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Guidelines for Running OSPF Over Frame Relay Networks (RFC1586)

IP.com Disclosure Number: IPCOM000002420D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 5 page(s) / 14K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

O. deSouza: AUTHOR [+2]

Abstract

This memo specifies guidelines for implementors and users of the Open Shortest Path First (OSPF) routing protocol to bring about improvements in how the protocol runs over frame relay networks. We show how to configure frame relay interfaces in a way that obviates the "full-mesh" connectivity required by current OSPF implementations. This allows for simpler, more economic network designs. These guidelines do not require any protocol changes; they only provide recommendations for how OSPF should be implemented and configured to use frame relay networks efficiently.

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Network Working Group O. deSouza

Request for Comments: 1586 M. Rodrigues

Category: Informational AT&T Bell Laboratories

March 1994

Guidelines for Running OSPF

Over Frame Relay Networks

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

Abstract

This memo specifies guidelines for implementors and users of the Open

Shortest Path First (OSPF) routing protocol to bring about

improvements in how the protocol runs over frame relay networks. We

show how to configure frame relay interfaces in a way that obviates

the "full-mesh" connectivity required by current OSPF

implementations. This allows for simpler, more economic network

designs. These guidelines do not require any protocol changes; they

only provide recommendations for how OSPF should be implemented and

configured to use frame relay networks efficiently.

Acknowledgements

This memo is the result of work done in the OSPF Working Group of the

IETF. Comments and contributions from several sources, especially

Fred Baker of ACC, John Moy of Proteon, and Bala Rajagopalan of AT&T

Bell Laboratories are included in this work.

1. Introduction

A frame relay (FR) network provides virtual circuits (VCs) to

interconnect attached devices. Each VC is uniquely identified at each

FR interface by a Data Link Connection Identifier (DLCI). RFC 1294

specifies the encapsulation of multiprotocol traffic over FR [1].

The devices on a FR network may either be fully interconnected with a

"mesh" of VCs, or partially interconnected. OSPF characterizes FR

networks as non-broadcast multiple access (NBMA) because they can

support more than two attached routers, but do not have a broadcast

capability [2]. Under the NBMA model, the physical FR interface on a

router corresponds to a single OSPF interface through which the

router is connected to one or more neighbors on the FR network; all

the neighboring routers must also be directly connected to each other

over the FR network. Hence OSPF implementations that use the NBMA

model for FR do not work when the routers are partially

interconnected. Further, the topological representation of a

multiple access network has each attached router bi-directionally

connected to the network vertex with a single link metric assigned to

the edge directed into the ver...