Network Working Group                                       M. Boucadair
Internet-Draft                                              C. Jacquenet
Intended status: Standards Track                          France Telecom
Expires: August 27, 2010                                        D. Cheng
                                                                  Huawei
                                                                  Y. Lee
                                                                 Comcast
                                                       February 23, 2010


       Multi-Topology/Multi-Instance ISIS for IPv4-Embedded IPv6
                    draft-boucadair-isis-v4v6-mt-02

Abstract

   This document defines two new Multi Topology Routing Identifiers (MT
   IDs), based on [RFC5120] and two new Instance Identifiers (MI IDs),
   based on [I-D.ietf-isis-mi], respectively, in the Intermediate System
   to Intermediate System.  With these identifiers, an IPv4-Embedded
   IPv6 topology is maintained for both IPv6 unicast and multicast
   traffic.  The purpose of running separate instances or topologies for
   IPv4-Embedded IPv6 traffic is to distinguish from the native IPv6
   routing topology, and the topology that is used for routing IPv4-
   Embedded IPv6 datagrams only.  Separate instances/topologies are also
   meant to prevent any overload of the native IPv6 routing tables by
   IPv4-Embedded IPv6 routes.

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 to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 4
   2.  IPv4-Embedded IPv6 IS-IS Topologies . . . . . . . . . . . . . . 4
   3.  IPv4-Embedded IPv6 IS-IS Instances  . . . . . . . . . . . . . . 5
   4.  Provisioning  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Forwarding  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     9.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7





































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1.  Introduction

   Within the double context of public IPv4 address exhaustion and IPv6-
   IPv4 interconnection, numerous solutions are being elaborated within
   IETF.  Both translation (e.g., [I-D.ietf-behave-v6v4-xlate-stateful]
   and [I-D.ietf-behave-v6v4-xlate]) and encapsulation (e.g.,
   [I-D.boucadair-dslite-interco-v4v6] and
   [I-D.boucadair-behave-ipv6-portrange]) based schemes are proposed to
   allow IPv6-IPv4 interconnection.  These solutions require the
   injection of routes to IPv4-Embedded IPv6 prefixes
   [I-D.ietf-behave-address-format] in intra-domain routing protocols .

   In order to prevent any overload of the native IPv6 routing table
   with IPv4-Embedded IPv6 routes, this document defines new MT IDs
   (resp., MI IDs) which are required for the activation of multiple
   topologies (resp., Instances), where the native IPv6 topology (resp.,
   Instance) would be distinct from the IPv4-Embedded IPv6 topology
   (resp., Instance).  Operational reasons also motivate this approach
   which is meant to ease the migration to full IPv6.  As a result, the
   unicast IPv4-Embedded IPv6 topology (resp., Instance) is used for
   unicast IPv4-Embedded IPv6 route computation purposes, and the
   multicast IPv4-Embedded IPv6 topology (resp., Instance) is used for
   multicast IPv4-Embedded IPv6 route computation purposes.

   This document does not make any preference between the solution
   described in [RFC5120] and [I-D.ietf-isis-mi].  Network
   administrators have to make their decisions based on local policies.
   If the multi-instance mechanism is deployed in an IS-IS network as a
   preference for multiple topologies, the MI extensions defined in this
   document may be used to support unicast/multicast IPv4-Embedded IPv6
   routing.  If M-ISIS mechanism is deployed in an IS-IS network as a
   preference for multiple topologies, the MT extensions defined in this
   document may be used to support unicast/multicast IPv4-Embedded IPv6
   routing.


2.  IPv4-Embedded IPv6 IS-IS Topologies

   M-ISIS [RFC5120] is a mechanism that has been specified to run within
   a single IS-IS [RFC1195] domain where various logical IS-IS
   topologies are deployed, based on several criteria such as the need
   to differentiate IPv6 topologies from IPv4 topologies.  Distinct MT
   IDs (Multi Topology Identifiers) are assigned by IANA (e.g., MT ID #
   0 for standard topology, MT ID # 2 for IPv6 routing topology, etc.).
   MT ID # 6-#3995 range is reserved for IETF consensus.  This document
   requests the assignment of two new MT IDs for the following usages:





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   o  IPv4-Embedded IPv6 unicast topology;

   o  IPv4-Embedded IPv6 multicast topology.


