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Multiprotocol Extensions for BGP-4 (RFC2283)

IP.com Disclosure Number: IPCOM000002845D
Original Publication Date: 1998-Feb-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 7 page(s) / 18K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

T. Bates: AUTHOR [+4]

Abstract

Currently BGP-4 [BGP-4] is capable of carrying routing information only for IPv4 [IPv4]. This document defines extensions to BGP-4 to enable it to carry routing information for multiple Network Layer protocols (e.g., IPv6, IPX, etc...). The extensions are backward compatible - a router that supports the extensions can interoperate with a router that doesn't support the extensions.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 17% of the total text.

Network Working Group T. Bates

Request for Comments: 2283 Cisco Systems

Category: Standards Track R. Chandra

Cisco Systems

D. Katz

Juniper Networks

Y. Rekhter

Cisco Systems

February 1998

Multiprotocol Extensions for BGP-4

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1998). All Rights Reserved.

2. Abstract

Currently BGP-4 [BGP-4] is capable of carrying routing information

only for IPv4 [IPv4]. This document defines extensions to BGP-4 to

enable it to carry routing information for multiple Network Layer

protocols (e.g., IPv6, IPX, etc...). The extensions are backward

compatible - a router that supports the extensions can interoperate

with a router that doesn't support the extensions.

3. Overview

The only three pieces of information carried by BGP-4 that are IPv4

specific are (a) the NEXT_HOP attribute (expressed as an IPv4

address), (b) AGGREGATOR (contains an IPv4 address), and (c) NLRI

(expressed as IPv4 address prefixes). This document assumes that any

BGP speaker (including the one that supports multiprotocol

capabilities defined in this document) has to have an IPv4 address

(which will be used, among other things, in the AGGREGATOR

attribute). Therefore, to enable BGP-4 to support routing for

multiple Network Layer protocols the only two things that have to be

added to BGP-4 are (a) the ability to associate a particular Network

Layer protocol with the next hop information, and (b) the ability to

associated a particular Network Layer protocol with NLRI. To identify

individual Network Layer protocols this document uses Address Family,

as defined in [RFC1700].

One could further observe that the next hop information (the

information provided by the NEXT_HOP attribute) is meaningful (and

necessary) only in conjunction with the advertisements of reachable

destinations - in conjunction with the advertisements of unreachable

destinations (withdrawing routes from service) the next hop

information is meaningless. This suggests that the advertisement of

reachable destinations should be grouped with the advertisement of

the next hop to be used for these destinat...