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Critique of X.25 (RFC0874) Disclosure Number: IPCOM000003923D
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 12 page(s) / 36K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M.A. Padlipsky: AUTHOR

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< INC-PROJECT, MAP-CRITIQUE.NLS.10, >, 12-Aug-83 11:46 AMW ;;;;

RFC 874 September 1982





Bedford, Massachusetts


The widely touted network interface protocol, "X.25", and

its attendant conceptual framework, the International Standards

Organization's Reference Model for Open System Interconnection

(ISORM), are analyzed and found wanting. The paper is a

companion piece to M82-48, and M82-51.



M. A. Padlipsky


According to some sources, the International Standards

Organization's (ISO) "Open System Interconnection" (OSI) effort

has adopted the International Consultative Committee on Telephony

and Telegraphy (CCITT) developed X.25 protocol(s) as its Levels

1-3. ("Loose constructionists" of the ISORM would hold that X.25

is a mechanization of L1-L3 rather than the mechanization, and at

least one British source holds that "we in the U.K. don't believe

that ISO have adopted X.25.") In the U.S. Government arena,

where the author spends much of his time, the Government

Accounting Office (GAO) has suggested that the Department of

Defense (DoD) ought to consider adopting "X.25 networks,"

apparently in preference to networks based on protocols developed

by the DoD-sponsored intercomputer networking research community.

That intercomputer networking research community in turn has,

with a few recent exceptions, adhered to its commitment to the

Oral Tradition and not taken up the cudgels against X.25 in the

open literature, even though X.25 is an object of considerable

scorn in personal communications.

Although the DoD Protocol Standards Technical Panel has

begun to evolve a "Reference Model" different from ISO's for

reasons which will be touched on below, there seems to be a need

to address the deficiencies of X.25 on their own demerits as soon

as possible. Without pretending to completeness*, this paper will

attempt to do just that.

The overall intent is to deal with X.25 in the abstract;

because of who pays the bills, though, a necessary preliminary is

to at least sketch the broad reasons why the DoD in particular