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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 8934: PCE Communication Protocol (PCEP) Extensions for Label Switched Path (LSP) Scheduling with Stateful PCE</title>
<meta content="Huaimo Chen" name="author">
<meta content="Yan Zhuang" name="author">
<meta content="Qin Wu" name="author">
<meta content="Daniele Ceccarelli" name="author">
<meta content="
       This document defines a set of extensions to the stateful
      PCE Communication Protocol (PCEP) to
      enable Label Switched Path (LSP) path computation, 
      activation, setup, and deletion based on scheduled time intervals for
      the LSP and 
      the actual network resource usage 
      in a centralized network environment, as stated in
      RFC 8413. 
    " name="description">
<meta content="xml2rfc 3.3.0" name="generator">
<meta content="Path Computation Element" name="keyword">
<meta content="8934" name="rfc.number">
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<link href="rfc8934.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*

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

  Once the style has stabilized and has been adopted as an official RFC style,
  this can be consolidated so that style settings occur only in one place, but
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  commented changes found necssary during the development of the v3
  formatters.

*/

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@-ms-viewport {
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/* general and mobile first */
html {
}
body {
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*/
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}

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/* pagination */
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/* This is commented out here, as the string-set: doesn't
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@page {
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/* Changes introduced to fix issues found during implementation */
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section {
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/* Top align author divs, to avoid names without organization dropping level with org names */
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a.toplink {
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/* Fix the dl styling to match the RFC 7992 attributes */
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}
dl.dlNewline > dt {
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/* Provide styling for table cell text alignment */
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table td.text-center,
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table td.text-right,
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/* Make the alternative author contact informatio look less like just another
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address .non-ascii {
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table {
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address.vcard {
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/* For address alignment dependent on LTR or RTL scripts */
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address div.right {
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/* Provide table alignment support.  We can't use the alignX classes above
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table.right {
 margin-left: auto;
 margin-right: 0;
}
table.center {
 margin-left: auto;
 margin-right: auto;
}
table.left {
 margin-left: 0;
 margin-right: auto;
}

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

@media print {
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  /* avoid overwriting the top border line with the ToC header */
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  /* Avoid page breaks inside dl and author address entries */
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}
/* Tweak the bcp14 keyword presentation */
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}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
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 }
 h3 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
 h4 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
/* Float artwork pilcrow to the right */
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}
/* Make pilcrows on dd visible */
@media screen {
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}
/* Make the placement of figcaption match that of a table's caption
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.alignCenter,
.alignRight {
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/* In print, the pilcrow won't show on hover, so prevent it from taking up space,
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}
/* Styling for the external metadata */
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<table class="ears">
<thead><tr>
<td class="left">RFC 8934</td>
<td class="center">PCEP Extensions for LSP Scheduling</td>
<td class="right">October 2020</td>
</tr></thead>
<tfoot><tr>
<td class="left">Chen, 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/rfc8934" class="eref">8934</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="2020-10" class="published">October 2020</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">H. Chen, <span class="editor">Ed.</span>
</div>
<div class="org">Futurewei</div>
</div>
<div class="author">
      <div class="author-name">Y. Zhuang, <span class="editor">Ed.</span>
</div>
<div class="org">Huawei</div>
</div>
<div class="author">
      <div class="author-name">Q. Wu</div>
<div class="org">Huawei</div>
</div>
<div class="author">
      <div class="author-name">D. Ceccarelli</div>
<div class="org">Ericsson</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 8934</h1>
<h1 id="title">PCE Communication Protocol (PCEP) Extensions for Label Switched Path (LSP) Scheduling with Stateful PCE</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document defines a set of extensions to the stateful
      PCE Communication Protocol (PCEP) to
      enable Label Switched Path (LSP) path computation, 
      activation, setup, and deletion based on scheduled time intervals for
      the LSP and 
      the actual network resource usage 
      in a centralized network environment, as stated in
      RFC 8413.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
</section>
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            This is an Internet Standards Track document.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
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            (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>
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            Information about the current status of this document, any
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        <a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
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<li class="ulEmpty 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><a href="#section-toc.1-1.1.1" class="pilcrow">¶</a></p>
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          <li class="ulEmpty 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-conventions-used-in-this-do" class="xref">Conventions Used in This Document</a><a href="#section-toc.1-1.2.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
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                <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-terminology" class="xref">Terminology</a><a href="#section-toc.1-1.2.2.1.1" class="pilcrow">¶</a></p>
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            </ul>
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          <li class="ulEmpty 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-motivation-and-objectives" class="xref">Motivation and Objectives</a><a href="#section-toc.1-1.3.1" class="pilcrow">¶</a></p>
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          <li class="ulEmpty 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-procedures-and-mechanisms" class="xref">Procedures and Mechanisms</a><a href="#section-toc.1-1.4.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty compact toc" id="section-toc.1-1.4.2.1">
                <p id="section-toc.1-1.4.2.1.1"><a href="#section-4.1" class="xref">4.1</a>.  <a href="#name-lsp-scheduling-overview" class="xref">LSP Scheduling Overview</a><a href="#section-toc.1-1.4.2.1.1" class="pilcrow">¶</a></p>
</li>
              <li class="ulEmpty compact toc" id="section-toc.1-1.4.2.2">
                <p id="section-toc.1-1.4.2.2.1"><a href="#section-4.2" class="xref">4.2</a>.  <a href="#name-support-of-lsp-scheduling" class="xref">Support of LSP Scheduling</a><a href="#section-toc.1-1.4.2.2.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty compact toc" id="section-toc.1-1.4.2.2.2.1">
                    <p id="section-toc.1-1.4.2.2.2.1.1"><a href="#section-4.2.1" class="xref">4.2.1</a>.  <a href="#name-lsp-scheduling" class="xref">LSP Scheduling</a><a href="#section-toc.1-1.4.2.2.2.1.1" class="pilcrow">¶</a></p>
</li>
                  <li class="ulEmpty compact toc" id="section-toc.1-1.4.2.2.2.2">
                    <p id="section-toc.1-1.4.2.2.2.2.1"><a href="#section-4.2.2" class="xref">4.2.2</a>.  <a href="#name-periodical-lsp-scheduling" class="xref">Periodical LSP Scheduling</a><a href="#section-toc.1-1.4.2.2.2.2.1" class="pilcrow">¶</a></p>
</li>
                </ul>
</li>
              <li class="ulEmpty compact toc" id="section-toc.1-1.4.2.3">
                <p id="section-toc.1-1.4.2.3.1"><a href="#section-4.3" class="xref">4.3</a>.  <a href="#name-scheduled-lsp-creation" class="xref">Scheduled LSP Creation</a><a href="#section-toc.1-1.4.2.3.1" class="pilcrow">¶</a></p>
</li>
              <li class="ulEmpty compact toc" id="section-toc.1-1.4.2.4">
                <p id="section-toc.1-1.4.2.4.1"><a href="#section-4.4" class="xref">4.4</a>.  <a href="#name-scheduled-lsp-modifications" class="xref">Scheduled LSP Modifications</a><a href="#section-toc.1-1.4.2.4.1" class="pilcrow">¶</a></p>
</li>
              <li class="ulEmpty compact toc" id="section-toc.1-1.4.2.5">
                <p id="section-toc.1-1.4.2.5.1"><a href="#section-4.5" class="xref">4.5</a>.  <a href="#name-scheduled-lsp-activation-an" class="xref">Scheduled LSP Activation and Deletion</a><a href="#section-toc.1-1.4.2.5.1" class="pilcrow">¶</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty 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-pcep-objects-and-tlvs" class="xref">PCEP Objects and TLVs</a><a href="#section-toc.1-1.5.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty 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-capability-tlv" class="xref">Stateful PCE Capability TLV</a><a href="#section-toc.1-1.5.2.1.1" class="pilcrow">¶</a></p>
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              <li class="ulEmpty 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-lsp-object" class="xref">LSP Object</a><a href="#section-toc.1-1.5.2.2.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty compact toc" id="section-toc.1-1.5.2.2.2.1">
                    <p id="section-toc.1-1.5.2.2.2.1.1"><a href="#section-5.2.1" class="xref">5.2.1</a>.  <a href="#name-sched-lsp-attribute-tlv" class="xref">SCHED-LSP-ATTRIBUTE TLV</a><a href="#section-toc.1-1.5.2.2.2.1.1" class="pilcrow">¶</a></p>
</li>
                  <li class="ulEmpty compact toc" id="section-toc.1-1.5.2.2.2.2">
                    <p id="section-toc.1-1.5.2.2.2.2.1"><a href="#section-5.2.2" class="xref">5.2.2</a>.  <a href="#name-sched-pd-lsp-attribute-tlv" class="xref">SCHED-PD-LSP-ATTRIBUTE TLV</a><a href="#section-toc.1-1.5.2.2.2.2.1" class="pilcrow">¶</a></p>
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                </ul>
</li>
            </ul>
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          <li class="ulEmpty 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-the-pcep-messages" class="xref">The PCEP Messages</a><a href="#section-toc.1-1.6.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty 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-pcrpt-message" class="xref">The PCRpt Message</a><a href="#section-toc.1-1.6.2.1.1" class="pilcrow">¶</a></p>
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              <li class="ulEmpty 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-pcupd-message" class="xref">The PCUpd Message</a><a href="#section-toc.1-1.6.2.2.1" class="pilcrow">¶</a></p>
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              <li class="ulEmpty compact toc" id="section-toc.1-1.6.2.3">
                <p id="section-toc.1-1.6.2.3.1"><a href="#section-6.3" class="xref">6.3</a>.  <a href="#name-the-pcinitiate-message" class="xref">The PCInitiate Message</a><a href="#section-toc.1-1.6.2.3.1" class="pilcrow">¶</a></p>
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                <p id="section-toc.1-1.6.2.4.1"><a href="#section-6.4" class="xref">6.4</a>.  <a href="#name-the-pcreq-message" class="xref">The PCReq message</a><a href="#section-toc.1-1.6.2.4.1" class="pilcrow">¶</a></p>
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                <p id="section-toc.1-1.6.2.5.1"><a href="#section-6.5" class="xref">6.5</a>.  <a href="#name-the-pcrep-message" class="xref">The PCRep Message</a><a href="#section-toc.1-1.6.2.5.1" class="pilcrow">¶</a></p>
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                <p id="section-toc.1-1.6.2.6.1"><a href="#section-6.6" class="xref">6.6</a>.  <a href="#name-the-pcerr-message" class="xref">The PCErr Message</a><a href="#section-toc.1-1.6.2.6.1" class="pilcrow">¶</a></p>
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            <p id="section-toc.1-1.7.1"><a href="#section-7" class="xref">7</a>.  <a href="#name-security-considerations" class="xref">Security Considerations</a><a href="#section-toc.1-1.7.1" class="pilcrow">¶</a></p>
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</li>
          <li class="ulEmpty 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-iana-considerations" class="xref">IANA Considerations</a><a href="#section-toc.1-1.9.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty 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-pcep-tlv-type-indicators" class="xref">PCEP TLV Type Indicators</a><a href="#section-toc.1-1.9.2.1.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty compact toc" id="section-toc.1-1.9.2.1.2.1">
                    <p id="section-toc.1-1.9.2.1.2.1.1"><a href="#section-9.1.1" class="xref">9.1.1</a>.  <a href="#name-sched-pd-lsp-attribute-tlv-" class="xref">SCHED-PD-LSP-ATTRIBUTE TLV Opt Field</a><a href="#section-toc.1-1.9.2.1.2.1.1" class="pilcrow">¶</a></p>
</li>
                  <li class="ulEmpty compact toc" id="section-toc.1-1.9.2.1.2.2">
                    <p id="section-toc.1-1.9.2.1.2.2.1"><a href="#section-9.1.2" class="xref">9.1.2</a>.  <a href="#name-schedule-tlvs-flag-field" class="xref">Schedule TLVs Flag Field</a><a href="#section-toc.1-1.9.2.1.2.2.1" class="pilcrow">¶</a></p>
</li>
                </ul>
</li>
              <li class="ulEmpty 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-stateful-pce-capability-tlv-" class="xref">STATEFUL-PCE-CAPABILITY TLV Flag Field</a><a href="#section-toc.1-1.9.2.2.1" class="pilcrow">¶</a></p>
</li>
              <li class="ulEmpty 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-pcep-error-object-error-typ" class="xref">PCEP-ERROR Object Error Types and Values</a><a href="#section-toc.1-1.9.2.3.1" class="pilcrow">¶</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty 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-references" class="xref">References</a><a href="#section-toc.1-1.10.1" class="pilcrow">¶</a></p>
<ul class="ulEmpty compact toc">
<li class="ulEmpty 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-normative-references" class="xref">Normative References</a><a href="#section-toc.1-1.10.2.1.1" class="pilcrow">¶</a></p>
</li>
              <li class="ulEmpty 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-informative-references" class="xref">Informative References</a><a href="#section-toc.1-1.10.2.2.1" class="pilcrow">¶</a></p>
</li>
            </ul>
</li>
          <li class="ulEmpty compact toc" id="section-toc.1-1.11">
            <p id="section-toc.1-1.11.1"><a href="#section-appendix.a" class="xref"></a><a href="#name-acknowledgments" class="xref">Acknowledgments</a><a href="#section-toc.1-1.11.1" class="pilcrow">¶</a></p>
</li>
          <li class="ulEmpty compact toc" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-contributors" class="xref">Contributors</a><a href="#section-toc.1-1.12.1" class="pilcrow">¶</a></p>
</li>
          <li class="ulEmpty compact toc" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#section-appendix.c" class="xref"></a><a href="#name-authors-addresses" class="xref">Authors' Addresses</a><a href="#section-toc.1-1.13.1" class="pilcrow">¶</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<div id="intro">
<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 PCE Communication Protocol (PCEP) defined in
      <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> is used between a Path
      Computation Element (PCE) and a Path Computation Client (PCC) (or other
      PCE) to enable path computation of Multiprotocol Label Switching (MPLS)
      Traffic Engineering Label Switched Paths (TE LSPs).<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2"><span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> describes a set of
      extensions to PCEP to provide stateful control.  A stateful PCE has
      access to not only the information carried by the network's Interior
      Gateway Protocol (IGP) but also the set of active paths and their
      reserved resources for its computations.  The additional state allows
      the PCE to compute constrained paths while considering individual LSPs
      and their interactions.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">Traditionally, the usage and allocation of network resources,
      especially bandwidth, can be supported by a Network Management System
      (NMS)
      operation such as path pre-establishment. However, this does not provide
      efficient usage of network resources. The established paths reserve the
      resources forever, so they cannot be used by other services even 
      when they are not used
      for transporting any service. <span>[<a href="#RFC8413" class="xref">RFC8413</a>]</span>
      then
      provides a framework that describes and discusses the problem and
      defines an appropriate architecture for the scheduled reservation of TE
      resources.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">
      The scheduled reservation of TE resources allows network operators to
      reserve resources in advance according to the agreements with their
      customers and allows them to transmit data about scheduling, such as
      a specified start time and duration (for example, for a scheduled
      bulk data replication between data centers). 


