability-s"></span><div id="PCEP-SUBTYPE-IND">
<table class="center" id="table-2">
          <caption>
<a href="#table-2" class="selfRef">Table 2</a>:
<a href="#name-path-setup-type-capability-s" class="selfRef">PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators Subregistry Addition</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Value</th>
              <th class="text-left" rowspan="1" colspan="1">Meaning</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">1</td>
              <td class="text-left" rowspan="1" colspan="1">PCECC-CAPABILITY</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-10.2">
        <h3 id="name-pcecc-capability-sub-tlvs-f">
<a href="#section-10.2" class="section-number selfRef">10.2. </a><a href="#name-pcecc-capability-sub-tlvs-f" class="section-name selfRef">PCECC-CAPABILITY Sub-TLV's Flag Field</a>
        </h3>
<p id="section-10.2-1">This document defines the
      PCECC-CAPABILITY sub-TLV; IANA has created a new subregistry to
      manage the value of the PCECC-CAPABILITY sub-TLV's 32-bit Flag field.   New
   values are to be assigned by Standards Action <span>[<a href="#RFC8126" class="xref">RFC8126</a>]</span>.  Each bit
   should be tracked with the following qualities:<a href="#section-10.2-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-10.2-2.1">bit number (counting from bit 0 as the most significant bit)<a href="#section-10.2-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-10.2-2.2">capability description<a href="#section-10.2-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-10.2-2.3">defining RFC<a href="#section-10.2-2.3" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-10.2-3">Currently, there is one allocation in this registry.<a href="#section-10.2-3" class="pilcrow">¶</a></p>
<span id="name-initial-contents-of-the-pce"></span><div id="PCEP-CAP-SubTLv">
<table class="center" id="table-3">
          <caption>
<a href="#table-3" class="selfRef">Table 3</a>:
<a href="#name-initial-contents-of-the-pce" class="selfRef">Initial Contents of the PCECC-CAPABILITY Sub-TLV Subregistry</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Bit</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">0-30</td>
              <td class="text-left" rowspan="1" colspan="1">Unassigned</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">31</td>
              <td class="text-left" rowspan="1" colspan="1">Label</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-10.3">
        <h3 id="name-pcep-path-setup-type-regist">
<a href="#section-10.3" class="section-number selfRef">10.3. </a><a href="#name-pcep-path-setup-type-regist" class="section-name selfRef">PCEP Path Setup Type Registry</a>
        </h3>
<p id="section-10.3-1"><span>[<a href="#RFC8408" class="xref">RFC8408</a>]</span> created a subregistry within the "Path Computation Element
   Protocol (PCEP) Numbers" registry called "PCEP Path Setup Types".
   IANA has allocated a new codepoint within this registry,
   as follows:<a href="#section-10.3-1" class="pilcrow">¶</a></p>
<span id="name-path-setup-type-registry-co"></span><div id="PCEP-PATH-TYPE">
<table class="center" id="table-4">
          <caption>
<a href="#table-4" class="selfRef">Table 4</a>:
<a href="#name-path-setup-type-registry-co" class="selfRef">Path Setup Type Registry Codepoint Addition</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">2</td>
              <td class="text-left" rowspan="1" colspan="1">Traffic engineering path is set up using PCECC mode</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-10.4">
        <h3 id="name-pcep-object">
<a href="#section-10.4" class="section-number selfRef">10.4. </a><a href="#name-pcep-object" class="section-name selfRef">PCEP Object</a>
        </h3>
<p id="section-10.4-1">IANA has allocated new codepoints in the "PCEP Objects" subregistry for the CCI object as follows:<a href="#section-10.4-1" class="pilcrow">¶</a></p>
<span id="name-pcep-objects-subregistry-ad"></span><div id="PCEP-OBJECT">
<table class="center" id="table-5">
          <caption>
<a href="#table-5" class="selfRef">Table 5</a>:
<a href="#name-pcep-objects-subregistry-ad" class="selfRef">PCEP Objects Subregistry Additions</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Object-Class Value</th>
