Network	Working	Group						  J. Moy
Request	for Comments: 2328		     Ascend Communications, Inc.
STD: 54							      April 1998
Obsoletes: 2178
Category: Standards Track


			     OSPF Version 2


Status of this Memo(RFC1661に同じ)

Copyright Notice

    Copyright (C) The Internet Society (1998).	All Rights Reserved.

Abstract

    This memo documents	version	2 of the OSPF protocol.	 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 recalculates routes quickly in	the face of topological	changes,
    utilizing a	minimum	of routing protocol traffic.  OSPF provides
    support for	equal-cost multipath.  An area routing capability is
    provided, enabling an additional level of routing protection and a
    reduction in routing protocol traffic.  In addition, all OSPF
    routing protocol exchanges are authenticated.

    The	differences between this memo and RFC 2178 are explained in
    Appendix G.	All differences	are backward-compatible	in nature.

    Implementations of this memo and of	RFCs 2178, 1583, and 1247 will
    interoperate.

    Please send	comments to ospf@gated.cornell.edu.


1.  Introduction

    This document is a specification of	the Open Shortest Path First
    (OSPF) TCP/IP internet routing protocol.  OSPF is classified as an
    Interior Gateway Protocol (IGP).  This means that it distributes
    routing information	between	routers	belonging to a single Autonomous
    System.  The OSPF protocol is based	on link-state or SPF technology.
    This is a departure	from the Bellman-Ford base used	by traditional
    TCP/IP internet routing protocols.

    The	OSPF protocol was developed by the OSPF	working	group of the
    Internet Engineering Task Force.  It has been designed expressly for
    the	TCP/IP internet	environment, including explicit	support	for CIDR
    and	the tagging of externally-derived routing information.	OSPF
    also provides for the authentication of routing updates, and
    utilizes IP	multicast when sending/receiving the updates.  In
    addition, much work	has been done to produce a protocol that
    responds quickly to	topology changes, yet involves small amounts of
    routing protocol traffic.

    1.1.  Protocol overview(以下，略)