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From: oconnor@SCCGATE.SCC.COM (Michael J. O'Connor)
Newsgroups: comp.protocols.tcp-ip
Subject: Idle chatter about reference models
Message-ID: <8711140153.AA09162@sccgate.scc.com>
Date: Fri, 13-Nov-87 20:53:39 EST
Article-I.D.: sccgate.8711140153.AA09162
Posted: Fri Nov 13 20:53:39 1987
Date-Received: Sat, 21-Nov-87 01:51:07 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 44

Caveat:  Since this is idle chatter (see Subject:) the words martian, bogon,
	fuzzball, and playpen will not appear in the body of this message.


	My office-mate just received a colorful poster from CMC comparing
a seven-layer DoD Internet reference model to the seven-layer ISORM.  I've
attatched a little chart comparing those two RMs to the old four-layer
ARM [1] for the idly curious.
	The most glaring oddity (aside from typos and a cute phone number)
is the depiction of EGP, GGP and HMP as Transport layer protocols.  When I
expressed my surprise at this to my office-mate he wanted to know where they
did belong (magic-marker in hand).  My instinctive answer was that EGP and
GGP belonged in the Internetwork layer and that HMP belonged in Massachusetts.
	Since I'm just a hanger-on in this field, I was wondering to which
layer the protocol police would assign EGP and GGP (and their descendants).
I would also like to know if the aforementioned ARM has ever been supplanted.


				Mike


1. While displaying an affinity for M. Padlipsky's naming scheme (RFC871),
   the four-layer model to which I refer is the one described by B. Leiner,
   et. al. in "The DARPA Internet Protocol Suite".

--------------------------------------------------------
ISORM		CMCRM			   ARM
--------------------------------------------------------
Application	Application		Application
--------------------------------
Presentation	
		Utility
Session
--------------------------------------------------------
Transport	Transport		Service
--------------------------------------------------------
		Internetwork		Internetwork
				------------------------
Network		Network			Network
--------------------------------
Data Link	Data Link
--------------------------------
Physical	Physical
--------------------------------------------------------