              <th class="text-left" rowspan="1" colspan="1">Name</th>
              <th class="text-left" rowspan="1" colspan="1">Object-Type</th>
              <th class="text-left" rowspan="1" colspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">44</td>
              <td class="text-left" rowspan="1" colspan="1">CCI Object-Type</td>
              <td class="text-left" rowspan="1" colspan="1">
                <ul class="text-left ulBare ulEmpty compact">
<li class="text-left ulBare ulEmpty compact" id="section-10.4-2.2.1.3.1.1">0: Reserved<a href="#section-10.4-2.2.1.3.1.1" class="pilcrow">¶</a>
</li>
                  <li class="text-left ulBare ulEmpty compact" id="section-10.4-2.2.1.3.1.2">1: MPLS Label<a href="#section-10.4-2.2.1.3.1.2" class="pilcrow">¶</a>
</li>
                  <li class="text-left ulBare ulEmpty compact" id="section-10.4-2.2.1.3.1.3">2-15: Unassigned<a href="#section-10.4-2.2.1.3.1.3" class="pilcrow">¶</a>
</li>
                </ul>
</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-10.5">
        <h3 id="name-cci-object-flag-field">
<a href="#section-10.5" class="section-number selfRef">10.5. </a><a href="#name-cci-object-flag-field" class="section-name selfRef">CCI Object Flag Field</a>
        </h3>
<p id="section-10.5-1">IANA has created a new subregistry to manage the Flag field
           of the CCI object called "CCI Object Flag Field for MPLS Label". New
   values are to be assigned by Standards Action <span>[<a href="#RFC8126" class="xref">RFC8126</a>]</span>.  Each bit
   should be tracked with the following qualities:<a href="#section-10.5-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-10.5-2.1">bit number (counting from bit 0 as the most significant bit)<a href="#section-10.5-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-10.5-2.2">capability description<a href="#section-10.5-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-10.5-2.3">defining RFC<a href="#section-10.5-2.3" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-10.5-3">Two bits are defined for the CCI Object flag field in this document as follows:<a href="#section-10.5-3" class="pilcrow">¶</a></p>
<span id="name-cci-object-flag-field-for-m"></span><div id="CCI-FLAG">
<table class="center" id="table-6">
          <caption>
<a href="#table-6" class="selfRef">Table 6</a>:
<a href="#name-cci-object-flag-field-for-m" class="selfRef">CCI Object Flag Field for MPLS Label Initial Contents</a>
          </caption>
<thead>
            <tr>
              <th class="text-left" rowspan="1" colspan="1">Bit</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">0-13</td>
              <td class="text-left" rowspan="1" colspan="1">Unassigned</td>
              <td class="text-left" rowspan="1" colspan="1"></td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">14</td>
              <td class="text-left" rowspan="1" colspan="1">C Bit - PCC allocation</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">15</td>
              <td class="text-left" rowspan="1" colspan="1">O Bit - Specifies label is out-label</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-10.6">
        <h3 id="name-pcep-error-object">
<a href="#section-10.6" class="section-number selfRef">10.6. </a><a href="#name-pcep-error-object" class="section-name selfRef">PCEP-Error Object</a>
        </h3>
<p id="section-10.6-1">IANA has allocated new error types and error values within
         the "PCEP-ERROR Object Error Types and Values" subregistry of the
         "Path Computation Element Protocol (PCEP) Numbers" registry for the following errors:<a href="#section-10.6-1" class="pilcrow">¶</a></p>
<span id="name-pcep-error-object-error-typ"></span><div id="error-type">
<table class="center" id="table-7">
          <caption>
<a href="#table-7" class="selfRef">Table 7</a>:
<a href="#name-pcep-error-object-error-typ" class="selfRef">PCEP-ERROR Object Error Types and Values Additions</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">6</td>
              <td class="text-left" rowspan="1" colspan="1">Mandatory Object missing</td>
              <td class="text-left" rowspan="1" colspan="1">17: CCI object missing</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">10</td>
              <td class="text-left" rowspan="1" colspan="1">Reception of an invalid object</td>
