One document matched: draft-boucadair-pcp-deployment-cases-00.xml


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<rfc category="info" docName="draft-boucadair-pcp-deployment-cases-00"
     ipr="trust200902">
  <front>
    <title abbrev="PCP Deployment Cases">PCP Deployment Models</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>

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

    <workgroup>PCP Working Group</workgroup>

    <abstract>
      <t>This document lists a set of PCP deployment models.</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 lists a set of PCP <xref target="RFC6887"></xref>
      deployment models. </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>
        </list><?rfc subcompact="no" ?></t>
    </section>

    <section title="Single Homed CPE Model: Local PCP Server">
      <t>This model assumes PCP is enabled in the LAN side to control
      functions located in the CPE. The PCP server is reachable with the IP
      address of the private-faced interface. </t>

      <t><figure>
          <artwork><![CDATA[
   +-------------+
   |    PCP      |
   |   Client    |----+                           ,-----------.
   +-------------+    |   +------------+        ,'             `--.
                      +---|    CPE     |        /                   :
                          | PCP Server |_______;        ISP         |
                      +---| NAT+FW+..  |       :                    |
   +-------------+    |   +------------+        \                   |
   |    PCP      |----+                          -------------------.
   |   Client    |
   +-------------+ 

]]></artwork>
        </figure></t>

      <t></t>
    </section>

    <section title="Single Homed CPE Model: Multiple PCP Servers">
      <t>This model assumes a customer site is connected to the same ISP's
      network. One or multiple PCP servers are deployed in the ISP's domain;
      each of them manage distinct set of functions. In example shown in the
      following figure:<list style="symbols">
          <t>NAT64 device are used to interwork with IPv4-only devices.</t>

          <t>NPTv6 function is used for engineering motivation internal to the
          ISP.</t>
        </list></t>

      <t><figure>
          <artwork><![CDATA[
   +-------------+
   |    PCP      |
   |   Client    |----+                            ,-----------.
   +-------------+    |   +------------+         ,'    ISP     `--.
                      +---|    CPE     |         /                :
                          |            |________;    NAT64        |
                      +---|            |        :                 |
   +-------------+    |   +------------+         \        NPTv6   |
   |    PCP      |----+                           ----------------.
   |   Client    |
   +-------------+ 

]]></artwork>
        </figure></t>

      <t>Internal PCP client must discover both the external IPv4 address and
      port numbers assigned by the NAT64 and the external IPv6 address
      assigned by the NPTv6. These external addresses are used for example in
      referrals to indicate to remote peers both the IPv4 address and IPv6
      address to reach an internal server deployed in an IPv6-only domain.</t>

      <t>The use of anycast-based addressing model is not recommended for this
      deployment case because two state entries are to be created in both
      NAT64 and NPTv6.</t>

      <t>The use of NAT64 and NPTv6 is for illustration purposes; other
      functions can be enabled.</t>
    </section>

    <section title="Hide PCP Servers Model">
      <t></t>

      <section title="PCP Proxy Model">
        <t>In order to hide PCP servers deployed within an administrative
        domain, an administrative entity may decide to deploy in front of PCP
        clients PCP Proxies that are responsible for relaying PCP requests to
        appropriate PCP servers:<list style="symbols">
            <t>In order to prevent single failure scenarios, multiple PCP
            proxies can be hosted within an administrative domain.</t>

            <t>A PCP Proxy can be configured with one or multiple servers.</t>

            <t>Multiple PCP Proxies can be enabled; each of them manages a set
            of PCP servers.</t>

            <t>A PCP Proxy can be configured with the logic indicating how it
            should proceed to contact upstream PCP servers.</t>

            <t>Internal PCP clients are configured with the IP address(es) of
            the appropriate PCP proxy.<list style="symbols">
                <t>If all PCP Proxies interact with the same PCP Server(s),
                the same IP address can be provisioned to PCP clients.</t>

                <t>If PCP Proxies do not interact with the same set of PCP
                Server(s), appropriate IP address(es) are to be returned to
                each requesting PCP Client.</t>
              </list></t>
          </list></t>

        <t><figure>
            <artwork><![CDATA[               +------------------------------------+
               | Administrative Domain              |
+----------+   |    +-------------------+           |
|PCP Client|---|----|    PCP Proxy      |           |
+----------+   |    +-------------------+           |
               |        |            |              |
               |        |            |              |
               | +------+------+   +-+------------+ |
               | | PCP Server  |   | PCP Server   | | 
               | +-------------+   +--------------+ |  
               +------------------------------------+
]]></artwork>
          </figure></t>

        <t></t>
      </section>

      <section title="HTTP-Triggered PCP Client Model">
        <t>Another deployment model to hide deployed PCP servers is to relay
        on HTTP to interact with the PCP service. This model can also be used
        by operators to accommodate cases where the PCP client is not
        available at the customer side. </t>

