<?xml version='1.0' encoding='utf-8'?>
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std" consensus="true" docName="draft-ietf-pce-association-group-10" indexInclude="true" ipr="trust200902" number="8697" prepTime="2020-01-31T10:29:51" scripts="Common,Latin" sortRefs="false" submissionType="IETF" symRefs="true" tocDepth="3" tocInclude="true" xml:lang="en">
  <link href="https://datatracker.ietf.org/doc/draft-ietf-pce-association-group-10" rel="prev"/>
  <link href="https://dx.doi.org/10.17487/rfc8697" rel="alternate"/>
  <link href="urn:issn:2070-1721" rel="alternate"/>
  <front>
    <title abbrev="PCE Association Group">Path Computation Element Communication Protocol (PCEP) Extensions for Establishing Relationships between Sets of Label Switched Paths (LSPs)</title>
    <seriesInfo name="RFC" value="8697" stream="IETF"/>
    <author fullname="Ina Minei" initials="I." surname="Minei">
      <organization showOnFrontPage="true">Google, Inc.</organization>
      <address>
        <postal>
          <street>1600 Amphitheatre Parkway</street>
          <city>Mountain View</city>
          <region>CA</region>
          <code>94043</code>
          <country>United States of America</country>
        </postal>
        <email>inaminei@google.com</email>
      </address>
    </author>
    <author fullname="Edward Crabbe" initials="E." surname="Crabbe">
      <organization showOnFrontPage="true">Individual Contributor</organization>
      <address>
        <email>edward.crabbe@gmail.com</email>
      </address>
    </author>
    <author fullname="Siva Sivabalan" initials="S." surname="Sivabalan">
      <organization showOnFrontPage="true">Cisco Systems, Inc.</organization>
      <address>
        <postal>
          <street>170 West Tasman Dr.</street>
          <city>San Jose</city>
          <region>CA</region>
          <code>95134</code>
          <country>United States of America</country>
        </postal>
        <email>msiva@cisco.com</email>
      </address>
    </author>
    <author fullname="Hariharan Ananthakrishnan" initials="H." surname="Ananthakrishnan">
      <organization showOnFrontPage="true">Netflix</organization>
      <address>
        <email>hari@netflix.com</email>
      </address>
    </author>
    <author fullname="Dhruv Dhody" initials="D." surname="Dhody">
      <organization showOnFrontPage="true">Huawei</organization>
      <address>
        <postal>
          <street>Divyashree Techno Park, Whitefield</street>
          <city>Bangalore</city>
          <region>KA</region>
          <code>560066</code>
          <country>India</country>
        </postal>
        <email>dhruv.ietf@gmail.com</email>
      </address>
    </author>
    <author fullname="Yosuke Tanaka" initials="Y." surname="Tanaka">
      <organization showOnFrontPage="true">NTT Communications Corporation</organization>
      <address>
        <postal>
          <street>Granpark Tower 3-4-1 Shibaura, Minato-ku</street>
          <region>Tokyo</region>
          <code>108-8118</code>
          <country>Japan</country>
        </postal>
        <email>yosuke.tanaka@ntt.com</email>
      </address>
    </author>
    <date month="01" year="2020"/>
    <keyword>PCE</keyword>
    <keyword>PCEP</keyword>
    <keyword>Association</keyword>
    <keyword>Group</keyword>
    <abstract pn="section-abstract">
      <t pn="section-abstract-1">This document introduces a generic mechanism to create a grouping of Label Switched Paths (LSPs) in the
       context of a Path Computation Element (PCE).
       This grouping can then be used to define associations between sets of LSPs or between a
       set of LSPs and a set of attributes (such as configuration parameters
       or behaviors), and it is equally applicable to the stateful PCE (active and passive modes) and the stateless PCE.
      </t>
    </abstract>
    <boilerplate>
      <section anchor="status-of-memo" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.1">
        <name slugifiedName="name-status-of-this-memo">Status of This Memo</name>
        <t pn="section-boilerplate.1-1">
            This is an Internet Standards Track document.
        </t>
        <t pn="section-boilerplate.1-2">
            This document is a product of the Internet Engineering Task Force
            (IETF).  It represents the consensus of the IETF community.  It has
            received public review and has been approved for publication by
            the Internet Engineering Steering Group (IESG).  Further
            information on Internet Standards is available in Section 2 of 
            RFC 7841.
        </t>
        <t pn="section-boilerplate.1-3">
            Information about the current status of this document, any
            errata, and how to provide feedback on it may be obtained at
            <eref target="https://www.rfc-editor.org/info/rfc8697" brackets="none"/>.
        </t>
      </section>
      <section anchor="copyright" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.2">
        <name slugifiedName="name-copyright-notice">Copyright Notice</name>
        <t pn="section-boilerplate.2-1">
            Copyright (c) 2020 IETF Trust and the persons identified as the
            document authors. All rights reserved.
        </t>
        <t pn="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<eref target="https://trustee.ietf.org/license-info" brackets="none"/>) in effect on the date of
            publication of this document. Please review these documents
            carefully, as they describe your rights and restrictions with
            respect to this document. Code Components extracted from this
            document must include Simplified BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Simplified BSD License.
        </t>
      </section>
    </boilerplate>
    <toc>
      <section anchor="toc" numbered="false" removeInRFC="false" toc="exclude" pn="section-toc.1">
        <name slugifiedName="name-table-of-contents">Table of Contents</name>
        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1">
          <li pn="section-toc.1-1.1">
            <t keepWithNext="true" pn="section-toc.1-1.1.1"><xref derivedContent="1" format="counter" sectionFormat="of" target="section-1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-introduction">Introduction</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.1.2">
              <li pn="section-toc.1-1.1.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.1.2.1.1"><xref derivedContent="1.1" format="counter" sectionFormat="of" target="section-1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-language">Requirements Language</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.2">
            <t keepWithNext="true" pn="section-toc.1-1.2.1"><xref derivedContent="2" format="counter" sectionFormat="of" target="section-2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-terminology">Terminology</xref></t>
          </li>
          <li pn="section-toc.1-1.3">
            <t keepWithNext="true" pn="section-toc.1-1.3.1"><xref derivedContent="3" format="counter" sectionFormat="of" target="section-3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-architectural-overview">Architectural Overview</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.3.2">
              <li pn="section-toc.1-1.3.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.3.2.1.1"><xref derivedContent="3.1" format="counter" sectionFormat="of" target="section-3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-motivations">Motivations</xref></t>
              </li>
              <li pn="section-toc.1-1.3.2.2">
                <t keepWithNext="true" pn="section-toc.1-1.3.2.2.1"><xref derivedContent="3.2" format="counter" sectionFormat="of" target="section-3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-relationship-to-the-svec-li">Relationship to the SVEC List</xref></t>
              </li>
              <li pn="section-toc.1-1.3.2.3">
                <t keepWithNext="true" pn="section-toc.1-1.3.2.3.1"><xref derivedContent="3.3" format="counter" sectionFormat="of" target="section-3.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-operational-overview">Operational Overview</xref></t>
              </li>
              <li pn="section-toc.1-1.3.2.4">
                <t keepWithNext="true" pn="section-toc.1-1.3.2.4.1"><xref derivedContent="3.4" format="counter" sectionFormat="of" target="section-3.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-operator-configured-associa">Operator-Configured Association Range</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.4">
            <t keepWithNext="true" pn="section-toc.1-1.4.1"><xref derivedContent="4" format="counter" sectionFormat="of" target="section-4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-discovery-of-supported-asso">Discovery of Supported Association Types</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.4.2">
              <li pn="section-toc.1-1.4.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.4.2.1.1"><xref derivedContent="4.1" format="counter" sectionFormat="of" target="section-4.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-assoc-type-list-tlv">ASSOC-Type-List TLV</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.4.2.1.2">
                  <li pn="section-toc.1-1.4.2.1.2.1">
                    <t keepWithNext="true" pn="section-toc.1-1.4.2.1.2.1.1"><xref derivedContent="4.1.1" format="counter" sectionFormat="of" target="section-4.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-procedure">Procedure</xref></t>
                  </li>
                </ul>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.5">
            <t keepWithNext="true" pn="section-toc.1-1.5.1"><xref derivedContent="5" format="counter" sectionFormat="of" target="section-5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-operator-configured-associat">Operator-Configured Association Range TLV</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.5.2">
              <li pn="section-toc.1-1.5.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.5.2.1.1"><xref derivedContent="5.1" format="counter" sectionFormat="of" target="section-5.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-procedure-2">Procedure</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.6">
            <t keepWithNext="true" pn="section-toc.1-1.6.1"><xref derivedContent="6" format="counter" sectionFormat="of" target="section-6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-association-object">ASSOCIATION Object</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2">
              <li pn="section-toc.1-1.6.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.6.2.1.1"><xref derivedContent="6.1" format="counter" sectionFormat="of" target="section-6.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-object-definition">Object Definition</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.1.2">
                  <li pn="section-toc.1-1.6.2.1.2.1">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.1.2.1.1"><xref derivedContent="6.1.1" format="counter" sectionFormat="of" target="section-6.1.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-global-association-source-t">Global Association Source TLV</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.1.2.2">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.1.2.2.1"><xref derivedContent="6.1.2" format="counter" sectionFormat="of" target="section-6.1.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-extended-association-id-tlv">Extended Association ID TLV</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.1.2.3">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.1.2.3.1"><xref derivedContent="6.1.3" format="counter" sectionFormat="of" target="section-6.1.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-association-source">Association Source</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.1.2.4">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.1.2.4.1"><xref derivedContent="6.1.4" format="counter" sectionFormat="of" target="section-6.1.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-unique-identification-for-a">Unique Identification for an Association Group</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.2">
                <t keepWithNext="true" pn="section-toc.1-1.6.2.2.1"><xref derivedContent="6.2" format="counter" sectionFormat="of" target="section-6.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-relationship-to-the-rsvp-as">Relationship to the RSVP ASSOCIATION Object</xref></t>
              </li>
              <li pn="section-toc.1-1.6.2.3">
                <t keepWithNext="true" pn="section-toc.1-1.6.2.3.1"><xref derivedContent="6.3" format="counter" sectionFormat="of" target="section-6.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-object-encoding-in-pcep-mes">Object Encoding in PCEP Messages</xref></t>
                <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2.3.2">
                  <li pn="section-toc.1-1.6.2.3.2.1">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.3.2.1.1"><xref derivedContent="6.3.1" format="counter" sectionFormat="of" target="section-6.3.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-stateful-pcep-messages">Stateful PCEP Messages</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.3.2.2">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.3.2.2.1"><xref derivedContent="6.3.2" format="counter" sectionFormat="of" target="section-6.3.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-request-message">Request Message</xref></t>
                  </li>
                  <li pn="section-toc.1-1.6.2.3.2.3">
                    <t keepWithNext="true" pn="section-toc.1-1.6.2.3.2.3.1"><xref derivedContent="6.3.3" format="counter" sectionFormat="of" target="section-6.3.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-reply-message">Reply Message</xref></t>
                  </li>
                </ul>
              </li>
              <li pn="section-toc.1-1.6.2.4">
                <t keepWithNext="true" pn="section-toc.1-1.6.2.4.1"><xref derivedContent="6.4" format="counter" sectionFormat="of" target="section-6.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-processing-rules">Processing Rules</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.7">
            <t keepWithNext="true" pn="section-toc.1-1.7.1"><xref derivedContent="7" format="counter" sectionFormat="of" target="section-7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-iana-considerations">IANA Considerations</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.7.2">
              <li pn="section-toc.1-1.7.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.7.2.1.1"><xref derivedContent="7.1" format="counter" sectionFormat="of" target="section-7.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-pcep-object">PCEP Object</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.2">
                <t keepWithNext="true" pn="section-toc.1-1.7.2.2.1"><xref derivedContent="7.2" format="counter" sectionFormat="of" target="section-7.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-pcep-tlv">PCEP TLV</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.3">
                <t keepWithNext="true" pn="section-toc.1-1.7.2.3.1"><xref derivedContent="7.3" format="counter" sectionFormat="of" target="section-7.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-association-flags">Association Flags</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.4">
                <t keepWithNext="true" pn="section-toc.1-1.7.2.4.1"><xref derivedContent="7.4" format="counter" sectionFormat="of" target="section-7.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-association-type">Association Type</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.5">
                <t keepWithNext="true" pn="section-toc.1-1.7.2.5.1"><xref derivedContent="7.5" format="counter" sectionFormat="of" target="section-7.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-pcep-error-object">PCEP-Error Object</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.8">
            <t keepWithNext="true" pn="section-toc.1-1.8.1"><xref derivedContent="8" format="counter" sectionFormat="of" target="section-8"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security-considerations">Security Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.9">
            <t keepWithNext="true" pn="section-toc.1-1.9.1"><xref derivedContent="9" format="counter" sectionFormat="of" target="section-9"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-manageability-consideration">Manageability Considerations</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.9.2">
              <li pn="section-toc.1-1.9.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.1.1"><xref derivedContent="9.1" format="counter" sectionFormat="of" target="section-9.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-control-of-function-and-pol">Control of Function and Policy</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.2">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.2.1"><xref derivedContent="9.2" format="counter" sectionFormat="of" target="section-9.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-information-and-data-models">Information and Data Models</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.3">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.3.1"><xref derivedContent="9.3" format="counter" sectionFormat="of" target="section-9.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-liveness-detection-and-moni">Liveness Detection and Monitoring</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.4">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.4.1"><xref derivedContent="9.4" format="counter" sectionFormat="of" target="section-9.4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-verifying-correct-operation">Verifying Correct Operation</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.5">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.5.1"><xref derivedContent="9.5" format="counter" sectionFormat="of" target="section-9.5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-on-other-proto">Requirements on Other Protocols</xref></t>
              </li>
              <li pn="section-toc.1-1.9.2.6">
                <t keepWithNext="true" pn="section-toc.1-1.9.2.6.1"><xref derivedContent="9.6" format="counter" sectionFormat="of" target="section-9.6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-impact-on-network-operation">Impact on Network Operations</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.10">
            <t keepWithNext="true" pn="section-toc.1-1.10.1"><xref derivedContent="10" format="counter" sectionFormat="of" target="section-10"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-references">References</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.10.2">
              <li pn="section-toc.1-1.10.2.1">
                <t keepWithNext="true" pn="section-toc.1-1.10.2.1.1"><xref derivedContent="10.1" format="counter" sectionFormat="of" target="section-10.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-normative-references">Normative References</xref></t>
              </li>
              <li pn="section-toc.1-1.10.2.2">
                <t keepWithNext="true" pn="section-toc.1-1.10.2.2.1"><xref derivedContent="10.2" format="counter" sectionFormat="of" target="section-10.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-informative-references">Informative References</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.11">
            <t keepWithNext="true" pn="section-toc.1-1.11.1"><xref derivedContent="Appendix A" format="default" sectionFormat="of" target="section-appendix.a"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-example-of-an-operator-conf">Example of an Operator-Configured Association Range</xref></t>
          </li>
          <li pn="section-toc.1-1.12">
            <t keepWithNext="true" pn="section-toc.1-1.12.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.b"/><xref derivedContent="" format="title" sectionFormat="of" target="name-acknowledgments">Acknowledgments</xref></t>
          </li>
          <li pn="section-toc.1-1.13">
            <t keepWithNext="true" pn="section-toc.1-1.13.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.c"/><xref derivedContent="" format="title" sectionFormat="of" target="name-contributors">Contributors</xref></t>
          </li>
          <li pn="section-toc.1-1.14">
            <t keepWithNext="true" pn="section-toc.1-1.14.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.d"/><xref derivedContent="" format="title" sectionFormat="of" target="name-authors-addresses">Authors' Addresses</xref></t>
          </li>
        </ul>
      </section>
    </toc>
  </front>
  <middle>
    <section numbered="true" toc="include" removeInRFC="false" pn="section-1">
      <name slugifiedName="name-introduction">Introduction</name>
      <t pn="section-1-1"><xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> describes the Path Computation Element (PCE)
      Communication Protocol (PCEP).  PCEP enables communication between a
      Path Computation Client (PCC) and a PCE, or between a PCE and another
      PCE, for the purpose of the computation of Multiprotocol Label Switching
      (MPLS) as well as Generalized MPLS (GMPLS) Traffic Engineering Label
      Switched Path (TE LSP) characteristics.
