One document matched: draft-ietf-pcp-dhcp-09.xml


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<rfc category="std" docName="draft-ietf-pcp-dhcp-09" ipr="trust200902">
  <front>
    <title abbrev="PCP DHCP Options">DHCP Options for the Port Control
    Protocol (PCP)</title>

    <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
      <organization>France Telecom</organization>

      <address>
        <postal>
          <street></street>

          <city>Rennes</city>

          <region></region>

          <code>35000</code>

          <country>France</country>
        </postal>

        <email>mohamed.boucadair@orange.com</email>
      </address>
    </author>

    <author fullname="Reinaldo Penno" initials="R." surname="Penno">
      <organization>Cisco</organization>

      <address>
        <postal>
          <street></street>

          <code></code>

          <country>USA</country>
        </postal>

        <email>repenno@cisco.com</email>
      </address>
    </author>

    <author fullname="Dan Wing" initials="D." surname="Wing">
      <organization abbrev="Cisco">Cisco Systems, Inc.</organization>

      <address>
        <postal>
          <street>170 West Tasman Drive</street>

          <city>San Jose</city>

          <region>California</region>

          <code>95134</code>

          <country>USA</country>
        </postal>

        <email>dwing@cisco.com</email>
      </address>
    </author>

    <date day="05" month="November" year="2013" />

    <workgroup>PCP Working Group</workgroup>

    <keyword>PCP Server discovery, Port Mapping, Shared Address</keyword>

    <abstract>
      <t>This document specifies DHCP (IPv4 and IPv6) options to configure
      hosts with Port Control Protocol (PCP) Server IP addresses. The use of
      DHCPv4 or DHCPv6 depends on the PCP deployment scenario.</t>
    </abstract>

    <note title="Requirements Language">
      <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">RFC 2119</xref>.</t>
    </note>
  </front>

  <middle>
    <section title="Introduction">
      <t>This document defines DHCPv4 <xref target="RFC2131"></xref> and
      DHCPv6 <xref target="RFC3315"></xref> options that can be used to
      provision PCP server <xref target="RFC6887"></xref> IP addresses.</t>

      <t>This specification assumes a PCP server is reachable with one or
      multiple IP addresses. As such, a list of IP addresses can be returned
      in the PCP server DHCP option.</t>

      <t>This specification allows returning one or multiple instances of the
      PCP server DHCP option. This is used as a hint to guide the PCP client
      when determining whether to send PCP requests to one or multiple PCP
      servers. For guidelines on how a PCP client can use multiple IP
      addresses and multiple PCP servers, see <xref
      target="I-D.ietf-pcp-server-selection"></xref>.</t>

      <t>The use of DHCPv4 or DHCPv6 depends on the PCP deployment
      scenarios.</t>
    </section>

    <section title="Terminology">
      <t>This document makes use of the following terms:<?rfc subcompact="yes" ?></t>

      <t><list style="symbols">
          <t>PCP server denotes a functional element that receives and
          processes PCP requests from a PCP client. A PCP server can be
          co-located with or be separated from the function (e.g., NAT,
          Firewall) it controls. Refer to <xref target="RFC6887"></xref>.</t>

          <t>PCP client denotes a PCP software instance responsible for
          issuing PCP requests to a PCP server. Refer to <xref
          target="RFC6887"></xref>.</t>

          <t>DHCP refers to both DHCPv4 <xref target="RFC2131"></xref> and
          DHCPv6 <xref target="RFC3315"></xref>.</t>

          <t>DHCP client (or client) denotes a node that initiates requests to
          obtain configuration parameters from one or more DHCP servers.</t>

          <t>DHCP server (or server) refers to a node that responds to
          requests from DHCP clients.</t>
        </list><?rfc subcompact="no" ?></t>
    </section>

    <section title="DHCPv6 PCP Server Option">
      <t></t>

      <section title="Format">
        <t>The PCP server DHCPv6 option can be used to configure a list of
        IPv6 addresses of a PCP server.</t>

        <t>The format of this option is shown in <xref
        target="dhcpv6_name_option"></xref>.</t>

        <t><figure anchor="dhcpv6_name_option"
            title="PCP Server  DHCPv6 Option">
            <preamble></preamble>

            <artwork><![CDATA[    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      OPTION_PCP_SERVER        |         Option-length         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                         ipv6-address                          |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                         ipv6-address                          |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

]]></artwork>

            <postamble></postamble>
          </figure>The fields of the option shown in <xref
        target="dhcpv6_name_option"></xref> are as follows:<?rfc subcompact="yes" ?></t>

