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Port Control Protocol                                           R. Penno
Internet-Draft                                          Juniper Networks
Intended status: Standards Track                        October 20, 2011
Expires: April 22, 2012


                PCP Support for Multi-Zone Environments
                        draft-penno-pcp-zones-01

Abstract

   A zone is a notion which denotes a routing instance, a set interfaces
   or prefixes characterized by having a different address realm and/or
   security policy.  A NAT device can route packets with the same source
   IP address to different zones depending on configuration policies
   such as destination IP address.  This functionality has been present
   for many years in NAT devices from multiple vendors.  PCP allows a
   host to interact with a PCP-controlled NAT device and request an
   external IP and port.  Therefore a PCP Server that controls the NAT
   device and receives a PCP request from a host needs to know from
   which NAT pool to allocate an external IP address and port.  This
   document specifies an extension to PCP to support the zone concept.

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 April 22, 2012.

Copyright Notice




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   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
   publication of this document.  Please review these documents
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   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
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . 3
     1.3.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   2.  PCP Base Support for Multiple Zones . . . . . . . . . . . . . . 4
     2.1.  PCP PEER Request  . . . . . . . . . . . . . . . . . . . . . 4
     2.2.  PCP MAP Request . . . . . . . . . . . . . . . . . . . . . . 5
   3.  PCP Extension for Multiple Zones  . . . . . . . . . . . . . . . 5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 8




















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1.  Introduction

   A zone is a routing instance, set interfaces or prefixes
   characterized by having a different address domain or security
   policy.  A NAT device is present on each zone through NAT pools which
   are used to translate packet to and from a zone.  The PCP protocol
   allows a host to interact with a NAT device and request a external IP
   and port.  Since a NAT Device can route packets with the same source
   IP address to different Zones depending on policy or packet match
   conditions, the PCP Server that interacts with the NAT device and
   receives a PCP request from a host needs to know from which NAT pool
   to allocate an IP address and port.

1.1.  Terminology

   This document uses PCP terminology defined in [I-D.ietf-pcp-base]].
   In addition the following terms are defined in this document:

   o  Zone: A routing instance, set of interfaces or network prefixes
      that has a separate addressing domain or security policy.

   o  Address Domain: A collection of IP addresses.  A NAT device is
      present on each domain through one or more NAT pools associated
      with each Zone.

1.2.  Problem Statement

   A PCP Server can control a NAT attached to distinct zones; each zone
   is characterised by one or several address pools.  In such
   environment the NAT must rely on a pre-configured policy to determine
   which address pool to use when handling an IP packet coming from an
   internal host.  An example of such policy may be to rely on the
   destination IP address, DSCP value(s), protocol (e.g., SIP, RTP,
   RTSP), etc.

















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                                                   ,-----.
                                                 ,'       `.
                                               .( Zone IPTV )
              ,-------.                     .-'  `.       ,'
           ,-'  Zone   `-.                .'       `-----'
        Host   Access     \ CGN        .-'          ,-------.
    +----+-----+       +---+------+  .'           ,'         `.
    |PCP Client|-------|PCP Server|.'------------(Zone Internet)
    +----+-----+       +---+------+ `-.           `.         ,'
          \               /            `.           `-------'  \
           `-.         ,-'               `-.      ,-----.       `.
              `-------'                     `.   /       \        )
                                              `-( Zone VPN-------'
                                                 \       /
                                                  `-----'

   The core of the problem is that packets from the same source IP
   address can be routed to any of the zones depending on match
   conditions based on the 5-tuple.  Moreover, sessions could be
   initiated from any of these zones toward the host.  These zones many
   times have different addressing domains and therefore different NAT
   pools.  This means that packets from the host will use a different
   NAT pool depending on the destination zone.

   It is important to notice that zones (or similar concept) has been
   present in Enteprise NAT and CGN from multiple vendors for many
   years.  It is the advent and interaction with PCP that has created a
   need for a standardized approach.

1.3.  Scope

   The matching conditions that ultimately decide where to route a
   packet can be very elaborate including even application layer
   information.  But the scope of this document is to abstract such
   implementation specific approaches behind the concept of a Zone-ID.


2.  PCP Base Support for Multiple Zones

   Before discussing extensions to the PCP protocol in the following
   sections we discuss how to support multiple zones with the current
   methods present in the base PCP protocol.

2.1.  PCP PEER Request

   A PCP PEER request could contains the destination IP address, port
   and Transport protocol of the peer the host will be trying to
   communicate .  In that case, if the NAT device maintains a mapping of



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   zones (and associated NAT pools) to network prefixes it can choose
   the appropriate NAT pool.  It is important to understand that this
   will only work if the policy that decides to which Zone to route
   packets is only based on the information present on the PCP PEER
   request.

   Therefore if the PCP Client knows it is behind a NAT with zone
   support, it is RECOMMENDED that it includes the remote peer's 5-tuple
   in the PCP PEER request in the connect-then-lifetime case.  If the
   peer's 5-tuple is not present in the PCP request, the external IP and
   port returned in the message is non-deterministic.

