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Exchanging Routing Information Across Provider Boundaries in the CIDR Environment (RFC1520)

IP.com Disclosure Number: IPCOM000002351D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 7 page(s) / 19K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

Y. Rekhter: AUTHOR [+2]

Abstract

Classless Inter-Domain Routing (CIDR) has been adopted as a solution to the scaling problem in the Internet. The overall CIDR architecture is described in [1]. The architecture for IP address assignment with CIDR is covered in [2] and [3]. The inter-domain routing protocols that are capable of supporting CIDR are covered in [4], [5], and [6].

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 16% of the total text.

Network Working Group Y. Rekhter

Request for Comments: 1520 T.J. Watson Research Center, IBM Corp.

Category: Informational C. Topolcic

CNRI

September 1993

Exchanging Routing Information Across Provider Boundaries

in the CIDR Environment

Status of this Memo

This memo provides information for the Internet community. It does

not specify an Internet standard. Distribution of this memo is

unlimited.

1. Introduction

Classless Inter-Domain Routing (CIDR) has been adopted as a solution

to the scaling problem in the Internet. The overall CIDR architecture

is described in [1]. The architecture for IP address assignment with

CIDR is covered in [2] and [3]. The inter-domain routing protocols

that are capable of supporting CIDR are covered in [4], [5], and [6].

The purpose of this document is twofold. First, it describes various

alternatives for exchanging inter-domain routing information across

domain boundaries, where one of the peering domain is CIDR-capable

and another is not. Second, it addresses the implications of running

CIDR-capable inter-domain routing protocols (e.g., BGP-4, IDRP) on

intra-domain routing.

This document is not intended to cover all the cases (either real or

imaginable). Rather, it focuses on what are viewed to be the most

common cases. We expect that individual service providers will use

this document as guidelines in establishing their specific

operational plans for the transition to CIDR.

The concepts of "network service provider" and "network service

subscriber" were introduced in [3]. For the sake of brevity, we will

use the term "provider" or "service provider" here to mean either

"network service provider" or "network service subscriber", since for

the most part, the distinction is not important to this discussion.

Furthermore, we use the same terms to refer to the network and to the

organization that operates the network. We feel that the context

makes it amply clear whether we are talking about hardware or people,

and defining different terms would only make this paper harder to

read.

This document defines a CIDR-capable provider as the provider that

can perform correct IP packet forwarding (both internally and to

other adjacent providers) when the inter-domain routing information

acquired by the provider is expressed solely in terms of IP address

prefixes (with no distinction between A/B/C class of addresses).

This document defines CIDR-capable forwarding as the ability of a

router to maintain its forwarding table and to perform correct

forwarding of IP packets without making any assumptions about the

class of IP addresses.

This document defines CIDR reachability information as reachability

information that may...