   It enables the activation of
   bandwidth usage at the time the service is really being used while
   letting other services use the bandwidth when it is not being used by this
   service.
      The requirement of
      scheduled LSP provisioning is mentioned in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>
      and <span>[<a href="#RFC7399" class="xref">RFC7399</a>]</span>. 
      Also, for
      deterministic networks <span>[<a href="#RFC8655" class="xref">RFC8655</a>]</span>, 
      the scheduled LSP or temporal LSP can provide better network
      resource usage for guaranteed links. This idea can also be applied in
      segment routing <span>[<a href="#RFC8402" class="xref">RFC8402</a>]</span>
      to schedule the network resources over the whole network
      in a centralized manner.<a href="#section-1-4" class="pilcrow">¶</a></p>
<p id="section-1-5">With this in mind, this document defines a set of needed extensions
      to PCEP used for stateful PCEs
      so as to enable LSP scheduling for path computation
      and LSP setup/deletion based on the actual network resource usage
      duration of a traffic service. A scheduled LSP is characterized by a
      start time and a duration. When the end of the LSP life is reached,
      it is deleted to free up the resources for other LSPs (scheduled or
      not).<a href="#section-1-5" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-2">
      <h2 id="name-conventions-used-in-this-do">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-conventions-used-in-this-do" class="section-name selfRef">Conventions Used in This Document</a>
      </h2>
<p id="section-2-1">
    The key words "<span class="bcp14">MUST</span>", "<span class="bcp14">MUST NOT</span>",
    "<span class="bcp14">REQUIRED</span>", "<span class="bcp14">SHALL</span>", "<span class="bcp14">SHALL NOT</span>", "<span class="bcp14">SHOULD</span>", "<span class="bcp14">SHOULD NOT</span>",
    "<span class="bcp14">RECOMMENDED</span>", "<span class="bcp14">NOT RECOMMENDED</span>",
    "<span class="bcp14">MAY</span>", and "<span class="bcp14">OPTIONAL</span>" in this document are
    to be interpreted as
    described in BCP 14 <span>[<a href="#RFC2119" class="xref">RFC2119</a>]</span> <span>[<a href="#RFC8174" class="xref">RFC8174</a>]</span> 
    when, and only when, they appear in all capitals, as shown here.<a href="#section-2-1" class="pilcrow">¶</a></p>
<section id="section-2.1">
        <h3 id="name-terminology">
<a href="#section-2.1" class="section-number selfRef">2.1. </a><a href="#name-terminology" class="section-name selfRef">Terminology</a>
        </h3>
<p id="section-2.1-1">The following terminology is reused from existing PCE
        documents.<a href="#section-2.1-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-2.1-2.1">Active Stateful PCE <span>[<a href="#RFC8051" class="xref">RFC8051</a>]</span><a href="#section-2.1-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.2">Delegation <span>[<a href="#RFC8051" class="xref">RFC8051</a>]</span><a href="#section-2.1-2.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.3">PCE-initiated LSP <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span><a href="#section-2.1-2.3" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.4">PCC <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span><a href="#section-2.1-2.4" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.5">PCE <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span><a href="#section-2.1-2.5" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.6">TE LSP <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span><a href="#section-2.1-2.6" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.7">TED (Traffic Engineering Database) <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span><a href="#section-2.1-2.7" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.1-2.8">LSP-DB (LSP State Database) <span>[<a href="#RFC8051" class="xref">RFC8051</a>]</span><a href="#section-2.1-2.8" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-2.1-3">In addition, this document defines the following
        terminologies.<a href="#section-2.1-3" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-2.1-4">
          <dt id="section-2.1-4.1">Scheduled TE LSP (or Scheduled LSP for short):</dt>
          <dd style="margin-left: 1.5em" id="section-2.1-4.2">
            An LSP with scheduling
            attributes that carries traffic flow demand at a start time and
            lasts for a certain duration (or from a start time to an end time,
            where the end time is the start time plus the duration). 
            A scheduled LSP is also called a "temporal LSP".
            The PCE operates path computation per
            LSP availability for the required time and duration.<a href="#section-2.1-4.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.1-4.3">Scheduled LSP-DB (SLSP-DB):</dt>
          <dd style="margin-left: 1.5em" id="section-2.1-4.4">A database of scheduled LSPs.<a href="#section-2.1-4.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.1-4.5">Scheduled TED:</dt>
          <dd style="margin-left: 1.5em" id="section-2.1-4.6">Traffic engineering database with the
            awareness of scheduled resources for TE. This database is
            generated by the PCE from the information in the TED and scheduled
     LSP-DB;
            it allows knowing, at any time, 
            the expected amount of available resources (discounting
            the possibility of failures in the future).<a href="#section-2.1-4.6" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.1-4.7">Start time (Start-Time):</dt>
          <dd style="margin-left: 1.5em" id="section-2.1-4.8">This value indicates when
            the scheduled LSP is used and the corresponding LSP must be set up
            and active. At other times (i.e., before the start time or after
            the start time plus duration), the LSP can be inactive to
            include the possibility of the resources being used by other
            services.<a href="#section-2.1-4.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.1-4.9">Duration:</dt>
          <dd style="margin-left: 1.5em" id="section-2.1-4.10">This value indicates the length of time that
            the LSP carries a traffic flow and the corresponding LSP
            must be set up and active. At the end of the duration, the LSP is
     torn down
            and removed from the database.<a href="#section-2.1-4.10" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
</section>
</section>
<section id="section-3">
      <h2 id="name-motivation-and-objectives">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-motivation-and-objectives" class="section-name selfRef">Motivation and Objectives</a>
      </h2>
<p id="section-3-1">A stateful PCE <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> can support
      better efficiency 
      by using LSP scheduling
      described in the use case of <span>[<a href="#RFC8051" class="xref">RFC8051</a>]</span>. 
      This requires the PCE to
      maintain the scheduled LSPs and their associated resource usage (e.g.,
      bandwidth for packet-switched network) as well as have the ability to
      trigger signaling for the LSP setup/tear-down at the correct time.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">Note that existing configuration tools can be used for LSP
      scheduling, but as highlighted in <span><a href="https://www.rfc-editor.org/rfc/rfc8231#section-3.1.3" class="relref">Section 3.1.3</a> of [<a href="#RFC8231" class="xref">RFC8231</a>]</span>  
      as well as discussions in
      <span>[<a href="#RFC8413" class="xref">RFC8413</a>]</span>, doing this as a part of PCEP
      in a
      centralized manner has obvious advantages.<a href="#section-3-2" class="pilcrow">¶</a></p>
<p id="section-3-3">This document provides a set of extensions to PCEP to enable LSP
      scheduling for LSP creation/deletion under the stateful control of a
      PCE and according to traffic service requests from customers, so as
      to improve the usage of network resources.<a href="#section-3-3" class="pilcrow">¶</a></p>
</section>
<section id="section-4">
      <h2 id="name-procedures-and-mechanisms">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-procedures-and-mechanisms" class="section-name selfRef">Procedures and Mechanisms</a>
      </h2>
<div id="LSPSchedulingOverview">
<section id="section-4.1">
        <h3 id="name-lsp-scheduling-overview">
<a href="#section-4.1" class="section-number selfRef">4.1. </a><a href="#name-lsp-scheduling-overview" class="section-name selfRef">LSP Scheduling Overview</a>
        </h3>
<p id="section-4.1-1">LSP scheduling allows PCEs and PCCs to provide scheduled LSP
        for customers' traffic services at its actual usage time, so as to
        improve the network resource utilization efficiency.<a href="#section-4.1-1" class="pilcrow">¶</a></p>
<p id="section-4.1-2">For stateful PCE supporting LSP scheduling, there are two types of
        LSP databases used in this document. One is the LSP-DB defined in PCEP
        <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, while the other is the
 scheduled LSP database (SLSP-DB). The SLSP-DB records
 scheduled LSPs and is used in conjunction with 
        the TED and LSP-DB. Note that the two types of LSP
        databases can be implemented in one physical database or two different
        databases. This is an implementation matter, and this document does
 not state any preference.<a href="#section-4.1-2" class="pilcrow">¶</a></p>
<p id="section-4.1-3">Furthermore, a scheduled TED can be generated from the scheduled
        LSP-DB, LSP-DB, and TED to indicate the network links and nodes with
        resource availability information for now and the future. The
 scheduled
        TED <span class="bcp14">MUST</span> be maintained by all PCEs within the network
        environment.<a href="#section-4.1-3" class="pilcrow">¶</a></p>
<p id="section-4.1-4">In the case of implementing PCC-initiated scheduled LSPs, when
        delegating a scheduled LSP, a PCC <span class="bcp14">MUST</span> include that
        LSP's scheduling parameters (see <a href="#SCHED-LSP-ATTRIBUTE" class="xref">Section 5.2.1</a>), including the start time and duration, using a
        Path Computation State Report (PCRpt) message.  Since the LSP is not
        yet signaled, at the time of delegation, the LSP would be in down
        state.  Upon receiving the delegation of the scheduled LSP, a stateful
        PCE <span class="bcp14">MUST</span> check whether the parameters are valid. If
        they are valid, it <span class="bcp14">SHALL</span> check the scheduled TED for
        the network resource availability on network nodes, compute a path for
        the LSP with the scheduling information, and update to the PCC as per
        the active stateful PCE techniques <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.<a href="#section-4.1-4" class="pilcrow">¶</a></p>
<p id="section-4.1-5">Note that the active stateful PCE can update to the PCC with the
        path for the scheduled LSP at any time. However, the PCC should not
        signal the LSP over the path after receiving these messages since the
        path is not active yet; the PCC signals the LSP at the start time.<a href="#section-4.1-5" class="pilcrow">¶</a></p>
<p id="section-4.1-6">In the case of multiple PCEs within a single domain, the PCE would
        need to synchronize their scheduling information with other PCEs
        within the domain. 

