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
Multi-Topology IS-IS for IPv4-mapped IPv6
draft-boucadair-isis-v4v6-mt-01
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Copyright Notice
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Abstract
This memo defines two new Multi Topology Routing Identifiers (MT IDs)
to be used by the Intermediate System to Intermediate System (M-ISIS,
[RFC5120]) routing protocol within a Multi-Topology (MT) context.
These new M-ISIS topologies are meant to convey routing information
which is specific to IPv4-mapped IPv6 addresses
[I-D.ietf-behave-address-format]. The 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
enforce 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. Multi-Topology Reachable IPv4 Mapped IPv6 Prefixes TLV . . . . 4
3. Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
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:
o Unicast IPv4-mapped IPv6 IS-IS routing topology;
o Multicast IPv4-mapped IPv6 IS-IS routing topology.
Within the 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] destinations 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 M-ISIS IDs which
are required for the activation of multiple M-ISIS topologies,
including one topology that is dedicated to IPv4-mapped routing (both
unicast and multicast). This is motivated also for operational
reasons and to ease the migration to full IPv6. As a result, an
unicast IPv4-mapped IPv6 topology may be established and used for
unicast IPv4-mapped IPv6 route computation purposes, and a multicast
IPv4-mapped IPv6 topology may be established and used for multicast
IPv4-mapped IPv6 route computation purposes.
2. Multi-Topology Reachable IPv4 Mapped IPv6 Prefixes TLV
No new TLV is required to indicate that the LSP packet conveys IPv4-
mapped IPv6 (unicast and multicast, respectively) routes. TLV type
237 [RFC5120] must be used to announce IPv4 mapped IPv6 prefixes.
3. Procedure
This document does not require any modification to the procedure
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specified in [RFC5120]. Nevertheless, only routes to IPv4-mapped
IPv6 prefixes MUST be instantiated within an IPv4-mapped IPv6 routing
MT. 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.
4. Forwarding
Only incoming datagrams destined to IPv4-mapped IPv6 addresses are
forwarded according to the IPv4-inferred IPv6 routing topology. WKP
and/or LIR prefix defined in [I-D.ietf-behave-address-format] MUST be
configured in all participating nodes.
5. IANA Considerations
This document requests the following IS-IS MT IDs:
o MT ID# for unicast IPv4-mapped IPv6 topology
o MT ID# for multicast IPv4-mapped IPv6 topology.
6. Security Considerations
This document does not introduce any security issue in addition to
those defined in [RFC5120].
7. Acknowledgements
TBC
8. References
8.1. 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
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
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Intermediate Systems (IS-ISs)", RFC 5120, February 2008.
8.2. 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.
Authors' Addresses
Mohamed Boucadair
France Telecom
3, Av Francois Chateau
Rennes, 35000
France
Email: mohamed.boucadair@orange-ftgroup.com
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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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