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NSFNET backbone SPF based Interior Gateway Protocol (RFC1074)

IP.com Disclosure Number: IPCOM000001883D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 4 page(s) / 10K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Rekhter: AUTHOR

Abstract

Status of this Memo

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 30% of the total text.

Network Working Group J. Rekhter

Request for Comments 1074 T.J. Watson Research Center

IBM Corporation

October 1988

The NSFNET Backbone SPF based Interior Gateway Protocol

Status of this Memo

This memo is an implementation description of the standard ANSI IS-IS

and ISO ES-IS routing protocols within the NSFNET backbone network.

Distribution of this memo is unlimited.

Acknowledgements

I would like to express my thanks to Hans-Werner Braun (MERIT) for

his contribution to this document.

1. Overview

This document provides an overview of the NSFNET Backbone routing

with specific emphasis on the intra-backbone routing.

By the end of 1987, the American National Standardization Institute

(ANSI) forwarded a specification for an Intermediate System to

Intermediate System routing protocol to the International

Standardization Organizations (ISO) for the adaptation as an

international standard. This ANSI IS-IS protocol is used as the

interior gateway protocol (IGP) of the NSFNET backbone. Documented

here is an implementation description which also includes further

definitions that were necessary for the integration into an Internet

Protocol (IP) environment. Therefore, it should be viewed as a

continuation of the specifications of the ANSI IS-IS protocol [1] and

the ISO standard End System to Intermediate System (ES-IS) protocol

[2]. While the ANSI IS-IS protocol suffices as an IGP, additional

methods are used to orchestrate routing between the backbone and the

attached mid-level networks; most notably the Exterior Gateway

Protocol (EGP). Further information about the overall NSFNET routing

as well as some future aspects can be found in [3], [4], [5] and [6].

2. A brief overview of the NSFNET backbone

The NSFNET backbone is a wide area network which currently connects

thirteen sites within the continental United States. All connections

are permanent point-to-point links at T1 speed (1.544Mbps). These T1

links may contain multiple logical links at sub-T1 and up to the full

T1 speed. The result is a hybrid circuit/packet switching network

able to contain a connectivity-richer logical topology than the

underlying physical topology would allow by itself. Each site has a

Nodal Switching Subsystem (NSS) which is responsible for packet

switching. Each NSS is a RISC technology based multiprocessor system

using IBM RT/PC processors which operate a modified version of a

4.3BSD kernel. For the purpose of routing, each NSS is considered as

a single entity which has connections to both other NSS (via the

logical network infrastructure) and to regional networks (via local

area network attachments; typically an Ethernet).

The routing protocol which is used for the inter-NSS routing within

the NSFNET backbone is an adaptation of the ANSI IS-IS routing

pr...