RFC 1247 (rfc1247) - Page 1 of 189
OSPF Version 2
Alternative Format: Original Text Document
Network Working Group J. Moy Request for Comments: 1247 Proteon, Inc. Obsoletes: RFC 1131 July 1991 OSPF Version 2 Status of this Memo This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the ``IAB Official Protocol Standards'' 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 based 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. Version 1 of the OSPF protocol was documented in RFC 1131. The differences between the two versions are explained in Appendix F. Please send comments to ospf@trantor.umd.edu. 1. Introduction This document is a specification of the Open Shortest Path First (OSPF) internet routing protocol. OSPF is classified as an Internal Gateway Protocol (IGP). This means that it distributes routing information between routers belonging to a single Autonomous System. The OSPF protocol is based on SPF or link-state technology. This is a departure [Moy]