3.  IPv4-Embedded IPv6 IS-IS Instances

   [I-D.ietf-isis-mi] specifies a mechanism to map each address family
   (AF) to a separate IS-IS Instance identified by an ID.  Accepted ID
   values are 0 to 65535.  Instance ID#0 is used by default (legacy
   systems).  This document requests the assignment of two new MI-IS-IS
   Instance IDs for the following usages:

   o  IPv4-Embedded IPv6 unicast AF;

   o  IPv4-Embedded IPv6 multicast AF.


4.  Provisioning

   Adequate provisioning must be done according to [RFC5120] and
   [I-D.ietf-isis-mi], respectively, based on the corresponding
   mechanism that is actually used in an IS-IS network, in order to have
   a fully-connected IPv4-Embedded IPv6 unicast or multicast topology.


5.  Procedure

   This document does not require any modification to the procedure
   specified in [RFC5120] nor in [I-D.ietf-isis-mi].  Nevertheless,
   routes to IPv4-Embedded IPv6 addresses or prefixes MUST be
   instantiated within an IPv4-Embedded IPv6 M-ISIS (resp., MI-ISIS).
   Concretely, the WKP prefix (i.e., 64:FF9B::/96) defined in
   [I-D.ietf-behave-address-format] must be supported by default.
   Service providers may also choose a LIR prefix to build the IPv4-
   Embedded IPv6 addresses.


6.  Forwarding

   Only incoming datagrams destined to IPv4-Embedded IPv6 addresses are
   associated (and forwarded accordingly) with the IPv4-Embedded IPv6
   unicast/multicast topology, respectively.  WKP (i.e., 64:FF9B::/96)
   and/or LIR prefix defined in [I-D.ietf-behave-address-format] must be
   configured in all participating nodes.






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7.  IANA Considerations

   TBC.


8.  Security Considerations

   This document does not introduce any security issue in addition to
   those defined in [RFC5120] and [I-D.ietf-isis-mi].


9.  References

9.1.  Normative References

   [I-D.ietf-isis-mi]
              Previdi, S., Ginsberg, L., Shand, M., Ward, D., and A.
              Roy, "IS-IS Multi-Instance", draft-ietf-isis-mi-02 (work
              in progress), October 2009.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, December 1990.

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

   [RFC5120]  Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
              Topology (MT) Routing in Intermediate System to
              Intermediate Systems (IS-ISs)", RFC 5120, February 2008.

9.2.  Informative References

   [I-D.boucadair-behave-ipv6-portrange]
              Boucadair, M., Levis, P., Grimault, J., Villefranque, A.,
              Kassi-Lahlou, M., Bajko, G., Lee, Y., Melia, T., and O.
              Vautrin, "Flexible IPv6 Migration Scenarios in the Context
              of IPv4 Address Shortage",
              draft-boucadair-behave-ipv6-portrange-04 (work in
              progress), October 2009.

   [I-D.boucadair-dslite-interco-v4v6]
              Boucadair, M., Jacquenet, C., Grimault, J., Kassi-Lahlou,
              M., Levis, P., Cheng, D., and Y. Lee, "Deploying Dual-
              Stack lite in IPv6-only Network",
              draft-boucadair-dslite-interco-v4v6-02 (work in progress),
              October 2009.

   [I-D.ietf-behave-address-format]



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              Huitema, C., Bao, C., Bagnulo, M., Boucadair, M., and X.
              Li, "IPv6 Addressing of IPv4/IPv6 Translators",
              draft-ietf-behave-address-format-04 (work in progress),
              January 2010.

   [I-D.ietf-behave-v6v4-xlate]
              Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
              Algorithm", draft-ietf-behave-v6v4-xlate-09 (work in
              progress), February 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-08 (work in
              progress), January 2010.


Authors' Addresses

   Mohamed Boucadair
   France Telecom
   3, Av Francois Chateau
   Rennes,   35000
   France

   Email: mohamed.boucadair@orange-ftgroup.com


   Christian Jacquenet
   France Telecom
   3, Av Francois Chateau
   Rennes,   35000
   France

   Email: christian.jacquenet@orange-ftgroup.com


   Dean Cheng
   Huawei
   USA

   Email: Chengd@huawei.com








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   Yiu L. Lee
   Comcast
   USA

   Email: Yiu_Lee@Cable.Comcast.com














































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