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PCP Working Group                                           M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Informational                             July 03, 2014
Expires: January 4, 2015


             Port Control Protocol (PCP) Deployment Models
                draft-boucadair-pcp-deployment-cases-03

Abstract

   This document lists a set of Port Control Protocol (PCP) deployment
   models.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 4, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.






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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  CPE Models  . . . . . . . . . . . . . . . . . . . . . . . . .   2
     3.1.  Single Homed CPE Model: Local PCP Server  . . . . . . . .   3
     3.2.  Single Homed CPE Model: Multiple PCP Servers  . . . . . .   3
     3.3.  Multi-Homed CPE Model: One Single PCP Server  . . . . . .   4
     3.4.  Multi-Homed CPE Model: Multiple PCP Servers . . . . . . .   5
     3.5.  PCP Proxy Model . . . . . . . . . . . . . . . . . . . . .   6
     3.6.  UPnP IGD-PCP Interworking Model . . . . . . . . . . . . .   7
     3.7.  HTTP-based User Interface . . . . . . . . . . . . . . . .   8
     3.8.  Cascaded PCP-controlled Nodes Model . . . . . . . . . . .   8
   4.  Hide PCP Servers Model  . . . . . . . . . . . . . . . . . . .  10
     4.1.  PCP Proxy Model . . . . . . . . . . . . . . . . . . . . .  10
     4.2.  HTTP-Triggered PCP Client Model . . . . . . . . . . . . .  11
   5.  Separated PCP Server & PCP-controlled Device Model  . . . . .  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   This document lists a set of PCP [RFC6887] deployment models.

2.  Terminology

   This document makes use of the following terms:

   o  PCP client denotes a functional element responsible for issuing
      PCP requests to a PCP server.  Refer to [RFC6887].
   o  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 [RFC6887].
   o  PCP proxy refers to a functional elements that is responsible for
      relaying PCP requests received from PCP client to upstream PCP
      servers.

3.  CPE Models








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3.1.  Single Homed CPE Model: Local PCP Server

   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 of the CPE.  Typical
   functions that can be controlled by PCP in this model are NAT and
   firewall.

      +-------------+
      |    PCP      |
      |   Client    |----+                           ,-----------.
      +-------------+    |   +------------+        ,'             `--.
                         +---|    CPE     |        /                   :
                             | PCP server |_______;        ISP         |
                         +---| NAT+FW+..  |       :                    |
      +-------------+    |   +------------+        \                   |
      |    PCP      |----+                          -------------------.
      |   Client    |
      +-------------+


   PCP client can be configured with their PCP server using DHCP for
   instance [I-D.ietf-pcp-dhcp].  If no PCP server is configured, PCP
   clients assume their default gateway is the PCP server.

   This model applies for both residential or corporate markets.

3.2.  Single Homed CPE Model: Multiple PCP Servers

   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 the
   example shown in the following figure:

   o  NAT64 device [RFC6146] are used to interwork with IPv4-only
      devices.

   o  NPTv6 function [RFC6296] is used for engineering motivation
      internal to the ISP.












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      +-------------+
      |    PCP      |
      |   Client    |----+                            ,-----------.
      +-------------+    |   +------------+         ,'    ISP     `--.
                         +---|    CPE     |         /                :
                             |            |________;    NAT64        |
                         +---|            |        :                 |
      +-------------+    |   +------------+         \        NPTv6   |
      |    PCP      |----+                           ----------------.
      |   Client    |
      +-------------+


   The use of NAT64 and NPTv6 functions is for illustration purposes;
   other functions can be enabled in the ISP's network side.

   PCP clients located behind the CPE, 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.

   The use of a PCP anycast address ([I-D.ietf-pcp-anycast]) is not
   recommended for this deployment case because two state entries must
   be created in both NAT64 and NPTv6.  Explicit means such as
   [I-D.ietf-pcp-dhcp] must be used instead to provision IP addresses of
   available PCP servers.