              <td class="text-left" rowspan="1" colspan="1">33: Missing PCECC Capability sub-TLV</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">19</td>
              <td class="text-left" rowspan="1" colspan="1">Invalid Operation</td>
              <td class="text-left" rowspan="1" colspan="1">
                <p id="section-10.6-2.2.3.3.1">16: Attempted PCECC operations when PCECC capability was not advertised<a href="#section-10.6-2.2.3.3.1" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.3.3.2">17: Stateful PCE capability was not advertised<a href="#section-10.6-2.2.3.3.2" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.3.3.3">18: Unknown Label<a href="#section-10.6-2.2.3.3.3" class="pilcrow">¶</a></p>
</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">31</td>
              <td class="text-left" rowspan="1" colspan="1">PCECC failure</td>
              <td class="text-left" rowspan="1" colspan="1">
                <p id="section-10.6-2.2.4.3.1">1: Label out of range<a href="#section-10.6-2.2.4.3.1" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.4.3.2">2: Instruction failed<a href="#section-10.6-2.2.4.3.2" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.4.3.3">3: Invalid CCI<a href="#section-10.6-2.2.4.3.3" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.4.3.4">4: Unable to allocate the specified CCI<a href="#section-10.6-2.2.4.3.4" class="pilcrow">¶</a></p>
<p id="section-10.6-2.2.4.3.5">5: Invalid next-hop information<a href="#section-10.6-2.2.4.3.5" class="pilcrow">¶</a></p>
</td>
              <td class="text-left" rowspan="1" colspan="1">RFC 9050</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
</section>
<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="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="RFC5511">[RFC5511]</dt>
        <dd>
<span class="refAuthor">Farrel, A.</span>, <span class="refTitle">"Routing Backus-Naur Form (RBNF): A Syntax Used to Form Encoding Rules in Various Routing Protocol Specifications"</span>, <span class="seriesInfo">RFC 5511</span>, <span class="seriesInfo">DOI 10.17487/RFC5511</span>, <time datetime="2009-04" class="refDate">April 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5511">https://www.rfc-editor.org/info/rfc5511</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="RFC8126">[RFC8126]</dt>
        <dd>
<span class="refAuthor">Cotton, M.</span>, <span class="refAuthor">Leiba, B.</span>, and <span class="refAuthor">T. Narten</span>, <span class="refTitle">"Guidelines for Writing an IANA Considerations Section in RFCs"</span>, <span class="seriesInfo">BCP 26</span>, <span class="seriesInfo">RFC 8126</span>, <span class="seriesInfo">DOI 10.17487/RFC8126</span>, <time datetime="2017-06" class="refDate">June 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8126">https://www.rfc-editor.org/info/rfc8126</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="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="RFC8408">[RFC8408]</dt>
        <dd>
<span class="refAuthor">Sivabalan, S.</span>, <span class="refAuthor">Tantsura, J.</span>, <span class="refAuthor">Minei, I.</span>, <span class="refAuthor">Varga, R.</span>, and <span class="refAuthor">J. Hardwick</span>, <span class="refTitle">"Conveying Path Setup Type in PCE Communication Protocol (PCEP) Messages"</span>, <span class="seriesInfo">RFC 8408</span>, <span class="seriesInfo">DOI 10.17487/RFC8408</span>, <time datetime="2018-07" class="refDate">July 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8408">https://www.rfc-editor.org/info/rfc8408</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>
<dt id="RFC8779">[RFC8779]</dt>
      <dd>
<span class="refAuthor">Margaria, C., Ed.</span>, <span class="refAuthor">Gonzalez de Dios, O., Ed.</span>, and <span class="refAuthor">F. Zhang, Ed.</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for GMPLS"</span>, <span class="seriesInfo">RFC 8779</span>, <span class="seriesInfo">DOI 10.17487/RFC8779</span>, <time datetime="2020-07" class="refDate">July 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8779">https://www.rfc-editor.org/info/rfc8779</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="RFC4655">[RFC4655]</dt>
        <dd>