This could be achieved by proprietary database-synchronization techniques or
via a possible PCEP extension (see <span>[<a href="#I-D.litkowski-pce-state-sync" class="xref">PCE-STATE-SYNC</a>]</span>). The technique used to synchronize an
SLSP-DB is out of scope for this document.  When the scheduling information is
out of synchronization among some PCEs, some scheduled LSPs may not be set up
successfully.<a href="#section-4.1-6" class="pilcrow">¶</a></p>
<p id="section-4.1-7">The scheduled LSP can also be initiated by a PCE itself.  In the
        case of implementing a PCE-initiated scheduled LSP, the stateful PCE
        <span class="bcp14">SHALL</span> check the network resource availability for the
        traffic, compute a path for the scheduled LSP, and initiate a
        scheduled LSP at the PCC and synchronize the scheduled LSP to other
        PCEs. Note that the PCC could be notified immediately or at the start
        time of the scheduled LSP, based on the local policy.  In the former
        case, the SCHED-LSP-ATTRIBUTE TLV (see <a href="#SCHED-LSP-ATTRIBUTE" class="xref">Section 5.2.1</a>) <span class="bcp14">MUST</span>
        be included in the message, whereas for the latter, the
        SCHED-LSP-ATTRIBUTE TLV <span class="bcp14">SHOULD NOT</span> be included.  Either
        way, the synchronization to other PCEs <span class="bcp14">MUST</span> be done
        when the scheduled LSP is created.<a href="#section-4.1-7" class="pilcrow">¶</a></p>
<p id="section-4.1-8">In both modes, for activation of scheduled LSPs, the PCC
 <span class="bcp14">MUST</span> 
          initiate the setup of the scheduled LSP at the start time. 
          Similarly, on the scheduled usage expiry, the PCC
   <span class="bcp14">MUST</span>
     initiate the removal of the LSP
          based on the flag set in the SCHED-LSP-ATTRIBUTE TLV.<a href="#section-4.1-8" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-4.2">
        <h3 id="name-support-of-lsp-scheduling">
<a href="#section-4.2" class="section-number selfRef">4.2. </a><a href="#name-support-of-lsp-scheduling" class="section-name selfRef">Support of LSP Scheduling</a>
        </h3>
<section id="section-4.2.1">
          <h4 id="name-lsp-scheduling">
<a href="#section-4.2.1" class="section-number selfRef">4.2.1. </a><a href="#name-lsp-scheduling" class="section-name selfRef">LSP Scheduling</a>
          </h4>
<p id="section-4.2.1-1">For a scheduled LSP, a user configures it with an arbitrary
          scheduling period from time Ta to time Tb, which may be
          represented as [Ta, Tb].<a href="#section-4.2.1-1" class="pilcrow">¶</a></p>
<p id="section-4.2.1-2">When an LSP is configured with arbitrary scheduling period [Ta,
          Tb], a path satisfying the constraints for the LSP in the scheduling
          period is computed, and the LSP along the path is set up to carry
          traffic from time Ta to time Tb.<a href="#section-4.2.1-2" class="pilcrow">¶</a></p>
</section>
<section id="section-4.2.2">
          <h4 id="name-periodical-lsp-scheduling">
<a href="#section-4.2.2" class="section-number selfRef">4.2.2. </a><a href="#name-periodical-lsp-scheduling" class="section-name selfRef">Periodical LSP Scheduling</a>
          </h4>
<p id="section-4.2.2-1">In addition to LSP scheduling at an arbitrary time period, there
          is also periodical LSP scheduling.<a href="#section-4.2.2-1" class="pilcrow">¶</a></p>
<p id="section-4.2.2-2">Periodical LSP scheduling means an LSP has multiple time
   intervals
          and the LSP is set up to carry traffic in every time
          interval. It has a scheduling period such as [Ta, Tb], a number of
          repeats such as 10 (repeats 10 times), and a repeat cycle/time
          interval such as a week (repeats every week). The scheduling
          interval "[Ta, Tb] repeats n times with repeat cycle C" represents
          n+1 scheduling intervals as follows:<a href="#section-4.2.2-2" class="pilcrow">¶</a></p>
<p style="margin-left: 1.5em" id="section-4.2.2-3">
[Ta, Tb], [Ta+C, Tb+C], [Ta+2C, Tb+2C], ..., [Ta+nC, Tb+nC]<a href="#section-4.2.2-3" class="pilcrow">¶</a></p>
<p id="section-4.2.2-4">When an LSP is configured with a scheduling interval such as
          "[Ta, Tb] repeats 10 times with a repeat cycle of a week"
          (representing 11 scheduling intervals), a path satisfying the
          constraints for the LSP in every interval represented by the
          periodical scheduling interval is computed once.  Note that the path
          computed for one recurrence may be different from the path for
          another recurrence.  And then the LSP along the path is set up to
          carry traffic in each of the scheduling intervals. If there is no
          path satisfying the constraints for some of the intervals, the LSP
          <span class="bcp14">MUST NOT</span> be set up at all.


          It <span class="bcp14">MUST</span> generate a PCEP Error (PCErr) with 
          Error-Type = 29 (Path computation failure) and 
          Error-value = 5 (Constraints could not be met for some intervals).<a href="#section-4.2.2-4" class="pilcrow">¶</a></p>
<section id="section-4.2.2.1">
            <h5 id="name-elastic-time-lsp-scheduling">
<a href="#section-4.2.2.1" class="section-number selfRef">4.2.2.1. </a><a href="#name-elastic-time-lsp-scheduling" class="section-name selfRef">Elastic Time LSP Scheduling</a>
            </h5>
<p id="section-4.2.2.1-1">In addition to the basic LSP scheduling at an arbitrary time
            period, another option is elastic time intervals, which is
            represented as within -P and Q, where P and Q are amounts of time
            such as 300 seconds. P is called the elastic range lower bound,
     and Q
            is called the elastic range upper bound.<a href="#section-4.2.2.1-1" class="pilcrow">¶</a></p>
<p id="section-4.2.2.1-2">For a simple time interval such as [Ta, Tb] with an elastic
            range, elastic time interval "[Ta, Tb] within -P and Q" means a
            time period from (Ta+X) to (Tb+X), where -P &lt;= X &lt;= Q. Note
            that both Ta and Tb are shifted by the same X.
            
            This elastic time interval is suitable for the case where
            a user wants to have a scheduled LSP up to carry the traffic 
            in time interval [Ta, Tb] and has some flexibility on shifting 
            the time interval a little bit, such as up to P seconds
     earlier/left or 
            some time such as up to Q seconds later/right.<a href="#section-4.2.2.1-2" class="pilcrow">¶</a></p>
<p id="section-4.2.2.1-3">When an LSP is configured with elastic time interval "[Ta, Tb]
            within -P and Q", a path is computed such that the path satisfies
            the constraints for the LSP in the time period from (Ta+Xv) to
            (Tb+Xv), and an optimization is performed on Xv from -P to Q.
            The optimization makes 
            [Ta+Xv, Tb+Xv] the time interval closest to time interval
            [Ta, Tb] within the elastic range. The LSP along the path is set
            up to carry traffic in the time period from (Ta+Xv) to
     (Tb+Xv).<a href="#section-4.2.2.1-3" class="pilcrow">¶</a></p>
<p id="section-4.2.2.1-4">Similarly, for a recurrent time interval with an elastic range,
            elastic time interval "[Ta, Tb] repeats n times with repeat cycle
            C within -P and Q" represents n+1 simple elastic time intervals as
            follows:<a href="#section-4.2.2.1-4" class="pilcrow">¶</a></p>
<p style="margin-left: 1.5em" id="section-4.2.2.1-5"> [Ta+X0, Tb+X0], [Ta+C+X1, Tb+C+X1],
            ..., [Ta+nC+Xn, Tb+nC+Xn], where -P &lt;= Xi &lt;= Q, i = 0, 1, 2,
            ..., n.<a href="#section-4.2.2.1-5" class="pilcrow">¶</a></p>
<p id="section-4.2.2.1-6">If a user wants to keep the same repeat cycle between any two
            adjacent time intervals, elastic time interval "[Ta, Tb] repeats n
            times with repeat cycle C within -P and Q SYNC" may be used, which
            represents n+1 simple elastic time intervals as follows:<a href="#section-4.2.2.1-6" class="pilcrow">¶</a></p>
<p style="margin-left: 1.5em" id="section-4.2.2.1-7"> [Ta+X, Tb+X], [Ta+C+X, Tb+C+X], ..., [Ta+nC+X,
            Tb+nC+X], where -P &lt;= X &lt;= Q.<a href="#section-4.2.2.1-7" class="pilcrow">¶</a></p>
</section>
<section id="section-4.2.2.2">
            <h5 id="name-grace-periods">
<a href="#section-4.2.2.2" class="section-number selfRef">4.2.2.2. </a><a href="#name-grace-periods" class="section-name selfRef">Grace Periods</a>
            </h5>
<p id="section-4.2.2.2-1">Besides the stated time scheduling, a user may want to have
            some grace periods (short for "graceful time periods") for each or
            some of the time intervals for the LSP. Two grace periods may be
            configured for a time interval. One is the grace period before the
            time interval, called "Grace-Before", which extends the lifetime
            of the LSP by an amount of time (such as 30 seconds)
            before the time interval. The other grace period is after the
            time interval and is called "Grace-After"; it extends the lifetime
            of the LSP by an amount of time (such as 60 seconds)
            after the time interval.  Note that no network resources such as
            link bandwidth will be reserved for the LSP during the grace
            periods.<a href="#section-4.2.2.2-1" class="pilcrow">¶</a></p>
<p id="section-4.2.2.2-2">When an LSP is configured with a simple time interval such as
            [Ta, Tb] with grace periods such as Grace-Before GrB and
            Grace-After GrA, a path is computed such that the path satisfies
            the constraints for the LSP in the time period from Ta to Tb. The
            LSP along the path is set up to carry traffic in the time period
            from (Ta-GrB) to (Tb+GrA). 