      </t>
      <t pn="section-1-2"><xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/> specifies a set of extensions to PCEP
      to enable stateful control of TE LSPs within and across PCEP sessions in
      compliance with <xref target="RFC4657" format="default" sectionFormat="of" derivedContent="RFC4657"/>. It includes mechanisms to
      effect LSP State Synchronization between PCCs and PCEs, delegation of
      control over LSPs to PCEs, and PCE control of timing and sequence of
      path computations within and across PCEP sessions. The operational model
      whereby LSPs are initiated from the PCE is described in <xref target="RFC8281" format="default" sectionFormat="of" derivedContent="RFC8281"/>.
      </t>
      <t pn="section-1-3"><xref target="RFC4872" format="default" sectionFormat="of" derivedContent="RFC4872"/> defines the RSVP ASSOCIATION object, which
      was defined in the context of GMPLS-controlled LSPs to be used to
      associate recovery LSPs with the LSP they are protecting. This object
      also has broader applicability as a mechanism to associate RSVP
      state. <xref target="RFC6780" format="default" sectionFormat="of" derivedContent="RFC6780"/> describes how the ASSOCIATION object can
      be more generally applied by defining the Extended ASSOCIATION
      object.</t>
      <t pn="section-1-4"> This document introduces a generic mechanism to create a grouping of LSPs.
       This grouping can then be used to define associations between sets of LSPs or between a
       set of LSPs and a set of attributes (such as configuration parameters
       or behaviors), and it is equally applicable to the stateful PCE (active
       and passive modes) and the stateless PCE.
       The associations could be created dynamically and conveyed to a PCEP
       peer within PCEP, or they could be configured manually by an operator
       on the PCEP peers. Refer to <xref target="Operation-overview" format="default" sectionFormat="of" derivedContent="Section 3.3"/> for
       more details.
      </t>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-1.1">
        <name slugifiedName="name-requirements-language">Requirements Language</name>
        <t pn="section-1.1-1">The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
    "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
    "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
    "<bcp14>SHOULD NOT</bcp14>",
    "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
    "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are
    to be interpreted as described in BCP 14 <xref target="RFC2119" format="default" sectionFormat="of" derivedContent="RFC2119"/>
          <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/> when, and only when, they appear in all capitals,
    as shown here.</t>
      </section>
    </section>
    <section numbered="true" toc="include" removeInRFC="false" pn="section-2">
      <name slugifiedName="name-terminology">Terminology</name>
      <t pn="section-2-1">This document uses the following terms defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>:</t>
      <ul spacing="normal" bare="false" empty="false" pn="section-2-2">
        <li pn="section-2-2.1">PCC</li>
        <li pn="section-2-2.2">PCE</li>
        <li pn="section-2-2.3">PCEP Peer</li>
        <li pn="section-2-2.4">Path Computation Request (PCReq)</li>
        <li pn="section-2-2.5">Path Computation Reply (PCRep)</li>
        <li pn="section-2-2.6">PCEP Error (PCErr)</li>
      </ul>
      <t pn="section-2-3">This document uses the following terms defined in <xref target="RFC8051" format="default" sectionFormat="of" derivedContent="RFC8051"/>:</t>
      <ul spacing="normal" bare="false" empty="false" pn="section-2-4">
        <li pn="section-2-4.1">Stateful PCE</li>
        <li pn="section-2-4.2">Active Stateful PCE</li>
        <li pn="section-2-4.3">Passive Stateful PCE</li>
        <li pn="section-2-4.4">Delegation</li>
      </ul>
      <t pn="section-2-5">This document uses the following terms defined in <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>:</t>
      <ul spacing="normal" bare="false" empty="false" pn="section-2-6">
        <li pn="section-2-6.1">LSP State Report (PCRpt)</li>
        <li pn="section-2-6.2">LSP Update Request (PCUpd)</li>
        <li pn="section-2-6.3">State Timeout Interval</li>
      </ul>
      <t pn="section-2-7">This document uses the following terms defined in <xref target="RFC8281" format="default" sectionFormat="of" derivedContent="RFC8281"/>:</t>
      <ul spacing="normal" bare="false" empty="false" pn="section-2-8">
        <li pn="section-2-8.1">PCE-initiated LSP</li>
        <li pn="section-2-8.2">LSP Initiate Request (PCInitiate)</li>
      </ul>
    </section>
    <section anchor="Overview" numbered="true" toc="include" removeInRFC="false" pn="section-3">
      <name slugifiedName="name-architectural-overview">Architectural Overview</name>
      <section anchor="Motivation" numbered="true" toc="include" removeInRFC="false" pn="section-3.1">
        <name slugifiedName="name-motivations">Motivations</name>
        <t pn="section-3.1-1">A stateful PCE provides the ability to update existing LSPs and to
     instantiate new ones. There are various situations where several
     LSPs need to share common information. For example, to support
     PCE-controlled make-before-break, an association between the original
     path and the reoptimized path is desired. Similarly, for end-to-end
     protection, an association between working and protection LSPs is
     required (see <xref target="I-D.ietf-pce-stateful-path-protection" format="default" sectionFormat="of" derivedContent="PCE-PROTECTION"/>). For diverse paths, an
     association between a group of LSPs could be used (see <xref target="I-D.ietf-pce-association-diversity" format="default" sectionFormat="of" derivedContent="PCE-DIVERSITY"/>).  Another use for an LSP grouping would be to apply
     a common set of configuration parameters or behaviors to a set of LSPs.
        </t>
        <t pn="section-3.1-2">
      For a  stateless PCE, it might be useful to associate a PCReq message to an association group, thus enabling it to associate
      a common set of policies, configuration parameters, or behaviors with the request.
        </t>
        <t pn="section-3.1-3">Some associations could be created dynamically, such as an association
     between the working and protection LSPs of a tunnel, whereas
     some associations could be created by the operator manually, such as
     a policy-based association where the LSP could join an
     operator-configured existing association.</t>
        <t pn="section-3.1-4">
     Rather than creating separate mechanisms for each use case, this document
     defines a generic mechanism that can be reused as needed.
        </t>
      </section>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-3.2">
        <name slugifiedName="name-relationship-to-the-svec-li">Relationship to the SVEC List</name>
        <t pn="section-3.2-1">Note that <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> defines a mechanism for the
       synchronization of a set of PCReq messages by using the SVEC
       (Synchronization VECtor) object, which specifies the list of
       synchronized requests that can be either dependent or independent. The
       SVEC object identifies the relationship between the set of
       PCReq messages, identified by "Request-ID-number" in the RP
       (Request Parameters) object. <xref target="RFC6007" format="default" sectionFormat="of" derivedContent="RFC6007"/> further clarifies
       the use of the SVEC list for synchronized path computations when
       computing dependent requests, and it describes a number of usage
       scenarios for SVEC lists within single-domain and multi-domain
       environments.</t>
        <t pn="section-3.2-2">The motivations behind the association group defined in this document
   and the SVEC object are quite different, though some use cases may
   overlap.  PCEP extensions that define a new Association Type should
   clarify the relationship between the SVEC object and the Association
   Type, if any.</t>
      </section>
      <section anchor="Operation-overview" numbered="true" toc="include" removeInRFC="false" pn="section-3.3">
        <name slugifiedName="name-operational-overview">Operational Overview</name>
        <t pn="section-3.3-1">
     LSPs are associated with other LSPs with which they interact by
     adding them to a common association group.  Association groups as
     defined in this document can be applied to LSPs originating at the same
     headend or different headends.</t>
        <t pn="section-3.3-2">Some associations could be created dynamically by a PCEP speaker, and
     the associations (along with the set of LSPs) are conveyed to a PCEP
     peer. Whereas some associations are configured by the operator
     beforehand on the PCEP peers in question, a PCEP speaker could then ask
     an LSP to join the Operator-configured Association. Usage of dynamic and
     configured associations is usually dependent on the type of
     association.</t>
        <t pn="section-3.3-3">For Operator-configured Associations, the association
parameters, such as the Association Identifier (Association ID), Association Type, and
the Association Source IP address, are manually configured by the
operator. In the case of a dynamic association, the association parameters,
such as the Association ID, are allocated dynamically by the
PCEP speaker. The Association Source is set as the local PCEP speaker
address unless local policy dictates otherwise, in which case the
Association Source is set based on the local policy.</t>
        <t pn="section-3.3-4">The dynamically created association can be reported to the PCEP peer
     via the PCEP messages as per the stateful extensions. When the
     Operator-configured Association is known to the PCEP peer beforehand, a
     PCEP peer could ask an LSP to join the Operator-configured Association
     via the stateful PCEP messages.</t>
        <t pn="section-3.3-5">The associations are properties of the LSP and thus could be stored in
    the LSP state database. The dynamic association exists as long as the LSP
state exists. In the case of PCEP session termination, the LSP state cleanup
    <bcp14>MUST</bcp14> also take care of associations.</t>
        <t pn="section-3.3-6">Multiple types of associations can exist, each with its own
     Association ID space. The definition of the different Association
     Types and their behaviors is outside the scope of this document.  The
     establishment and removal of the association relationship can be done on
     a per-LSP basis. An LSP may join multiple association groups that have
     the same Association Type or different Association Types.</t>
      </section>
      <section anchor="Range" numbered="true" toc="include" removeInRFC="false" pn="section-3.4">
        <name slugifiedName="name-operator-configured-associa">Operator-Configured Association Range</name>
        <t pn="section-3.4-1">Some Association Types are dynamic, some are operator configured,
       and some could be both. For the Association Types that could be both
       dynamic and operator configured and use the same
       Association Source, it is necessary to distinguish a range of
       Association IDs that are marked for Operator-configured
       Associations, to avoid any Association ID clashes within the
       scope of the Association Source. This document assumes that these two
       ranges are configured.
