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Versions: 00 01 02 03                                                   
Network Working Group                                       M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Standards Track                                R. Penno
Expires: November 25, 2011                              Juniper Networks
                                                                 D. Wing
                                                                   Cisco
                                                            May 24, 2011


             Some Extensions to Port Control Protocol (PCP)
                   draft-boucadair-pcp-extensions-01

Abstract

   This document extends Port Control Protocol (PCP) with new
   functionalities.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on November 25, 2011.

Copyright Notice

   Copyright (c) 2011 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



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   publication of this document.  Please review these documents
   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 . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  DESCRIPTION  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  DSCP_POLICY  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  CAPABILITY . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  RECEIVED_PORT  . . . . . . . . . . . . . . . . . . . . . . . .  8
   6.  SCOPE  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
   8.  CLIENT_IDENTIFIER  . . . . . . . . . . . . . . . . . . . . . . 11
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
   12. Normative References . . . . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14




























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1.  Introduction

   This document extends the base PCP [I-D.ietf-pcp-base] with various
   PCP Options.

   Some of these options may be defined as new PCP OpCodes.

   The main goal of this document is to kick-off discussions on the need
   to define some useful PCP options which are not part of base PCP.


2.  DESCRIPTION

   This option (Code TBA, Figure 1) MAY be included in a PCP MAPx
   request to include a description associated with a requested mapping.
   This option is optional to be supported by PCP Servers and PCP
   Clients.  The maximum length SHOULD be a configurable option in the
   PCP Server.  If a PCP Client includes a Description PCP option with a
   length exceeding the maximum length supported by the PCP Server, only
   the portion of the Description field fitting that maximum length is
   stored by the PCP Server.

   This option can be used by a user to indicate a description
   associated with a given mapping such as "My mapping for my FTP
   server" or "My remote access to my CP router", etc.  In addition, in
   the some deployment scenarios, this field can be used for
   troubleshooting purposes and can be used to convey values as the ones
   listed hereafter:

   o  "This is the mapping for my specific IPsec implementation"

   o  "This is the mapping for subscriber bob@example.com"

   o  "This is the mapping for special subscriber
      adsl-line-1234@example.com"

   o  "This is the mapping that failed before due to XYZ"

   Issues related to the usage of this field for troubleshooting or for
   any further usage are out of scope of this document.











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        This Option:

            Name: Description Option (DESCRIPTION)

            Number: TBA (IANA)

            Purpose: Used to associate a text description with a mapping

            is valid for OpCodes: MAP4, MAP6

            Length: Variable (multiple of 4)

            May appear in: both request and response

            Maximum occurrences: 1

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | DESCRIPTION   |  Reserved     |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Description                         |
      :                                                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                       Figure 1: Description Option


3.  DSCP_POLICY

   In some scenarios, the DSCP marking in the internal interface (i.e.,
   customer-facing interface) and the external one (i.e., Internet-
   facing interface) of the PCP-controlled device may be distinct.  A
   Service Provider MAY allow its customers to configure their DSCP
   marking policies in an upstream device.  Distinct DSCP marking
   policies can be implemented in the internal and external sides of the
   PCP-controlled device.  A PCP Client MAY issue a PCP MAPx request
   indicating its internal DS code point and the external DSCP value.
   Instructed forwarding policies are applied only for packets marked
   with a given DSCP value.

   A Service Provider may not support DSCP re-marking feature and adopt
   a transparent scheme to QoS policy enforcement, that is, not
   controllable by subscribers.  Generic QoS enforcement policies can be
   enforced for all customers: such as leave DSCP field values
   unchanged.




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   This option is mandatory to process.

   This option (Code TBA, Figure 2) allows to:

   o  Re-write any DSCP value to a specific value;

   o  Re-write a specific DSCP value to another specific value.


      This Option:

         Name: PCP DSCP Marking Policy Option (DSCP_POLICY)

         Number: TBA (IANA); mandatory to process

         Purpose: Associated a DSCP re-marking policy with a mapping

         is valid for OpCodes: MAP4, MAP6

         Length: 0x04

         May appear in: both request and response

         Maximum occurrences: none

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  DSCP_POLICY  |  Reserved     |            0x04               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |DIR| Int DSCP  | Ext DSCP  |         00...00                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     DIR     : Indicates the direction:
               0  Inbound
               1  Outbound
               2  Both
     Int DSCP: Indicates the DSCP value in the customer-faced interface.
               0x3F is used to indicate ANY value.
     Ext DSCP: Indicates the DSCP value in the Internet-faced interface.
               0x3F is used to indicate ANY value.


                       Figure 2: DSCP Marking option







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4.  CAPABILITY

   The CAPABILITY option (Code: TBA, Figure 3) is used by a PCP Server
   to indicate to a requesting PCP Client the capabilities it supports
   with regards to port forwarding operations.  Several Capability
   options MAY be conveyed in the same PCP response message 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.


