Browse Prior Art Database

Extensible field addressing (RFC0730)

IP.com Disclosure Number: IPCOM000003777D
Original Publication Date: 1977-May-20
Included in the Prior Art Database: 2000-Sep-13
Document File: 4 page(s) / 9K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Postel: AUTHOR

Abstract

This memo discusses the need for and advantages of the expression of addresses in a network environment as a set of fields. The suggestion is that as the network grows the address can be extended by three techniques: adding fields on the left, adding fields on the right, and increasing the size of individual fields. Carl Sunshine has described this type of addressing in a paper on source routing [1].

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 31% of the total text.

RFC 730 20 May 77

Extensible Field Addressing

Network Working Group Jon Postel

Request for Comments: 730 USC-ISI

NIC: 40400 20 May 1977

Extensible Field Addressing

Introduction

This memo discusses the need for and advantages of the expression of

addresses in a network environment as a set of fields. The suggestion

is that as the network grows the address can be extended by three

techniques: adding fields on the left, adding fields on the right, and

increasing the size of individual fields. Carl Sunshine has described

this type of addressing in a paper on source routing [1].

Motivation

Change in the Host-IMP Interface

The revised Host-IMP interface provides for a larger address space for

hosts and IMPs [2]. The old inteface allowed for a 2 bit host field and

a 6 bit IMP field. The new interface allows a 8 bit host field and a 16

bit IMP field. In using the old interface it was common practice to

treat the two fields as a single eight bit quantity. When it was

necessary to refer to a host by number a decimal number was often used.

For example host 1 on IMP 1 was called host 65. Doug Wells has pointed

out some of problems associated with attempting to continue such useage

as the new interface comes into use [3]. If a per field notation had

been used no problems would arise.

Some examples of old and new host numbers are:

Host Name Host IMP old # new #

--------------------------------------

SRI-ARC 0 2 2 2

UCLA-CCN 1 1 65 65537

ISIA 1 22 86 65558

ARPA-TIP 2 28 156 131100

BBNA 3 5 197 196613

Multinetwork Systems

The prospect of interconnections of networks to form a complex

multinetwork system poses additional addressing problems. The new

Host-IMP interface specification has reserved fields in the leader to

Extensible Field Addressing

carry network addresses [2]. There is experimental work in progress on

interconnecting networks [4, 5, 6]. We should be prepared for these

extensions to the address space.

The addressing scheme should be expandable to increase in scope when

interconnections are made between complex systems.

Multiprocessor Hosts

There may be configurations of hardware that could be interfaced to a

network as a single host that in fact contain multiple processors.

Tasks could be associated with processors such that it is desirable to

dispatch network messages associated with certain sockets or messag...