</t>
        <t pn="section-3.4-2">A range of Association IDs for each Association Type (and
       Association Source) is kept for the Operator-configured
       Associations. Dynamic associations <bcp14>MUST NOT</bcp14> use the
       Association ID from this range. </t>
        <t pn="section-3.4-3">This range, as set at the PCEP speaker (a PCC or PCE, as an
       Association Source), needs to be communicated to a PCEP peer in the
       Open message. A new TLV is defined in this specification for this
       purpose (<xref target="Range-tlv" format="default" sectionFormat="of" derivedContent="Section 5"/>). See <xref target="ex" format="default" sectionFormat="of" derivedContent="Appendix A"/> for an
       example.</t>
        <t pn="section-3.4-4">The Association ID range for sources other than the PCEP
       speaker (for example, a Network Management System (NMS)) is not
       communicated in PCEP, and the procedure for Operator-configured
       Association Range settings is outside the scope of this document.</t>
      </section>
    </section>
    <section anchor="Discovery" numbered="true" toc="include" removeInRFC="false" pn="section-4">
      <name slugifiedName="name-discovery-of-supported-asso">Discovery of Supported Association Types</name>
      <t pn="section-4-1">This section defines PCEP extensions so as to support
   the capability advertisement of the Association Types supported by a PCEP speaker.</t>
      <t pn="section-4-2">A new PCEP ASSOC-Type-List (Association Types list) TLV is defined.  The
   PCEP ASSOC-Type-List TLV is carried within an OPEN object.  This way, during
   the PCEP session-setup phase, a PCEP speaker can advertise to a PCEP peer
   the list of supported Association Types.</t>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-4.1">
        <name slugifiedName="name-assoc-type-list-tlv">ASSOC-Type-List TLV</name>
        <t pn="section-4.1-1">The PCEP ASSOC-Type-List TLV is <bcp14>OPTIONAL</bcp14>.  It <bcp14>MAY</bcp14> be carried within an OPEN
   object sent by a PCEP speaker in an Open message to a PCEP peer so as to
   indicate the list of supported Association Types.</t>
        <t pn="section-4.1-2">The PCEP ASSOC-Type-List TLV format is compliant with the PCEP TLV format defined
   in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>.  That is, the TLV is composed of 2 octets
   for the type, 2 octets specifying the TLV length, and a Value field.  The Length
   field defines the length of the value portion in octets.  The TLV is
   padded to 4-octet alignment, and padding is not included in the
   Length field (e.g., a 3-octet value would have a length of three, but
   the total size of the TLV would be 8 octets).</t>
        <t pn="section-4.1-3">The PCEP ASSOC-Type-List TLV has the following format:</t>
        <figure anchor="ASSOC-Type-List" align="left" suppress-title="false" pn="figure-1">
          <name slugifiedName="name-the-assoc-type-list-tlv-for">The ASSOC-Type-List TLV Format</name>
          <artwork name="" type="" align="left" alt="" pn="section-4.1-4.1">
   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                  |            Length             |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  
  |          Assoc-Type #1        |      Assoc-Type #2            |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //                                                             //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |          Assoc-Type #N        |       padding                 |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ </artwork>
        </figure>
        <dl newline="false" spacing="normal" pn="section-4.1-5">
          <dt pn="section-4.1-5.1">Type:</dt>
          <dd pn="section-4.1-5.2">35</dd>
          <dt pn="section-4.1-5.3">Length:</dt>
          <dd pn="section-4.1-5.4">N * 2 (where N is the number of Association Types).</dd>
          <dt pn="section-4.1-5.5">Value:</dt>
          <dd pn="section-4.1-5.6">List of 2-byte Association Type code points, identifying
    the Association Types supported by the sender of the Open
    message.</dd>
          <dt pn="section-4.1-5.7">Assoc-Type (2 bytes):</dt>
          <dd pn="section-4.1-5.8">Association Type code point identifier.
  IANA manages the "ASSOCIATION Type Field" code point registry (see <xref target="iana_assoc_type" format="default" sectionFormat="of" derivedContent="Section 7.4"/>).</dd>
        </dl>
        <section numbered="true" toc="include" removeInRFC="false" pn="section-4.1.1">
          <name slugifiedName="name-procedure">Procedure</name>
          <t pn="section-4.1.1-1">An ASSOC-Type-List TLV within an OPEN object in an Open
   message is included by a PCEP speaker in order to advertise a set of one or
   more supported Association Types.  The ASSOC-Type-List TLV <bcp14>MUST NOT</bcp14> appear more than
   once in an OPEN object.  If it appears more than once, the PCEP
   session <bcp14>MUST</bcp14> be rejected with Error-Type 1 and Error-value 1 (PCEP
   session establishment failure / Reception of an invalid Open
   message). As specified in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>, a PCEP peer that does not recognize the
   ASSOC-Type-List TLV will silently ignore it.</t>
          <t pn="section-4.1.1-2">The Association Type (to be defined in future documents) can specify if
the Association Type advertisement is mandatory for it. 
Thus, the ASSOC-Type-List TLV <bcp14>MUST</bcp14> be included if at least one mandatory
 Association Type needs to be advertised, and the ASSOC-Type-List TLV <bcp14>MAY</bcp14> be
 included otherwise. For an Association Type that specifies that the
 advertisement is mandatory, a missing Assoc-Type in the ASSOC-Type-List TLV
 (or a missing ASSOC-Type-List TLV) is to be interpreted as meaning that the
 Association Type is not supported by the PCEP speaker.</t>
          <t pn="section-4.1.1-3">The absence of the ASSOC-Type-List TLV in an OPEN object <bcp14>MUST</bcp14> be
   interpreted as an absence of information in the list of supported
   Association Types (rather than an indication that the Association Type is
   not supported). In this case, the PCEP
   speaker could still use the ASSOCIATION object: if the peer does not
   support the association, it will react as per the procedure described
   in <xref target="Rules" format="default" sectionFormat="of" derivedContent="Section 6.4"/>.</t>
          <t pn="section-4.1.1-4">If the use of the ASSOC-Type-List TLV is triggered by support for a
   mandatory Association Type, then it is <bcp14>RECOMMENDED</bcp14> that the PCEP
   implementation include all supported Association Types (including optional
   types) to ease the operations of the PCEP peer.</t>
        </section>
      </section>
    </section>
    <section anchor="Range-tlv" numbered="true" toc="include" removeInRFC="false" pn="section-5">
      <name slugifiedName="name-operator-configured-associat">Operator-Configured Association Range TLV</name>
      <t pn="section-5-1">This section defines a PCEP extension to support
   the advertisement of the Operator-configured Association Range used for an Association Type by the PCEP speaker (as an Association Source).</t>
      <t pn="section-5-2">A new PCEP OP-CONF-ASSOC-RANGE (Operator-configured Association Range)
   TLV is defined.  The PCEP OP-CONF-ASSOC-RANGE TLV is carried within an OPEN
   object.  This way, during the PCEP session-setup phase, a PCEP speaker can
   advertise to a PCEP peer the Operator-configured Association Range for an
   Association Type.</t>
      <t pn="section-5-3">The PCEP OP-CONF-ASSOC-RANGE TLV is <bcp14>OPTIONAL</bcp14>.  It <bcp14>MAY</bcp14> be carried within
   an OPEN object sent by a PCEP speaker in an Open message to a PCEP peer. 
   The OP-CONF-ASSOC-RANGE TLV format is compliant with the PCEP TLV format
   defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>.  That is, the TLV is composed of 2
   bytes for the type, 2 bytes specifying the TLV length, and a Value field.
   The Length field defines the length of the value portion in bytes.</t>
      <t pn="section-5-4">The PCEP OP-CONF-ASSOC-RANGE TLV has the following format:</t>
      <figure anchor="OP-CONF-ASSOC-RANGE" align="left" suppress-title="false" pn="figure-2">
        <name slugifiedName="name-the-op-conf-assoc-range-tlv">The OP-CONF-ASSOC-RANGE TLV Format</name>
        <artwork name="" type="" align="left" alt="" pn="section-5-5.1">
   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                  |            Length             |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |             Reserved          |          Assoc-Type #1        |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      Start-Assoc-ID #1        |           Range #1            |        
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //                                                             //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |             Reserved          |          Assoc-Type #N        |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      Start-Assoc-ID #N        |           Range #N            |        
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ </artwork>
      </figure>
      <dl newline="false" spacing="normal" pn="section-5-6">
        <dt pn="section-5-6.1">Type:</dt>
        <dd pn="section-5-6.2">29</dd>
        <dt pn="section-5-6.3">Length:</dt>
        <dd pn="section-5-6.4">N * 8 (where N is the number of Association Types).</dd>
        <dt pn="section-5-6.5">Value:</dt>
        <dd pn="section-5-6.6">
          <t pn="section-5-6.6.1">Includes the following fields, repeated for each
Association Type:

</t>
          <dl newline="false" spacing="normal" pn="section-5-6.6.2">
            <dt pn="section-5-6.6.2.1">Reserved (2 bytes):</dt>
            <dd pn="section-5-6.6.2.2">
              <bcp14>MUST</bcp14> be set to 0 on transmission and <bcp14>MUST</bcp14> be
   ignored on receipt.</dd>
            <dt pn="section-5-6.6.2.3">Assoc-Type (2 bytes):</dt>
            <dd pn="section-5-6.6.2.4">The Association Type (<xref target="iana_assoc_type" format="default" sectionFormat="of" derivedContent="Section 7.4"/>). The Association Types will be defined in future
   documents.</dd>
            <dt pn="section-5-6.6.2.5">Start-Assoc-ID (2 bytes):</dt>
            <dd pn="section-5-6.6.2.6">The "start association" identifier for the
   Operator-configured Association Range for the particular Association
   Type. The values 0 and 0xffff <bcp14>MUST NOT</bcp14> be used; on receipt of these
   values in the TLV, the session is rejected, and an error message is sent
   (see <xref target="pro" format="default" sectionFormat="of" derivedContent="Section 5.1"/>).</dd>
            <dt pn="section-5-6.6.2.7">Range (2 bytes):</dt>
            <dd pn="section-5-6.6.2.8">The number of associations marked for the
   Operator-configured Associations. Range <bcp14>MUST</bcp14> be greater than 0, and it
   <bcp14>MUST</bcp14> be such that (Start-Assoc-ID + Range) does not cross the
   largest Association ID value of 0xffff. If this condition is not satisfied, the session
   is rejected, and an error message is sent (see <xref target="pro" format="default" sectionFormat="of" derivedContent="Section 5.1"/>).</dd>
          </dl>
        </dd>
      </dl>
      <section anchor="pro" numbered="true" toc="include" removeInRFC="false" pn="section-5.1">
        <name slugifiedName="name-procedure-2">Procedure</name>
        <t pn="section-5.1-1">A PCEP speaker <bcp14>MAY</bcp14> include an OP-CONF-ASSOC-RANGE TLV within an OPEN object in an Open
   message sent to a PCEP peer in order to advertise the Operator-configured Association Range for an Association Type. 
   The OP-CONF-ASSOC-RANGE TLV <bcp14>MUST NOT</bcp14> appear more than
   once in an OPEN object.  If it appears more than once, the PCEP
   session <bcp14>MUST</bcp14> be rejected with Error-Type 1 and Error-value 1 (PCEP
   session establishment failure / Reception of an invalid Open
   message).</t>
        <t pn="section-5.1-2">As specified in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>, a PCEP peer that does not recognize the
   OP-CONF-ASSOC-RANGE TLV will silently ignore it.</t>
        <t pn="section-5.1-3">The Operator-configured Association Range <bcp14>SHOULD</bcp14> be included for each
   Association Type that could be both dynamic and operator configured. For
   Association Types that are only dynamic or only operator configured, this
   TLV <bcp14>MAY</bcp14> be skipped, in which case the full range of Association IDs
   is considered dynamic or operator configured, respectively. Each
   Association Type (to be defined in future documents) can specify the default
   value for its Operator-configured Association Range.</t>
        <t pn="section-5.1-4">The absence of the OP-CONF-ASSOC-RANGE TLV in an OPEN object <bcp14>MUST</bcp14> be
   interpreted as an absence of an explicit Operator-configured Association Range at the PCEP peer. 