<span class="refAuthor">Farrel, A.</span>, <span class="refAuthor">Vasseur, JP.</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="RFC7025">[RFC7025]</dt>
        <dd>
<span class="refAuthor">Otani, T.</span>, <span class="refAuthor">Ogaki, K.</span>, <span class="refAuthor">Caviglia, D.</span>, <span class="refAuthor">Zhang, F.</span>, and <span class="refAuthor">C. Margaria</span>, <span class="refTitle">"Requirements for GMPLS Applications of PCE"</span>, <span class="seriesInfo">RFC 7025</span>, <span class="seriesInfo">DOI 10.17487/RFC7025</span>, <time datetime="2013-09" class="refDate">September 2013</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7025">https://www.rfc-editor.org/info/rfc7025</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7399">[RFC7399]</dt>
        <dd>
<span class="refAuthor">Farrel, A.</span> and <span class="refAuthor">D. King</span>, <span class="refTitle">"Unanswered Questions in the Path Computation Element Architecture"</span>, <span class="seriesInfo">RFC 7399</span>, <span class="seriesInfo">DOI 10.17487/RFC7399</span>, <time datetime="2014-10" class="refDate">October 2014</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7399">https://www.rfc-editor.org/info/rfc7399</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="RFC7491">[RFC7491]</dt>
        <dd>
<span class="refAuthor">King, D.</span> and <span class="refAuthor">A. Farrel</span>, <span class="refTitle">"A PCE-Based Architecture for Application-Based Network Operations"</span>, <span class="seriesInfo">RFC 7491</span>, <span class="seriesInfo">DOI 10.17487/RFC7491</span>, <time datetime="2015-03" class="refDate">March 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7491">https://www.rfc-editor.org/info/rfc7491</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8232">[RFC8232]</dt>
        <dd>
<span class="refAuthor">Crabbe, E.</span>, <span class="refAuthor">Minei, I.</span>, <span class="refAuthor">Medved, J.</span>, <span class="refAuthor">Varga, R.</span>, <span class="refAuthor">Zhang, X.</span>, and <span class="refAuthor">D. Dhody</span>, <span class="refTitle">"Optimizations of Label Switched Path State Synchronization Procedures for a Stateful PCE"</span>, <span class="seriesInfo">RFC 8232</span>, <span class="seriesInfo">DOI 10.17487/RFC8232</span>, <time datetime="2017-09" class="refDate">September 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8232">https://www.rfc-editor.org/info/rfc8232</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8283">[RFC8283]</dt>
        <dd>
<span class="refAuthor">Farrel, A., Ed.</span>, <span class="refAuthor">Zhao, Q., Ed.</span>, <span class="refAuthor">Li, Z.</span>, and <span class="refAuthor">C. Zhou</span>, <span class="refTitle">"An Architecture for Use of PCE and the PCE Communication Protocol (PCEP) in a Network with Central Control"</span>, <span class="seriesInfo">RFC 8283</span>, <span class="seriesInfo">DOI 10.17487/RFC8283</span>, <time datetime="2017-12" class="refDate">December 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8283">https://www.rfc-editor.org/info/rfc8283</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8741">[RFC8741]</dt>
        <dd>
<span class="refAuthor">Raghuram, A.</span>, <span class="refAuthor">Goddard, A.</span>, <span class="refAuthor">Karthik, J.</span>, <span class="refAuthor">Sivabalan, S.</span>, and <span class="refAuthor">M. Negi</span>, <span class="refTitle">"Ability for a Stateful Path Computation Element (PCE) to Request and Obtain Control of a Label Switched Path (LSP)"</span>, <span class="seriesInfo">RFC 8741</span>, <span class="seriesInfo">DOI 10.17487/RFC8741</span>, <time datetime="2020-03" class="refDate">March 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8741">https://www.rfc-editor.org/info/rfc8741</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-teas-pcecc-use-cases">[PCECC]</dt>
        <dd>
