draft-townsley-troan-ipv6-ce-transitioning.xml

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<rfc category="info" docName="draft-townsley-troan-ipv6-ce-transitioning-01" ipr="trust200902">
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  <!-- ***** FRONT MATTER ***** -->

  <front>
    <!-- The abbreviated title is used in the page header - it is only
         necessary if the full title is longer than 39 characters -->

    <title abbrev="IPv6 CE router requirements">Basic Requirements for IPv6
    Customer Edge Routers - multihoming and transition</title>

    <!-- add 'role="editor"' below for the editors if appropriate -->
    <!-- Another author who claims to be an editor -->
    <author fullname="Mark Townsley" initials="M" surname="Townsley">
      <organization>cisco</organization>
      <address>
        <postal>
          <street></street>
          <code></code>
          <city></city>
          <region></region>
          <country></country>
        </postal>
        <email></email>
        <!-- uri and facsimile elements may also be added -->
      </address>
    </author>
    <author fullname="Ole Troan" initials="O" surname="Troan">
      <organization>cisco</organization>
      <address>
        <postal>
          <street></street>
          <code></code>
          <city></city>
          <region></region>
          <country></country>
        </postal>
        <email></email>
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      </address>
    </author>

    <date month="December" year="2011" />

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    <area>General</area>

    <workgroup>Internet Engineering Task Force</workgroup>

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    <abstract>
      <t>This document specifies general IPv6 multihoming and
      specific 6rd transitioning requirements for an IPv6 Customer
      Edge (CE) router.</t>
    </abstract>
  </front>

  <middle>

    <section title="Introduction">
      <t>This document defines transitioning and multihoming IPv6
      features for a residential or small office router referred to as
      an IPv6 CE router. Typically these routers also support
      IPv4.</t>

      <section 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>
      </section>
    </section>


    <section title="Terminology">
      <t><list hangIndent="26" style="hanging">

	<t hangText="SRIB">A Source Address Routing Information Base
	containing an entry per delegated prefix. Each entry points to
	one or more Destination Address Routing Tables (DRIB).</t>

	<t hangText="DRIB">A Destination Address Routing Information
	Base used for destination address longest matching
	lookups. Each entry points to one or more next-hops.</t>
      </list></t>
    </section>

    <section title="IPv6 Multi-Prefix Multihoming" anchor="mpmh_sec">
      <t>A multihomed, multiprefix, IPv6 CE router has multiple WAN
      interfaces connecting it to one or more Service Providers. The
      interfaces may be "real" or "virtual" in the case of tunneling
      technology such as 6rd. The CE router receives one or more
      delegated prefixes, each associated with one or more WAN
      interfaces. The CE router has a single SRIB, and one DRIB
      associated with each WAN Interface.</t>

      <t>WAN interfaces are used to send Ingress traffic from the
      Internet to the End-User, and Egress traffic from the End-User
      network to the Internet. Ingress traffic may be received on any
      active interface at any time. Egress traffic follows a set of
      rules within the CE in order to choose the proper WAN
      interface. This is important not only in order to choose the
      best path, but also because the networks that the CE are
      connected to typically employ source address verification
      mechanisms.</t>

      <t>Packets arriving at the CE have an IPv6 source address chosen
      by the host <xref target="RFC3484"></xref>. The SRIB contains an
      entry for each delegated prefix with a pointer to one or more
      DRIBs.  A longest matching lookup based upon the source address
      of each arriving packet is performed within the SRIB to
      determine the DRIB(s).  The egress WAN interface to use for
      sending a packet is then chosen by performing a longest matching
      lookup within the resulting DRIB(s). </t>

      <t>Multihoming requirements:<list style='format MH-%d:'>

	<t>An IPv6 CE router MUST create a separate DRIB for each WAN
	interface (real or virtual) and installs a route for the
	associated delegated prefix, default route and more specific
	routes.</t>

	<t>An IPv6 CE router MUST create an SRIB containing entries
	for associated delegated prefixes.  Each entry points to one
	or more DRIBs. An entry points to multiple DRIBs only in the
	case where an identical delegated prefix is associated with
	multiple WAN interfaces.</t>
          
	<t>When forwarding a packet from a LAN interface, the CE
	router MUST do a longest matching lookup based on the packet's
	Source Address in the SRIB. A Destination Address lookup is
	then performed in the corresponding DRIB or DRIBs. When there
	are multiple equal matches, the route with the lowest cost is
	chosen.</t>
      </list></t>

    </section>

    <section title="6rd Sunsetting Requirements">

      <t><list style='format 6RDS-%d:'>

	  <t>Multihoming as defined in section <xref
	  target="mpmh_sec"/> MUST be supported, allowing 6rd and
	  native packets to be sent and received as long as 6rd
	  configuration is provided by the ISP.</t>

	  <t>By default, the 6rd virtual interface MUST be assigned a
	  higher routing cost than a native IPv6 interface.</t>

	  <t>The IPv6 CE router MUST support that 6rd and native IPv6
	  delegated prefixes are identical or different, and operate
	  as defined in the multihoming section.</t>

        </list></t>

    </section>

    <section title="Security Considerations">
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>This memo includes no request to IANA.</t>
    </section>

  </middle>

  <!--  *****BACK MATTER ***** -->

  <back>

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    <!-- Change Log

v02 2009-10-26  OTD   Initial version. Merged content from Donley, Singh
                      drafts and new content.

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