Path: utzoo!utgpu!watserv1!watmath!att!tut.cis.ohio-state.edu!ucbvax!ANDREW.CMU.EDU!ms6b+
From: ms6b+@ANDREW.CMU.EDU (Marvin Sirbu)
Newsgroups: comp.protocols.iso
Subject: Re: question about transport layer protocol
Message-ID: <4baVtPi00VADA3ueBG@andrew.cmu.edu>
Date: 20 Jan 91 22:48:59 GMT
References: <1991Jan18.220611.14357@bronze.ucs.indiana.edu>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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An example of a Class A network would be a reliable X.25 network.
(Some people may think that is an oxymoron, but what
constitutes "reliable" depends on your
requirements.)


An example of a Class B network would be an X.25 network that has a lot
of Resets which require re-establishing the network connection.  Early 
experience with some European X.25 networks (Transpac in particular,
I believe) led the standards developers to develop classses within the
transport layer protocol which were more resistant to these resets
(Class 1 and 3) as opposed to simply having a transport class which
presumed the network connection was reliable and stayed up (Classes 0
and 2).

Marvin Sirbu
CMU