Network Working Group M. Boucadair
Internet-Draft C. Jacquenet
Intended status: Standards Track France Telecom
Expires: April 23, 2010 D. Cheng
Huawei
Y. Lee
Comcast
October 20, 2009
IPv4-mapped IPv6 Instance IDs in IS-IS
draft-boucadair-isis-v4v6-mi-01
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Copyright Notice
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Abstract
This memo defines two new Instance Identifiers (Instance IDs) in
IS-IS [RFC1195]). These new Instance IDs [I-D.ietf-isis-mi] are
meant to instantiate distinct IS-IS instances to convey routing
information which is restricted to IPv4-mapped IPv6 addresses
[I-D.ietf-behave-address-format]. The ultimate goal of running
separate instances for IPv4-mapped IPv6 routes is to isolate the IPv6
routing table from the IPv4 routing table, and to avoid any overload
due to the population of the table by IPv4-mapped IPv6 routes. This
isolation is motivated also from an operational perspective to allow
the enforcement of specific routing policies for each topology.
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].
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
[I-D.ietf-isis-mi] specifies a mechanism to map each address family
to a separate IS-IS [RFC1195] 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 Unicast IPv4-mapped IPv6 IS-IS routing instance;
o Multicast IPv4-mapped IPv6 IS-IS routing instance.
Within the double context of IPv4 address exhaustion and the 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]) schemes are proposed to
facilitate IPv6-IPv4 interconnection. These solutions require the
injection of routes to IPv4-mapped IPv6
[I-D.ietf-behave-address-format] destination prefixes in intra-domain
routing protocols. In order to prevent any overload of the native
IPv6 routing table with IPv4-mapped IPv6 routes, this memo defines
new Instance IDs which are required for the activation of several
IS-IS instances for unicast/multicast IPv4-mapped IPv6. Such new
instances are also meant to facilitate the operation of networks that
convey IPv4 and IPv6 traffic and to ease the migration to full IPv6.
As a result, when a separate IS-IS instance for unicast IPv4-mapped
IPv6 address family is activated, a distinct IS-IS adjacency table is
created, based on which unicast IPv4-mapped IPv6 routes is computed.
Likewise, when a separate IS-IS instance for multicast IPv4- mapped
IPv6 address family is activated, a distinct IS-IS adjacency table is
created for multicast IPv4-mapped IPv6 route computation purposes.
In case [RFC5120] is deployed, new Multi Topology IDs are required to
be defined. As a reminder, [RFC5120] specifies a mechanism to
maintain multiple IS-IS topologies within the same IS-IS domain.
This memo 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 and preferences. If the
multi-instance mechanism [I-D.ietf-isis-mi] is deployed in an IS-IS
network as a preference for multiple topologies, the extensions as
defined in this memo may be used to support unicast/multicast IPv4-
mapped IPv6 routing, respectively.
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2. Procedure
This document does not require any modification to the procedure
specified in [I-D.ietf-isis-mi]. Nevertheless, only routes to IPv4-
mapped IPv6 prefixes MUST be instantiated within a IPv4-mapped IPv6
routing M-ISIS Concretely, the IANA prefix 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-
mapped IPv6 addresses.
3. Forwarding
Only incoming datagrams destined to IPv4-mapped IPv6 addresses are
associated (and therefore are forwarded) with the IPv4-mapped IPv6
unicast/multicast IS-IS Instance, respectively. WKP and/or LIR
prefix defined in [I-D.ietf-behave-address-format] MUST be configured
in all participating nodes.
4. IANA Considerations
This document requests the following IS-IS Instance IDs:
o Instance ID# for IPv4-mapped IPv6 unicast AF;
o Instance ID# for multicast IPv4-mapped IPv6 AF.
5. Security Considerations
This document does not introduce any security issue in addition to
those defined in [I-D.ietf-isis-mi].
6. Acknowledgements
TBC
7. References
7.1. Normative References
[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
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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.
7.2. Informative References
[I-D.boucadair-behave-ipv6-portrange]
Boucadair, M., Levis, P., Grimault, J., Villefranque, A.,
Kassi-Lahlou, M., Bajko, G., Lee, Y., and T. Melia,
"Flexible IPv6 Migration Scenarios in the Context of IPv4
Address Shortage",
draft-boucadair-behave-ipv6-portrange-03 (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]
Huitema, C., Bao, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators",
draft-ietf-behave-address-format-00 (work in progress),
August 2009.
[I-D.ietf-behave-v6v4-xlate]
Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", draft-ietf-behave-v6v4-xlate-01 (work in
progress), September 2009.
[I-D.ietf-behave-v6v4-xlate-stateful]
Bagnulo, M., Matthews, P., and I. Beijnum, "NAT64: Network
Address and Protocol Translation from IPv6 Clients to IPv4
Servers", draft-ietf-behave-v6v4-xlate-stateful-02 (work
in progress), October 2009.
[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.
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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
Yiu L. Lee
Comcast
USA
Email: Yiu_Lee@Cable.Comcast.com
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