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Toward an Internet standard scheme for subnetting (RFC0940)

IP.com Disclosure Number: IPCOM000004356D
Original Publication Date: 1985-Apr-01
Included in the Prior Art Database: 2000-Oct-12
Document File: 3 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

Gateway Algorithms and Data Structures Task Force: AUTHOR

Abstract

Several sites now contain a complex of local links connected to the Internet via a gateway. The details of the internal connectivity are of little interest to the rest of the Internet.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 41% of the total text.

Network Working Group GADS

Request for Comments: 940

April 1985

Toward an Internet Standard Scheme for Subnetting

STATUS OF THIS MEMO

This RFC discusses standardizing the protocol used in subnetted

environments in the ARPA-Internet. Distribution of this memo is

unlimited.

The author of this RFC is the Gateway Algorithms and Data Structures

(GADS) Task Force, chaired by David L. Mills.

INTRODUCTION

Several sites now contain a complex of local links connected to the

Internet via a gateway. The details of the internal connectivity are

of little interest to the rest of the Internet.

One way of organizing these local complexes of links is to use the

same strategy as the Internet uses to organize networks, that is, to

declare each link to be an entity (like a network) and to

interconnect the links with devices that perform routing functions

(like gateways). This general scheme is called subnetting, the

individual links are called subnets, and the connecting devices are

called subgateways (or bridges, or gateways).

All hosts in the Internet must make a decision when sending a

datagram, that is, they must answer the question "Is this datagram

addressed to a host on a directly connected network, or must it be

sent to a gateway?". In a subnetted environment, this question is

extended to "Is this datagram addressed to a host on a directly

connected subnet, or must it be sent to a (sub)gateway?". Let us

call answering this question "making the routing decision".

Because the hosts used in a subnetted environment must implement in

their IP or network interface software procedures for making the

routing decision, and because such hosts may be acquired from various

sources, it is important that a standard subnetting scheme be

identified so that different suppliers can provide compatible hosts

(that is, hosts compatible with the complexes at different sites and

each other). Without a designated standard for a subnetting scheme

suppliers can not create compatible hosts.

The potential problem is that if different subnetting schemes are

developed by different suppliers a customer that installs hosts from

two or more suppliers may find that they do not work together.

RFC 940 April 1985

Toward an Internet Standard Scheme for Subnetting

This topic has been discussed in a set of RFCs [1,2,3,4] and in a

flurry of messages in the Gateway Algorithms and Data Structures Task

Force. It is strongly s...