2.2.  PCP MAP Request

   In the case of PCP MAP request the NAT device does not know from
   which zone to install a mapping and consequently from which NAT pool
   to choose an external IP address and port.  A FILTER Option may be
   included to allow the PCP Server select the external address pool to
   use.  If other information than the destination IP address is used to
   drive the selection of the external address pool, additional
   information is required to be conveyed in the PCP MAP request (e.g.,
   DSCP marking policy (see http://tools.ietf.org/html/
   draft-boucadair-pcp-extensions-01#section-3).


3.  PCP Extension for Multiple Zones

   The proposed PCP extension is a new PCP Option that would convey the
   Zone-ID.  The Zone-ID is an opaque identifier that is known by the
   PCP Client and the PCP-controlled NAT device.  The procedure to
   provision the Zone-ID is out of scope.

   When the NAT device receives a PCP request with a Zone-ID, it will
   use that or a derivative of it to determine the NAT pool from which
   to allocate an IP address and port.

      Option Name: ZONEID

      Number: TBA (IANA); Mandatory to process

      Purpose: It allows the client request and server indicate from
      which Zone-ID the external IP:port were allocated.

      Valid for Opcodes: MAP, PEER

      Length: Variable





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      May appear in: both

      Maximum occurrences: 1


4.  IANA Considerations

   TBD


5.  Security Considerations

   Subscribers can only request ports for the specific Zone-IDs allowed
   in their security profile.  For example, in a typical Wireless
   deployment, mobile terminals could request mappings in zones
   'Internet', 'HTTP Proxy Farm', and 'Video Farm'.  A PCP request that
   contains a zone-id considered a security violation would be silently
   dropped.


6.  Acknowledgements

   Thanks to Mohamed Boucadair for early review comments


7.  References

7.1.  Normative References

   [RFC0959]  Postel, J. and J. Reynolds, "File Transfer Protocol",
              STD 9, RFC 959, October 1985.

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

   [RFC2766]  Tsirtsis, G. and P. Srisuresh, "Network Address
              Translation - Protocol Translation (NAT-PT)", RFC 2766,
              February 2000.

   [RFC2960]  Stewart, R., Xie, Q., Morneault, K., Sharp, C.,
              Schwarzbauer, H., Taylor, T., Rytina, I., Kalla, M.,
              Zhang, L., and V. Paxson, "Stream Control Transmission
              Protocol", RFC 2960, October 2000.

   [RFC4787]  Audet, F. and C. Jennings, "Network Address Translation
              (NAT) Behavioral Requirements for Unicast UDP", BCP 127,
              RFC 4787, January 2007.




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   [RFC4966]  Aoun, C. and E. Davies, "Reasons to Move the Network
              Address Translator - Protocol Translator (NAT-PT) to
              Historic Status", RFC 4966, July 2007.

   [RFC5382]  Guha, S., Biswas, K., Ford, B., Sivakumar, S., and P.
              Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142,
              RFC 5382, October 2008.

   [RFC5508]  Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT
              Behavioral Requirements for ICMP", BCP 148, RFC 5508,
              April 2009.

7.2.  Informative References

   [I-D.ietf-behave-address-format]
              Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
              Li, "IPv6 Addressing of IPv4/IPv6 Translators",
              draft-ietf-behave-address-format-10 (work in progress),
              August 2010.

   [I-D.ietf-behave-dns64]
              Bagnulo, M., Sullivan, A., Matthews, P., and I. Beijnum,
              "DNS64: DNS extensions for Network Address Translation
              from IPv6 Clients to IPv4 Servers",
              draft-ietf-behave-dns64-11 (work in progress),
              October 2010.

   [I-D.ietf-behave-ftp64]
              Beijnum, I., "An FTP ALG for IPv6-to-IPv4 translation",
              draft-ietf-behave-ftp64-12 (work in progress), July 2011.

   [I-D.ietf-behave-v6v4-framework]
              Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
              IPv4/IPv6 Translation",
              draft-ietf-behave-v6v4-framework-10 (work in progress),
              August 2010.

   [I-D.ietf-behave-v6v4-xlate-stateful]
              Bagnulo, M., Matthews, P., and I. Beijnum, "Stateful
              NAT64: Network Address and Protocol Translation from IPv6
              Clients to IPv4 Servers",
              draft-ietf-behave-v6v4-xlate-stateful-12 (work in
              progress), July 2010.

   [I-D.ietf-pcp-base]
              Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)",
              draft-ietf-pcp-base-16 (work in progress), October 2011.



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   [I-D.wing-behave-dns64-config]
              Wing, D., "IPv6-only and Dual Stack Hosts on the Same
              Network with DNS64", draft-wing-behave-dns64-config-03
              (work in progress), February 2011.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

   [RFC5245]  Rosenberg, J., "Interactive Connectivity Establishment
              (ICE): A Protocol for Network Address Translator (NAT)
              Traversal for Offer/Answer Protocols", RFC 5245,
              April 2010.

   [RFC5853]  Hautakorpi, J., Camarillo, G., Penfield, R., Hawrylyshen,
              A., and M. Bhatia, "Requirements from Session Initiation
              Protocol (SIP) Session Border Control (SBC) Deployments",
              RFC 5853, April 2010.


Author's Address

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

   Email: rpenno@juniper.net





















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