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From: mo@LBL-CSAM.ARPA
Newsgroups: net.unix-wizards
Subject: AT&T ISN net
Message-ID: <12774@sri-arpa.UUCP>
Date: Fri, 24-Aug-84 08:09:12 EDT
Article-I.D.: sri-arpa.12774
Posted: Fri Aug 24 08:09:12 1984
Date-Received: Thu, 30-Aug-84 01:36:39 EDT
Lines: 28

I just saw some detailed drawings of ISN in one fo the trade rags and
it looks to me almost exactly like DATAKIT, except that the switch data rate
seemed slow. However, if like you say, they use a KMC to interface it,
then I am certain it is just DATAKIT with a new name.  DATAKIT is an interesting
concept, but it is rather at odds with most local networking products currently
available.  Some AT&T person said in the article I read that they could
probably cobble up an Ethernet-to-ISN network if they wanted to. That would
be pretty weird since Ethernet is a datagram-based broadcast medium and
DATAKIT is a point-to-point virtual circuit packet-stream switch with
central call supervision (sounds like a telephone, no?).  I belive there
are a couple of 4.2 sites at Bell Labs or Bellcore which tunnel through
a DATAKIT network running IP/TCP, but operationally, it is just like
connecting the machines with point-to-point DMC's.  They only use the
DATAKIT link because it is in place connecting the physical sites in question.

>>> Thrust levers to 80%

I am fundamentally an end-to-end person and don't trust anyone's network
to get my data there without some protocol at my level saying it is OK.
Therefore, just give me a  Proteon Ring or an Ethernet and get out of my way.
The concept of a local network wherein one begins a connection with
"Hello Central" is abhorrent in the extreme.  It might be fine as a dataswitch
for dumb terminals (you don't expect dataswitch connections to be reliable
anyway), but their days are numbered (just not in small integers) and
Why get an ISN network for terminal switching when there are MUCH better
data/voice switches available?

	-Mike