   In this case, the default behavior as per each Association Type applies. If the Association 
   Source is not a PCEP speaker, the default value for the Operator-configured Association Range is used for the Association Source.</t>
        <t pn="section-5.1-5">If the Assoc-Type is not recognized or supported by the PCEP speaker, it <bcp14>MUST</bcp14> ignore that respective (Start-Assoc-ID + Range). If the Assoc-Type is recognized/supported but Start-Assoc-ID or Range is set incorrectly, the PCEP
   session <bcp14>MUST</bcp14> be rejected with Error-Type 1 and Error-value 1 (PCEP
   session establishment failure / Reception of an invalid Open
   message). The incorrect range includes the case when the
   (Start-Assoc-ID + Range) crosses the largest Association ID value of
   0xffff.</t>
        <t pn="section-5.1-6">A given Assoc-Type <bcp14>MAY</bcp14> appear more than once in the
   OP-CONF-ASSOC-RANGE TLV in the case of a non-contiguous
   Operator-configured Association Range. The PCEP speaker originating this
   TLV <bcp14>MUST NOT</bcp14> send overlapping ranges for an Association Type. If a PCEP
   peer receives overlapping ranges for an Association Type, it <bcp14>MUST</bcp14> consider
   the Open message malformed and <bcp14>MUST</bcp14> reject the PCEP session with
   Error-Type 1 and Error-value 1 (PCEP session establishment failure /
   Reception of an invalid Open message).</t>
        <t pn="section-5.1-7">There may be cases where an Operator-configured Association was
   configured with association parameters (such as an Association ID, Association Type, and Association Source) at the local
   PCEP speaker, and the PCEP session is later established with the
   Association Source and a new operator-configured range is learned
   during session establishment. At this time, the local PCEP speaker <bcp14>MUST</bcp14>
   remove any associations that are not in the new operator-configured range
   (by disassociating any LSPs that are part of it (and notifying the
   PCEP peer of this change)). If a PCEP speaker receives an association for an
   Operator-configured Association and the Association ID is not in
   the Operator-configured Association Range for the Association Type and
   Association Source, it <bcp14>MUST</bcp14> generate an error (as described in <xref target="Rules" format="default" sectionFormat="of" derivedContent="Section 6.4"/>).</t>
      </section>
    </section>
    <section anchor="association" numbered="true" toc="include" removeInRFC="false" pn="section-6">
      <name slugifiedName="name-association-object">ASSOCIATION Object</name>
      <section anchor="Definition" numbered="true" toc="include" removeInRFC="false" pn="section-6.1">
        <name slugifiedName="name-object-definition">Object Definition</name>
        <t pn="section-6.1-1">Association groups and their memberships are defined using a new
     ASSOCIATION object.
        </t>
        <t pn="section-6.1-2">The ASSOCIATION Object-Class value is 40.</t>
        <t pn="section-6.1-3">The ASSOCIATION Object-Type value is 1 for IPv4, and its format is
    shown in <xref target="Association-Object-Fmt1" format="default" sectionFormat="of" derivedContent="Figure 3"/>:</t>
        <figure anchor="Association-Object-Fmt1" align="left" suppress-title="false" pn="figure-3">
          <name slugifiedName="name-the-ipv4-association-object">The IPv4 ASSOCIATION Object Format</name>
          <artwork name="" type="" align="left" alt="" pn="section-6.1-4.1">
   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
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |         Reserved              |            Flags            |R|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      Association Type         |      Association ID           |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |              IPv4 Association Source                          |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //                   Optional TLVs                             //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  </artwork>
        </figure>
        <t pn="section-6.1-5">The ASSOCIATION Object-Type value is 2 for IPv6, and its format is
    shown in <xref target="Association-Object-Fmt2" format="default" sectionFormat="of" derivedContent="Figure 4"/>:</t>
        <figure anchor="Association-Object-Fmt2" align="left" suppress-title="false" pn="figure-4">
          <name slugifiedName="name-the-ipv6-association-object">The IPv6 ASSOCIATION Object Format</name>
          <artwork name="" type="" align="left" alt="" pn="section-6.1-6.1">
   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
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |         Reserved              |            Flags            |R|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      Association Type         |      Association ID           |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
  |                    IPv6 Association Source                    |
  |                                                               |
  |                                                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //                   Optional TLVs                             //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ </artwork>
        </figure>
        <dl newline="false" spacing="normal" pn="section-6.1-7">
          <dt pn="section-6.1-7.1">Reserved (2 bytes):</dt>
          <dd pn="section-6.1-7.2">
            <bcp14>MUST</bcp14> be set to 0 and ignored upon
    receipt.</dd>
          <dt pn="section-6.1-7.3">Flags (2 bytes):</dt>
          <dd pn="section-6.1-7.4">
            <t pn="section-6.1-7.4.1">The following flag is currently defined:

            </t>
            <dl newline="false" spacing="normal" pn="section-6.1-7.4.2">
              <dt pn="section-6.1-7.4.2.1">R (Removal - 1 bit):</dt>
              <dd pn="section-6.1-7.4.2.2">When set, the requesting
       PCEP peer requires the removal of an LSP from the association group. 
       When unset, the PCEP peer indicates that the LSP is added or retained
       as part of the association group. This flag is used for the ASSOCIATION
       object in the Path Computation Report (PCRpt) and
       Path Computation Update (PCUpd) messages.  It is ignored in other
       PCEP messages.</dd>
            </dl>
          </dd>
        </dl>
        <t pn="section-6.1-8">The unassigned flags <bcp14>MUST</bcp14> be set to 0 on transmission and <bcp14>MUST</bcp14> be
  ignored on receipt.</t>
        <dl newline="false" spacing="normal" pn="section-6.1-9">
          <dt pn="section-6.1-9.1">Association Type (2 bytes):</dt>
          <dd pn="section-6.1-9.2">The Association Type
  (<xref target="iana_assoc_type" format="default" sectionFormat="of" derivedContent="Section 7.4"/>). The Association Types
  will be defined in future documents.</dd>
          <dt pn="section-6.1-9.3">Association ID (2 bytes):</dt>
          <dd pn="section-6.1-9.4">The identifier of the association
    group.  When combined with other association parameters, such as an
    Association Type and Association Source, this value uniquely identifies an
    association group. The values 0xffff and 0x0 are reserved. The value
    0xffff is used to indicate all association groups and could be used with
    the R flag to indicate removal for all associations for the LSP within the
    scope of the Association Type and Association Source.</dd>
          <dt pn="section-6.1-9.5">Association Source:</dt>
          <dd pn="section-6.1-9.6">Contains a valid IPv4 address (4 bytes)
    if the ASSOCIATION Object-Type is 1 or a valid IPv6 address (16 bytes) if
    the ASSOCIATION Object-Type is 2. The address provides scoping for the
    Association ID. See <xref target="AssocSrc" format="default" sectionFormat="of" derivedContent="Section 6.1.3"/> for details.</dd>
          <dt pn="section-6.1-9.7">Optional TLVs:</dt>
          <dd pn="section-6.1-9.8">The optional TLVs follow the PCEP TLV format
    defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. This document defines two optional
    TLVs. Other documents can define more TLVs in the future.</dd>
        </dl>
        <section anchor="Global-association-src" numbered="true" toc="include" removeInRFC="false" pn="section-6.1.1">
          <name slugifiedName="name-global-association-source-t">Global Association Source TLV</name>
          <t pn="section-6.1.1-1"> The Global Association Source TLV is an optional TLV for use in the ASSOCIATION object. 
        The meaning and usage of the Global Association Source TLV are as per
<xref target="RFC6780" sectionFormat="of" section="4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6780#section-4" derivedContent="RFC6780"/>.
          </t>
          <figure anchor="Global-Association-Object-Fmt1" align="left" suppress-title="false" pn="figure-5">
            <name slugifiedName="name-the-global-association-sour">The Global Association Source TLV Format</name>
            <artwork name="" type="" align="left" alt="" pn="section-6.1.1-2.1">
   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                  |            Length             |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |              Global Association Source                        |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ </artwork>
          </figure>
          <dl newline="false" spacing="normal" pn="section-6.1.1-3">
            <dt pn="section-6.1.1-3.1">Type:</dt>
            <dd pn="section-6.1.1-3.2">30</dd>
            <dt pn="section-6.1.1-3.3">Length:</dt>
            <dd pn="section-6.1.1-3.4">Fixed value of 4 bytes.</dd>
            <dt pn="section-6.1.1-3.5">Global Association Source:</dt>
            <dd pn="section-6.1.1-3.6">As defined in
<xref target="RFC6780" sectionFormat="of" section="4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6780#section-4" derivedContent="RFC6780"/>.</dd>
          </dl>
        </section>
        <section anchor="EXT-association" numbered="true" toc="include" removeInRFC="false" pn="section-6.1.2">
          <name slugifiedName="name-extended-association-id-tlv">Extended Association ID TLV</name>
          <t pn="section-6.1.2-1"> The Extended Association ID TLV is an optional TLV for use in
      the ASSOCIATION object. The meaning and usage of the
      Extended Association ID TLV are as per 
<xref target="RFC6780" sectionFormat="of" section="4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6780#section-4" derivedContent="RFC6780"/>.
          </t>
          <figure anchor="Ext-id-Object-Fmt1" align="left" suppress-title="false" pn="figure-6">
            <name slugifiedName="name-the-extended-association-id">The Extended Association ID TLV Format</name>
            <artwork name="" type="" align="left" alt="" pn="section-6.1.2-2.1">
   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                  |            Length             |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //                Extended Association ID                      //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ </artwork>
          </figure>
          <dl newline="false" spacing="normal" pn="section-6.1.2-3">
            <dt pn="section-6.1.2-3.1">Type:</dt>
            <dd pn="section-6.1.2-3.2">31</dd>
            <dt pn="section-6.1.2-3.3">Length:</dt>
            <dd pn="section-6.1.2-3.4">Variable.</dd>
            <dt pn="section-6.1.2-3.5">Extended Association ID:</dt>
            <dd pn="section-6.1.2-3.6">As defined in 
<xref target="RFC6780" sectionFormat="of" section="4" format="default" derivedLink="https://rfc-editor.org/rfc/rfc6780#section-4" derivedContent="RFC6780"/>.</dd>
          </dl>
        </section>
        <section anchor="AssocSrc" numbered="true" toc="include" removeInRFC="false" pn="section-6.1.3">
          <name slugifiedName="name-association-source">Association Source</name>
          <t pn="section-6.1.3-1">The Association Source field in the ASSOCIATION object is 
   set to a valid IP address to identify the node that originated the
   association. In the case of dynamic associations, the Association Source is
   usually set as the local PCEP speaker address unless local policy dictates
   otherwise, in which case the Association Source is set based on the local
    policy. In the case of PCE redundancy, local policy could set the source
    as a virtual IP address that identifies all instances of the PCE. In the
    case of Operator-configured Associations, the Association Source is
    manually configured, and it could be set as one of the PCEP speakers, an
    NMS, or any other valid IP address that scopes the Association ID for the Association Type.</t>
        </section>
        <section anchor="id" numbered="true" toc="include" removeInRFC="false" pn="section-6.1.4">
          <name slugifiedName="name-unique-identification-for-a">Unique Identification for an Association Group</name>
          <t pn="section-6.1.4-1">The combination of the mandatory fields Association Type, Association
    ID, and Association Source in the ASSOCIATION object uniquely identifies
    the association group. If the optional TLVs (Global Association Source and
    Extended Association ID) are included, then they <bcp14>MUST</bcp14> be included in
    combination with mandatory fields to uniquely identify the association
    group. In this document, all these fields are collectively called
    "association parameters". Note that the ASSOCIATION object <bcp14>MAY</bcp14> include
    other optional TLVs (not defined in this document) based on the 
    Association Types. These TLVs provide "information" related to the
    Association Type. This document refers to this information as
    "association information".</t>
        </section>
      </section>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-6.2">
        <name slugifiedName="name-relationship-to-the-rsvp-as">Relationship to the RSVP ASSOCIATION Object</name>
        <t pn="section-6.2-1">The format of the PCEP ASSOCIATION object defined in this document
       is aligned with the RSVP ASSOCIATION object <xref target="RFC6780" format="default" sectionFormat="of" derivedContent="RFC6780"/>. Various Association Types related to RSVP
       association are defined in <xref target="RFC4872" format="default" sectionFormat="of" derivedContent="RFC4872"/>, <xref target="RFC4873" format="default" sectionFormat="of" derivedContent="RFC4873"/>, and <xref target="RFC7551" format="default" sectionFormat="of" derivedContent="RFC7551"/>. The PCEP extensions
       that define new Association Types should clarify how the PCEP
       associations would work with RSVP associations and vice versa.</t>
      </section>
      <section anchor="Object-Encoding" numbered="true" toc="include" removeInRFC="false" pn="section-6.3">
        <name slugifiedName="name-object-encoding-in-pcep-mes">Object Encoding in PCEP Messages</name>
        <t pn="section-6.3-1">Message formats in this document are expressed using Routing BNF
     (RBNF) as used in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> and defined in <xref target="RFC5511" format="default" sectionFormat="of" derivedContent="RFC5511"/>.</t>
        <section numbered="true" toc="include" removeInRFC="false" pn="section-6.3.1">
          <name slugifiedName="name-stateful-pcep-messages">Stateful PCEP Messages</name>
          <t pn="section-6.3.1-1">The ASSOCIATION object <bcp14>MAY</bcp14> be carried in the PCUpd, PCRpt, and
    Path Computation Initiate (PCInitiate) messages. </t>
          <t pn="section-6.3.1-2">When carried in a PCRpt message, this object is used to report the
    association group membership pertaining to an LSP to a stateful PCE. 