During grace periods from (Ta-GrB) to Ta and from Tb to (Tb+GrA), the LSP is
up to carry traffic in best effort.<a href="#section-4.2.2.2-2" class="pilcrow">¶</a></p>
</section>
</section>
</section>
<section id="section-4.3">
        <h3 id="name-scheduled-lsp-creation">
<a href="#section-4.3" class="section-number selfRef">4.3. </a><a href="#name-scheduled-lsp-creation" class="section-name selfRef">Scheduled LSP Creation</a>
        </h3>
<p id="section-4.3-1">In order to realize PCC-initiated scheduled LSPs in a centralized
        network environment, a PCC <span class="bcp14">MUST</span> separate the setup of
 an LSP into two
        steps. The first step is to request/delegate and get an LSP but not
 signal it
        over the network. The second step is to signal the scheduled LSP over
        the Label Switching Routers (LSRs) at its start time.<a href="#section-4.3-1" class="pilcrow">¶</a></p>
<p id="section-4.3-2">For PCC-initiated scheduled LSPs, a PCC <span class="bcp14">MUST</span>
 delegate the scheduled LSP 
        by sending a PCRpt
        message by including its demanded
        resources with the scheduling information to a stateful
        PCE. Note that the PCC <span class="bcp14">MAY</span> use Path Computation
 Request (PCReq) and Path Computation Reply (PCRep) messages with
 scheduling information before delegating.<a href="#section-4.3-2" class="pilcrow">¶</a></p>
<p id="section-4.3-3">Upon receiving the delegation via PCRpt message, the stateful PCE
        <span class="bcp14">MUST</span> compute a path for the scheduled LSP per its start
 time and
        duration based on the network resource availability stored in the
        scheduled TED (see <a href="#LSPSchedulingOverview" class="xref">Section 4.1</a>).<a href="#section-4.3-3" class="pilcrow">¶</a></p>
<p id="section-4.3-4">The stateful PCE will send a Path Computation Update Request
 (PCUpd)
        message with the scheduled path information and the scheduled resource
        information for the scheduled LSP to the PCC.
      The stateful PCE <span class="bcp14">MUST</span> update its local scheduled LSP-DB
      and
      scheduled TED with the scheduled LSP and would need to synchronize the  
      scheduling information with other PCEs in the domain.<a href="#section-4.3-4" class="pilcrow">¶</a></p>
<p id="section-4.3-5">For a PCE-initiated scheduled LSP, the stateful PCE
        <span class="bcp14">MUST</span> automatically compute a path for the scheduled LSP
        per requests from network management systems, based on the network
        resource availability in the scheduled TED, and send an LSP Initiate
        Request (PCInitiate) message with the path information to the
        PCC. Based on the local policy, the PCInitiate message could be sent
        immediately to ask the PCC to create a scheduled LSP (as per this
        document), or the PCInitiate message could be sent at the start time
        to the PCC to create a normal LSP (as per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>).<a href="#section-4.3-5" class="pilcrow">¶</a></p>
<p id="section-4.3-6">For both PCC-initiated and PCE-initiated Scheduled LSPs:<a href="#section-4.3-6" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-4.3-7.1">The stateful PCE <span class="bcp14">MUST</span> update its local scheduled
   LSP-DB
            and scheduled TED with the scheduled LSP.<a href="#section-4.3-7.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-4.3-7.2">Upon receiving the PCUpd message or PCInitiate message for the
   scheduled
            LSP from PCEs with a found path, the PCC determines that it is a
            scheduled path for the LSP by the 
            SCHED-LSP-ATTRIBUTE TLV (see <a href="#SCHED-LSP-ATTRIBUTE" class="xref">Section 5.2.1</a>) or
            SCHED-PD-LSP-ATTRIBUTE TLV (see <a href="#SCHED-PD-LSP-ATTRIBUTE" class="xref">Section 5.2.2</a>)
            in the message and 
            does not trigger signaling for the LSP
            setup on LSRs immediately.<a href="#section-4.3-7.2" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-4.3-7.3">The stateful PCE <span class="bcp14">MUST</span> update the scheduled LSP
            parameters on any network events using the PCUpd message to the
     PCC. These
            changes are also synchronized to other PCEs.<a href="#section-4.3-7.3" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-4.3-7.4">When it is time for the LSP to be set up
            (i.e., at the start time), based on the value of the C flag for
     the
            scheduled TLV,
            either the PCC <span class="bcp14">MUST</span> trigger the LSP to be signaled
     or the delegated 
            PCE <span class="bcp14">MUST</span> send a PCUpd message to the head-end LSR
         providing the updated path to be signaled 
            (with the A flag set to indicate LSP activation).<a href="#section-4.3-7.4" class="pilcrow">¶</a>
</li>
        </ul>
</section>
<div id="lsp-modify">
<section id="section-4.4">
        <h3 id="name-scheduled-lsp-modifications">
<a href="#section-4.4" class="section-number selfRef">4.4. </a><a href="#name-scheduled-lsp-modifications" class="section-name selfRef">Scheduled LSP Modifications</a>
        </h3>
<p id="section-4.4-1">After a scheduled LSP is configured, a user may change its
        parameters, including the requested time and the bandwidth.
        For a periodic-scheduled LSP, its unused recurrences can be modified 
        or canceled.
        For a scheduled LSP that is currently active, its duration (the
 lifetime)
        can be reduced.<a href="#section-4.4-1" class="pilcrow">¶</a></p>
<p id="section-4.4-2">In the PCC-initiated case, the PCC <span class="bcp14">MUST</span> send the PCE
        a PCRpt message for the scheduled LSP with updated parameters, as well
        as scheduled information included in the SCHED-LSP-ATTRIBUTE TLV (see
        <a href="#SCHED-LSP-ATTRIBUTE" class="xref">Section 5.2.1</a>) or
        SCHED-PD-LSP-ATTRIBUTE TLV (see <a href="#SCHED-PD-LSP-ATTRIBUTE" class="xref">Section 5.2.2</a>) carried in the LSP object.  The PCE
        <span class="bcp14">SHOULD</span> take the updated resources and schedule into
        consideration, and update the new path for the scheduled LSP to the
        PCC, and synchronize to other PCEs in the network.

If the path cannot be set based on new requirements, the previous LSP will not
be impacted, and this <span class="bcp14">MUST</span> be conveyed by the use of an empty
Explicit Route Object (ERO) in the PCEP messages.<a href="#section-4.4-2" class="pilcrow">¶</a></p>
<p id="section-4.4-3">In the PCE-initiated case, the stateful PCE would recompute the
 path based on 
         updated parameters and scheduled information. If it has 
         already conveyed this information to the PCC by sending a PCInitiate 
         message, it <span class="bcp14">SHOULD</span> update the path and other
  scheduling and resource 
         information by sending a PCUpd message.<a href="#section-4.4-3" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-4.5">
        <h3 id="name-scheduled-lsp-activation-an">
<a href="#section-4.5" class="section-number selfRef">4.5. </a><a href="#name-scheduled-lsp-activation-an" class="section-name selfRef">Scheduled LSP Activation and Deletion</a>
        </h3>
<p id="section-4.5-1">In the PCC-initiated case, when it is time for the LSP to be set up
        (i.e., at the start time), based on the value of the C flag for the
        scheduled TLV, either the PCC <span class="bcp14">MUST</span> trigger the LSP to
        be signaled, or the delegated PCE <span class="bcp14">MUST</span> send a PCUpd
        message to the head-end LSR providing the updated path to be signaled
        (with the A flag set to indicate LSP activation).  The PCC
        <span class="bcp14">MUST</span> report the status of the active LSP as per the
        procedures in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>, and at this
        time, the LSP <span class="bcp14">MUST</span> be considered part of the LSP-DB.
        The A flag <span class="bcp14">MUST</span> be set in the scheduled TLV to indicate
        that the LSP is active now. After the scheduled duration expires,
        based on the C flag, the PCC <span class="bcp14">MUST</span> trigger the LSP
        deletion on itself, or the delegated PCE <span class="bcp14">MUST</span> send a
        PCUpd message to the PCC to delete the LSP as per the procedures in
        <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.<a href="#section-4.5-1" class="pilcrow">¶</a></p>
<p id="section-4.5-2">In the PCE-initiated case, based on the local policy, if the
 scheduled LSP is 
             already conveyed to the PCC at the time of creation, the handling
      of LSP 
             activation and deletion is handled in the same way as the
      PCC-initiated case,
             as per the setting of the C flag. Otherwise, the PCE
           <span class="bcp14">MUST</span> send the PCInitiate message 
             to the PCC at the start time to create a normal LSP without the
      scheduled TLV 
             and remove the LSP after the duration expires, as per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-4.5-2" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-5">
      <h2 id="name-pcep-objects-and-tlvs">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-pcep-objects-and-tlvs" class="section-name selfRef">PCEP Objects and TLVs</a>
      </h2>
<section id="section-5.1">
        <h3 id="name-stateful-pce-capability-tlv">
<a href="#section-5.1" class="section-number selfRef">5.1. </a><a href="#name-stateful-pce-capability-tlv" class="section-name selfRef">Stateful PCE Capability TLV</a>
        </h3>
<p id="section-5.1-1">A PCC and a PCE indicate their ability to support LSP scheduling
        during their PCEP session establishment phase. For an environment with
        multiple PCEs, the PCEs <span class="bcp14">SHOULD</span> also establish a PCEP
        session and indicate its ability to support LSP scheduling among PCEP
        peers. The OPEN object in the Open message contains the
        STATEFUL-PCE-CAPABILITY TLV. Note that the STATEFUL-PCE-CAPABILITY TLV
        is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> and updated in
        <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> and <span>[<a href="#RFC8232" class="xref">RFC8232</a>]</span>.  In this document, we define a new flag bit B
        (LSP-SCHEDULING-CAPABILITY) in the Flags field of the
        STATEFUL-PCE-CAPABILITY TLV to indicate the support of LSP
        scheduling. We also define another flag bit PD (PD-LSP-CAPABILITY) to
        indicate the support of LSP periodical scheduling.<a href="#section-5.1-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.1-2">
          <dt id="section-5.1-2.1">B (LSP-SCHEDULING-CAPABILITY) - 1 bit (Bit Position 22):</dt>
          <dd style="margin-left: 1.5em" id="section-5.1-2.2">If set to 1
              by a PCC, the B flag indicates that the PCC allows LSP
              scheduling; if set to 1 by a PCE, the B flag indicates that the
              PCE is capable of LSP scheduling. The B bit <span class="bcp14">MUST</span>
       be set by both
              PCEP peers in order to support LSP scheduling for path
              computation.<a href="#section-5.1-2.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-5.1-2.3">PD (PD-LSP-CAPABILITY) - 1 bit (Bit Position - 21):</dt>
          <dd style="margin-left: 1.5em" id="section-5.1-2.4">
              If set to 1 by a
              PCC, the PD flag indicates that the PCC allows LSP scheduling
              periodically; if set to 1 by a PCE, the PD flag indicates that
              the PCE is capable of periodical LSP scheduling. Both the PD bit
       and 
              the B bit
              <span class="bcp14">MUST</span>
              be set to 1 by both PCEP peers in order to support periodical
       LSP
              scheduling for path computation. 

              If the PD bit or B bit is 0, then
              the periodical LSP scheduling capability <span class="bcp14">MUST</span> be
   ignored.<a href="#section-5.1-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
</section>
<section id="section-5.2">
        <h3 id="name-lsp-object">
<a href="#section-5.2" class="section-number selfRef">5.2. </a><a href="#name-lsp-object" class="section-name selfRef">LSP Object</a>
        </h3>
<p id="section-5.2-1">The LSP object is defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>. 
          This document adds an
          optional SCHED-LSP-ATTRIBUTE TLV for normal LSP scheduling and an
          optional SCHED-PD-LSP-ATTRIBUTE TLV for periodical LSP
          scheduling. The LSP object for a scheduled LSP <span class="bcp14">MUST NOT</span> include
          these two TLVs. Only one scheduling, either normal or periodical,
          is allowed for a scheduled LSP.<a href="#section-5.2-1" class="pilcrow">¶</a></p>
<p id="section-5.2-2">The presence of the SCHED-LSP-ATTRIBUTE TLV in the LSP object
          indicates that this LSP is normal scheduling while the
          SCHED-PD-LSP-ATTRIBUTE TLV indicates that this scheduled LSP is
          periodical. The SCHED-LSP-ATTRIBUTE TLV <span class="bcp14">MUST</span> be
     present in the LSP object for each normal-scheduled LSP carried in
       the PCEP messages. The
          SCHED-PD-LSP-ATTRIBUTE TLV <span class="bcp14">MUST</span> be used in the LSP
   object for each periodic-scheduled LSP carried in the PCEP
   messages.<a href="#section-5.2-2" class="pilcrow">¶</a></p>
<p id="section-5.2-3">Only one SCHED-LSP-ATTRIBUTE TLV <span class="bcp14">SHOULD</span> be present
 in the LSP object. 
             If more than one SCHED-LSP-ATTRIBUTE TLV is found, 
             the first instance is processed and others ignored.