        <t><list style="symbols">
            <t>Option-code: OPTION_PCP_SERVER (TBA, see <xref
            target="iana6"></xref>)</t>

            <t>Option-length: Length of the 'PCP server IP Address(es)' field
            in octets. MUST be a multiple of 16.</t>

            <t>PCP server IPv6 Addresses: Includes one or more IPv6 addresses
            <xref target="RFC4291"></xref> of the PCP server to be used by the
            PCP client. Note, IPv4-mapped IPv6 addresses (Section 2.5.5.2 of
            <xref target="RFC4291"></xref>) are allowed to be included in this
            option.</t>
          </list></t>

        <t><?rfc subcompact="no" ?></t>
      </section>

      <section title="Client Behavior">
        <t>To discover a PCP server, the DHCPv6 client requests PCP server IP
        addresses by including OPTION _PCP_SERVER in an Option Request Option
        (ORO), as described in Section 22.7 of <xref
        target="RFC3315"></xref>.</t>

        <t>The client MUST be prepared to receive multiple instances of the
        DHCPv6 PCP server option; each instance is to be treated as a separate
        PCP server.</t>

        <t>If an IPv4-mapped IPv6 address is received in an OPTION_PCP_SERVER
        option, it indicates that the PCP server has the corresponding IPv4
        address.</t>

        <t>When multiple instances of the PCP server DHCPv6 option or multiple
        IPv6 addresses are received from the DHCPv6 server, the PCP client
        follows the behavior specified in <xref
        target="I-D.ietf-pcp-server-selection"></xref>.</t>
      </section>
    </section>

    <section title="DHCPv4 PCP Option">
      <t></t>

      <section title="Format">
        <t>The PCP server DHCPv4 option can be used to configure a list of
        IPv4 addresses of a PCP server. The format of this option is
        illustrated in <xref target="dhcppcp"></xref>.</t>

        <t><figure anchor="dhcppcp" title="PCP Server DHCPv4 Option">
            <preamble></preamble>

            <artwork><![CDATA[
    Code   Len   PCP server IPv4 Address  PCP server IPv4 Address
   +-----+-----+-----+-----+-----+-----+-----+-----+--
   | TBA |  n  |  a1 |  a2 |  a3 |  a4 |  a1 |  a2 | ...
   +-----+-----+-----+-----+-----+-----+-----+-----+--

]]></artwork>

            <postamble>This format assumes that an IPv4 address is encoded as
            a1.a2.a3.a4.</postamble>
          </figure></t>

        <t>The description of the fields is as follows:<?rfc subcompact="yes" ?><list
            style="symbols">
            <t>Code: OPTION_PCP_SERVER (TBA, see <xref
            target="iana4"></xref>);</t>

            <t>Length: Includes the length of included IP address(es) in
            octets; MUST be a multiple of 4.</t>

            <t>PCP server IPv4 Addresses: Contains one or more IPv4 addresses
            of the PCP server to be used by the PCP client.</t>
          </list></t>

        <t><?rfc subcompact="no" ?></t>
      </section>

      <section title="Client Behavior">
        <t>To discover a PCP server, the DHCPv4 client requests PCP server IP
        addresses by including OPTION_PCP_SERVER in a Parameter Request List
        Option <xref target="RFC2132"></xref>.</t>

        <t>The client MUST be prepared to receive multiple instances of the
        DHCPv4 PCP server option; each instance is to be treated as a separate
        PCP server.</t>
      </section>
    </section>

    <section title="DHCP Server Configuration Guidelines">
      <t>DHCP servers supporting the DHCP PCP server option can be configured
      with a list of IP addresses of the PCP server(s). If multiple IP
      addresses are configured, the DHCP server MUST be explicitly configured
      whether all or some of these addresses refer to:</t>

      <t><list style="numbers">
          <t>the same PCP server: the DHCP server returns multiple addresses
          in the same instance of the DHCP PCP server option.</t>

          <t>distinct PCP servers: the DHCP server returns multiple instances
          of the DHCP PCP server option to the requesting client; each
          instance is referring to a distinct PCP server. For example,
          multiple OPTION_PCP_SERVER instances may be configured to a PCP
          client in some deployment contexts such as multi-homing. It is out
          of scope of this document to enumerate all deployment scenarios that
          require multiple OPTION_PCP_SERVER instances to be returned.</t>
        </list></t>