        This Option:

           Name: PCP Capabilities Option (CAPABILITY)

           Number: TBA (IANA)

           Purpose: Retrieve the capabilities of a PCP-controlled device

           is valid for OpCodes: can be returned in a error message

           Length: 0x04

           May appear in: both request and response

           Maximum occurrences: None

      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     |            0x04               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |F T P A S C I O|              00...00                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                        Figure 3: Capability option

   Below is provided a description of the F, T, P, A, S, C, I and O
   bits:








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   Name Description
   ---- ----------------------------------------------------------------
     F  This bit indicates the address family of the source address
        issued by internal hosts
     T  This bit indicates the address family of the source address of
        the packets forwarded in the external side of the PCP-controlled
        device
     P  This bit indicates whether the source port number is translated
        or not.
     A  This bit indicates whether the source IP address is translated
        or not.
     S  This bit indicates whether the controlled device supports the
        ability to assign a set or ports
     C  This bit indicates whether the PCP-controlled devices inspects
        the received packets and if it can block them
     I  This bit indicates whether incoming packets are rejected unless
        an explicit rule is enforced in the PCP-controlled device
     O  This bit indicates whether outbound packets are inspected or not
        before being granted to leave the internal realm.

   The value of the F, T, P, A, S, C, I and O bits are as follows:

        Position Name               Meaning
        -------- ------------------ ------------------------------
            1    From (F)           0=from IPv4, 1=from IPv6
            2    To (T)             0=to IPv4, 1=to IPv6
            3    Port-Xlate (P)     1=translated, 0=not translated
            4    Addr-Xlate (A)     1=translated, 0=not translated
            5    Port-Set (S)       1=enabled, 0=not supported
            6    Packet-Control (C) 1=enabled, 0=not supported
            7    Direction-Out (I)  1=enabled, 0=disabled
            8    Direction-In (O)   1=enabled, 0=disabled

   A stateless NAT64 [RFC6145] would have the following values:

     From=0 (IPv4)
     To=1 (IPv6)
     Port-Xlate=0 (No)
     Addr-Xlate=1 (Yes)
     Port-Set=0  (No)
     Packet-control=0 (No)
     Direction-out (0) (No)
     Direction-In=0 (No)


   A stateful NAT64 [RFC6146] would have the following values:





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     From=0 (IPv4)
     To=1 (IPv6)
     Port-Xlate=1 (Yes)
     Addr-Xlate=1 (Yes)
     Port-Set=0  (No)
     Packet-control=0 (No)
     Direction-out (0) (No)
     Direction-In=0 (No)


   A NAT44 would be characterized as follows:

     From=0 (IPv4)
     To=0 (IPv4)
     Port-Xlate=1 (Yes)
     Addr-Xlate=1 (Yes)
     Port-Set=0  (No)
     Packet-control=0 (No)
     Direction-out (0) (No)
     Direction-In=0 (No)



5.  RECEIVED_PORT

   This option (Code TBA, Figure 4) is used by a PCP Server to indicate
   in a PCP response the source port of PCP messages received from a PCP
   Client.  Together with the IP Address of the PCP Client conveyed in
   the common PCP header, a PCP Client uses this information to detect
   whether a NAT is present in the path to reach its PCP Server.

   A PCP Client MAY include this option to learn the port number as
   perceived by the PCP Server.  When this option is received by the PCP
   Server, it uses the source port of the received PCP request to set
   the Received Port.
















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         This Option:

            Name: PCP Received Port Option (RECEIVED_PORT )

            Number: TBA (IANA)

            Purpose: Detect the presence of a NAT in the path

            is valid for OpCodes: MAP4, MAP6

            Length: 0x04

            May appear in: both request and response

            Maximum occurrences: 1

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | RECEIVED_PORT |  Reserved     |            0x04               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Received Port |                 00...00                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Received Port: The source port number of the received PCP request
          as seen by the PCP Server.


               Figure 4: Received IP address/port PCP option


6.  SCOPE

   The Scope Option (Code TBA, Figure 5) is used by a PCP Client to
   indicate to the PCP Server the scope of the flows that will use a
   given mapping.  This object is meant to be used in the context of
   cascaded PCP Servers/NAT levels.  Two values are defined:

                              Value Meaning
                              ----- --------
                               0x00 Internet
                               0x01 Internal

   When 0x00 value is used, the PCP Proxy MUST propagate the mapping
   request to its upstream PCP Server.  When 0x01 value is used, the
   mapping is to be instantiated only in the first PCP-controlled
   device; no mapping is instantiated in the upstream PCP-controlled
   device.



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   When no Scope Option is included in a PCP message, this is equivalent
   to including a Scope Option with a scope value of "Internet".