             The SCHED-PD-LSP-ATTRIBUTE TLV is the same as the 
             SCHED-LSP-ATTRIBUTE TLV with regard to its presence in the LSP
 object.<a href="#section-5.2-3" class="pilcrow">¶</a></p>
<div id="SCHED-LSP-ATTRIBUTE">
<section id="section-5.2.1">
          <h4 id="name-sched-lsp-attribute-tlv">
<a href="#section-5.2.1" class="section-number selfRef">5.2.1. </a><a href="#name-sched-lsp-attribute-tlv" class="section-name selfRef">SCHED-LSP-ATTRIBUTE TLV</a>
          </h4>
<p id="section-5.2.1-1">The SCHED-LSP-ATTRIBUTE TLV <span class="bcp14">MAY</span> be included as an
   optional TLV
            within the LSP object for LSP scheduling for the requesting
            traffic service.<a href="#section-5.2.1-1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-2">This TLV <span class="bcp14">MUST NOT</span> be included unless both PCEP
   peers have set the B
            (LSP-SCHEDULING-CAPABILITY) bit in the STATEFUL-PCE-CAPABILITY TLV
            carried in the Open message to one.
            If the TLV is received by a peer when both peers
            didn't set the B bit to one, the peer <span class="bcp14">MUST</span> generate
            a PCEP Error (PCErr) with a PCEP-ERROR object
            having Error-Type = 19 (Invalid Operation) and 
            Error-value = 15 (Attempted LSP scheduling while the scheduling 
            capability was not advertised).<a href="#section-5.2.1-2" class="pilcrow">¶</a></p>
<p id="section-5.2.1-3">The format of the SCHED-LSP-ATTRIBUTE TLV is shown in <a href="#sched-lsp-attr-tlv" class="xref">Figure 1</a>.<a href="#section-5.2.1-3" class="pilcrow">¶</a></p>
<span id="name-sched-lsp-attribute-tlv-2"></span><div id="sched-lsp-attr-tlv">
<figure id="figure-1">
            <div class="artwork art-text alignLeft" id="section-5.2.1-4.1">
<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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|             Type (49)         |          Length               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |R|C|A|G|               Reserved (0)                    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       Start-Time                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         Duration                              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   GrB / Elastic-Lower-Bound   |   GrA / Elastic-Upper-Bound   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-sched-lsp-attribute-tlv-2" class="selfRef">SCHED-LSP-ATTRIBUTE TLV</a>
            </figcaption></figure>
</div>
<p id="section-5.2.1-5">The type of the TLV is 49, and the TLV has a fixed length of
            16 octets.<a href="#section-5.2.1-5" class="pilcrow">¶</a></p>
<p id="section-5.2.1-6">The fields in the format are:<a href="#section-5.2.1-6" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2.1-7">
            <dt id="section-5.2.1-7.1">Flags (8 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-7.2">
              <p id="section-5.2.1-7.2.1">The following flags are defined in this document.<a href="#section-5.2.1-7.2.1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2.1-7.2.2">
                <dt id="section-5.2.1-7.2.2.1">R (1 bit):</dt>
                <dd style="margin-left: 1.5em" id="section-5.2.1-7.2.2.2">
                  <p id="section-5.2.1-7.2.2.2.1">
                Set to 1 to indicate that the Start-Time is a relative time,
 which is the number of seconds from the
                current time. 
                The PCEs and PCCs <span class="bcp14">MUST</span> synchronize their clocks 
                when relative time is used. 
                It is <span class="bcp14">RECOMMENDED</span> that the Network Time
 Protocol 
                <span>[<a href="#RFC5905" class="xref">RFC5905</a>]</span> 
                be used to synchronize clocks among them.  
                When the transmission delay from a PCE or PCC to another PCE
 or PCC 
                is too big (such as greater than 1 second), the scheduling
 interval
                represented is not accurate if the delay is not considered.
                Set to 0 to indicate that the 32-bit Start-Time is an
                absolute time, which is the number of seconds since the epoch.
                The epoch is 1 January 1970 at 00:00 UTC.
                It wraps around every 2^32 seconds, which is roughly
                136 years. The next wraparound will occur in the year 2106.
         The received Start-Time is considered after the
         wraparound if the resulting value is less than the current time.
         In that case, the value of the 32-bit Start-Time is considered
         to be the number of seconds from the time of wraparound (because
         the Start-Time is always a future time).<a href="#section-5.2.1-7.2.2.2.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.2.2.2.2"></p>
</dd>
                <dd class="break"></dd>
<dt id="section-5.2.1-7.2.2.3">C (1 bit):</dt>
                <dd style="margin-left: 1.5em" id="section-5.2.1-7.2.2.4">
                  <p id="section-5.2.1-7.2.2.4.1">Set to 1 to indicate that the 
                PCC is responsible to set up and remove the scheduled LSP
 based on the 
                Start-Time and Duration. 
                The PCE holds these responsibilities when the bit is set to
 zero.<a href="#section-5.2.1-7.2.2.4.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.2.2.4.2"></p>
</dd>
                <dd class="break"></dd>
<dt id="section-5.2.1-7.2.2.5">A (1 bit):</dt>
                <dd style="margin-left: 1.5em" id="section-5.2.1-7.2.2.6">
                  <p id="section-5.2.1-7.2.2.6.1">Set to 1 to indicate that the 
                scheduled LSP has been activated.<a href="#section-5.2.1-7.2.2.6.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.2.2.6.2"></p>
</dd>
                <dd class="break"></dd>
<dt id="section-5.2.1-7.2.2.7">G (1 bit):</dt>
                <dd style="margin-left: 1.5em" id="section-5.2.1-7.2.2.8">
                  <p id="section-5.2.1-7.2.2.8.1">Set to 1 to indicate that the 
                grace period is included in the fields 
                GrB/Elastic-Lower-Bound and GrA/Elastic-Upper-Bound; 
                set to 0 to indicate that the elastic range is included in the
 fields.<a href="#section-5.2.1-7.2.2.8.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.2.2.8.2"></p>
</dd>
              <dd class="break"></dd>
</dl>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-7.3">Reserved (24 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-7.4">
              <p id="section-5.2.1-7.4.1">This field <span class="bcp14">MUST</span> be set to
                zero on transmission and <span class="bcp14">MUST</span> be ignored on
 receipt.<a href="#section-5.2.1-7.4.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.4.2"></p>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-7.5">Start-Time (32 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-7.6">
              <p id="section-5.2.1-7.6.1">This value, in seconds,
                indicates when the scheduled LSP is used to carry traffic and
                the corresponding LSP <span class="bcp14">MUST</span> be set up and
 activated. 
 
