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From: goldstein@delni.dec.com
Newsgroups: comp.protocols.iso
Subject: Re: ISDN and OSI relationship
Message-ID: <3012@shlump.dec.com>
Date: 16 Jun 89 15:52:02 GMT
Sender: news@shlump.dec.com
Organization: Digital Equipment Corporation
Lines: 22


In article <1989Jun15.160207.18925@gpu.utcs.utoronto.ca> craig@gpu.utcs.utoronto.ca (Craig Hubley) writes:
>......  I am interested specifically in connecting private OSI LANs
>to common-carrier ISDN WANs.  I have *no interest* in implementation details
>save those directly relevant to application design.

The Corporation for Open Systems (COS) has a COS Profile Selection which
includes ISDN in some of its profiles.  While these are still in draft 
form (I personally question the need for ISO 8208 below 8473 and above
7776 in circuit mode...), the profiles do illustrate ways to use ISDN in 
an OSI context.

ISDN provides packet mode service up to Layer 3 (CONS or CO-subnet) as 
well as circuit-mode service (switched L1) at various speeds, so long as 
they're 64 kbps. :-)  The standards also define circuit-switched H 
channels at 384, 1472, 1536, and 1920 kbps, but I don't think those are 
close to implementation in any of your common central office switches.
Their applicability to any given application of course depends upon
bandwidth requirements.  Applications, of course, should be sufficiently 
isolated from lower layers that it shouldn't matter whether you're on an 
ISDN or what-have-you, other than bandwith, speed and the other usual WAN 
issues.