Retrieving the Capabilities of a PCP-controlled Device
draft-boucadair-pcp-capability-03

Versions: 00 01 02 03                                                   
PCP Working Group                                           M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Standards Track                                T. Reddy
Expires: May 29, 2014                                              Cisco
                                                       November 25, 2013


         Retrieving the Capabilities of a PCP-controlled Device
                   draft-boucadair-pcp-capability-03

Abstract

   This document extends Port Control Protocol (PCP) with the ability to
   retrieve the capabilities of PCP-controlled device: CAPABILITY
   Option.

Requirements Language

   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 [RFC2119].

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
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on May 29, 2014.

Copyright Notice

   Copyright (c) 2013 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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  CAPABILITY  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  PCP Client/Server Behavior  . . . . . . . . . . . . . . . . .   3
   4.  Option Usage  . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   This document extends the base PCP [RFC6887] with a new feature to
   discover the capabilities of a PCP-controlled device.  Retrieving the
   capabilities of a PCP-controlled device would allow to avoid error,
   provide a hint why some applications fails, help select the OpCode to
   issue, etc.

   This option can be elected to be defined as a new OpCode.

2.  CAPABILITY

   The CAPABILITY option (Code: TBA, Figure 1) is used by a PCP Server
   to indicate to a requesting PCP Client the capabilities it supports
   with regards to port forwarding operations.

   One single Capability option is conveyed in the same PCP response
   message even if several functions are co-located in the same PCP-
   controlled device (e.g., NAT44 and NAT64, NAT44 and ports set
   assignment capability, etc.).

   This option, when received from a PCP Server, is used by a PCP Client
   to constraint the content of its requests and therefore avoid errors.

       0                   1                   2                   3
       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | CAPABILITY    |  Reserved     |            Length=16          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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      |A|                           Capability                        |
      +-+                                                             |
      :                                                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         This Option:

         Option Name: PCP Capabilities Option (CAPABILITY)
         Number: TBA (IANA)
         Purpose: Retrieve the capabilities of a PCP-controlled device
         Valid for Opcodes: ANNOUNCE, MAP, PEER
         Length: 16
         May appear in: both request and response
         Maximum occurrences: None


                        Figure 1: Capability option

   A-bit when set (i.e., 1) indicates the PCP Server supports
   authentication.  If this bit is set to 0, is indicates plain PCP is
   supported.

   The Capability Field is encoded in 127 bits.  Each bit in the
   Capability bit mask is used to represent the PCP-controlled device
   capability.  Several bits can be set if several functions are co-
   located in the same device.  The following values for the Capability
   field are:

      Bit #: Description
      1: NAT44
      2: Stateless NAT64 [RFC6145].
      4: Stateful NAT64 [RFC6146].
      8: A+P Port Range Router [RFC6346]
      9: Supports PORT_SET option [I-D.ietf-pcp-port-set].
      16: IPv4 firewall.
      32: IPv6 Firewall [RFC6092].
      64: NPTv6 [RFC6296].
      125: DSCP re-marking function.
      126: FLOWDATA-aware function ([I-D.wing-pcp-flowdata]).
      127: ILNP Translator [RFC6740].

3.  PCP Client/Server Behavior

   This section specifies the behavior of the PCP Client and the PCP
   Server to handle the CAPABILITY Option.

   The PCP Server MAY be configured to return the CAPABILITY Option even
   if it is not included in the request.



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   Once the PCP Client is configured with its PCP Server(s), it MAY
   issue an ANNOUNCE OpCode which enclose a CAPABILITY Option.  Sending
   the ANNOUNCE OpCode and the CAPABILITY Option allows the PCP Client
   to determine whether the PCP Server is alive and also to retrieve its
   capabilities.  Based on the received capabilities, the PCP Client may
   decide to tune its requests (e.g., Section 4) and decide whether all
   PCP Servers need to be contacted in parallel or only a subset of them
   should be contacted.

   Upon receipt of a PCP request from a PCP Client requiring the PCP
   Server to enforce an operation beyond its capabilities, the PCP
   Server MAY return an error code together with the CAPABILITY option.

   When a new PCP Server joins the network then it MAY send an ANNOUNCE
   OpCode with its capabilities (i.e., CAPABILITY Option).

4.  Option Usage

   Below are provided examples of the CAPABILITY Option usage:

   o  In an IPv6 network with NPTv6 [RFC6296], Firewalls implementing
      the PCP Server are on different devices: the PCP Client learns of
      the available PCP Servers by using DHCP [I-D.ietf-pcp-dhcp] or any
      other PCP Server discovery technique defined in future
      specifications.  PCP Client learns the PCP Server capabilities
      using CAPABILITY Option.  The PCP Client sends MAP PCP request to
      PCP-controlled NPTv6 device with Internal Port=0 and Protocol=0
      (which means 'all ports for all protocols') to find the external
      IP address.  This PCP request has to be sent only once since NPTv6
      is stateless and provides a 1:1 relationship between addresses in
      the "inside" and "outside" prefixes.  The PCP Client will send PCP
      re-request to NTPv6 only before the Assigned Lifetime of the MAP
      response expires or when the host embedding the PCP Client
      acquires a new IPv6 address using "inside" prefix.  However PCP
      Client will send MAP/PEER requests to Firewall to create/delete
      dynamic outbound mapping or use PCP instead of its default
      application keep-alives to maintain the Firewall state alive.