    The PCRpt message is used for initial State Synchronization operations
    (<xref target="RFC8231" sectionFormat="of" section="5.6" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8231#section-5.6" derivedContent="RFC8231"/>), as well as whenever the
    state of the LSP changes. If the LSP belongs to an association group, then
    the associations <bcp14>MUST</bcp14> be included during the State Synchronization
    operations.</t>
          <t pn="section-6.3.1-3">The PCRpt message can also be used to remove an LSP from one or more
    association groups by setting the R flag to 1 in the ASSOCIATION
    object.</t>
          <t pn="section-6.3.1-4">When an LSP is first reported to the PCE, the PCRpt message <bcp14>MUST</bcp14>
    include all the association groups that it belongs to. Any subsequent
    PCRpt message <bcp14>SHOULD</bcp14> include only the associations that are being
    modified or removed.</t>
          <t pn="section-6.3.1-5"> The PCRpt message is defined in <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>
    and updated as shown below:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-6">
   &lt;PCRpt Message&gt; ::= &lt;Common Header&gt;
                       &lt;state-report-list&gt;
</sourcecode>
          <t pn="section-6.3.1-7">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-8">
      &lt;state-report-list&gt; ::= &lt;state-report&gt;[&lt;state-report-list&gt;]

      &lt;state-report&gt; ::= [&lt;SRP&gt;]
                         &lt;LSP&gt;
                         [&lt;association-list&gt;]
                         &lt;path&gt;
</sourcecode>
          <t pn="section-6.3.1-9">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-10">
      &lt;path&gt;::= &lt;intended-path&gt;
                [&lt;actual-attribute-list&gt;&lt;actual-path&gt;]
                &lt;intended-attribute-list&gt;

      &lt;association-list&gt; ::= &lt;ASSOCIATION&gt; [&lt;association-list&gt;]
</sourcecode>
          <t pn="section-6.3.1-11"> When an LSP is delegated to a stateful PCE, the stateful PCE can create
    a new association group for this LSP or associate it with one or more existing
    association groups. This is done by including the  ASSOCIATION object in a
    PCUpd message.  A stateful PCE can also remove a delegated
    LSP from one or more association groups by setting the R flag to 1 in the ASSOCIATION object.</t>
          <t pn="section-6.3.1-12">The PCUpd message <bcp14>SHOULD</bcp14> include the association groups that are being modified or removed. There is no need to include associations that remain unchanged.</t>
          <t pn="section-6.3.1-13">The PCUpd message is defined in <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>
    and updated as shown below:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-14">
 &lt;PCUpd Message&gt; ::= &lt;Common Header&gt;
                     &lt;update-request-list&gt;
</sourcecode>
          <t pn="section-6.3.1-15">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-16">
    &lt;update-request-list&gt; ::= &lt;update-request&gt;[&lt;update-request-list&gt;]

    &lt;update-request&gt; ::= &lt;SRP&gt;
                         &lt;LSP&gt;
                         [&lt;association-list&gt;]
                         &lt;path&gt;
</sourcecode>
          <t pn="section-6.3.1-17">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-18">
    &lt;path&gt;::= &lt;intended-path&gt;&lt;intended-attribute-list&gt;

    &lt;association-list&gt; ::= &lt;ASSOCIATION&gt; [&lt;association-list&gt;]
</sourcecode>
          <t pn="section-6.3.1-19">Unless a PCEP speaker wants to delete an association
    from an LSP or make changes to the association, it does not need to
    include the ASSOCIATION object in future stateful messages.</t>
          <t pn="section-6.3.1-20">A PCE initiating a new LSP can also include the association groups that this LSP belongs to. This is done by including the ASSOCIATION object in a
    PCInitiate message. The PCInitiate message <bcp14>MUST</bcp14> include all the association groups that it belongs to.
    The PCInitiate message is defined in <xref target="RFC8281" format="default" sectionFormat="of" derivedContent="RFC8281"/>
    and updated as shown below:
          </t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-21">
&lt;PCInitiate Message&gt; ::= &lt;Common Header&gt;
                         &lt;PCE-initiated-lsp-list&gt;
</sourcecode>
          <t pn="section-6.3.1-22">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-23">
&lt;PCE-initiated-lsp-list&gt; ::= &lt;PCE-initiated-lsp-request&gt;
                             [&lt;PCE-initiated-lsp-list&gt;]

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

&lt;PCE-initiated-lsp-instantiation&gt; ::= &lt;SRP&gt;
                                      &lt;LSP&gt;
                                      [&lt;END-POINTS&gt;]
                                      &lt;ERO&gt;
                                      [&lt;association-list&gt;]
                                      [&lt;attribute-list&gt;]
</sourcecode>
          <t pn="section-6.3.1-24">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.1-25">
&lt;association-list&gt; ::= &lt;ASSOCIATION&gt; [&lt;association-list&gt;]
</sourcecode>
        </section>
        <section numbered="true" toc="include" removeInRFC="false" pn="section-6.3.2">
          <name slugifiedName="name-request-message">Request Message</name>
          <t pn="section-6.3.2-1">
    In the case of a passive (stateful or stateless) PCE, the ASSOCIATION
    object is <bcp14>OPTIONAL</bcp14> and <bcp14>MAY</bcp14> be carried in the PCReq message.
          </t>
          <t pn="section-6.3.2-2">
    When carried in a PCReq message, the ASSOCIATION object is used to
    associate the path computation request to an association group. The
    association (and the other LSPs) should be known to the PCE
    beforehand. These could be operator configured or dynamically learned
    beforehand via stateful PCEP messages. The R flag in the ASSOCIATION
    object within a PCReq message <bcp14>MUST</bcp14> be set to 0 while sending and ignored
    on receipt.
          </t>
          <t pn="section-6.3.2-3">
   The PCReq message is defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> and updated in
   <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>. It is further updated below for
   association groups:
          </t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.2-4">
&lt;PCReq Message&gt;::= &lt;Common Header&gt;
                   [&lt;svec-list&gt;]
                   &lt;request-list&gt;
</sourcecode>
          <t pn="section-6.3.2-5">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.2-6">
   &lt;svec-list&gt;::= &lt;SVEC&gt;[&lt;svec-list&gt;]
   &lt;request-list&gt;::= &lt;request&gt;[&lt;request-list&gt;]

   &lt;request&gt;::= &lt;RP&gt;
                &lt;END-POINTS&gt;
                [&lt;LSP&gt;]
                [&lt;LSPA&gt;]
                [&lt;BANDWIDTH&gt;]
                [&lt;metric-list&gt;]
                [&lt;association-list&gt;]
                [&lt;RRO&gt;[&lt;BANDWIDTH&gt;]]
                [&lt;IRO&gt;]
                [&lt;LOAD-BALANCING&gt;]
</sourcecode>
          <t pn="section-6.3.2-7">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.2-8">
   &lt;association-list&gt; ::= &lt;ASSOCIATION&gt; [&lt;association-list&gt;]
</sourcecode>
          <t pn="section-6.3.2-9">
   Note that the LSP object <bcp14>MAY</bcp14> be present for the passive stateful
   PCE mode.
          </t>
        </section>
        <section numbered="true" toc="include" removeInRFC="false" pn="section-6.3.3">
          <name slugifiedName="name-reply-message">Reply Message</name>
          <t pn="section-6.3.3-1">
    In the case of a passive (stateful or stateless) PCE, the ASSOCIATION
    object is <bcp14>OPTIONAL</bcp14> and <bcp14>MAY</bcp14> be carried in the PCRep message with the
    NO-PATH object. The ASSOCIATION object in the PCRep message indicates the
    association group that caused the PCE to fail to find a path.
          </t>
          <t pn="section-6.3.3-2">
   The PCRep message is defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> and updated in
   <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>. It is further updated below for association groups:
          </t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.3-3">
&lt;PCRep Message&gt; ::= &lt;Common Header&gt;
                    &lt;response-list&gt;
</sourcecode>
          <t pn="section-6.3.3-4">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.3-5">
   &lt;response-list&gt;::=&lt;response&gt;[&lt;response-list&gt;]

   &lt;response&gt;::=&lt;RP&gt;
                [&lt;LSP&gt;]
                [&lt;NO-PATH&gt;]
                [&lt;association-list&gt;]
                [&lt;attribute-list&gt;]
                [&lt;path-list&gt;]
</sourcecode>
          <t pn="section-6.3.3-6">Where:</t>
          <sourcecode type="rbnf" markers="false" pn="section-6.3.3-7">
   &lt;association-list&gt; ::= &lt;ASSOCIATION&gt; [&lt;association-list&gt;]
</sourcecode>
          <t pn="section-6.3.3-8">
   Note that the LSP object <bcp14>MAY</bcp14> be present for the passive stateful
   PCE mode.
          </t>
        </section>
      </section>
      <section anchor="Rules" numbered="true" toc="include" removeInRFC="false" pn="section-6.4">
        <name slugifiedName="name-processing-rules">Processing Rules</name>
        <t pn="section-6.4-1">
    Association groups can be operator configured on the necessary PCEP
    speakers, and the PCEP speakers can join the existing association groups. 
    In addition, a PCC or a PCE can create association groups dynamically, and
    the PCEP speaker can also report the associations to its peer via PCEP
    messages. The Operator-configured Associations are created via
    configurations (where all association parameters are manually set) and
    exist until explicitly removed via configurations. The PCEP speaker can
    add LSPs to these configured associations and provide this information
    via stateful PCEP messages. The dynamic associations are created
    dynamically by the PCEP speaker (where all association parameters are
    populated dynamically). The association group is attached to the LSP
    state, and the association group exists until there is at least one LSP as
    part of the association. As described in <xref target="id" format="default" sectionFormat="of" derivedContent="Section 6.1.4"/>, the
    association parameters are the combination of Association Type,
    Association ID, and Association Source, as well as the optional Global
    Association Source and Extended Association ID TLVs; this combination
    uniquely identifies an association group. The information
    related to the Association Types encoded via the TLVs of a particular
    Association Type (not described in this document) is the association
    information (<xref target="id" format="default" sectionFormat="of" derivedContent="Section 6.1.4"/>).</t>
        <t pn="section-6.4-2">If a PCEP speaker does not recognize the ASSOCIATION object in the
    stateful message, it will return a PCErr message with Error-Type  "Unknown
    Object" as described in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. In the case of a PCReq
    message, the PCE would react based on the P flag as per <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. If a PCEP speaker understands the ASSOCIATION object
    but does not support the Association Type, it <bcp14>MUST</bcp14> return a PCErr message
    with Error-Type 26 "Association Error" and
    Error-value 1 "Association Type is not supported". If any association
    parameters are invalid in the ASSOCIATION object, the PCEP speaker would
    consider this object malformed and process it as a malformed message <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. On receiving a PCEP message with an ASSOCIATION
    object, if a PCEP speaker finds that too many LSPs belong to the
    association group, it <bcp14>MUST</bcp14> return a PCErr message with Error-Type 26
     "Association Error" and Error-value 2 "Too
    many LSPs in the association group". If a PCEP speaker cannot handle a new
    association, it <bcp14>MUST</bcp14> return a PCErr message with Error-Type 26
     "Association Error" and Error-value 3 "Too many
    association groups". These numbers <bcp14>MAY</bcp14> be set by the operator or chosen
    based on a local policy. </t>
        <t pn="section-6.4-3">If a PCE peer is unwilling or unable to process the ASSOCIATION object
    in the stateful message, it <bcp14>MUST</bcp14> return a PCErr message with the
    Error-Type "Not supported object" and follow the relevant procedures
    described in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. In the case of a PCReq message, the
    PCE would react based on the P flag as per <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. On
    receiving a PCEP message with an ASSOCIATION object, if a PCEP speaker
    could not add the LSP to the association group for any reason, it <bcp14>MUST</bcp14>
    return a PCErr message with Error-Type 26 
    "Association Error" and Error-value 7 "Cannot join the association
    group".</t>
        <t pn="section-6.4-4">If a PCEP speaker receives an ASSOCIATION object for an Operator-configured Association 
      and the Association ID is not in the Operator-configured Association Range
      for the Association Type and Association Source, it <bcp14>MUST</bcp14> return a PCErr message with Error-Type 26 
      "Association Error" and Error-value 8 "Association ID not in range".