   [I-D.ietf-pcp-dhcp] may be used to provision the IP addresses of
   these PCP servers, or the CPE must embed a PCP proxy function that
   must follow [I-D.ietf-pcp-server-selection] to contact all PCP
   servers.

3.3.  Multi-Homed CPE Model: One Single PCP Server

   A typical example of this model is shown in the following figure:














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                        ====================
                        |    Internet       |
                        =====================
                           |              |
                           |              |
                      +----+--------+   +-+------------+
                      | ISP1        |   | ISP2         |
                      |             |   |              |
                      +----+--------+   +-+------------+
                           |              |
                           |              |
         ..............................................................
                           |              |
                           | Port1        | Port2    Subscriber Network
                           |              |
                      +----------------------+
                      |   NAT & PCP servers  |
                      |       GW Router      |
                      +----+-----------------+
                           |
                           |
                           |
                      -----+--------------
                           |
                         +-+-----+
                         | Hosts |  (private address space)
                         +-------+


   Internal PCP clients can interact with one single PCP server.

3.4.  Multi-Homed CPE Model: Multiple PCP Servers

   A typical example of this model is shown in the following figure:

















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                          ==================
                          |    Internet    |
                          ==================
                             |          |
                             |          |
                        +----+-+      +-+----+
                        | ISP1 |      | ISP2 |
                        +----+-+      +-+----+
                             |          |
       .........................................................
                             |          |
                             |          |        Subscriber Network
                     +-------+---+ +----+------+
                     | rtr1 with | | rtr2 with |
                     |   FW1     | |    FW2    |
                     +-------+---+ +----+------+
                             |          |
                             |          |
                             |          |
                      -------+----------+------
                             |
                           +-+-----+
                           | Hosts |
                           +-------+

   The PCP client must interact with all PCP servers; otherwise
   complications arise to communicate with remote peers.  The procedure
   defined in [I-D.ietf-pcp-server-selection] is used to contact those
   servers.

   The use of anycast-based model ([I-D.ietf-pcp-anycast]) might induce
   failures when communicating with external peers (e.g., incoming
   packets will be dropped by one of the firewalls).

3.5.  PCP Proxy Model

   This model assumes no PCP-controlled function is located in the CPE
   (e.g., DS-Lite case).  The upstream PCP server is located in the
   ISP's network.  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.

   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).






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      +-------------+
      |   Host      |
      |             |----+                         ,-----------.
      +-------------+    |   +------------+      ,'             `--.
                         +---|    CPE     |      /     ISP           :
                             | PCP proxy  |_____;    PCP server 1    |
                         +---| PCP client |     :    PCP server i    |
      +-------------+    |   +------------+      \                   |
      |    PCP      |----+                        -------------------.
      |   Client    |
      +-------------+


3.6.  UPnP IGD-PCP Interworking Model

   This model is specified in [RFC6970].  The interworking function must
   be provisioned with the IP address(es) of remote PCP server(s).

   (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
      +-------------+








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3.7.  HTTP-based User Interface

   This deployment model relies on the following:

   o  An HTTP administration based interface (e.g.  GUI) is provided to
      the user to manage its flow-based forwarding rules.  This
      interface is part of the CPE management interface.

   o  The CPE embeds a PCP client.

   o  HTTP requests are translated into appropriate PCP requests in
      order to install the requested state.

   o  The PCP client uses THIRD_PARTY option.

   o  The PCP client should be configured with the PCP server that
      controls the on-path PCP-controlled device for that user.

   o  One or multiple PCP servers can be deployed.  The logic of
      contacting these PCP servers may be explicitly configured to the
      PCP client.  If not, the procedure defined in
      [I-D.ietf-pcp-server-selection] is used to contact those PCP
      servers.

   o  The use of a well-known address ([I-D.ietf-pcp-anycast]) to reach
      internal PCP servers might not be convenient if all PCP servers do
      not manage the same set of mapping entries (e.g., NAT64, NPTv6,
      IPv6 firewall, etc.).

