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<rfc category="std" docName="draft-wu-pce-discovery-priority-allocation-01"
     ipr="trust200902">
  <?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>

  <?rfc toc="yes" ?>

  <?rfc symrefs="yes" ?>

  <?rfc sortrefs="yes"?>

  <?rfc iprnotified="no" ?>

  <?rfc strict="yes" ?>

  <front>
    <title abbrev="IGP for PCEP Transport">IGP extension for PCEP transport
    capability support in the PCE discovery</title>

    <author fullname="Qin Wu" initials="Q." surname="Wu">
      <organization>Huawei</organization>

      <address>
        <postal>
          <street>101 Software Avenue, Yuhua District</street>

          <city>Nanjing</city>

          <region>Jiangsu</region>

          <code>210012</code>

          <country>China</country>
        </postal>

        <email>sunseawq@huawei.com</email>
      </address>
    </author>

    <date year="2013" />

    <area>Routing Area</area>

    <workgroup>PCE working group</workgroup>

    <keyword>RFC</keyword>

    <keyword>Request for Comments</keyword>

    <keyword>I-D</keyword>

    <keyword>Internet-Draft</keyword>

    <keyword>Path Computation Element</keyword>

    <abstract>
      <t>[RFC5088][RFC5089] define a method to advertise path computation
      capabilities using IGP flooding. OSPF and ISIS are extended to support
      such capabilities advertisement. However [RFC5088][RFC5089]don’t provide
      a method to advertise PCEP over TLS support capability.</t>

      <t>This document proposes new capability flag bit for PCE-CAP-FLAGS
      sub-TLV that can be announced as attribute in the IGP advertisement
      (defined in [RFC5088 ][RFC5089]) to distribute transport support
      information.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="intro" title="Introduction">
      <t>As described in [RFC5440], PCEP communication privacy is one
      importance issue, especially in an inter-AS context, where PCEP
      communication end-points do not reside in the same AS, as an attacker
      that intercepts a PCE message could obtain sensitive information related
      to computed paths and resources.</t>

      <t>Among the possible solutions mentioned in these documents, Transport
      Layer Security (TLS) [RFC5246] provides support for peer authentication,
      and message encryption and integrity. In order for a PCC to begin a
      connection with a PCE server using TLS, PCC should know whether PCE
      server Support TLS as transport.</t>

      <t>[RFC5088][RFC5089] define a method to advertise path computation
      capabilities using IGP flooding. OSPF and ISIS are extended to support
      such capabilities advertisement. However [RFC5088][RFC5089]don’t provide
      a method to advertise PCEP over TLS support capability.</t>

      <t>This document proposes new capability flag bit for PCE-CAP-FLAGS
      sub-TLV that can be announced as attribute in the IGP advertisement
      (defined in [RFC5088 ][RFC5089]) to distribute transport support
      information.</t>
    </section>

    <section title="Conventions used in this document">
      <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
      "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
      document are to be interpreted as described in <xref
      target="RFC2119">RFC2119</xref>.</t>
    </section>

    <section title="IGP extension for PCEP transport capability support">
      <t>The PCE-CAP-FLAGS sub-TLV is defined in section 4.5 of
      [RFC5088][RFC5089] and an optional sub-TLV used to advertise PCE
      capabilities. In this section, we extend the PCE-CAP-FLAGS sub-TLV to
      include the capability and indications that are described for PCEP over
      TLS support in the present document.</t>

      <t>In the PCE-CAP-FLAGS sub-TLV defined in [RFC5088][RFC5089], nine
      capability flags defined in [RFC4657] and two capability flags defined
      [RFC5557][RFC6006]are included and follows the following format: The
      PCE-CAP-FLAGS sub-TLV has the following format: <figure>
          <artwork>
   o  TYPE: 5
   o  LENGTH: Multiple of 4

   o  VALUE: This contains an array of units of 32 bit flags with the
      most significant bit as 0.  Each bit represents one PCE capability
</artwork>
        </figure></t>

      <t>and the processing rule of these flag bits are defined in
      [RFC5088][RFC5089]. In this document, we define one new capability flag
      bit that indicate TCP MD5 support, TCP AO support, PCEP over TLS support
      and PCEP over TLS and TCP AO support respectively as follows: <figure>
          <artwork>
     Bit         Capability Description
     xx         TCP MD5 support
     xx         TCP AO Support
     xx         PCEP over TLS support
     xx         PCEP over TLS support and TCP AO support
</artwork>
        </figure></t>

