Internet Draft I. Chen
<draft-chen-ospf-transition-to-ospfv3-00.txt> A. Lindem
Category: Informational Ericsson
Expires in 6 months January 26, 2014
OSPFv3 over IPv4 for IPv6 Transition
<draft-chen-ospf-transition-to-ospfv3-00.txt>
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Abstract
This draft defines a mechanism to use IPv4 to transport OSPFv3
I. Chen & A. Lindem Expires in 6 months [Page 1]Internet Draft transition-to-ospfv3 January 26, 2014
packets, in order to facilitate transition from IPv4-only to IPv6 and
dual-stack within a routing domain. Using OSPFv3 over IPv4 with the
existing OSPFv3 Address Family extension simplifies transition from
an OSFPv2 IPv4-only routing domain to an OSPFv3 dual-stack routing
domain, and later possibly to an IPv6-only routing domain.
I. Chen & A. Lindem Expires in 6 months [Page 2]Internet Draft transition-to-ospfv3 January 26, 2014Table of Contents
1. Introduction ....................................................3
2. Encapsulation in IPv4 ...........................................4
2.1. Source Address .............................................6
2.2. Destination ................................................6
2.3. Operation over Virtual Link ................................6
3. Security Considerations .........................................7
4. IANA Considerations .............................................7
5. References ......................................................7
1. Introduction
To facilitate transition from IPv4 [RFC791] to IPv6 [RFC2460], dual-
stack or IPv6 routing protocols should be gradually deployed. Dual-
stack routing protocols, such as Border Gateway Protocol [RFC4271],
have an advantage during the transition, because both IPv4 and IPv6
topologies can be transported using either IPv4 or IPv6. Some
IPv4-specific and IPv6-specific routing protocols share enough
similarities in their protocol packet formats and protocol signaling
that it is trivial to build an initial IPv6 routing domain over IPv4,
allowing IPv6 routing domains be deployed and tested before de-
commissioning IPv4 and moving to an IPv6-only network.
In the case of Open Shortest Path First (OSPF) interior gateway
routing protocol (IGP), OSPFv2 [RFC2328] is the IGP deployed over
IPv4, while OSPFv3 [RFC5340] is the IGP deployed over IPv6. OSPFv3
further supports multiple address families [RFC5838], including both
the IPv6 unicast address family and the IPv4 unicast address family.
Consequently, it is possible to deploy OSPFv3 over IPv4 without any
changes to to either OSPFv3 or IPv4.
This draft specifies how to use IPv4 packets to transport OSPFv3
packets. The mechanism takes advantage of the fact that OSPFv2 and
OSPFv3 share the same IP protocol number, 89. Additionally, OSPFv2
and OSPFv3 also share the same OSPF packet header format, while the
OSPF packet header has its own OSPF version number that distinguishes
an OSPFv2 packet from an OSPFv3 packet.
In normal operation, it is expected that the IPv4 topology within the