      +-------------+
      |   Host 1    |----+                         ,-----------.
      +-------------+    |   +------------+      ,'             `--.
                         +---|    CPE     |      /     ISP           :
                             | HTTP Server|_____;                    |
                         +---| PCP client |     :    PCP server i    |
      +-------------+    |   +------------+      \                   |
      |   Host 2    |----+                        -------------------.
      +-------------+


   This model can co-exist with the models discussed in Section 3.5 and
   Section 3.6.

3.8.  Cascaded PCP-controlled Nodes Model

   This model assumes cascaded PCP-controlled devices are deployed.  A
   typical example is provided below.




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                                                      ,-----------.
                               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       |
   +-------+    +------+               +-------+   \                   |
                                                    \                  ;
                                                     `------.       ,-'
                                                             `-----'

   This model requires a PCP proxy function [I-D.ietf-pcp-proxy] be
   deployed in intermediate PCP-controlled devices:

   o  The PCP client is not aware of the presence of more than one level
      of PCP servers.

   o  Each intermediate PCP proxy must contact the appropriate next hop
      PCP server(s).

   o  The use of PCP anaycast address may not be appropriate when the
      PCP server is co-located with the PCP-controlled device.



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4.  Hide PCP Servers Model

4.1.  PCP Proxy Model

   In order to hide PCP servers deployed within an administrative
   domain, an administrative entity may decide to deploy one or more PCP
   proxies [I-D.ietf-pcp-proxy] in front of PCP clients.  A PCP proxy is
   responsible for relaying PCP requests to the appropriate PCP
   server(s):

   o  In order to prevent single failure scenarios, multiple PCP proxies
      can be hosted within an administrative domain.

   o  A PCP proxy can be configured with one or multiple PCP servers.

   o  A PCP proxy can be configured with the logic indicating how it
      should proceed to contact upstream PCP servers.  The PCP proxy
      will then follow the procedure defined in
      [I-D.ietf-pcp-server-selection] to contact those PCP servers.

   o  Internal PCP clients may be configured with the IP address(es) of
      the appropriate PCP proxy (e.g., [I-D.ietf-pcp-dhcp]).

      *  If all PCP proxies interact with the same PCP server(s), the
         same IP address can be provisioned to PCP clients.

      *  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.

                  +------------------------------------+
                  | Administrative Domain              |
   +----------+   |    +-------------------+           |
   |PCP client|---|----|    PCP proxy      |           |
   +----------+   |    +-------------------+           |
                  |        |            |              |
                  |        |            |              |
                  | +------+------+   +-+------------+ |
                  | | PCP server  |   | PCP server   | |
                  | +-------------+   +--------------+ |
                  +------------------------------------+

   The PCP proxy should not use the PCP anycast address
   ([I-D.ietf-pcp-anycast]) if available PCP servers do not manage the
   same PCP-controlled device.  Deterministic means should be used
   instead.





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   PCP client should not use the PCP anycast address to reach a PCP
   proxy if deployed PCP proxies do not interact with the same PCP
   servers.  Explicit provisioning means should be preferred.

   If the PCP proxy is reachable using the PCP anycast address,
   available PCP servers must not be reachable using the same PCP
   anycast address.

4.2.  HTTP-Triggered PCP Client Model

   Another deployment model to hide the identity of back-end PCP servers
   is to rely on HTTP to invoke the PCP service.  This model can be used
   by operators to accommodate cases where a PCP client implementation
   is not available at the customer side (e.g., unmanaged CPE model).

