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RIPv1 Applicability Statement for Historic Status (RFC1923)

IP.com Disclosure Number: IPCOM000004236D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 3 page(s) / 5K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Halpern & S. Bradner: AUTHOR

Abstract

RIP Version 1 [RFC-1058] has been declared an historic document. This Applicability statement provides the supporting motivation for that declaration. The primary reason, as described below, is the Classful nature of RIPv1.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 52% of the total text.

Network Working Group J. Halpern

Request for Comments: 1923 Newbridge Networks

Category: Informational S. Bradner

Harvard University

March 1996

RIPv1 Applicability Statement for Historic Status

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

Abstract

RIP Version 1 [RFC-1058] has been declared an historic document.

This Applicability statement provides the supporting motivation for

that declaration. The primary reason, as described below, is the

Classful nature of RIPv1.

1.0 Introduction

RIP version 1 (RIPv1) (as defined by RFC 1058) was one of the first

dynamic routing protocols used in the internet. It was developed as

a technique for passing around network reachability information for

what we now consider relatively simple topologies.

The Internet has changed significantly since RIPv1 was defined,

particularly with the introduction and use of subnets and CIDR.

While RIPv1 is widely used in private networks, it can no longer be

considered applicable for use in the global Internet.

2.0 RIPv1 restrictions

RIPv1 has a number of restrictions and behaviors which restrict its

useability in the global Internet.

2.1 Classfulness

Chief among these is that it is a classful routing protocol. RIP

packets do not carry prefix masks. The prefix length is inferred

from the address. For non-local addresses, the prefix is always the

"natural" (classful) length. (e.g., 24 bits for a "Class C" network

address.) For networks to which a local interface exists, if the

interface is subnetted with some specific mask, then RIPv1 assumes

that the mask used locally is the correct mask to apply for all

subnets of that network.

This has a number of effects.

1) RIPv1 can not be used with variable length subnetting. In the

presence of variable length subnetting it will consistently

misinterpret prefix lengths.

2) RIPv1 is difficult to use with supernetting. All CIDR supernets

must be exploded and advertised to RIPv1 as individual "natural"

classful advertisements.

3) Even when the networks running RIPv1 are themselves only subnetted

in fixed ways, if the remainder of the network has variable

subnetting then one must carefully make sure that RIPv1 does not

destroy the mask i...