                Note that the transmission delay <span class="bcp14">SHOULD</span> be
 considered when R=1 
                and the value of Start-Time is small.<a href="#section-5.2.1-7.6.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.6.2"></p>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-7.7">Duration (32 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-7.8">
              <p id="section-5.2.1-7.8.1">This value, in seconds, indicates the duration that the LSP
              carries a traffic flow and the corresponding LSP
              <span class="bcp14">MUST</span> be up to carry traffic. At the expiry of
              this duration, the LSP <span class="bcp14">MUST</span> be torn down and
              deleted.  A value of 0 <span class="bcp14">MUST NOT</span> be used in Duration
              since it does not make any sense.  The value of Duration
              <span class="bcp14">SHOULD</span> be greater than a constant
              MINIMUM-DURATION seconds, where MINIMUM-DURATION is 5.<a href="#section-5.2.1-7.8.1" class="pilcrow">¶</a></p>
<p id="section-5.2.1-7.8.2"></p>
</dd>
          <dd class="break"></dd>
</dl>
<p id="section-5.2.1-8">Start-Time indicates a time at or before which the scheduled LSP
          <span class="bcp14">MUST</span> be set up. When the R bit is set to 0, the value
          of Start-Time represents the number of seconds since the epoch.
          When the R bit is set to 1, the value of Start-Time represents the
          number of seconds from the current time.<a href="#section-5.2.1-8" class="pilcrow">¶</a></p>
<p id="section-5.2.1-9">In addition, the SCHED-LSP-ATTRIBUTE TLV contains the G flag set
          to 1 and a nonzero Grace-Before and Grace-After in the fields
          GrB/Elastic-Lower-Bound and GrA/Elastic-Upper-Bound if grace periods
          are configured.  It includes the G flag set to 0 and a nonzero
          elastic range lower bound and upper bound in the fields if there is
          an elastic range configured.  A TLV can configure a nonzero grace
          period or elastic range, but it <span class="bcp14">MUST NOT</span> provide both
          for an LSP.<a href="#section-5.2.1-9" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2.1-10">
            <dt id="section-5.2.1-10.1">GrB (Grace-Before, 16 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-10.2">The grace period time
                length, in seconds, before the start time.<a href="#section-5.2.1-10.2" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-10.3">GrA (Grace-After, 16 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-10.4">The grace period time
     length,
                in seconds, after time interval [start time, start time +
                duration].<a href="#section-5.2.1-10.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-10.5">Elastic-Lower-Bound (16 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-10.6">The maximum amount of
     time,
                in seconds, that the time interval can shift lower/left.<a href="#section-5.2.1-10.6" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.1-10.7">Elastic-Upper-Bound (16 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.1-10.8">The maximum amount of
     time,
                in seconds, that the time interval can shift
 higher/right.<a href="#section-5.2.1-10.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
</div>
<div id="SCHED-PD-LSP-ATTRIBUTE">
<section id="section-5.2.2">
          <h4 id="name-sched-pd-lsp-attribute-tlv">
<a href="#section-5.2.2" class="section-number selfRef">5.2.2. </a><a href="#name-sched-pd-lsp-attribute-tlv" class="section-name selfRef">SCHED-PD-LSP-ATTRIBUTE TLV</a>
          </h4>
<p id="section-5.2.2-1">The periodical LSP is a special case of LSP scheduling. The
            traffic service happens in a series of repeated time intervals.
            The SCHED-PD-LSP-ATTRIBUTE TLV can be included as an optional TLV
            within the LSP object for this periodical LSP scheduling.<a href="#section-5.2.2-1" class="pilcrow">¶</a></p>
<p id="section-5.2.2-2">This TLV <span class="bcp14">MUST NOT</span> be included unless both PCEP
   peers have set the B
            (LSP-SCHEDULING-CAPABILITY) bit and PD (PD-LSP-CAPABILITY) bit in
            STATEFUL-PCE-CAPABILITY TLV carried in Open message to one.
            If the TLV is received by a peer when either bit is zero (or both
         bits are zero), the peer <span class="bcp14">MUST</span> generate
            a PCEP Error (PCErr) with a PCEP-ERROR object
                having Error-Type = 19 (Invalid Operation) and 
                Error-value = 15 (Attempted LSP scheduling while the
 scheduling
                capability was not advertised).<a href="#section-5.2.2-2" class="pilcrow">¶</a></p>
<p id="section-5.2.2-3">The format of the SCHED-PD-LSP-ATTRIBUTE TLV is shown in <a href="#sched-pd-lsp-attr-tlv" class="xref">Figure 2</a>.<a href="#section-5.2.2-3" class="pilcrow">¶</a></p>
<span id="name-sched-pd-lsp-attribute-tlv-2"></span><div id="sched-pd-lsp-attr-tlv">
<figure id="figure-2">
            <div class="artwork art-text alignLeft" id="section-5.2.2-4.1">
<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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|            Type (50)          |         Length                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Flags|R|C|A|G| Opt   |           NR          |  Reserved (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                           Start-Time                          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            Duration                           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                        Repeat-time-length                     |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   GrB / Elastic-Lower-Bound   |   GrA / Elastic-Upper-Bound   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-sched-pd-lsp-attribute-tlv-2" class="selfRef">SCHED-PD-LSP-ATTRIBUTE TLV</a>
            </figcaption></figure>
</div>
<p id="section-5.2.2-5">The type of the TLV is 50, and the TLV has a fixed length of 20
          octets. The description, format, and meaning of the flags (R, C, A,
          and G bits), Start-Time, Duration, GrB, GrA, Elastic-Lower-Bound,
          and Elastic-Upper-Bound fields remain the same as in the
          SCHED-LSP-ATTRIBUTE TLV.<a href="#section-5.2.2-5" class="pilcrow">¶</a></p>
<p id="section-5.2.2-6">The following fields are new:<a href="#section-5.2.2-6" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2.2-7">
            <dt id="section-5.2.2-7.1">Opt (4 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.2-7.2">
              <p id="section-5.2.2-7.2.1">Indicates options to repeat. 
                When a PCE receives a TLV with an unknown Opt value,
                it does not compute any path for the LSP. 
                It <span class="bcp14">MUST</span> generate a PCEP Error (PCErr) with a
 PCEP-ERROR object
                having Error-Type = 4 (Not supported object) and 
                Error-value = 4 (Unsupported parameter).<a href="#section-5.2.2-7.2.1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-5.2.2-7.2.2">
                <dt id="section-5.2.2-7.2.2.1"></dt>
                <dd style="margin-left: 1.5em" id="section-5.2.2-7.2.2.2">Opt = 1: repeat every month<a href="#section-5.2.2-7.2.2.2" class="pilcrow">¶</a>
</dd>
                <dd class="break"></dd>
<dt id="section-5.2.2-7.2.2.3"></dt>
                <dd style="margin-left: 1.5em" id="section-5.2.2-7.2.2.4">Opt = 2: repeat every year<a href="#section-5.2.2-7.2.2.4" class="pilcrow">¶</a>
</dd>
                <dd class="break"></dd>
<dt id="section-5.2.2-7.2.2.5"></dt>
                <dd style="margin-left: 1.5em" id="section-5.2.2-7.2.2.6">Opt = 3: repeat every Repeat-time-length<a href="#section-5.2.2-7.2.2.6" class="pilcrow">¶</a>
</dd>
              <dd class="break"></dd>
</dl>
<p id="section-5.2.2-7.2.3">
                A user may configure a Repeat-time-length in time units
                weeks, days, hours, minutes, and/or seconds.
                The value represented by these units
                is converted to the number of seconds in the TLV. 
                For example, repeat every 2 weeks is equivalent to repeat
 every 
                Repeat-time-length = 2*7*86,400 (seconds), where 86,400 is the 
                number of seconds per day.<a href="#section-5.2.2-7.2.3" class="pilcrow">¶</a></p>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.2-7.3">NR (12 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.2-7.4">The number of repeats.
                During each repetition, LSP carries traffic.<a href="#section-5.2.2-7.4" class="pilcrow">¶</a>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.2-7.5">Reserved (8 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.2-7.6">
              <p id="section-5.2.2-7.6.1">This field <span class="bcp14">MUST</span> be set to
                zero on transmission and <span class="bcp14">MUST</span> be ignored on
 receipt.<a href="#section-5.2.2-7.6.1" class="pilcrow">¶</a></p>
</dd>
            <dd class="break"></dd>
<dt id="section-5.2.2-7.7">Repeat-time-length (32 bits):</dt>
            <dd style="margin-left: 1.5em" id="section-5.2.2-7.8">The time in
                seconds between the Start-Time of one repetition and 
                the Start-Time of the next repetition.<a href="#section-5.2.2-7.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
</dl>
</section>
</div>
</section>
</section>
<div id="pcep-msgs">
<section id="section-6">
      <h2 id="name-the-pcep-messages">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-the-pcep-messages" class="section-name selfRef">The PCEP Messages</a>
      </h2>
<section id="section-6.1">
        <h3 id="name-the-pcrpt-message">
<a href="#section-6.1" class="section-number selfRef">6.1. </a><a href="#name-the-pcrpt-message" class="section-name selfRef">The PCRpt Message</a>
        </h3>
<p id="section-6.1-1">The Path Computation State Report (PCRpt) message is a PCEP message
 sent by a PCC
      to a PCE to report the status of one or more LSPs, as per <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>.  Each LSP State
      Report in a PCRpt message contains the actual LSP's path,
      bandwidth, operational and administrative status, etc.  An LSP
      Status Report carried in a PCRpt message is also used in
      delegation or revocation of control of an LSP to/from a PCE.  In the
      case of a scheduled LSP, a scheduled TLV <span class="bcp14">MUST</span> be carried
      in the LSP
      object, and the ERO conveys the intended path for the scheduled LSP. The
      scheduled LSP 
      <span class="bcp14">MUST</span> be delegated to a PCE.<a href="#section-6.1-1" class="pilcrow">¶</a></p>
</section>
<section id="section-6.2">
        <h3 id="name-the-pcupd-message">
<a href="#section-6.2" class="section-number selfRef">6.2. </a><a href="#name-the-pcupd-message" class="section-name selfRef">The PCUpd Message</a>
        </h3>
<p id="section-6.2-1">The Path Computation Update Request (PCUpd) message is a PCEP
 message sent by a
      PCE to a PCC to update LSP parameters on one or more LSPs, as per <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>. Each
      LSP Update Request in a PCUpd message contains all LSP
      parameters that a PCE wishes to be set for a given LSP. In the case of a
      scheduled LSP, a scheduled TLV <span class="bcp14">MUST</span> be carried in the LSP
      object, and the ERO conveys the intended path for the scheduled LSP. If
      no path can be found, an empty ERO is used. The A bit is used in the
      PCUpd
      message to indicate the activation of the scheduled LSP if the PCE is
      responsible for the activation (as per the C bit).<a href="#section-6.2-1" class="pilcrow">¶</a></p>
</section>
<section id="section-6.3">
        <h3 id="name-the-pcinitiate-message">
<a href="#section-6.3" class="section-number selfRef">6.3. </a><a href="#name-the-pcinitiate-message" class="section-name selfRef">The PCInitiate Message</a>
        </h3>
<p id="section-6.3-1">The LSP Initiate Request (PCInitiate) message is a PCEP message
 sent
          by a PCE to a PCC to trigger LSP instantiation or deletion, as per
     <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>. 
          In the case of a scheduled LSP, based on the local policy, the PCE
     <span class="bcp14">MAY</span> convey the scheduled LSP to the PCC by
     including 
 
          a scheduled TLV in the LSP object. Alternatively, the PCE would
     initiate the LSP only at the start time of the
          scheduled LSP, as per <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>,
   without the use of scheduled TLVs.<a href="#section-6.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-6.4">
        <h3 id="name-the-pcreq-message">
<a href="#section-6.4" class="section-number selfRef">6.4. </a><a href="#name-the-pcreq-message" class="section-name selfRef">The PCReq message</a>
        </h3>
<p id="section-6.4-1">The Path Computation Request (PCReq) message is a PCEP message sent 
            by a PCC to a PCE to request a path computation <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>, and it may 
            contain the LSP object <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>
     to identify the LSP for which the path 
            computation is requested. In the case of a scheduled LSP, a
     scheduled TLV 
            <span class="bcp14">MUST</span> be carried in the LSP object in the PCReq
     message to request the 
            path computation based on the scheduled TED and LSP-DB. A PCC
         <span class="bcp14">MAY</span> use the
            PCReq message to obtain the scheduled path before delegating the 
            LSP. The parameters of the LSP may be changed 
            (refer to <a href="#lsp-modify" class="xref">Section 4.4</a>).<a href="#section-6.4-1" class="pilcrow">¶</a></p>
</section>
<section id="section-6.5">
        <h3 id="name-the-pcrep-message">
<a href="#section-6.5" class="section-number selfRef">6.5. </a><a href="#name-the-pcrep-message" class="section-name selfRef">The PCRep Message</a>
        </h3>
<p id="section-6.5-1">The Path Computation Reply (PCRep) message is a PCEP message sent
 by a PCE to a PCC in reply to a path
 computation request <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>, and it
 may 
            contain the LSP object <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span>
         to identify the LSP for which the path 
            is computed.  A PCRep message can contain either a set of
      computed paths if the request can be satisfied or a negative
      reply if not.  A negative reply may indicate the reason why no
      path could be found. In the case of a scheduled LSP, a scheduled TLV 
            <span class="bcp14">MUST</span> be carried in the LSP object in PCRep message
     to indicate the 
            path computation based on the scheduled TED and LSP-DB. A PCC and
     PCE <span class="bcp14">MAY</span> use
            PCReq and PCRep messages to obtain the scheduled path before
     delegating the 
            LSP.<a href="#section-6.5-1" class="pilcrow">¶</a></p>
</section>
<section id="section-6.6">
        <h3 id="name-the-pcerr-message">
<a href="#section-6.6" class="section-number selfRef">6.6. </a><a href="#name-the-pcerr-message" class="section-name selfRef">The PCErr Message</a>
        </h3>
<p id="section-6.6-1">The PCEP Error (PCErr) message is a PCEP message, as described in
        <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>, for error reporting. This
        document defines new error values for several error types to cover
        failures specific to scheduling and reuses the applicable error types
        and error values of <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> and
        <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> wherever appropriate.<a href="#section-6.6-1" class="pilcrow">¶</a></p>
<p id="section-6.6-2">The PCEP extensions for scheduling <span class="bcp14">MUST NOT</span> be used
        if one or both of the PCEP speakers have not set the corresponding
        bits in the STATEFUL-PCE-CAPABILITY TLV in their respective Open
        messages to one.  If the PCEP speaker supports the extensions of this
        specification but did not advertise this capability, then upon receipt
        of LSP object with the scheduled TLV, it <span class="bcp14">MUST</span> generate
        a PCEP Error (PCErr) with Error-Type = 19 (Invalid

   Operation) and Error-value = 15 (Attempted LSP scheduling while the
   scheduling capability was not advertised), and it
   <span class="bcp14">SHOULD</span> ignore the TLV. As per <span><a href="https://www.rfc-editor.org/rfc/rfc5440#section-7.1" class="relref">Section 7.1</a> of [<a href="#RFC5440" class="xref">RFC5440</a>]</span>, 
   a legacy PCEP implementation that does not understand this specification
   would consider a scheduled TLV unknown and ignore it.<a href="#section-6.6-2" class="pilcrow">¶</a></p>
<p id="section-6.6-3">If the PCC
   decides that the scheduling parameters proposed in the PCUpd/PCInitiate
   message are
   unacceptable, it <span class="bcp14">MUST</span> report this error by including the
   LSP-ERROR-CODE TLV (<span><a href="https://www.rfc-editor.org/rfc/rfc8231#section-7.3.3" class="relref">Section 7.3.3</a> of [<a href="#RFC8231" class="xref">RFC8231</a>]</span>) 
   with LSP Error-value = 4 (Unacceptable parameters) in the LSP object 
   (with the scheduled TLV) in the PCRpt message to the PCE.<a href="#section-6.6-3" class="pilcrow">¶</a></p>
<p id="section-6.6-4">The scheduled TLV <span class="bcp14">MUST</span> be included in the LSP object
 for the scheduled LSPs. 
 If the TLV is missing, the receiving PCEP speaker <span class="bcp14">MUST</span>
 send a PCErr message with Error-Type = 6 (Mandatory Object missing)
 and

 Error-value = 16 (Scheduled TLV missing).<a href="#section-6.6-4" class="pilcrow">¶</a></p>
</section>
</section>
</div>
<section id="section-7">
      <h2 id="name-security-considerations">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-7-1">This document defines the LSP-SCHEDULING-CAPABILITY TLV and 
      SCHED-LSP-ATTRIBUTE TLV; the security considerations
      discussed 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. In some deployments,
      the scheduling information could provide details about the network
      operations that could be deemed extra sensitive.  
     Additionally, snooping of PCEP messages
   with such data or using PCEP messages for network reconnaissance may
   give an attacker sensitive information about the operations of the
   network.  
   A single PCEP message can now instruct a PCC to set up and tear down 
   an LSP every second for a number of times. That single message could  
   have a significant effect on the network.  