      <t>The DHCP server MAY be configurable with one or multiple FQDNs of the
      PCP server(s). In such case, the DHCP server MUST resolve these FQDNs
      into one or a list of IP addresses. If multiple FQDNs are configured to
      the DHCP server, the DHCP server MUST include multiple OPTION_PCP_SERVER
      instances; each of them carries one or a list of IP addresses that
      resulted from the FQDN resolution. DHCPv4 servers supporting PCP server
      option MUST resolve any configured FQDNs into IPv4 addresses while
      DHCPv6 servers may resolve any configured FQDNs into IPv6 and/or IPv4
      addresses. If an IPv4 address is retrieved by the DHCPv6 server, the
      corresponding IPv4-mapped IPv6 address is included in the
      OPTION_PCP_SERVER DHPCv6 option. If both IPv4 and IPv6 addresses are
      retrieved by the DHCPv6 server, these addresses are included in the same
      OPTION_PCP_SERVER DHPCv6 option (IPv4 addresses are represented as
      IPv4-mapped IPv6 addresses).<list style="empty">
          <t>Discussion: The motivation for this design is to accommodate
          deployment cases where an IPv4 connectivity service is provided
          while only DHPCv6 is in use (e.g., an IPv4-only PCP server in a
          DS-Lite context <xref target="RFC6333"></xref>).</t>
        </list></t>

      <t>For guidelines on providing context-specific configuration
      information (e.g., returning a regional-based configuration), and
      information on how a server might be configured with FQDNs that get
      resolved on demand, see <xref
      target="I-D.ietf-dhc-topo-conf"></xref>.</t>
    </section>

    <section title="Dual-Stack Hosts">
      <t>A Dual-Stack host might receive OPTION_PCP_SERVER via both DHCPv4 and
      DHCPv6. For guidance on how a client can handle PCP server IP lists for
      the same network but obtained via different mechanisms, see <xref
      target="I-D.ietf-pcp-server-selection"></xref>.</t>
    </section>

    <section anchor="mif" title="Hosts with Multiple Interfaces">
      <t>A host may have multiple network interfaces (e.g, 3G, IEEE 802.11,
      etc.); each configured differently. Each PCP server learned MUST be
      associated with the interface via which it was learned. Refer to <xref
      target="I-D.ietf-pcp-server-selection"></xref> and Section 8.4 of <xref
      target="RFC6887"></xref> for more discussion on multi-interface
      considerations.</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>The security considerations in <xref target="RFC2131"></xref> and
      <xref target="RFC3315"></xref> are to be considered. PCP-related
      security considerations are discussed in <xref
      target="RFC6887"></xref>.</t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t></t>

      <section anchor="iana6" title="DHCPv6 Option">
        <t>IANA is requested to assign the following new DHCPv6 Option Code in
        the registry maintained in
        http://www.iana.org/assignments/dhcpv6-parameters:</t>

        <texttable style="headers">
          <ttcol align="right">Option Name</ttcol>

          <ttcol>Value</ttcol>

          <c>OPTION_PCP_SERVER</c>

          <c>TBA</c>
        </texttable>
      </section>

      <section anchor="iana4" title="DHCPv4 Option">
        <t>IANA is requested to assign the following new DHCPv4 Option Code in
        the registry maintained in
        http://www.iana.org/assignments/bootp-dhcp-parameters/:</t>

        <texttable style="headers">
          <ttcol align="right">Option Name</ttcol>

          <ttcol>Value</ttcol>

          <c>OPTION_PCP_SERVER</c>

          <c>TBA</c>
        </texttable>

        <t></t>
      </section>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>Many thanks to B. Volz, C. Jacquenet, R. Maglione, D. Thaler, T.
      Mrugalski, T. Reddy, S. Cheshire and M. Wasserman for their review and
      comments.</t>

      <t>Special thanks to T. Lemon for the review and his continuous effort
      to enhance this specification.</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <?rfc include="reference.RFC.2119"
?>

      <?rfc include='reference.RFC.3315'?>

      <?rfc include='reference.RFC.2131'?>

      <?rfc include='reference.RFC.4291'?>

      <?rfc include='reference.RFC.2132'?>

      <?rfc include='reference.RFC.6887'?>
    </references>

    <references title="Informative References">
      <?rfc include='reference.I-D.ietf-dhc-topo-conf'?>

      <?rfc include='reference.I-D.ietf-pcp-server-selection'?>

      <?rfc include='reference.RFC.6333'?>
    </references>
  </back>
</rfc>

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