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Border Gateway Protocol (BGP) (RFC1105)

IP.com Disclosure Number: IPCOM000001914D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 14 page(s) / 34K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

K. Lougheed: AUTHOR [+2]

Abstract

The Border Gateway Protocol (BGP) is an inter-autonomous system routing protocol. It is built on experience gained with EGP as defined in RFC 904 [1] and EGP usage in the NSFNET Backbone as described in RFC 1092 [2] and RFC 1093 [3].

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 9% of the total text.

Network Working Group K. Lougheed

Request for Comments: 1105 cisco Systems

Y. Rekhter

T.J. Watson Research Center, IBM Corp.

June 1989

A Border Gateway Protocol (BGP)

Status of this Memo

This RFC outlines a specific approach for the exchange of network

reachability information between Autonomous Systems.

At the time of this writing, the Border Gateway Protocol

implementations exist for cisco routers as well as for the NSFNET

Nodal Switching Systems. A public domain version for "gated" is

currently being implemented.

Distribution of this memo is unlimited.

1. Introduction

The Border Gateway Protocol (BGP) is an inter-autonomous system

routing protocol. It is built on experience gained with EGP as

defined in RFC 904 [1] and EGP usage in the NSFNET Backbone as

described in RFC 1092 [2] and RFC 1093 [3].

The primary function of a BGP speaking system is to exchange network

reachability information with other BGP systems. This network

reachability information includes information on the autonomous

systems (AS's) that traffic must transit to reach these networks.

This information is sufficient to construct a graph of AS

connectivity from which routing loops may be pruned and policy

decisions at an AS level may be enforced.

BGP runs over a reliable transport level protocol. This eliminates

the need to implement explicit update fragmentation, retransmission,

acknowledgement, and sequencing. Any authentication scheme used by

the transport protocol may be used in addition to BGP's own

authentication mechanisms.

The initial BGP implementation is based on TCP [4], however any

reliable transport may be used. A message passing protocol such as

VMTP [5] might be more natural for BGP. TCP will be used, however,

since it is present in virtually all commercial routers and hosts.

In the following descriptions the phrase "transport protocol

connection" can be understood to refer to a TCP connection. BGP uses

TCP port 179 for establishing its connections.

2. Summary of Operation

Two hosts form a transport protocol connection between one another.

They exchange messages to open and confirm the connection parameters.

The initial data flow is the entire BGP routing table. Incremental

updates are sent as the routing tables change. Keepalive messages

are sent periodically to ensure the liveness of the connection.

Notification messages are sent in response to errors or special

conditions. If a connection encounters an error condition, a

notification message is sent and the connection is optionally closed.

The hosts executing the Border Gateway Protocol need not be routers.

A non-routing host could exchange routing information with routers

via EGP...