<span class="refAuthor">Li, Z. (.</span>, <span class="refAuthor">Dhody, D.</span>, <span class="refAuthor">Zhao, Q.</span>, <span class="refAuthor">Ke, K.</span>, <span class="refAuthor">Khasanov, B.</span>, <span class="refAuthor">Fang, L.</span>, <span class="refAuthor">Zhou, C.</span>, <span class="refAuthor">Zhang, B.</span>, <span class="refAuthor">Rachitskiy, A.</span>, and <span class="refAuthor">A. Gulida</span>, <span class="refTitle">"The Use Cases for Path Computation Element (PCE) as a Central Controller (PCECC)."</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-teas-pcecc-use-cases-07</span>, <time datetime="2021-03-08" class="refDate">8 March 2021</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-teas-pcecc-use-cases-07">https://datatracker.ietf.org/doc/html/draft-ietf-teas-pcecc-use-cases-07</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-pce-pcep-yang">[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://datatracker.ietf.org/doc/html/draft-ietf-pce-pcep-yang-16">https://datatracker.ietf.org/doc/html/draft-ietf-pce-pcep-yang-16</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-pce-pcep-extension-pce-controller-sr">[PCECC-SR]</dt>
        <dd>
<span class="refAuthor">Li, Z.</span>, <span class="refAuthor">Peng, S.</span>, <span class="refAuthor">Negi, M. S.</span>, <span class="refAuthor">Zhao, Q.</span>, and <span class="refAuthor">C. Zhou</span>, <span class="refTitle">"PCEP Procedures and Protocol Extensions for Using PCE as a Central Controller (PCECC) for Segment Routing (SR) MPLS Segment Identifier (SID) Allocation and Distribution."</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-pce-pcep-extension-pce-controller-sr-02</span>, <time datetime="2021-03-25" class="refDate">25 March 2021</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-pce-pcep-extension-pce-controller-sr-02">https://datatracker.ietf.org/doc/html/draft-ietf-pce-pcep-extension-pce-controller-sr-02</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.dhody-pce-pcep-extension-pce-controller-srv6">[PCECC-SRv6]</dt>
        <dd>
<span class="refAuthor">Li, Z.</span>, <span class="refAuthor">Peng, S.</span>, <span class="refAuthor">Geng, X.</span>, and <span class="refAuthor">M. S. Negi</span>, <span class="refTitle">"PCEP Procedures and Protocol Extensions for Using PCE as a Central Controller (PCECC) for SRv6"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-dhody-pce-pcep-extension-pce-controller-srv6-06</span>, <time datetime="2021-02-21" class="refDate">21 February 2021</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-dhody-pce-pcep-extension-pce-controller-srv6-06">https://datatracker.ietf.org/doc/html/draft-dhody-pce-pcep-extension-pce-controller-srv6-06</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.li-pce-controlled-id-space">[PCE-ID]</dt>
        <dd>
<span class="refAuthor">Li, C.</span>, <span class="refAuthor">Chen, M.</span>, <span class="refAuthor">Wang, A.</span>, <span class="refAuthor">Cheng, W.</span>, and <span class="refAuthor">C. Zhou</span>, <span class="refTitle">"PCE Controlled ID Space"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-li-pce-controlled-id-space-08</span>, <time datetime="2021-02-22" class="refDate">22 February 2021</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-li-pce-controlled-id-space-08">https://datatracker.ietf.org/doc/html/draft-li-pce-controlled-id-space-08</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.gont-numeric-ids-sec-considerations">[SECURITY-ID]</dt>
      <dd>
<span class="refAuthor">Gont, F.</span> and <span class="refAuthor">I. Arce</span>, <span class="refTitle">"Security Considerations for Transient Numeric Identifiers Employed in Network Protocols"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-gont-numeric-ids-sec-considerations-06</span>, <time datetime="2020-12-05" class="refDate">5 December 2020</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-gont-numeric-ids-sec-considerations-06">https://datatracker.ietf.org/doc/html/draft-gont-numeric-ids-sec-considerations-06</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<section id="appendix-A">
      <h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
      </h2>
<p id="appendix-A-1">We would like to thank <span class="contact-name">Robert Tao</span>, <span class="contact-name">Changjing Yan</span>, <span class="contact-name">Tieying Huang</span>, <span class="contact-name">Avantika</span>, and <span class="contact-name">Aijun Wang</span> for
   their useful comments and suggestions.<a href="#appendix-A-1" class="pilcrow">¶</a></p>