   The deployment model relies on the following:

   o  An HTTP administration based interface (e.g.  GUI) is provided to
      the user to manage its flow-based forwarding rules.

   o  The HTTP user interface can be part of a CPE management interface
      or be provided as part of the customer care portal.

   o  The HTTP server embeds also a PCP client.

   o  HTTP requests are translated into appropriate PCP requests in
      order to install the requested state.

   o  The PCP client uses THIRD_PARTY option.

   o  The PCP client should be configured with the PCP server that
      controls the on-path PCP-controlled device for that user.

   o  One or multiple PCP servers can be deployed.  The logic of
      contacting these PCP servers may be explicitly configured to the
      PCP client.  If not, the procedure defined in
      [I-D.ietf-pcp-server-selection] is used to contact those PCP
      servers.

   o  The use of a well-known address ([I-D.ietf-pcp-anycast]) to reach
      internal PCP servers might not be convenient if all PCP servers do
      not manage the same set of mapping entries (e.g., NAT64, NPTv6,
      IPv6 firewall, etc.).








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                  +------------------------------------+
                  | Administrative Domain              |
   +----------+   |    +----------------------+        |
   |  Host    |---|----|HTTP Server+PCP client|        |
   +----------+   |    +----------------------+        |
                  |        |            |              |
                  |        |            |              |
                  | +------+------+   +-+------------+ |
                  | | PCP server  |   | PCP server   | |
                  | +-------------+   +--------------+ |
                  +------------------------------------+

5.  Separated PCP Server & PCP-controlled Device Model

   This model assumes the PCP server is not co-located with the PCP-
   controlled device.  Moreover:

   o  In order to prevent single failure scenarios, multiple PCP servers
      can be hosted within an administrative domain.

   o  A PCP server can control one or many PCP-controlled devices.

   o  Multiple PCP servers can be enabled; each of them manages a set of
      PCP-controlled devices.

   o  Internal PCP clients are configured with the IP address(es) of the
      appropriate PCP server.

      *  If all PCP servers interact with the same PCP-controlled
         devices, the same PCP server's IP address can be provisioned to
         PCP clients.

      *  If PCP servers do not interact with the same set of PCP-
         controlled devices, PCP server IP address(es) are to be
         returned to each requesting PCP client.

   Note, PCP is not used between the PCP server and the PCP-controlled
   device.  Other protocols (e.g., H.248) can be used for that purpose.

6.  Security Considerations

   PCP-related security considerations are discussed in [RFC6887].

7.  IANA Considerations

   This document does not require any action from IANA.





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8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC6887]  Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)", RFC 6887, April
              2013.

8.2.  Informative References

   [I-D.ietf-pcp-anycast]
              Kiesel, S., Penno, R., and S. Cheshire, "PCP Anycast
              Address", draft-ietf-pcp-anycast-01 (work in progress),
              February 2014.

   [I-D.ietf-pcp-dhcp]
              Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
              the Port Control Protocol (PCP)", draft-ietf-pcp-dhcp-13
              (work in progress), April 2014.

   [I-D.ietf-pcp-proxy]
              Perreault, S., Boucadair, M., Penno, R., Wing, D., and S.
              Cheshire, "Port Control Protocol (PCP) Proxy Function",
              draft-ietf-pcp-proxy-05 (work in progress), February 2014.

   [I-D.ietf-pcp-server-selection]
              Boucadair, M., Penno, R., Wing, D., Patil, P., and T.
              Reddy, "PCP Server Selection", draft-ietf-pcp-server-
              selection-03 (work in progress), April 2014.

   [RFC6146]  Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
              NAT64: Network Address and Protocol Translation from IPv6
              Clients to IPv4 Servers", RFC 6146, April 2011.

   [RFC6296]  Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
              Translation", RFC 6296, June 2011.

   [RFC6970]  Boucadair, M., Penno, R., and D. Wing, "Universal Plug and
              Play (UPnP) Internet Gateway Device - Port Control
              Protocol Interworking Function (IGD-PCP IWF)", RFC 6970,
              July 2013.







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Author's Address

   Mohamed Boucadair
   France Telecom
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com











































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