        </t>
        <t pn="section-6.4-5">If a PCEP speaker receives an ASSOCIATION object in a PCReq message
      and the association is not known (the association is not configured, 
      was not created dynamically, or was not learned from a PCEP peer), it <bcp14>MUST</bcp14> return a
      PCErr message with Error-Type 26 "Association
      Error" and Error-value 4 "Association unknown".</t>
        <t pn="section-6.4-6">If the association information (related to the association group as a
    whole) received from the peer does not match the local operator-configured
    information, it <bcp14>MUST</bcp14> return a PCErr message with Error-Type 26 "Association Error" and Error-value 5
    "Operator-configured association information mismatch". On receiving
    association information (related to the association group as a whole) that
    does not match the association information previously received about the
    same association from a peer, it <bcp14>MUST</bcp14> return a PCErr message with
    Error-Type 26 "Association Error" and
    Error-value 6 "Association information mismatch". Note that information
    related to each LSP within the association as part of the association
    information TLVs could be different.
        </t>
        <t pn="section-6.4-7">If a PCEP speaker receives an ASSOCIATION object with the R bit set for
    removal and the association group (identified by association parameters)
    is not known, it <bcp14>MUST</bcp14> return a PCErr message with Error-Type 26
     "Association Error" and Error-value 4
    "Association unknown".</t>
        <t pn="section-6.4-8">The dynamic associations are cleared along with the LSP state
    information as per <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>. When a PCEP session is
    terminated, after expiry of the State Timeout Interval at the PCC, the LSP
    state associated with that PCEP session is reverted to operator-defined
    default parameters or behaviors. The same procedure is also followed for
    the association groups. On session termination at the PCE, when the LSP
    state reported by the PCC is cleared, the association groups are also
    cleared. When there are no LSPs in an association group, the association
    is considered empty and thus deleted.</t>
        <t pn="section-6.4-9">If the LSP is delegated to another PCE on session failure,
    the associations (and association information) set by the PCE remain
    intact, unless updated by the new PCE that takes over. </t>
        <t pn="section-6.4-10">Upon LSP delegation revocation, the PCC <bcp14>MAY</bcp14> clear the association
    created by the PCE, but in order to avoid traffic loss, it <bcp14>SHOULD</bcp14>
    perform this action in a make-before-break fashion (same as <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>).</t>
      </section>
    </section>
    <section anchor="IANA-considerations" numbered="true" toc="include" removeInRFC="false" pn="section-7">
      <name slugifiedName="name-iana-considerations">IANA Considerations</name>
      <t pn="section-7-1">IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
    registry at <eref brackets="angle" target="https://www.iana.org/assignments/pcep"/>.</t>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-7.1">
        <name slugifiedName="name-pcep-object">PCEP Object</name>
        <t pn="section-7.1-1">The "Path Computation Element Protocol (PCEP) Numbers" registry
        contains a subregistry called "PCEP Objects". IANA has allocated the
        following code point in the "PCEP Objects" registry.
        </t>
        <table anchor="tab-1" align="center" pn="table-1">
          <name slugifiedName="name-pcep-object-2">PCEP Object</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Object-Class Value</th>
              <th align="left" colspan="1" rowspan="1">Name</th>
              <th align="left" colspan="1" rowspan="1">Object-Type</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td rowspan="3" align="left" colspan="1">40</td>
              <td rowspan="3" align="left" colspan="1">ASSOCIATION</td>
              <td align="left" colspan="1" rowspan="1">0: Reserved</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">1: IPv4</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">2: IPv6</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
      </section>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-7.2">
        <name slugifiedName="name-pcep-tlv">PCEP TLV</name>
        <t pn="section-7.2-1">IANA has allocated the following
   code points in the "PCEP TLV Type Indicators" registry.
        </t>
        <table anchor="tab-2" align="center" pn="table-2">
          <name slugifiedName="name-pcep-tlv-type-indicators">PCEP TLV Type Indicators</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Value</th>
              <th align="left" colspan="1" rowspan="1">Meaning</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left" colspan="1" rowspan="1">29</td>
              <td align="left" colspan="1" rowspan="1">Operator-configured Association Range</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">30</td>
              <td align="left" colspan="1" rowspan="1">Global Association Source</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">31</td>
              <td align="left" colspan="1" rowspan="1">Extended Association ID</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
        <t pn="section-7.2-3">IANA has corrected the capitalization in the meaning for value 31 in the above registry
   to "Extended Association ID"; it was previously listed as "Extended
   Association Id".</t>
        <t pn="section-7.2-4">IANA has made a new assignment in
   the existing "PCEP TLV Type Indicators" registry as follows:
        </t>
        <table anchor="tab-3" align="center" pn="table-3">
          <name slugifiedName="name-assoc-type-list-pcep-tlv-ty">ASSOC-Type-List PCEP TLV Type Indicator</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Value</th>
              <th align="left" colspan="1" rowspan="1">Meaning</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left" colspan="1" rowspan="1">35</td>
              <td align="left" colspan="1" rowspan="1">ASSOC-Type-List</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
      </section>
      <section numbered="true" toc="include" removeInRFC="false" pn="section-7.3">
        <name slugifiedName="name-association-flags">Association Flags</name>
        <t pn="section-7.3-1">Per this document, IANA has created a subregistry of the
    "Path Computation Element Protocol (PCEP) Numbers" registry
    for the bits carried in the Flags field of the ASSOCIATION object.
    The subregistry is called "ASSOCIATION Flag Field". New values are
    assigned by Standards Action <xref target="RFC8126" format="default" sectionFormat="of" derivedContent="RFC8126"/>.  Each bit is
    tracked with the following qualities:

        </t>
        <ul spacing="normal" bare="false" empty="false" pn="section-7.3-2">
          <li pn="section-7.3-2.1">Bit number (counting from bit 0 as the most significant bit)</li>
          <li pn="section-7.3-2.2">Capability description</li>
          <li pn="section-7.3-2.3">Defining RFC</li>
        </ul>
        <table anchor="tab-4" align="center" pn="table-4">
          <name slugifiedName="name-new-association-flag-field">New ASSOCIATION Flag Field</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Bit</th>
              <th align="left" colspan="1" rowspan="1">Description</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left" colspan="1" rowspan="1">15</td>
              <td align="left" colspan="1" rowspan="1">R (Removal)</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
      </section>
      <section anchor="iana_assoc_type" numbered="true" toc="include" removeInRFC="false" pn="section-7.4">
        <name slugifiedName="name-association-type">Association Type</name>
        <t pn="section-7.4-1">Per this document, IANA has created a subregistry of the
        "Path Computation Element Protocol (PCEP) Numbers" registry for
        the Association Type field of the ASSOCIATION object.
        The subregistry is called "ASSOCIATION Type Field". New values are
        assigned by Standards Action <xref target="RFC8126" format="default" sectionFormat="of" derivedContent="RFC8126"/>.  Each
        value is tracked with the following qualities:

        </t>
        <ul spacing="normal" bare="false" empty="false" pn="section-7.4-2">
          <li pn="section-7.4-2.1">Type</li>
          <li pn="section-7.4-2.2">Name</li>
          <li pn="section-7.4-2.3">Reference</li>
        </ul>
        <table anchor="tab-5" align="center" pn="table-5">
          <name slugifiedName="name-new-association-type-field">New ASSOCIATION Type Field</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Type</th>
              <th align="left" colspan="1" rowspan="1">Name</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left" colspan="1" rowspan="1">0</td>
              <td align="left" colspan="1" rowspan="1">Reserved</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
        <t pn="section-7.4-4">
 Values 2-65535 are Unassigned. Future
          documents should request the assignment of Association Types from
          this subregistry.</t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-7.5">
        <name slugifiedName="name-pcep-error-object">PCEP-Error Object</name>
        <t pn="section-7.5-1">IANA has allocated the following
        code points within the "PCEP-ERROR Object Error Types and Values"
        subregistry of the "Path Computation Element Protocol (PCEP) Numbers"
        registry as follows:</t>
        <table anchor="tab-6" align="center" pn="table-6">
          <name slugifiedName="name-pcep-error-types-and-names">PCEP-ERROR Types and Names</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Error-Type</th>
              <th align="left" colspan="1" rowspan="1">Meaning</th>
              <th align="left" colspan="1" rowspan="1">Error-value</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td rowspan="9" align="left" colspan="1">26</td>
              <td rowspan="9" align="left" colspan="1">Association Error</td>
              <td align="left" colspan="1" rowspan="1">0: Unassigned</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">1: Association Type is not supported</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">2: Too many LSPs in the association group</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">3: Too many association groups</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">4: Association unknown</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">5: Operator-configured association information mismatch</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">6: Association information mismatch</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">7: Cannot join the association group</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
            <tr>
              <td align="left" colspan="1" rowspan="1">8: Association ID not in range</td>
              <td align="left" colspan="1" rowspan="1">RFC 8697</td>
            </tr>
          </tbody>
        </table>
      </section>
    </section>
    <section anchor="Security" numbered="true" toc="include" removeInRFC="false" pn="section-8">
      <name slugifiedName="name-security-considerations">Security Considerations</name>
      <t pn="section-8-1">The security considerations described in <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/> and <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> apply to the
   extensions described in this document as well.  Additional considerations
   related to a malicious PCEP speaker are introduced, as associations could
   be spoofed and could be used as an
   attack vector. An attacker could attempt to create too many associations in
   an attempt to load the PCEP peer. The PCEP peer responds with a PCErr
   message as described in <xref target="Rules" format="default" sectionFormat="of" derivedContent="Section 6.4"/>. An attacker could impact
   LSP operations by creating bogus associations. Further, association groups
   could provide an adversary with the opportunity to eavesdrop on the
   relationship between the LSPs. Thus, securing the PCEP session using
   Transport Layer Security (TLS) <xref target="RFC8253" format="default" sectionFormat="of" derivedContent="RFC8253"/>, as per the
   recommendations and best current practices in <xref target="RFC7525" format="default" sectionFormat="of" derivedContent="RFC7525"/>, is
   <bcp14>RECOMMENDED</bcp14>.

      </t>
      <t pn="section-8-2">Much of the information carried in the ASSOCIATION object as per this
  document is not extra sensitive. It often reflects information that can
  also be derived from the LSP database, but the association provides a much
  easier grouping of related LSPs and messages. Implementations and operators
  can, and should, use indirect values in the ASSOCIATION object as a way to
  hide any sensitive business relationships.</t>
    </section>
    <section toc="include" numbered="true" removeInRFC="false" pn="section-9">
      <name slugifiedName="name-manageability-consideration">Manageability Considerations</name>
      <t pn="section-9-1">
  All manageability requirements and considerations listed in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> and <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/> apply to PCEP protocol
  extensions defined in this document. In addition, requirements and
  considerations listed in this section apply. 
      </t>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.1">
        <name slugifiedName="name-control-of-function-and-pol">Control of Function and Policy</name>
        <t pn="section-9.1-1">
  A PCE or PCC implementation <bcp14>MUST</bcp14> allow Operator-configured Associations and
  <bcp14>SHOULD</bcp14> allow the setting of the Operator-configured Association Range (<xref target="Range" format="default" sectionFormat="of" derivedContent="Section 3.4"/>) as described in this document. 
        </t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.2">
        <name slugifiedName="name-information-and-data-models">Information and Data Models</name>
        <t pn="section-9.2-1">The PCEP YANG module is defined in <xref target="PCEP-YANG" format="default" sectionFormat="of" derivedContent="PCEP-YANG"/>. In the
   future, this YANG module should be extended or augmented to provide
   the following additional information related to association groups.</t>
        <t pn="section-9.2-2">An implementation <bcp14>SHOULD</bcp14> allow the operator to view the associations
  configured or created dynamically. Future implementations <bcp14>SHOULD</bcp14> allow
  the viewing of associations reported by each peer and the current set of
  LSPs in the association.</t>
        <t pn="section-9.2-3">It might also be useful to find out how many associations for each
  Association Type currently exist and to know how many free Association IDs are available for a particular Association Type and source.</t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.3">
        <name slugifiedName="name-liveness-detection-and-moni">Liveness Detection and Monitoring</name>
        <t pn="section-9.3-1">
  Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/>. 