<p id="appendix-A-2">Thanks to <span class="contact-name">Julien Meuric</span> for shepherding this document and providing valuable comments. Thanks to <span class="contact-name">Deborah Brungard</span> for being the responsible AD.<a href="#appendix-A-2" class="pilcrow">¶</a></p>
<p id="appendix-A-3">Thanks to <span class="contact-name">Victoria Pritchard</span> for a very detailed RTGDIR review. Thanks to <span class="contact-name">Yaron Sheffer</span> for the   
SECDIR review. Thanks to <span class="contact-name">Gyan Mishra</span> for the Gen-ART review.<a href="#appendix-A-3" class="pilcrow">¶</a></p>
<p id="appendix-A-4">Thanks to <span class="contact-name">Alvaro Retana</span>, <span class="contact-name">Murray Kucherawy</span>, <span class="contact-name">Benjamin Kaduk</span>, <span class="contact-name">Roman Danyliw</span>, <span class="contact-name">Robert Wilton</span>, <span class="contact-name">Éric Vyncke</span>, and <span class="contact-name">Erik Kline</span> for the IESG review.<a href="#appendix-A-4" class="pilcrow">¶</a></p>
</section>
<section id="appendix-B">
      <h2 id="name-contributors">
<a href="#name-contributors" class="section-name selfRef">Contributors</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">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>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Satish Karunanithi</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:satishk@huawei.com" class="email">satishk@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Adrian Farrel</span></div>
<div dir="auto" class="left"><span class="org">Old Dog Consulting</span></div>
<div dir="auto" class="left"><span class="country-name">United Kingdom</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:adrian@olddog.co.uk" class="email">adrian@olddog.co.uk</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Xuesong Geng</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:gengxuesong@huawei.com" class="email">gengxuesong@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">Katherine Zhao</span></div>
<div dir="auto" class="left"><span class="org">Futurewei Technologies</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:katherine.zhao@futurewei.com" class="email">katherine.zhao@futurewei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Boris Zhang</span></div>
<div dir="auto" class="left"><span class="org">Telus Ltd.</span></div>
<div dir="auto" class="left">
<span class="locality">Toronto</span>  </div>
<div dir="auto" class="left"><span class="country-name">Canada</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:boris.zhang@telus.com" class="email">boris.zhang@telus.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Alex Tokar</span></div>
<div dir="auto" class="left"><span class="org">Cisco Systems</span></div>
<div dir="auto" class="left"><span class="country-name">Slovakia</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:atokar@cisco.com" class="email">atokar@cisco.com</a>
</div>
</address>
</section>
<div id="authors-addresses">
<section id="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">Zhenbin 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 Bld., 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:lizhenbin@huawei.com" class="email">lizhenbin@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Shuping Peng</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">Huawei Bld., 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:pengshuping@huawei.com" class="email">pengshuping@huawei.com</a>
</div>
</address>
<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">Quintin Zhao</span></div>
<div dir="auto" class="left"><span class="org">Etheric Networks</span></div>
<div dir="auto" class="left"><span class="street-address">1009 S Claremont St.</span></div>
<div dir="auto" class="left">
<span class="locality">San Mateo</span>, <span class="region">CA</span> <span class="postal-code">94402</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:qzhao@ethericnetworks.com" class="email">qzhao@ethericnetworks.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Chao Zhou</span></div>
<div dir="auto" class="left"><span class="org">HPE</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:chaozhou_us@yahoo.com" class="email">chaozhou_us@yahoo.com</a>
</div>
</address>
</section>
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