      <section title="Use of PCEP transport capability support for PCE discovery">
        <t>TCP MD5, TCP AO, PCEP over TLS support and PCEP over TLS and TCP AO
        support flag bits are advertised using IGP flooding. If the PCE server
        supports only TCP MD5 as transport, IGP advertisement Should not
        include PCEP over TLS support flag bit or TCP AO support flag bit. If
        the PCE server supports both TCP MD5 and TCP AO, IGP advertisment
        Should include both TCP AO support flag bit and TCP MD5 support flag
        bit in the PCE-CAP-FLAGS sub-TLV. If the PCE server only supports TLS
        over TCP as transport, IGP advertisement MUST include PCEP over TLS
        support flag bit in the PCE-CAP-FLAGS sub-TLV.</t>

        <t>If the client is looking for connecting with PCE server with TCP AO
        support, the client MUST check if TCP AO support flag bit in the
        PCE-CAP-FLAGS sub-TLV is set before retrieving PCE location
        information from IGP message. if not, the client should discard PCEPD
        TLV with TCP AO support flag bit clear. If the client is looking for
        connecting with PCE server using TLS, the client MUST check if PCEP
        over TLS support flag bit in the PCE-CAP-FLAGS sub-TLV is set before
        retrieving PCE location information from IGP message. If not, then the
        client should discard PCED TLV with PCEP over TLS support flag bit
        clear.</t>
      </section>
    </section>

    <section title="Security Considerations">
      <t>This document raises no new security issues beyond those described in
      [RFC5088][RFC5089].</t>
    </section>

    <section title="IANA Considerations">
      <t>IANA is requested to allocate a new bit in "PCE Capability Flags"
      registry for PCEP over TLS support capability.</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <reference anchor="RFC2119">
        <front>
          <title abbrev="RFC Key Words">Key words for use in RFCs to Indicate
          Requirement Levels</title>

          <author fullname="Scott Bradner" initials="S." surname="Bradner">
            <organization>Harvard University</organization>

            <address>
              <postal>
                <street>1350 Mass. Ave.</street>

                <street>Cambridge</street>

                <street>MA 02138</street>
              </postal>

              <phone>- +1 617 495 3864</phone>

              <email>sob@harvard.edu</email>
            </address>
          </author>

          <date month="March" year="1997" />

          <area>General</area>

          <keyword>keyword</keyword>

          <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. Authors who follow these
            guidelines should incorporate this phrase near the beginning of
            their document: <list>
                <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
                "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
                "OPTIONAL" in this document are to be interpreted as described
                in RFC 2119.</t>
              </list></t>

            <t>Note that the force of these words is modified by the
            requirement level of the document in which they are used.</t>
          </abstract>
        </front>
      </reference>

      <reference anchor="RFC5088">
        <front>
          <title>OSPF Protocol Extensions for Path Computation Element (PCE)
          Discovery</title>

          <author fullname="JL. Le Roux" initials="JL." surname="Le Roux">
            <organization></organization>
          </author>

          <date month="January" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5088" />

        <format target="http://www.rfc-editor.org/rfc/rfc5088.txt" type="TXT" />
      </reference>

      <reference anchor="RFC5089">
        <front>
          <title>IS-IS Protocol Extensions for Path Computation Element (PCE)
          Discovery</title>

          <author fullname="JL. Le Roux" initials="JL." surname="Le Roux">
            <organization></organization>
          </author>

          <date month="January" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5089" />

        <format target="http://www.rfc-editor.org/rfc/rfc5089.txt" type="TXT" />
      </reference>
    </references>

    <references title="Informative References">
      <reference anchor="RFC5440">
        <front>
          <title>Path Computation Element (PCE) Communication Protocol
          (PCEP)</title>

          <author fullname="JL. Le Roux" initials="JL." surname="Le Roux">
            <organization></organization>
          </author>

          <date month="March" year="2009" />
        </front>

        <seriesInfo name="RFC" value="5440" />

        <format target="http://www.rfc-editor.org/rfc/rfc5440.txt" type="TXT" />
      </reference>

      <reference anchor="RFC5246">
        <front>
          <title>The Transport Layer Security (TLS) Protocol Version
          1.2</title>

          <author fullname="T. Dierks" initials="T." surname="Dierks">
            <organization></organization>
          </author>

          <date month="August" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5440" />

        <format target="http://www.rfc-editor.org/rfc/rfc5246.txt" type="TXT" />
      </reference>
    </references>
  </back>
</rfc>