        </t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.4">
        <name slugifiedName="name-verifying-correct-operation">Verifying Correct Operation</name>
        <t pn="section-9.4-1">
  Mechanisms defined in this document do not imply any new operation verification requirements in addition to those already listed in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> 
  and <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/>. 
        </t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.5">
        <name slugifiedName="name-requirements-on-other-proto">Requirements on Other Protocols</name>
        <t pn="section-9.5-1">Mechanisms defined in this document do not imply any new requirements on other protocols.</t>
      </section>
      <section toc="include" numbered="true" removeInRFC="false" pn="section-9.6">
        <name slugifiedName="name-impact-on-network-operation">Impact on Network Operations</name>
        <t pn="section-9.6-1">
  Mechanisms defined in <xref target="RFC5440" format="default" sectionFormat="of" derivedContent="RFC5440"/> 
  and 
  <xref target="RFC8231" format="default" sectionFormat="of" derivedContent="RFC8231"/> also apply to PCEP extensions defined in this document. </t>
      </section>
    </section>
  </middle>
  <back>
    <displayreference target="I-D.ietf-pce-stateful-path-protection" to="PCE-PROTECTION"/>
    <displayreference target="I-D.ietf-pce-association-diversity" to="PCE-DIVERSITY"/>
    <references pn="section-10">
      <name slugifiedName="name-references">References</name>
      <references pn="section-10.1">
        <name slugifiedName="name-normative-references">Normative References</name>
        <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119">
          <front>
            <title>Key words for use in RFCs to Indicate Requirement Levels</title>
            <author initials="S." surname="Bradner" fullname="S. Bradner">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="1997" month="March"/>
            <abstract>
              <t>In many standards track documents several words are used to signify the requirements in the specification.  These words are often capitalized. This document defines these words as they should be interpreted in IETF documents.  This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC5440" target="https://www.rfc-editor.org/info/rfc5440" quoteTitle="true" derivedAnchor="RFC5440">
          <front>
            <title>Path Computation Element (PCE) Communication Protocol (PCEP)</title>
            <author initials="JP." surname="Vasseur" fullname="JP. Vasseur" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="JL." surname="Le Roux" fullname="JL. Le Roux" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2009" month="March"/>
            <abstract>
              <t>This document specifies the Path Computation Element (PCE) Communication Protocol (PCEP) for communications between a Path Computation Client (PCC) and a PCE, or between two PCEs.  Such interactions include path computation requests and path computation replies as well as notifications of specific states related to the use of a PCE in the context of Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering.  PCEP is designed to be flexible and extensible so as to easily allow for the addition of further messages and objects, should further requirements be expressed in the future.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5440"/>
          <seriesInfo name="DOI" value="10.17487/RFC5440"/>
        </reference>
        <reference anchor="RFC5511" target="https://www.rfc-editor.org/info/rfc5511" quoteTitle="true" derivedAnchor="RFC5511">
          <front>
            <title>Routing Backus-Naur Form (RBNF): A Syntax Used to Form Encoding Rules in Various Routing Protocol Specifications</title>
            <author initials="A." surname="Farrel" fullname="A. Farrel">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2009" month="April"/>
            <abstract>
              <t>Several protocols have been specified in the Routing Area of the IETF using a common variant of the Backus-Naur Form (BNF) of representing message syntax.  However, there is no formal definition of this version of BNF.</t>
              <t>There is value in using the same variant of BNF for the set of protocols that are commonly used together.  This reduces confusion and simplifies implementation.</t>
              <t>Updating existing documents to use some other variant of BNF that is already formally documented would be a substantial piece of work.</t>
              <t>This document provides a formal definition of the variant of BNF that has been used (that we call Routing BNF) and makes it available for use by new protocols.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="5511"/>
          <seriesInfo name="DOI" value="10.17487/RFC5511"/>
        </reference>
        <reference anchor="RFC6780" target="https://www.rfc-editor.org/info/rfc6780" quoteTitle="true" derivedAnchor="RFC6780">
          <front>
            <title>RSVP ASSOCIATION Object Extensions</title>
            <author initials="L." surname="Berger" fullname="L. Berger">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="F." surname="Le Faucheur" fullname="F. Le Faucheur">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Narayanan" fullname="A. Narayanan">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2012" month="October"/>
            <abstract>
              <t>The RSVP ASSOCIATION object was defined in the context of GMPLS-controlled Label Switched Paths (LSPs).  In this context, the object is used to associate recovery LSPs with the LSP they are protecting.  This object also has broader applicability as a mechanism to associate RSVP state.  This document defines how the ASSOCIATION object can be more generally applied.  This document also defines Extended ASSOCIATION objects that, in particular, can be used in the context of the MPLS Transport Profile (MPLS-TP).  This document updates RFC 2205, RFC 3209, and RFC 3473.  It also generalizes the definition of the Association ID field defined in RFC 4872.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6780"/>
          <seriesInfo name="DOI" value="10.17487/RFC6780"/>
        </reference>
        <reference anchor="RFC7525" target="https://www.rfc-editor.org/info/rfc7525" quoteTitle="true" derivedAnchor="RFC7525">
          <front>
            <title>Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)</title>
            <author initials="Y." surname="Sheffer" fullname="Y. Sheffer">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Holz" fullname="R. Holz">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="P." surname="Saint-Andre" fullname="P. Saint-Andre">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="May"/>
            <abstract>
              <t>Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) are widely used to protect data exchanged over application protocols such as HTTP, SMTP, IMAP, POP, SIP, and XMPP.  Over the last few years, several serious attacks on TLS have emerged, including attacks on its most commonly used cipher suites and their modes of operation.  This document provides recommendations for improving the security of deployed services that use TLS and DTLS. The recommendations are applicable to the majority of use cases.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="195"/>
          <seriesInfo name="RFC" value="7525"/>
          <seriesInfo name="DOI" value="10.17487/RFC7525"/>
        </reference>
        <reference anchor="RFC8051" target="https://www.rfc-editor.org/info/rfc8051" quoteTitle="true" derivedAnchor="RFC8051">
          <front>
            <title>Applicability of a Stateful Path Computation Element (PCE)</title>
            <author initials="X." surname="Zhang" fullname="X. Zhang" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Minei" fullname="I. Minei" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="January"/>
            <abstract>
              <t>A stateful Path Computation Element (PCE) maintains information about Label Switched Path (LSP) characteristics and resource usage within a network in order to provide traffic-engineering calculations for its associated Path Computation Clients (PCCs).  This document describes general considerations for a stateful PCE deployment and examines its applicability and benefits, as well as its challenges and limitations, through a number of use cases.  PCE Communication Protocol (PCEP) extensions required for stateful PCE usage are covered in separate documents.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8051"/>
          <seriesInfo name="DOI" value="10.17487/RFC8051"/>
        </reference>
        <reference anchor="RFC8126" target="https://www.rfc-editor.org/info/rfc8126" quoteTitle="true" derivedAnchor="RFC8126">
          <front>
            <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
            <author initials="M." surname="Cotton" fullname="M. Cotton">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="B." surname="Leiba" fullname="B. Leiba">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="T." surname="Narten" fullname="T. Narten">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="June"/>
            <abstract>
              <t>Many protocols make use of points of extensibility that use constants to identify various protocol parameters.  To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper.  For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).</t>
              <t>To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed.  This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry.</t>
              <t>This is the third edition of this document; it obsoletes RFC 5226.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="26"/>
          <seriesInfo name="RFC" value="8126"/>
          <seriesInfo name="DOI" value="10.17487/RFC8126"/>
        </reference>
        <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174">
          <front>
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
            <author initials="B." surname="Leiba" fullname="B. Leiba">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="May"/>
            <abstract>
              <t>RFC 2119 specifies common key words that may be used in protocol  specifications.  This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the  defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
        <reference anchor="RFC8231" target="https://www.rfc-editor.org/info/rfc8231" quoteTitle="true" derivedAnchor="RFC8231">
          <front>
            <title>Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE</title>
            <author initials="E." surname="Crabbe" fullname="E. Crabbe">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Minei" fullname="I. Minei">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J." surname="Medved" fullname="J. Medved">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Varga" fullname="R. Varga">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="September"/>
            <abstract>
              <t>The Path Computation Element Communication Protocol (PCEP) provides mechanisms for Path Computation Elements (PCEs) to perform path computations in response to Path Computation Client (PCC) requests.</t>
              <t>Although PCEP explicitly makes no assumptions regarding the information available to the PCE, it also makes no provisions for PCE control of timing and sequence of path computations within and across PCEP sessions.  This document describes a set of extensions to PCEP to enable stateful control of MPLS-TE and GMPLS Label Switched Paths (LSPs) via PCEP.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8231"/>
          <seriesInfo name="DOI" value="10.17487/RFC8231"/>
        </reference>
        <reference anchor="RFC8281" target="https://www.rfc-editor.org/info/rfc8281" quoteTitle="true" derivedAnchor="RFC8281">
          <front>
            <title>Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model</title>
            <author initials="E." surname="Crabbe" fullname="E. Crabbe">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Minei" fullname="I. Minei">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S." surname="Sivabalan" fullname="S. Sivabalan">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Varga" fullname="R. Varga">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="December"/>
            <abstract>
              <t>The Path Computation Element Communication Protocol (PCEP) provides mechanisms for Path Computation Elements (PCEs) to perform path computations in response to Path Computation Client (PCC) requests.</t>
              <t>The extensions for stateful PCE provide active control of Multiprotocol Label Switching (MPLS) Traffic Engineering Label Switched Paths (TE LSPs) via PCEP, for a model where the PCC delegates control over one or more locally configured LSPs to the PCE.  This document describes the creation and deletion of PCE-initiated LSPs under the stateful PCE model.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8281"/>
          <seriesInfo name="DOI" value="10.17487/RFC8281"/>
        </reference>
      </references>
      <references pn="section-10.2">
        <name slugifiedName="name-informative-references">Informative References</name>
        <reference anchor="RFC4657" target="https://www.rfc-editor.org/info/rfc4657" quoteTitle="true" derivedAnchor="RFC4657">
          <front>
            <title>Path Computation Element (PCE) Communication Protocol Generic Requirements</title>
            <author initials="J." surname="Ash" fullname="J. Ash" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J.L." surname="Le Roux" fullname="J.L. Le Roux" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2006" month="September"/>
            <abstract>
              <t>The PCE model is described in the "PCE Architecture" document and facilitates path computation requests from Path Computation Clients (PCCs) to Path Computation Elements (PCEs).  This document specifies generic requirements for a communication protocol between PCCs and PCEs, and also between PCEs where cooperation between PCEs is desirable.  Subsequent documents will specify application-specific requirements for the PCE communication protocol.  This memo provides information for the Internet community.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4657"/>
          <seriesInfo name="DOI" value="10.17487/RFC4657"/>
        </reference>
        <reference anchor="RFC4872" target="https://www.rfc-editor.org/info/rfc4872" quoteTitle="true" derivedAnchor="RFC4872">
          <front>
            <title>RSVP-TE Extensions in Support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS) Recovery</title>
            <author initials="J.P." surname="Lang" fullname="J.P. Lang" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Y." surname="Rekhter" fullname="Y. Rekhter" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Papadimitriou" fullname="D. Papadimitriou" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="May"/>
            <abstract>
              <t>This document describes protocol-specific procedures and extensions for Generalized Multi-Protocol Label Switching (GMPLS) Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE) signaling to support end-to-end Label Switched Path (LSP) recovery that denotes protection and restoration.  A generic functional description of GMPLS recovery can be found in a companion document, RFC 4426.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4872"/>
          <seriesInfo name="DOI" value="10.17487/RFC4872"/>
        </reference>
        <reference anchor="RFC4873" target="https://www.rfc-editor.org/info/rfc4873" quoteTitle="true" derivedAnchor="RFC4873">
          <front>
            <title>GMPLS Segment Recovery</title>
            <author initials="L." surname="Berger" fullname="L. Berger">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I." surname="Bryskin" fullname="I. Bryskin">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Papadimitriou" fullname="D. Papadimitriou">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="A." surname="Farrel" fullname="A. Farrel">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2007" month="May"/>
