Support of Address Families in OSPFv3
RFC 5838
Internet Engineering Task Force (IETF) A. Lindem, Ed.
Request for Comments: 5838 Ericsson
Category: Standards Track S. Mirtorabi
ISSN: 2070-1721 A. Roy
M. Barnes
Cisco Systems
R. Aggarwal
Juniper Networks
April 2010
Support of Address Families in OSPFv3
Abstract
This document describes a mechanism for supporting multiple address
families (AFs) in OSPFv3 using multiple instances. It maps an AF to
an OSPFv3 instance using the Instance ID field in the OSPFv3 packet
header. This approach is fairly simple and minimizes extensions to
OSPFv3 for supporting multiple AFs.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5838.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Lindem, et al. Standards Track [Page 1]
RFC 5838 OSPFv3 AF April 2010
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Design Considerations . . . . . . . . . . . . . . . . . . 2
1.2. Requirements Notation . . . . . . . . . . . . . . . . . . 3
2. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Instance ID Values for New AFs . . . . . . . . . . . . . . 3
2.2. OSPFv3 Options Changes . . . . . . . . . . . . . . . . . . 4
2.3. Advertising Prefixes in AFs Other Than IPv6 . . . . . . . 4
2.4. Changes to the Hello Packet Processing . . . . . . . . . . 4
2.5. Next-Hop Calculation for IPv4 Unicast and Multicast AFs . 5
2.6. AS-External-LSA and NSSA-LSA Forwarding Address for
IPv4 Unicast and IPv4 Multicast AFs . . . . . . . . . . . 5
2.7. Database Description Maximum Transmission Unit (MTU)
Specification for Non-IPv6 AFs . . . . . . . . . . . . . . 6
2.8. Operation over Virtual Links . . . . . . . . . . . . . . . 8
3. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.1. Normative References . . . . . . . . . . . . . . . . . . . 11
6.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 12
1. Introduction
OSPFv3 [OSPFV3] has been defined to support the base IPv6 unicast
address family (AF). There are requirements to advertise other AFs
in OSPFv3, including multicast IPv6, unicast IPv4, and multicast
IPv4. This document supports these other AFs in OSPFv3 by mapping
each AF to a separate Instance ID and OSPFv3 instance.
1.1. Design Considerations
This section describes the rationale for using the multiple Instance
ID approach to support multiple address families in OSPFv3. As
described earlier, OSPFv3 is designed to support multiple instances.
Hence, mapping an instance to an address family doesn't introduce any
new mechanisms to the protocol. It minimizes the protocol extensions
required, and it simplifies the implementation. The presence of a
separate link state database per address family is also easier to
debug and operate. Additionally, it doesn't change the existing
instance, area, and interface-based configuration model in most
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