OSPF Standardization Report
RFC 2329
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RFC - Informational
(April 1998; No errata)
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2013-03-02
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RFC 2329 (Informational)
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Network Working Group J. Moy
Request for Comments: 2329 Ascend Communications, Inc.
Category: Informational April 1998
OSPF Standardization Report
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
Abstract
This memo documents how the requirements for advancing a routing
protocol to Full Standard, set out in [Ref2], have been met for
OSPFv2.
Please send comments to ospf@gated.cornell.edu.
Table of Contents
1 Introduction ........................................... 2
2 Modifications since Draft Standard status .............. 3
2.1 Point-to-MultiPoint interface .......................... 4
2.2 Cryptographic Authentication ........................... 5
3 Updated implementation and deployment experience ....... 5
4 Protocol Security ...................................... 7
References ............................................. 8
Security Considerations ................................ 8
Author's Address ....................................... 8
Full Copyright Statement ............................... 9
Moy Informational [Page 1]
RFC 2329 OSPF Standardization Report April 1998
1. Introduction
OSPFv2, herein abbreviated simply as OSPF, is an IPv4 routing
protocol documented in [Ref8]. OSPF is a link-state routing
protocol. It is designed to be run internal to a single Autonomous
System. Each OSPF router maintains an identical database describing
the Autonomous System's topology. From this database, a routing
table is calculated by constructing a shortest-path tree. OSPF
features include the following:
o OSPF responds quickly to topology changes, expending a minimum
of network bandwidth in the process.
o Support for CIDR addressing.
o OSPF routing exchanges can be authenticated, providing routing
security.
o Equal-cost multipath.
o An area routing capability is provided, enabling an Autonomous
system to be split into a two level hierarchy to further reduce
the amount of routing protocol traffic.
o OSPF allows import of external routing information into the
Autonomous System, including a tagging feature that can be
exploited to exchange extra information at the AS boundary (see
[Ref7]).
An analysis of OSPF together with a more detailed description of
OSPF features was originally provided in [Ref6], as a part of
promoting OSPF to Draft Standard status. The analysis of OSPF
remains unchanged. Two additional major features have been developed
for OSPF since the protocol achieved Draft Standard status: the
Point-to-MultiPoint interface and Cryptographic Authentication.
These features are described in Sections 2.1 and 2.2 respectively of
this memo.
The OSPF MIB is documented in [Ref4]. It is currently at Draft
Standard status.
Moy Informational [Page 2]
RFC 2329 OSPF Standardization Report April 1998
2. Modifications since Draft Standard status
OSPF became a Draft Standard with the release of RFC 1583 [Ref3].
Implementations of the new specification in [Ref8] are backward-
compatible with RFC 1583. The differences between the two documents
are described in the Appendix Gs of [Ref1] and [Ref8]. These
differences are listed briefly below. Two major features were also
added, the Point-to-MultiPoint interface and Cryptographic
Authentication, which are described in separate sections.
o Configuration requirements for OSPF area address ranges have
been relaxed to allow greater flexibility in area assignment.
See Section G.3 of [Ref1] for details.
o The OSPF flooding algorithm was modified to a) improve database
convergence in networks with low speed links b) resolve a
problem where unnecessary LSA retransmissions could occur as a
result of differing clock granularities, c) remove race
conditions between the flooding of MaxAge LSAs and the Database
Exchange process, d) clarify the use of the MinLSArrival
constant, and e) rate-limit the response to less recent LSAs
received via flooding. See Sections G.4 and G.5 of [Ref1] and
Section G.1 of [Ref8] for details.
o To resolve the long-standing confusion regarding representation
of point-to-point links in OSPF, the specification now
optionally allows advertisement of a stub link to a point-to-
point link's subnet, ala RIP. See Section G.6 of [Ref1].
o Several problems involving advertising the same external route
from multiple areas were found and fixed, as described in
Section G.7 of [Ref1] and Section G.2 of [Ref8]. Without the
fixes, persistent routing loops could form in certain such
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