            <abstract>
              <t>This document describes protocol specific procedures for GMPLS (Generalized Multi-Protocol Label Switching) RSVP-TE (Resource ReserVation Protocol - Traffic Engineering) signaling extensions to support label switched path (LSP) segment protection and restoration. These extensions are intended to complement and be consistent with the RSVP-TE Extensions for End-to-End GMPLS Recovery (RFC 4872). Implications and interactions with fast reroute are also addressed. This document also updates the handling of NOTIFY_REQUEST objects.  [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4873"/>
          <seriesInfo name="DOI" value="10.17487/RFC4873"/>
        </reference>
        <reference anchor="RFC6007" target="https://www.rfc-editor.org/info/rfc6007" quoteTitle="true" derivedAnchor="RFC6007">
          <front>
            <title>Use of the Synchronization VECtor (SVEC) List for Synchronized Dependent Path Computations</title>
            <author initials="I." surname="Nishioka" fullname="I. Nishioka">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="King" fullname="D. King">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2010" month="September"/>
            <abstract>
              <t>A Path Computation Element (PCE) may be required to perform dependent path computations.  Dependent path computations are requests that need to be synchronized in order to meet specific objectives.  An example of a dependent request would be a PCE computing a set of services that are required to be diverse (disjointed) from each other.  When a PCE computes sets of dependent path computation requests concurrently, use of the Synchronization VECtor (SVEC) list is required for association among the sets of dependent path computation requests.  The SVEC object is optional and carried within the Path Computation Element Communication Protocol (PCEP) PCRequest (PCReq) message.</t>
              <t>This document does not specify the PCEP SVEC object or procedure. This informational document clarifies the use of the SVEC list for synchronized path computations when computing dependent requests. The document also describes a number of usage scenarios for SVEC lists within single-domain and multi-domain environments.   This document is not an Internet Standards Track specification; it is published for informational purposes.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6007"/>
          <seriesInfo name="DOI" value="10.17487/RFC6007"/>
        </reference>
        <reference anchor="RFC7551" target="https://www.rfc-editor.org/info/rfc7551" quoteTitle="true" derivedAnchor="RFC7551">
          <front>
            <title>RSVP-TE Extensions for Associated Bidirectional Label Switched Paths (LSPs)</title>
            <author initials="F." surname="Zhang" fullname="F. Zhang" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Jing" fullname="R. Jing">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="R." surname="Gandhi" fullname="R. Gandhi" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2015" month="May"/>
            <abstract>
              <t>This document describes Resource Reservation Protocol (RSVP) extensions to bind two point-to-point unidirectional Label Switched Paths (LSPs) into an associated bidirectional LSP.  The association is achieved by defining new Association Types for use in ASSOCIATION and in Extended ASSOCIATION Objects. One of these types enables independent provisioning of the associated bidirectional LSPs on both sides, while the other enables single-sided provisioning.  The REVERSE_LSP Object is also defined to enable a single endpoint to trigger creation of the reverse LSP and to specify parameters of the reverse LSP in the single-sided provisioning case.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7551"/>
          <seriesInfo name="DOI" value="10.17487/RFC7551"/>
        </reference>
        <reference anchor="RFC8253" target="https://www.rfc-editor.org/info/rfc8253" quoteTitle="true" derivedAnchor="RFC8253">
          <front>
            <title>PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)</title>
            <author initials="D." surname="Lopez" fullname="D. Lopez">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="O." surname="Gonzalez de Dios" fullname="O. Gonzalez de Dios">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="Q." surname="Wu" fullname="Q. Wu">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="D." surname="Dhody" fullname="D. Dhody">
              <organization showOnFrontPage="true"/>
            </author>
            <date year="2017" month="October"/>
            <abstract>
              <t>The Path Computation Element Communication Protocol (PCEP) defines the mechanisms for the communication between a Path Computation Client (PCC) and a Path Computation Element (PCE), or among PCEs. This document describes PCEPS -- the usage of Transport Layer Security (TLS) to provide a secure transport for PCEP.  The additional security mechanisms are provided by the transport protocol supporting PCEP; therefore, they do not affect the flexibility and extensibility of PCEP.</t>
              <t>This document updates RFC 5440 in regards to the PCEP initialization phase procedures.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8253"/>
          <seriesInfo name="DOI" value="10.17487/RFC8253"/>
        </reference>
        <reference anchor="PCEP-YANG" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-13" derivedAnchor="PCEP-YANG">
          <front>
            <title>A YANG Data Model for Path Computation Element Communications Protocol (PCEP)</title>
            <author initials="D" surname="Dhody" fullname="Dhruv Dhody" role="editor">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J" surname="Hardwick" fullname="Jonathan Hardwick">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="V" surname="Beeram" fullname="Vishnu Beeram">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="J" surname="Tantsura" fullname="Jeff Tantsura">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="October" day="31" year="2019"/>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-pce-pcep-yang-13"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
        <reference anchor="I-D.ietf-pce-stateful-path-protection" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-pce-stateful-path-protection-11" derivedAnchor="PCE-PROTECTION">
          <front>
            <title>PCEP Extensions for Associating Working and Protection LSPs with Stateful PCE</title>
            <author initials="H" surname="Ananthakrishnan" fullname="Hariharan Ananthakrishnan">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S" surname="Sivabalan" fullname="Siva Sivabalan">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C" surname="Barth" fullname="Colby Barth">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="I" surname="Minei" fullname="Ina Minei">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M" surname="Negi" fullname="Mahendra Negi">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="September" day="25" year="2019"/>
            <abstract>
              <t>An active stateful Path Computation Element (PCE) is capable of computing as well as controlling via Path Computation Element Communication Protocol (PCEP) Multiprotocol Label Switching Traffic Engineering (MPLS-TE) Label Switched Paths (LSPs).  Furthermore, it is also possible for an active stateful PCE to create, maintain, and delete LSPs.  This document defines the PCEP extension to associate two or more LSPs to provide end-to-end path protection.</t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-pce-stateful-path-protection-11"/>
          <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-pce-stateful-path-protection-11.txt"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
        <reference anchor="I-D.ietf-pce-association-diversity" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-pce-association-diversity-14" derivedAnchor="PCE-DIVERSITY">
          <front>
            <title>Path Computation Element Communication Protocol (PCEP) Extension for LSP Diversity Constraint Signaling</title>
            <author initials="S" surname="Litkowski" fullname="Stephane Litkowski">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="S" surname="Sivabalan" fullname="Siva Sivabalan">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="C" surname="Barth" fullname="Colby Barth">
              <organization showOnFrontPage="true"/>
            </author>
            <author initials="M" surname="Negi" fullname="Mahendra Negi">
              <organization showOnFrontPage="true"/>
            </author>
            <date month="January" day="26" year="2020"/>
            <abstract>
              <t>This document introduces a simple mechanism to associate a group of Label Switched Paths (LSPs) via an extension to the Path Computation Element (PCE) communication Protocol (PCEP) with the purpose of computing diverse (disjointed) paths for those LSPs.  The proposed extension allows a Path Computation Client (PCC) to advertise to a PCE that a particular LSP belongs to a particular disjoint-group, thus the PCE knows that the LSPs in the same group need to be disjoint from each other.</t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-pce-association-diversity-14"/>
          <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-pce-association-diversity-14.txt"/>
          <refcontent>Work in Progress</refcontent>
        </reference>
      </references>
    </references>
    <section anchor="ex" numbered="true" toc="include" removeInRFC="false" pn="section-appendix.a">
      <name slugifiedName="name-example-of-an-operator-conf">Example of an Operator-Configured Association Range</name>
      <t pn="section-appendix.a-1">Consider an Association Type T1 (which allows both dynamic and
    Operator-configured Associations with a default range of
    &lt;0x1000, 0xffff&gt;). Consider that, because of the needs of the
    network, the PCE needs to create more dynamic associations and would like
    to change the Association Range to &lt;0xbffe, 0xffff&gt; instead. During
    PCEP session establishment, the PCE would advertise the new range. The PCC
    could skip advertising, as the default values are used. If a PCC is
    creating a dynamic association (with the PCC as the Association Source),
    it needs to pick a free Association ID for type T1 in the range
    &lt;0x1, 0x0fff&gt;, whereas if a PCE is creating a dynamic association
    (with the PCE as the Association Source), it needs to pick a free
    Association ID from the range &lt;0x1, 0xbffd&gt;. Similarly, if
    an Operator-configured Association is manually configured with the PCC as
    the Association Source, it should be from the range &lt;0x1000,
    0xffff&gt;, whereas if the PCE is the Association Source, it should be
    from the range &lt;0xbffe, 0xffff&gt;. If the Association Source is
    not a PCEP peer (for example, an NMS), then the default range of
    &lt;0x1000, 0xffff&gt; is considered.</t>
    </section>
    <section anchor="Acknowledgments" numbered="false" toc="include" removeInRFC="false" pn="section-appendix.b">
      <name slugifiedName="name-acknowledgments">Acknowledgments</name>
      <t pn="section-appendix.b-1">We would like to thank <contact fullname="Yuji Kamite"/> and <contact fullname="Joshua George"/> for
     their contributions to this document. Thanks also to <contact fullname="Venugopal Reddy"/>,
     <contact fullname="Cyril Margaria"/>, <contact fullname="Rakesh      Gandhi"/>, <contact fullname="Mike Koldychev"/>, and <contact fullname="Adrian Farrel"/> for their useful comments.</t>
      <t pn="section-appendix.b-2">We would like to thank <contact fullname="Julien Meuric"/> for shepherding this
   document and providing comments with text suggestions.</t>
      <t pn="section-appendix.b-3">Thanks to <contact fullname="Stig Venaas"/> for the RTGDIR review comments.</t>
      <t pn="section-appendix.b-4">Thanks to <contact fullname="Alvaro Retana"/>, <contact fullname="Mirja Kühlewind"/>, <contact fullname="Martin Vigoureux"/>,
      <contact fullname="Barry Leiba"/>, <contact fullname="Eric Vyncke"/>,
      <contact fullname="Suresh Krishnan"/>, and <contact fullname="Benjamin Kaduk"/> for the IESG comments.</t>
    </section>
    <section anchor="Contributors" numbered="false" toc="include" removeInRFC="false" pn="section-appendix.c">
      <name slugifiedName="name-contributors">Contributors</name>
      <contact fullname="Stephane Litkowski">
        <organization showOnFrontPage="true">Orange</organization>
        <address>
          <postal>
</postal>
          <email>stephane.litkowski@orange.com</email>
        </address>
      </contact>
      <contact fullname="Xian Zhang">
        <organization showOnFrontPage="true">Huawei Technologies</organization>
        <address>
          <postal>
            <extaddr>F3-1-B RnD Center, Huawei Base</extaddr>
            <street>Bantian, Longgang District</street>
            <region>Shenzhen</region>
            <code>518129</code>
            <country>China</country>
          </postal>
          <email>zhang.xian@huawei.com</email>
        </address>
      </contact>
      <contact fullname="Mustapha Aissaoui">
        <organization showOnFrontPage="true">Nokia</organization>
        <address>
          <postal>
</postal>
          <email>mustapha.aissaoui@nokia.com</email>
        </address>
      </contact>
    </section>
    <section anchor="authors-addresses" numbered="false" removeInRFC="false" toc="include" pn="section-appendix.d">
      <name slugifiedName="name-authors-addresses">Authors' Addresses</name>
      <author fullname="Ina Minei" initials="I." surname="Minei">
        <organization showOnFrontPage="true">Google, Inc.</organization>
        <address>
          <postal>
            <street>1600 Amphitheatre Parkway</street>
            <city>Mountain View</city>
            <region>CA</region>
            <code>94043</code>
            <country>United States of America</country>
          </postal>
          <email>inaminei@google.com</email>
        </address>
      </author>
      <author fullname="Edward Crabbe" initials="E." surname="Crabbe">
        <organization showOnFrontPage="true">Individual Contributor</organization>
        <address>
          <email>edward.crabbe@gmail.com</email>
        </address>
      </author>
      <author fullname="Siva Sivabalan" initials="S." surname="Sivabalan">
        <organization showOnFrontPage="true">Cisco Systems, Inc.</organization>
        <address>
          <postal>
            <street>170 West Tasman Dr.</street>
            <city>San Jose</city>
            <region>CA</region>
            <code>95134</code>
            <country>United States of America</country>
          </postal>
          <email>msiva@cisco.com</email>
        </address>
      </author>
      <author fullname="Hariharan Ananthakrishnan" initials="H." surname="Ananthakrishnan">
        <organization showOnFrontPage="true">Netflix</organization>
        <address>
          <email>hari@netflix.com</email>
        </address>
      </author>
      <author fullname="Dhruv Dhody" initials="D." surname="Dhody">
        <organization showOnFrontPage="true">Huawei</organization>
        <address>
          <postal>
            <street>Divyashree Techno Park, Whitefield</street>
            <city>Bangalore</city>
            <region>KA</region>
            <code>560066</code>
            <country>India</country>
          </postal>
          <email>dhruv.ietf@gmail.com</email>
        </address>
      </author>
      <author fullname="Yosuke Tanaka" initials="Y." surname="Tanaka">
        <organization showOnFrontPage="true">NTT Communications Corporation</organization>
        <address>
          <postal>
            <street>Granpark Tower 3-4-1 Shibaura, Minato-ku</street>
            <region>Tokyo</region>
            <code>108-8118</code>
            <country>Japan</country>
          </postal>
          <email>yosuke.tanaka@ntt.com</email>
        </address>
      </author>
    </section>
  </back>
</rfc>