         This Option:

            Name: PCP Scope Policy Option (SCOPE)

            Number: TBA (IANA)

            Purpose: Restrict the scope of PCP requests

            is valid for OpCodes: MAP4, MAP6

            Length: 0x04

            May appear in: both request and response

            Maximum occurrences: 1

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   SCOPE       |  Reserved     |            0x04               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Scope      |                 00...00                       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                          Figure 5: Scope Option


7.  REPORT

   The Report PCP Option (Code TBA, Figure 6) is used by a PCP Client to
   report a set of useful information to the PCP Server.  Several Report
   Options with distinct Report Sub-Code values MAY be conveyed in the
   same PCP message.  Only report data associated with the PCP Server to
   which this option is sent MUST be included in a Report Option.

   This option can be used for troubleshooting or diagnose purposes.










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          This Option:

             Name: PCP Report Option (REPORT)

             Number: TBA (IANA)

             Purpose: Send a set of report data

             is valid for OpCodes: MAP4, MAP6

             Length: Variable

             May appear in: both request and response

             Maximum occurrences: Multiple

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   SCOPE       |  Reserved     |            Length             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    Report Sub-Code            |          00...00              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           Report Data                         |
       :                                                               :
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                          Figure 6: Report Option

   The following Report Sub-Code values are defined:

   Position Meaning
   -------- ------------------------------------------------------------
     0x00   Time since last reboot/boot
     0x01   Count of transmitted PCP messages to the PCP Server since
            last boot
     0x02   Count of retransmitted PCP messages to the PCP Server since
            last boot
     0x03   Count of received PCP Error messages from the PCP Server


8.  CLIENT_IDENTIFIER

   PCP CLIENT_ID (Code TBA, Figure 7) is a token randomly [RFC4086]
   generated by the PCP Client.  Only one CLIENT_ID Option MUST be
   present in a PCP message.  The PCP Client and PCP Server MUST store
   the value included in this Option in a PCP MAPx request.



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   o  The CLIENT_ID MUST be generated by the PCP Client and not the PCP
      Server;

   o  Upon change of the IP address of the PCP Client (or a third party
      on behalf of which a mapping has been created), the CLIENT_ID is
      used to update related mappings (e.g., PCP MAP delete request and
      PCP MAP create request);

   o  The same CLIENT_ID MUST be used for all requested mappings, unless
      a new CLIENT_ID is generated by the PCP Client (e.g., reboot, OS
      crash, etc.);

   o  The CLIENT_ID is stored by the PCP Server for all mappings
      (persistent storage);


          This Option:

             Name: PCP Client Identifier Option (CLIENT_ID)

             Number: TBA (IANA); mandatory to process option

             Purpose: Associate an identifier with the mappings

             is valid for OpCodes: MAP4, MAP6

             Length: Variable

             May appear in: both request and response

             Maximum occurrences: 1

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | CLIENT_ID     |  Reserved     |            Length             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          Client Identifier                    |
       :                                                               :
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                      Figure 7: CLIENT_ID PCP Option

   The length of the CLIENT_ID is encoded in the Length field in bytes.
   The length of the CLIENT_ID MUST be at least 4 bytes and MUST NOT
   exceed 16 bytes.




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   The RECOMMENDED value is 16 bytes so as to have a robust random
   CLIENT_ID.  If a CLIENT_ID longer than 16 bytes or shorter than 4
   bytes is received, the PCP Server MUST issue a PCP Error message with
   an error cause equal to "Invalid Client-ID".

   For sanity checks, a PCP Server maintains the same CLIENT_ID value
   (which is used in the latest PCP request) for a given PCP Client for
   all mappings associated with the same internal IP address belonging
   to the same subscriber.  Indeed, the PCP Server maintains an
   additional identifier denoted as subscriber-Id.  A subscriber-is can
   be an IP address, IPv6 prefix or a subscriber identifier configured
   locally.


9.  Security Considerations

   Security considerations discussed in [I-D.ietf-pcp-base] must be
   considered.  The use of CLIENT_ID option allows to soften issues
   related to stale mappings.


10.  IANA Considerations

   The following PCP Option Codes are to be allocated:

      DESCRIPTION

      DSCP_POLICY: The "O" bit MUST be set to 1.

      CAPABILITY

      RECEIVED_PORT

      SCOPE

      REPORT

      CLIENT_IDENTIFIER: The "O" bit MUST be set to 1.


11.  Acknowledgements

   TBC.


12.  Normative References

   [I-D.ietf-pcp-base]



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              Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)",
              draft-ietf-pcp-base-12 (work in progress), May 2011.

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

   [RFC4086]  Eastlake, D., Schiller, J., and S. Crocker, "Randomness
              Requirements for Security", BCP 106, RFC 4086, June 2005.

   [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.


Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes,   35000
   France

   Email: mohamed.boucadair@orange-ftgroup.com


   Reinaldo Penno
   Juniper Networks
   1194 N Mathilda Avenue
   Sunnyvale, California  94089
   USA

   Email: rpenno@juniper.net


   Dan Wing
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, California  95134
   USA

   Email: dwing@cisco.com







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