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OSPF Version 2 (RFC1583)

IP.com Disclosure Number: IPCOM000002417D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2001-Nov-09

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Moy: AUTHOR

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.

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Network Working Group                                             J. Moy

Request for Comments: 1583                                 Proteon, Inc.

Obsoletes: 1247                                               March 1994

Category: Standards Track

                             OSPF Version 2

Status of this Memo

    This document specifies an Internet standards track protocol for the

    Internet community, and requests discussion and suggestions for

    improvements.  Please refer to the current edition of the "Internet

    Official Protocol Standards" (STD 1) for the standardization state

    and status of this protocol.  Distribution of this memo is

    unlimited.

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.  Separate routes can be calculated

    for each IP Type of Service.  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.

    OSPF Version 2 was originally documented in RFC 1247. The

    differences between RFC 1247 and this memo are explained in Appendix

    E. The differences consist of bug fixes and clarifications, and are

    backward-compatible in nature. Implementations of RFC 1247 and of

    this memo will interoperate.

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

Moy                                                             [Page 1]

RFC 1583                     OSPF Version 2                   March 1994

Table of Contents

    1       Introduction ........................................... 5

    1.1     Protocol Overview ...................................... 5

    1.2     Definitions of commonly used terms ..................... 6

    1.3     Brief history of link-state routing technology ......... 9

    1.4     Organization of this document .......................... 9

    2       The Topological Database .............................. 10

    2.1     The shortest-path tree ................................ 13

    2.2     Use of external routing information ................... 16

    2.3     Equal-cost multipath .................................. 20

    2.4     TOS-based routing ..................................... 20

    3       Splitting the AS into Areas ........................... 21

    3.1     The backbone of the Autonomous System ................. 22

    3.2     Inter-area routing .................................... 22

    3.3     Classification of routers ............................. 23

    3.4     A sample area configuration ........................... 24

    3.5     IP subnetting support ................................. 30

    3.6     Supporting stub areas ................................. 31

    3.7     Partitions of areas ................................... 32

    4       Functional Summary .................................... 34

    4.1     Inter-area routing .................................... 35

    4.2     AS external routes .................................... 35

    4....