Exterior Gateway Protocol (EGP)
RFC 827
Document | Type |
RFC - Unknown
(October 1982; No errata)
Updated by RFC 904
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Authors | |||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 827 (Unknown) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
RFC 827 EXTERIOR GATEWAY PROTOCOL (EGP) Eric C. Rosen Bolt Beranek and Newman Inc. October 1982 It is proposed to establish a standard for Gateway to Gateway procedures that allow the Gateways to be mutually suspicious. This document is a DRAFT for that standard. Your comments are strongly encouraged. RFC 827 Bolt Beranek and Newman Inc. Eric C. Rosen Table of Contents 1 INTRODUCTION.......................................... 1 2 NEIGHBOR ACQUISITION.................................. 8 3 NEIGHBOR REACHABILITY PROTOCOL....................... 11 4 NETWORK REACHABILITY (NR) MESSAGE.................... 15 5 POLLING FOR NR MESSAGES.............................. 22 6 SENDING NR MESSAGES.................................. 25 7 INDIRECT NEIGHBORS................................... 27 8 HOW TO BE A STUB GATEWAY............................. 28 9 LIMITATIONS.......................................... 32 - i - RFC 827 Bolt Beranek and Newman Inc. Eric C. Rosen 1 INTRODUCTION The DARPA Catenet is expected to be a continuously expanding system, with more and more hosts on more and more networks participating in it. Of course, this will require more and more gateways. In the past, such expansion has taken place in a relatively unstructured manner. New gateways, often containing radically different software than the existing gateways, would be added and would immediately begin participating in the common routing algorithm via the GGP protocol. However, as the internet grows larger and larger, this simple method of expansion becomes less and less feasible. There are a number of reasons for this: - the overhead of the routing algorithm becomes excessively large; - the proliferation of radically different gateways participating in a single common routing algorithm makes maintenance and fault isolation nearly impossible, since it becomes impossible to regard the internet as an integrated communications system; - the gateway software and algorithms, especially the routing algorithm, become too rigid and inflexible, since any proposed change must be made in too many different places and by too many different people. - 1 - RFC 827 Bolt Beranek and Newman Inc. Eric C. Rosen In the future, the internet is expected to evolve into a set of separate domains or "autonomous systems", each of which consists of a set of one or more relatively homogeneous gateways. The protocols, and in particular the routing algorithm which these gateways use among themselves, will be a private matter, and need never be implemented in gateways outside the particular domain or system. In the simplest case, an autonomous system might consist of just a single gateway connecting, for example, a local network to the ARPANET. Such a gateway might be called a "stub gateway", since its only purpose is to interface the local network to the rest of the internet, and it is not intended to be used for handling any traffic which neither originated in nor is destined for that particular local network. In the near-term future, we will begin to think of the internet as a set of autonomous systems, one of which consists of the DARPA gateways on ARPANET and SATNET, and the others of which are stub gateways to local networks. The former system, which we shall call the "core" system, will be used as a transport or "long-haul" system by the latter systems. Ultimately, however, the internet may consist of a number of co-equal autonomous systems, any of which may be used (with certain restrictions which will be discussed later) as a - 2 - RFC 827 Bolt Beranek and Newman Inc. Eric C. Rosen transport medium for traffic originating in any system and destined for any system. When this more complex configurationShow full document text