   Thus, such deployments <span class="bcp14">SHOULD</span> employ suitable PCEP security
   mechanisms 
   like TCP Authentication Option (TCP-AO), which is discussed in <span>[<a href="#RFC5925" class="xref">RFC5925</a>]</span> and
   <span>[<a href="#RFC8253" class="xref">RFC8253</a>]</span>. Note that
   <span>[<a href="#RFC8253" class="xref">RFC8253</a>]</span> is considered a security
   enhancement and thus is much better
   suited for sensitive information.

   PCCs may also need to apply some form of rate limit to the processing of 
   scheduled LSPs.<a href="#section-7-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8">
      <h2 id="name-manageability-consideration">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-manageability-consideration" class="section-name selfRef">Manageability Consideration</a>
      </h2>
<section id="section-8.1">
        <h3 id="name-control-of-function-and-pol">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-control-of-function-and-pol" class="section-name selfRef">Control of Function and Policy</a>
        </h3>
<p id="section-8.1-1">The LSP scheduling feature <span class="bcp14">MUST</span> be controlled per
 tunnel by the
        active stateful PCE. The values for parameters like start time and
        duration <span class="bcp14">SHOULD</span> be configurable by customer
 applications and based on
        the local policy at PCE. 
        The suggested default values for start time and duration are 
        one day (in seconds) from the current time and one year (in seconds),
        respectively. 
        One day has 86,400 seconds. One year has 31,536,000 seconds.<a href="#section-8.1-1" class="pilcrow">¶</a></p>
<p id="section-8.1-2">When configuring the parameters for time, a user
 <span class="bcp14">SHOULD</span> 
        consider leap years and leap seconds.
        If a scheduled LSP has a time interval containing a leap year,
        the duration of the LSP is 366 days plus the rest of the interval.<a href="#section-8.1-2" class="pilcrow">¶</a></p>
</section>
<section id="section-8.2">
        <h3 id="name-information-and-data-models">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-information-and-data-models" class="section-name selfRef">Information and Data Models</a>
        </h3>
<p id="section-8.2-1"> An implementation <span class="bcp14">SHOULD</span> allow the operator to view
 the information 
   about each scheduled LSP
   defined in this document.  To serve this purpose, the PCEP YANG
   module <span>[<a href="#I-D.ietf-pce-pcep-yang" class="xref">PCE-PCEP-YANG</a>]</span> could be
 extended.<a href="#section-8.2-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.3">
        <h3 id="name-liveness-detection-and-moni">
<a href="#section-8.3" class="section-number selfRef">8.3. </a><a href="#name-liveness-detection-and-moni" class="section-name selfRef">Liveness Detection and Monitoring</a>
        </h3>
<p id="section-8.3-1">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-8.3-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.4">
        <h3 id="name-verify-correct-operations">
<a href="#section-8.4" class="section-number selfRef">8.4. </a><a href="#name-verify-correct-operations" class="section-name selfRef">Verify Correct Operations</a>
        </h3>
<p id="section-8.4-1">Mechanisms defined in this document do not imply any new
 operation verification requirements in addition to those already
 listed in
        <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.

