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From: BHUBER@USC-ECL.ARPA
Newsgroups: mod.protocols
Subject: SNA layer query
Message-ID: <[USC-ECL.ARPA].3-Jan-86.11:22:36.BHUBER>
Date: Fri, 3-Jan-86 14:22:00 EST
Article-I.D.: <[USC-ECL.ARPA].3-Jan-86.11:22:36.BHUBER>
Posted: Fri Jan  3 14:22:00 1986
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I am not sure if this is the correct distribution to be asking the following
question, but if this is not the correct list, would someone please advise
which is the right one.....

Two of us are working on a report about various aspects of data communications
and have come up with conflicting information concerning the number of layers
in SNA.  An IBM report [OSI and SNA: A Perspective, dated April 1981] says
that there are seven layers, and a DataPro Report [IBM Systems Network 
Architecture, dated August 1985] says that there are six layers.

Question:  (a) "How many layers are officially defined in the IBM SNA?",
           (b) "Is the 'physical' layer actually an IBM defined layer?",
           (c) "What is the source of your response to the above?"

Mucho thanx in advance for any assistance,
Bud