        <t>The deployment model relies on the following:<list style="symbols">
            <t>An HTTP administration based interface is provided to the user
            to create flow-bases forwarding rules.</t>

            <t>The HTTP GUI can be part of a CPE management interface or be
            provided as part of the customer care portal.</t>

            <t>HTTP requests are translated into appropriate PCP servers in
            order to install the requested state. The HTTP server embeds also
            a PCP client.</t>

            <t>The PCP client uses THIRD_PARTY option.</t>

            <t>The PCP Client should be configured with PCP server that
            controls the on-path PCP-controlled device for that user.</t>

            <t>One or multiple PCP Servers can be deployed.</t>

            <t>The use of a well-known address to reach internal PCP servers
            may not be convenient if all PCP server do not manage the same set
            of states.</t>
          </list></t>

        <t><figure>
            <artwork><![CDATA[               +------------------------------------+
               | Administrative Domain              |
+----------+   |    +----------------------+        |
|  Host    |---|----|HTTP Server+PCP Client|        |
+----------+   |    +----------------------+        |
               |        |            |              |
               |        |            |              |
               | +------+------+   +-+------------+ |
               | | PCP Server  |   | PCP Server   | | 
               | +-------------+   +--------------+ |  
               +------------------------------------+
]]></artwork>
          </figure></t>

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

    <section title="Separated PCP Server & PCP-controlled Device Model">
      <t>This model assumes the PCP server is not co-located with the
      PCP-controlled device. Moreover:</t>

      <t><list style="symbols">
          <t>In order to prevent single failure scenarios, multiple PCP
          servers can be hosted within an administrative domain.</t>

          <t>A PCP server can be control one or many PCP-controlled
          devices.</t>

          <t>Multiple PCP servers can be enabled; each of them manages a set
          of PCP-controlled devices.</t>

          <t>Internal PCP clients are configured with the IP address(es) of
          the appropriate PCP server.<list style="symbols">
              <t>If all PCP servers interact with the same PCP-controlled
              devices., the same IP address can be provisioned to PCP
              clients.</t>

              <t>If PCP servers do not interact with the same set of
              PCP-controlled devices, appropriate IP address(es) are to be
              returned to each requesting PCP Client.</t>
            </list></t>
        </list>Note, PCP is not used as interface between the PCP server and
      the PCP-controlled device. Other protocols (e.g., H.248) can be used for
      that purpose.</t>

      <t></t>
    </section>

    <section title="Cascaded PCP-controlled Nodes Model">
      <t>This model assumes cascaded PCP-controlled devices are deployed. A
      typical example is provided below.</t>

      <t><figure>
          <artwork><![CDATA[                                                      ,-----------.
                               PCP Server           ,'             `--.
   +-------+    +------+      +----------+         /                   :
   |PCP    |____|Home  |______|ISP CPE   |________;     Public         |
   |Client |    |Router|      |NAT Router|        :     Internet       |
   +-------+    +------+      +----------+         \                   |
                                                    \                  ;
                                                     `------.       ,-'
                                                             `-----'
                                                      ,-----------.
                              PCP Server            ,'             `--.
   +-------+    +------+      +-------+            /                   :
   |PCP    |____|CPE   |______|CGN/FW |___________;     Public         |
   |Client |    |      |      |       |           :     Internet       |
   +-------+    +------+      +-------+            \                   |
                                                    \                  ;
                                                     `------.       ,-'
                                                             `-----'
                                                      ,-----------.
               PCP Proxy               PCP Server   ,'             `--.
   +-------+    +------+               +-------+   /                   :
   |PCP    |____|CPE   |_______________|CGN/FW |__;     Public         |
   |Client |    |      |               |       |  :     Internet       |
   +-------+    +------+               +-------+   \                   |
                                                    \                  ;
                                                     `------.       ,-'
                                                             `-----'
                                                      ,-----------.
               PCP Server              PCP Server   ,'             `--.
   +-------+    +------+               +-------+   /                   :
   |PCP    |____|CPE   |_______________|CGN/FW |__;     Public         |
   |Client |    |      |               |       |  :     Internet       |
   +-------+    +------+               +-------+   \                   |
                                                    \                  ;
                                                     `------.       ,-'
                                                             `-----'
]]></artwork>
        </figure>This model requires a PCP Proxy function <xref
      target="I-D.ietf-pcp-proxy"></xref> be deployed in intermediate
      PCP-controlled devices:<list style="symbols">
          <t>The PCP client is not aware of the presence of more than one
          level of PCP servers.</t>

          <t>Each intermediate PCP proxy must contact the appropriate next hop
          PCP server.</t>

          <t>Because of the statefull nature of PCP, anycast-based addressing
          model may not be appropriate when the PCP Server is co-located with
          the PCP-controlled device.</t>
        </list></t>