        An implementation <span class="bcp14">SHOULD</span> allow a user to view
        information, including the status of a scheduled LSP, through a
        Command Line Interface (CLI) tool.  In addition, it <span class="bcp14">SHOULD</span>
        check and handle the cases where there is a significant time
        correction or a clock skew between PCC and PCE.<a href="#section-8.4-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.5">
        <h3 id="name-requirements-on-other-proto">
<a href="#section-8.5" class="section-number selfRef">8.5. </a><a href="#name-requirements-on-other-proto" class="section-name selfRef">Requirements on Other Protocols</a>
        </h3>
<p id="section-8.5-1">Mechanisms defined in this document do not imply any new
        requirements on other protocols.<a href="#section-8.5-1" class="pilcrow">¶</a></p>
</section>
<section id="section-8.6">
        <h3 id="name-impact-on-network-operation">
<a href="#section-8.6" class="section-number selfRef">8.6. </a><a href="#name-impact-on-network-operation" class="section-name selfRef">Impact on Network Operations</a>
        </h3>
<p id="section-8.6-1">Mechanisms defined in this document do not have any impact on
        network operations in addition to those already listed in
        <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.<a href="#section-8.6-1" class="pilcrow">¶</a></p>
</section>
</section>
<section id="section-9">
      <h2 id="name-iana-considerations">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<section id="section-9.1">
        <h3 id="name-pcep-tlv-type-indicators">
<a href="#section-9.1" class="section-number selfRef">9.1. </a><a href="#name-pcep-tlv-type-indicators" class="section-name selfRef">PCEP TLV Type Indicators</a>
        </h3>
<p id="section-9.1-1">IANA maintains the "PCEP TLV Type Indicators" subregistry within the
    "Path
    Computation Element Protocol (PCEP) Numbers" registry. IANA has made the
    following allocations in this subregistry for the new PCEP TLVs defined in
    this document.<a href="#section-9.1-1" class="pilcrow">¶</a></p>
<span id="name-additions-to-pcep-tlv-type-"></span><div id="PCEP-TLVs">
<table class="center" id="table-1">
          <caption>
<a href="#table-1" class="selfRef">Table 1</a>:
<a href="#name-additions-to-pcep-tlv-type-" class="selfRef">Additions to PCEP TLV Type Indicators Subregistry</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">49</td>
              <td class="text-left" rowspan="1" colspan="1">SCHED-LSP-ATTRIBUTE</td>
              <td class="text-left" rowspan="1" colspan="1">This document</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">50</td>
              <td class="text-left" rowspan="1" colspan="1">SCHED-PD-LSP-ATTRIBUTE</td>
              <td class="text-left" rowspan="1" colspan="1">This document</td>
            </tr>
          </tbody>
        </table>
</div>
<section id="section-9.1.1">
          <h4 id="name-sched-pd-lsp-attribute-tlv-">
<a href="#section-9.1.1" class="section-number selfRef">9.1.1. </a><a href="#name-sched-pd-lsp-attribute-tlv-" class="section-name selfRef">SCHED-PD-LSP-ATTRIBUTE TLV Opt Field</a>
          </h4>
<p id="section-9.1.1-1">IANA has created and will maintain a new
subregistry named "SCHED-PD-LSP-ATTRIBUTE TLV Opt Field" 
within the "Path Computation Element Protocol (PCEP) Numbers" registry.
Initial values for the subregistry are given below. 
New values are assigned by Standards Action <span>[<a href="#RFC8126" class="xref">RFC8126</a>]</span>.<a href="#section-9.1.1-1" class="pilcrow">¶</a></p>
<span id="name-new-sched-pd-lsp-attribute-"></span><div id="opt-field">
<table class="center" id="table-2">
            <caption>
<a href="#table-2" class="selfRef">Table 2</a>:
<a href="#name-new-sched-pd-lsp-attribute-" class="selfRef">New SCHED-PD-LSP-ATTRIBUTE TLV Opt Field Subregistry</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">0</td>
                <td class="text-left" rowspan="1" colspan="1">Reserved</td>
                <td class="text-left" rowspan="1" colspan="1"></td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">1</td>
                <td class="text-left" rowspan="1" colspan="1">REPEAT-EVERY-MONTH </td>
                <td class="text-left" rowspan="1" colspan="1">This document</td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">2</td>
                <td class="text-left" rowspan="1" colspan="1">REPEAT-EVERY-YEAR</td>
                <td class="text-left" rowspan="1" colspan="1">This document </td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">3</td>
                <td class="text-left" rowspan="1" colspan="1">REPEAT-EVERY-REPEAT-TIME-LENGTH</td>
                <td class="text-left" rowspan="1" colspan="1">This document </td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">4-14</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">15</td>
                <td class="text-left" rowspan="1" colspan="1">Reserved</td>
                <td class="text-left" rowspan="1" colspan="1"></td>
              </tr>
            </tbody>
          </table>
</div>
</section>
<section id="section-9.1.2">
          <h4 id="name-schedule-tlvs-flag-field">
<a href="#section-9.1.2" class="section-number selfRef">9.1.2. </a><a href="#name-schedule-tlvs-flag-field" class="section-name selfRef">Schedule TLVs Flag Field</a>
          </h4>
<p id="section-9.1.2-1">IANA has created a new subregistry named "Schedule TLVs Flag
          Field" within the "Path Computation Element Protocol (PCEP) Numbers"
          registry.  New values are 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-9.1.2-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-9.1.2-2.1">Bit number (counting from bit 0 as the most significant
     bit)<a href="#section-9.1.2-2.1" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-9.1.2-2.2">Capability description<a href="#section-9.1.2-2.2" class="pilcrow">¶</a>
</li>
            <li class="normal" id="section-9.1.2-2.3">Defining RFC<a href="#section-9.1.2-2.3" class="pilcrow">¶</a>
</li>
          </ul>
<p id="section-9.1.2-3">The following values are defined in this document:<a href="#section-9.1.2-3" class="pilcrow">¶</a></p>
<span id="name-new-schedule-tlvs-flag-fiel"></span><div id="schedule-tlvs">
<table class="center" id="table-3">
            <caption>
<a href="#table-3" class="selfRef">Table 3</a>:
<a href="#name-new-schedule-tlvs-flag-fiel" class="selfRef">New Schedule TLVs Flag Field Subregistry</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">0-3</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">4</td>
                <td class="text-left" rowspan="1" colspan="1">Relative Time (R-bit)</td>
                <td class="text-left" rowspan="1" colspan="1">This document</td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">5</td>
                <td class="text-left" rowspan="1" colspan="1">PCC Responsible (C-bit)</td>
                <td class="text-left" rowspan="1" colspan="1">This document</td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">6</td>
                <td class="text-left" rowspan="1" colspan="1">LSP Activated (A-bit)</td>
                <td class="text-left" rowspan="1" colspan="1">This document</td>
              </tr>
              <tr>
                <td class="text-left" rowspan="1" colspan="1">7</td>
                <td class="text-left" rowspan="1" colspan="1">Grace Period Included (G-bit)</td>
                <td class="text-left" rowspan="1" colspan="1">This document</td>
              </tr>
            </tbody>
          </table>
</div>
</section>
</section>
<section id="section-9.2">
        <h3 id="name-stateful-pce-capability-tlv-">
<a href="#section-9.2" class="section-number selfRef">9.2. </a><a href="#name-stateful-pce-capability-tlv-" class="section-name selfRef">STATEFUL-PCE-CAPABILITY TLV Flag Field</a>
        </h3>
<p id="section-9.2-1">This document defines new bits in the Flags field in the
        STATEFUL-PCE-CAPABILITY TLV in the OPEN object. IANA maintains the
        "STATEFUL-PCE-CAPABILITY TLV Flag Field" subregistry within the "Path
        Computation Element Protocol (PCEP) Numbers" registry. IANA has
        made the following allocations in this subregistry.<a href="#section-9.2-1" class="pilcrow">¶</a></p>
<span id="name-additions-to-stateful-pce-c"></span><div id="stateful-pce-flag">
<table class="center" id="table-4">
          <caption>
<a href="#table-4" class="selfRef">Table 4</a>:
<a href="#name-additions-to-stateful-pce-c" class="selfRef">Additions to STATEFUL-PCE-CAPABILITY TLV Flag Field Subregistry</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">22</td>
              <td class="text-left" rowspan="1" colspan="1">LSP-SCHEDULING-CAPABILITY (B-bit)</td>
              <td class="text-left" rowspan="1" colspan="1">This document</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">21</td>
              <td class="text-left" rowspan="1" colspan="1">PD-LSP-CAPABILITY (PD-bit)</td>
              <td class="text-left" rowspan="1" colspan="1">This document</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
<section id="section-9.3">
        <h3 id="name-pcep-error-object-error-typ">
<a href="#section-9.3" class="section-number selfRef">9.3. </a><a href="#name-pcep-error-object-error-typ" class="section-name selfRef">PCEP-ERROR Object Error Types and Values</a>
        </h3>
<p id="section-9.3-1">IANA has allocated the following new error types to the existing
 error values 
   within the "PCEP-ERROR Object Error Types and Values" subregistry of
   the "Path Computation Element Protocol (PCEP) Numbers" registry:<a href="#section-9.3-1" class="pilcrow">¶</a></p>
<span id="name-additions-to-pcep-error-obj"></span><div id="PCEP-error">
<table class="center" id="table-5">
          <caption>
<a href="#table-5" class="selfRef">Table 5</a>:
<a href="#name-additions-to-pcep-error-obj" class="selfRef">Additions to PCEP-ERROR Object Error Types and Values
  Subregistry</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>
            </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">16:  Scheduled TLV missing</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">15: Attempted LSP scheduling while the scheduling capability was not
      advertised</td>
            </tr>
            <tr>
              <td class="text-left" rowspan="1" colspan="1">29</td>
              <td class="text-left" rowspan="1" colspan="1">Path computation failure</td>
              <td class="text-left" rowspan="1" colspan="1">5: Constraints could not be met for some intervals</td>
            </tr>
          </tbody>
        </table>
</div>
</section>
</section>
<section id="section-10">
      <h2 id="name-references">
<a href="#section-10" class="section-number selfRef">10. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-10.1">
        <h3 id="name-normative-references">
<a href="#section-10.1" class="section-number selfRef">10.1. </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><span class="refAuthor"> and 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="RFC5905">[RFC5905]</dt>
        <dd>
<span class="refAuthor">Mills, D.</span><span class="refAuthor">, Martin, J., Ed.</span><span class="refAuthor">, Burbank, J.</span><span class="refAuthor">, and W. Kasch</span>, <span class="refTitle">"Network Time Protocol Version 4: Protocol and Algorithms Specification"</span>, <span class="seriesInfo">RFC 5905</span>, <span class="seriesInfo">DOI 10.17487/RFC5905</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5905">https://www.rfc-editor.org/info/rfc5905</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8126">[RFC8126]</dt>
        <dd>
<span class="refAuthor">Cotton, M.</span><span class="refAuthor">, Leiba, B.</span><span class="refAuthor">, and 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><span class="refAuthor">, and 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="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><span class="refAuthor">, and 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="RFC8281">[RFC8281]</dt>
        <dd>
<span class="refAuthor">Crabbe, E.</span><span class="refAuthor">, Minei, I.</span><span class="refAuthor">, Sivabalan, S.</span><span class="refAuthor">, and 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="RFC8413">[RFC8413]</dt>
      <dd>
<span class="refAuthor">Zhuang, Y.</span><span class="refAuthor">, Wu, Q.</span><span class="refAuthor">, Chen, H.</span><span class="refAuthor">, and A. Farrel</span>, <span class="refTitle">"Framework for Scheduled Use of Resources"</span>, <span class="seriesInfo">RFC 8413</span>, <span class="seriesInfo">DOI 10.17487/RFC8413</span>, <time datetime="2018-07" class="refDate">July 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8413">https://www.rfc-editor.org/info/rfc8413</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-10.2">
        <h3 id="name-informative-references">
<a href="#section-10.2" class="section-number selfRef">10.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="I-D.ietf-pce-pcep-yang">[PCE-PCEP-YANG]</dt>
        <dd>
<span class="refAuthor">Dhody, D.</span><span class="refAuthor">, Hardwick, J.</span><span class="refAuthor">, Beeram, V. P.</span><span class="refAuthor">, and 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-15</span>, <time datetime="2020-10-31" class="refDate">31 October 2020</time>, <span>&lt;<a href="https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-15">https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-15</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.litkowski-pce-state-sync">[PCE-STATE-SYNC]</dt>
        <dd>
<span class="refAuthor">Litkowski, S.</span><span class="refAuthor">, Sivabalan, S.</span><span class="refAuthor">, Li, C.</span><span class="refAuthor">, and H. Zheng</span>, <span class="refTitle">"Inter Stateful Path Computation Element (PCE) Communication Procedures."</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-litkowski-pce-state-sync-08</span>, <time datetime="2020-07-12" class="refDate">12 July 2020</time>, <span>&lt;<a href="https://tools.ietf.org/html/draft-litkowski-pce-state-sync-08">https://tools.ietf.org/html/draft-litkowski-pce-state-sync-08</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5925">[RFC5925]</dt>
        <dd>
<span class="refAuthor">Touch, J.</span><span class="refAuthor">, Mankin, A.</span><span class="refAuthor">, and R. Bonica</span>, <span class="refTitle">"The TCP Authentication Option"</span>, <span class="seriesInfo">RFC 5925</span>, <span class="seriesInfo">DOI 10.17487/RFC5925</span>, <time datetime="2010-06" class="refDate">June 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5925">https://www.rfc-editor.org/info/rfc5925</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7399">[RFC7399]</dt>
        <dd>
<span class="refAuthor">Farrel, A.</span><span class="refAuthor"> and 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="RFC8051">[RFC8051]</dt>
        <dd>
<span class="refAuthor">Zhang, X., Ed.</span><span class="refAuthor"> and I. Minei, Ed.</span>, <span class="refTitle">"Applicability of a Stateful Path Computation Element (PCE)"</span>, <span class="seriesInfo">RFC 8051</span>, <span class="seriesInfo">DOI 10.17487/RFC8051</span>, <time datetime="2017-01" class="refDate">January 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8051">https://www.rfc-editor.org/info/rfc8051</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><span class="refAuthor">, and 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="RFC8402">[RFC8402]</dt>
        <dd>
<span class="refAuthor">Filsfils, C., Ed.</span><span class="refAuthor">, Previdi, S., Ed.</span><span class="refAuthor">, Ginsberg, L.</span><span class="refAuthor">, Decraene, B.</span><span class="refAuthor">, Litkowski, S.</span><span class="refAuthor">, and R. Shakir</span>, <span class="refTitle">"Segment Routing Architecture"</span>, <span class="seriesInfo">RFC 8402</span>, <span class="seriesInfo">DOI 10.17487/RFC8402</span>, <time datetime="2018-07" class="refDate">July 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8402">https://www.rfc-editor.org/info/rfc8402</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8655">[RFC8655]</dt>
      <dd>
<span class="refAuthor">Finn, N.</span><span class="refAuthor">, Thubert, P.</span><span class="refAuthor">, Varga, B.</span><span class="refAuthor">, and J. Farkas</span>, <span class="refTitle">"Deterministic Networking Architecture"</span>, <span class="seriesInfo">RFC 8655</span>, <span class="seriesInfo">DOI 10.17487/RFC8655</span>, <time datetime="2019-10" class="refDate">October 2019</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8655">https://www.rfc-editor.org/info/rfc8655</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<section id="section-appendix.a">
      <h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
      </h2>
<p id="section-appendix.a-1">The authors of this document would also like to thank <span class="contact-name">Rafal Szarecki</span>, <span class="contact-name">Adrian Farrel</span>, and
      <span class="contact-name">Cyril Margaria</span> for the review and comments.<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
</section>
<section id="section-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</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">Xufeng Liu</span></div>
<div dir="auto" class="left"><span class="org">Ericsson</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:xliu@kuatrotech.com" class="email">xliu@kuatrotech.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Mehmet Toy</span></div>
<div dir="auto" class="left"><span class="org">Verizon</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:mehmet.toy@verizon.com" class="email">mehmet.toy@verizon.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Vic Liu</span></div>
<div dir="auto" class="left"><span class="org">China Mobile</span></div>
<div dir="auto" class="left"><span class="street-address">No.32 Xuanwumen West Street, Xicheng District</span></div>
<div dir="auto" class="left"><span class="locality">Beijing</span></div>
<div dir="auto" class="left"><span class="postal-code">100053</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:liu.cmri@gmail.com" class="email">liu.cmri@gmail.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Lei Liu</span></div>
<div dir="auto" class="left"><span class="org">Fujitsu</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:lliu@us.fujitsu.com" class="email">lliu@us.fujitsu.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Khuzema Pithewan</span></div>
<div dir="auto" class="left"><span class="org">Infinera</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:kpithewan@infinera.com" class="email">kpithewan@infinera.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Zitao Wang</span></div>
<div dir="auto" class="left"><span class="org">Huawei</span></div>
<div dir="auto" class="left"><span class="street-address">101 Software Avenue, Yuhua District</span></div>
<div dir="auto" class="left"><span class="locality">Nanjing</span></div>
<div dir="auto" class="left">
<span class="region">Jiangsu</span>, <span class="postal-code">210012</span>
</div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:wangzitao@huawei.com" class="email">wangzitao@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Xian Zhang</span></div>
<div dir="auto" class="left"><span class="org">Huawei Technologies</span></div>
<div dir="auto" class="left"><span class="street-address">Research Area F3-1B</span></div>
<div dir="auto" class="left"><span class="locality">Huawei Industrial Base</span></div>
<div dir="auto" class="left"><span class="locality">Shenzhen</span></div>
<div dir="auto" class="left"><span class="postal-code">518129</span></div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:zhang.xian@huawei.com" class="email">zhang.xian@huawei.com</a>
</div>
</address>
</section>
<div id="authors-addresses">
<section id="section-appendix.c">
      <h2 id="name-authors-addresses">
<a href="#name-authors-addresses" class="section-name selfRef">Authors' Addresses</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Huaimo Chen (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">Futurewei</span></div>
<div dir="auto" class="left">
<span class="locality">Boston</span>, <span class="region">MA</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:huaimo.chen@futurewei.com" class="email">huaimo.chen@futurewei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Yan Zhuang (<span class="role">editor</span>)</span></div>
<div dir="auto" class="left"><span class="org">Huawei</span></div>
<div dir="auto" class="left"><span class="extended-address">Yuhua District</span></div>
<div dir="auto" class="left"><span class="street-address">101 Software Avenue</span></div>
<div dir="auto" class="left"><span class="locality">Nanjing</span></div>
<div dir="auto" class="left">
<span class="region">Jiangsu</span>, <span class="postal-code">210012</span>
</div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:zhuangyan.zhuang@huawei.com" class="email">zhuangyan.zhuang@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Qin Wu</span></div>
<div dir="auto" class="left"><span class="org">Huawei</span></div>
<div dir="auto" class="left"><span class="extended-address">Yuhua District</span></div>
<div dir="auto" class="left"><span class="street-address">101 Software Avenue</span></div>
<div dir="auto" class="left"><span class="locality">Nanjing</span></div>
<div dir="auto" class="left">
<span class="region">Jiangsu</span>, <span class="postal-code">210012</span>
</div>
<div dir="auto" class="left"><span class="country-name">China</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:bill.wu@huawei.com" class="email">bill.wu@huawei.com</a>
</div>
</address>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Daniele Ceccarelli</span></div>
<div dir="auto" class="left"><span class="org">Ericsson</span></div>
<div dir="auto" class="left"><span class="street-address">Via A. Negrone 1/A</span></div>
<div dir="auto" class="left">
<span class="locality">Genova - Sestri Ponente</span> </div>
<div dir="auto" class="left"><span class="country-name">Italy</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:daniele.ceccarelli@ericsson.com" class="email">daniele.ceccarelli@ericsson.com</a>
</div>
</address>
</section>
</div>
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