RFC 1074 (rfc1074) - Page 1 of 5


NSFNET backbone SPF based Interior Gateway Protocol



Alternative Format: Original Text Document



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



Rekhter