      <section title="Single Homed CPE Model: PCP Proxy Model">
        <t>This model assumes no PCP-controlled function is located in the CPE
        (e.g., DS-Lite case). The ultimate PCP server is located in ISP side.
        The PCP server can be deduced from other provisioning parameters
        (e.g., use the IP address of the AFTR as PCP server); otherwise the IP
        address (s) must be discovered by other means.</t>

        <t>The use of an anycast-based model may not be convenient in some
        cases (e.g., multiple PCP-controlled devices are deployed; each of
        them manage a subset of services and state).</t>

        <t><figure>
            <artwork><![CDATA[
   +-------------+
   |   Host      |
   |             |----+                         ,-----------.
   +-------------+    |   +------------+      ,'             `--.
                      +---|    CPE     |      /     ISP           :
                          | PCP Proxy  |_____;    PCP Server 1    |
                      +---| PCP Client |     :    PCP Server i    |
   +-------------+    |   +------------+      \                   |
   |    PCP      |----+                        -------------------.
   |   Client    |
   +-------------+ 

]]></artwork>
          </figure></t>

        <t></t>
      </section>

      <section title="UPnP IGD-PCP Interworking Model">
        <t>This model is specified in <xref target="RFC6970"></xref>. The
        interworking function must be provisioned with the IP address(es) of
        remote PCP server(s).</t>

        <t><figure>
            <artwork><![CDATA[(a) 
   +-------------+
   | IGD Control |
   |   Point     |----+
   +-------------+    |   +-----+  +--------+               +------+
                      +---| IGD-|  |Provider|               |Remote|
                          | PCP |--|  NAT   |--<Internet>---| Host |
                      +---| IWF |  |        |               |      |
   +-------------+    |   +-----+  +--------+               +------+
   | Local Host  |----+
   +-------------+
                        LAN Side  External Side
   <======UPnP IGD==============><=====PCP=====>

(b) 
   +-------------+
   | IGD Control |
   |   Point     |----+
   +-------------+    |   +-----+  +--------+               +------+
                      +---| IGD-|  |Provider|               |Remote|
                          | PCP |--|  NAT   |--<Internet>---| Host |
                      +---| IWF |  |        |               |      |
   +-------------+    |   +-----+  +--------+               +------+
   | Local Host  |----+    NAT1           NAT2
   +-------------+

]]></artwork>
          </figure></t>

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

    <section title="Multi-Homed CPE Model: One Single PCP Server">
      <t>A typical example of this model is shown in the following figure:</t>

      <t><figure>
          <artwork><![CDATA[                     ====================
                     |    Internet       |
                     =====================
                        |              |
                        |              |
                   +----+--------+   +-+------------+
                   | ISP1        |   | ISP2         |
                   |             |   |              |
                   +----+--------+   +-+------------+  
                        |              |
                        |              |
      ..............................................................
                        |              |
                        | Port1        | Port2    Subscriber Network
                        |              |
                   +----------------------+
                   |   NAT & PCP servers  |
                   |       GW Router      |
                   +----+-----------------+
                        |
                        |
                        |
                   -----+--------------
                        |
                      +-+-----+
                      | Hosts |  (private address space)
                      +-------+

]]></artwork>
        </figure></t>

      <t>Internal PCP clients can interact with one single PCP servers.</t>
    </section>

    <section title="Multi-Homed CPE Model: Multiple PCP Servers">
      <t>A typical example of this model is shown in the following figure:</t>

      <t><figure>
          <artwork><![CDATA[                       ==================
                       |    Internet    |
                       ==================
                          |          |
                          |          |
                     +----+-+      +-+----+
                     | ISP1 |      | ISP2 |
                     +----+-+      +-+----+       
                          |          |
    .........................................................
                          |          |
                          |          |        Subscriber Network
                  +-------+---+ +----+------+
                  | rtr1 with | | rtr2 with |
                  |   FW1     | |    FW2    |
                  +-------+---+ +----+------+
                          |          |
                          |          |
                          |          |
                   -------+----------+------
                          |
                        +-+-----+
                        | Hosts |
                        +-------+]]></artwork>
        </figure></t>

      <t>The PCP client must interact with all PCP servers; otherwise
      complications arise to communicate with remote peers. The use of
      anycast-based model will induce failures in communicating with external
      peers (e.g., incoming packets will be dropped by one of the
      firewalls).</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>PCP-related security considerations are discussed in <xref
      target="RFC6887"></xref>.</t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>This document does not require any action from IANA.</t>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>TBC.</t>
    </section>
  </middle>

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

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

    <references title="Informative References">
      <?rfc include='reference.RFC.6970'?>

      <?rfc include='reference.I-D.ietf-pcp-proxy'?>
    </references>
  </back>
</rfc>

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