Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!A.ISI.EDU!LYNCH
From: LYNCH@A.ISI.EDU (Dan Lynch)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Does TCP/IP "comform" to ISO/OSI?
Message-ID: <12425346301.40.LYNCH@A.ISI.EDU>
Date: 25 Aug 88 22:25:46 GMT
References: <5883@nsc.nsc.com>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 19

Ron,  The OSI model is intended to be a reference model for discussing
and describing computer to computer communications.  It is an idealization
of how that communications should take place.  It was developed in the late 
70's.  It has a sevenlayer description that rather clearly describers
what should happen on each computer and with their communications devices.

TCP/IP when looked at from that model perspective has 4 or 5 layers distinctly
differentiated.  (Of ocurse, TCP/IP does all of the work, it just does it with
a different number of layers -- if you like cake, who cares if it is 5 or 7
layers?)

But, TCP/IP does not interoperate with the ISO implementations of OSI.
Saying that would be very "confusing".  I have seen IBM and DEC and Apple
documents that all compare their proprietary protocols to the OSI model
They all essentially say they conform to the OSI model.  They do, as
does TCP/IP.  It just does not mean much.  What matters is "can the two
computers send meaningful traffic back and forth?"

Dan
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