        PCP
       Client                              __________
   +-----------+   +------+   +------+    /          \   +-----------+
   |Application|___| NPTv6|___| FW   |____| Internet |___|Application|
   |  Client   |   |      |   |      |    |          |   |   Server  |
   +-----------+   +------+   +------+    \__________/   +-----------+

     Figure 2: NPTv6 and FW not collocated with PCP server Capability
   o  In a network with NAT64 [RFC6146], Firewall implementing PCP
      servers are on different devices: IPv6-only PCP Client can send



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      PREFIX64 PCP Option [I-D.ietf-pcp-nat64-prefix64] only to the PCP-
      controlled NAT64 device to learn the Prefix64(s) used to build
      IPv4-embedded IPv6 addresses.
   o  Multiple PCP-controlled devices: See Figure 3 the example of a
      network deploying several techniques to ensure interconnection
      with IPv4, provide IPv6-only connectivity, etc.  Of course, one
      can argue this configuration is no realistic.

                                        +-----+
                                  ______|NPTv6|___________
                                 /      +-----+           \
                                 |                        |
                                 |                     +-----+
   +-----------+   +------+      |                     | PRR |
   |Application|___| IPv6 |______|     SP Network      +-----+
   |PCP  Client|   |  FW  |      |                        |
   +-----------+   +------+      |                     +------+
                                 |                     | NAT64|
   +-----------+   +-------+     |                     |   +  |
   |PCP Client |___|A+P NAT|_____|                     |  FW  |
   +-----------+   +-------+     |      +-----+        +------+
                                 \______|NPTv6|___________/
                                        +-----+

                 Figure 3: Multiple PCP-controlled devoce
   o  In a IPv6 network with ILNP translator [RFC6740], Firewall
      implementing PCP servers are on different devices.  PCP client
      needs to send PCP request only to the PCP-controlled ILNP
      translator to find Global Locators associated with Internal
      Locators.
   o  When the PCP-controlled device is a PRR, the PCP Client should use
      PORT_SET [I-D.ietf-pcp-port-set] option.

5.  Security Considerations

   Security considerations discussed in [RFC6887] must be considered.

6.  IANA Considerations

   The following PCP Option Code is to be allocated in the optional-to-
   process range (the registry is maintained in http://www.iana.org/
   assignments/pcp-parameters/pcp-parameters.xml#options):

      CAPABILITY

   A sub-registry is required to track the set of capabilities of PCP-
   controlled devices.




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7.  References

7.1.  Normative References

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

   [RFC6145]  Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
              Algorithm", RFC 6145, April 2011.

   [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.

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

7.2.  Informative References

   [I-D.ietf-opsawg-firewalls]
              Baker, F. and P. Hoffman, "On Firewalls in Internet
              Security", draft-ietf-opsawg-firewalls-01 (work in
              progress), October 2012.

   [I-D.ietf-pcp-dhcp]
              Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
              the Port Control Protocol (PCP)", draft-ietf-pcp-dhcp-09
              (work in progress), November 2013.

   [I-D.ietf-pcp-nat64-prefix64]
              Boucadair, M., "Learning NAT64 PREFIX64s using PCP",
              draft-ietf-pcp-nat64-prefix64-04 (work in progress), July
              2013.

   [I-D.ietf-pcp-port-set]
              Qiong, Q., Boucadair, M., Sivakumar, S., Zhou, C., Tsou,
              T., and S. Perreault, "Port Control Protocol (PCP)
              Extension for Port Set Allocation", draft-ietf-pcp-port-
              set-04 (work in progress), November 2013.

   [I-D.wing-pcp-flowdata]
              Wing, D., Penno, R., and T. Reddy, "PCP Flowdata Option",
              draft-wing-pcp-flowdata-00 (work in progress), July 2013.







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   [RFC6092]  Woodyatt, J., "Recommended Simple Security Capabilities in
              Customer Premises Equipment (CPE) for Providing
              Residential IPv6 Internet Service", RFC 6092, January
              2011.

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

   [RFC6346]  Bush, R., "The Address plus Port (A+P) Approach to the
              IPv4 Address Shortage", RFC 6346, August 2011.

   [RFC6740]  Atkinson,, RJ., "Identifier-Locator Network Protocol
              (ILNP) Architectural Description", RFC 6740, November
              2012.

Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com


   Tirumaleswar Reddy
   Cisco Systems, Inc.
   Cessna Business Park, Varthur Hobli
   Sarjapur Marathalli Outer Ring Road
   Bangalore, Karnataka  560103
   India

   Email: tireddy@cisco.com


















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