Network Working Group M. Boucadair
Internet-Draft C. Jacquenet
Intended status: Standards Track France Telecom
Expires: August 16, 2010 D. Cheng
Huawei
Y. Lee
Comcast
February 12, 2010
Multi-Topology/Multi-Instance OSPFv3 for IPv4-Embedded IPv6
draft-boucadair-ospf-v4v6-ospfv3-mt-02
Abstract
This memo defines two new Multi Topology Routing Identifiers (MT
IDs), based on [I-D.ietf-ospf-mt-ospfv3] and two new Instance
Identifiers (MI IDs), based on [I-D.ietf-ospf-af-alt], respectively,
in OSPFv3. 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. IPv4-Embedded IPv6 OSPFv3 Topologies . . . . . . . . . . . . . 4
3. IPv4-Embedded IPv6 OSPFv3 Instances . . . . . . . . . . . . . . 5
4. Provisioning . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Advertising IPv4-Embedded IPv6 Routes . . . . . . . . . . . . . 5
7. Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
9. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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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 [I-D.ietf-ospf-mt-ospfv3] and [I-D.ietf-ospf-af-alt].
Network administrators have to make their decisions based on local
policies. If the multi-instance mechanism is deployed in an OSPFv3
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 MT-OSPFv3 mechanism is deployed in an
OSPFv3 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 OSPFv3 Topologies
MT-OSPFv3 [I-D.ietf-ospf-mt-ospfv3] is a mechanism that has been
specified to run various topologies based on several criteria such as
the need to distinguish the IPv6 unicast topology from the IPv4
routing topology. Distinct MT IDs (Multi-Topology Identifiers) are
assigned by IANA (e.g., MT ID# 0 for IPv6 routing topology, MT ID# 3
for IPv6 multicast topology, etc.). MT ID #5-#31 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 OSPFv3 Instances
[I-D.ietf-ospf-af-alt] specifies a mechanism to map each address
family (AF) to a separate OSPFv3 [RFC5340] Instance identified by an
ID. Many Instance IDs have been reserved for different AF (e.g.,
Instance ID#0 - #31 for IPv6 unicast AF, Instance ID#32 - #63 for
IPv6 multicast AF, etc.). Instance ID#0 is used by default for IPv6
unicast AF. This document requests the assignment of two new
Instance IDs for the IPv4-Embedded IPv6 AF:
o IPv4-Embedded IPv6 unicast AF;
o IPv4-Embedded IPv6 multicast AF.
4. Provisioning
Adequate provisioning must be done according to
[I-D.ietf-ospf-mt-ospfv3] and [I-D.ietf-ospf-af-alt], respectively,
based on the corresponding mechanism that is actually used in an
OSPFv3 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 [I-D.ietf-ospf-mt-ospfv3] nor in [I-D.ietf-ospf-af-alt].
Nevertheless, routes to IPv4-Embedded IPv6 addresses or prefixes MUST
be instantiated within an IPv4-Embedded IPv6 MT-OSPFv3 (resp., MI-
OSPFv3). 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-
Embedded IPv6 addresses.
6. Advertising IPv4-Embedded IPv6 Routes
With one of the mechanisms (i.e., a separate OSPFv3 instance or a
separate OSPFv3 topology) as described above, reachability of IPv4-
Embedded IPv6 destinations can be advertised in an IPv6 network using
OSPFv3.
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In general, IPv4-Embedded IPv6 addresses and prefixes are advertised
into an OSPFv3 network using AS External LSA [RFC5340], i.e.- with
the advertising scope throughout the entire Autonomous System. This
is because an advertising node in this case is most likely connected
to one or more IPv4 networks, and as such, it functions as an
Autonomous System Boundary Router (ASBR) in the perspective of OSPFv3
routing domain. Any OSPFv3 area that does not want to receive such
advertisement can be configured as a stub area or with other routing
policy.
By default, the metric in an AS External LSA that carries one or more
IPv4-Embedded IPv6 addresses and prefixes is a Type 1 external
metric, which is then to be added to the metric of an intra-AS path
during OSPFv3 routes calculation. By configuration on an ASBR, the
metric can be set to a Type 2 external metric, which is considered
much larger than any intra-AS path. The detail is referred to OSPFv3
specification [RFC5340]. In either case, an external metric may be
exact the same unit as in an IPv4 network (running OSPFv2 or others),
but may also be specified by a routing policy, the detail is outside
of the scope of this document.
Advertising IPv4-Embedded IPv6 addresses and prefixes using OSPFv3
inter-area prefix LSA is for future study.
7. 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.
8. IANA Considerations
This document requests the following MT-OSPFv3 IDs:
o MT ID# for IPv4-Embedded IPv6 unicast topology
o MT ID# for IPv4-Embedded IPv6 multicast topology.
and the following OSPFv3 Instance IDs:
o Instance ID# for IPv4-Embedded IPv6 unicast AF;
o Instance ID# for IPv4-Embedded IPv6 multicast AF.
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9. Security Considerations
This document does not introduce any security issue in addition to
those defined in [RFC5340].
10. Acknowledgements
TBC
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008.
11.2. 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]
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.
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[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.
[I-D.ietf-ospf-af-alt]
Lindem, A., Mirtorabi, S., Roy, A., Barnes, M., and R.
Aggarwal, "Support of address families in OSPFv3",
draft-ietf-ospf-af-alt-10 (work in progress),
December 2009.
[I-D.ietf-ospf-mt-ospfv3]
Mirtorabi, S. and A. Roy, "Multi-topology routing in
OSPFv3 (MT-OSPFv3)", draft-ietf-ospf-mt-ospfv3-03 (work in
progress), July 2007.
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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