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From: MAP@LCS.MIT.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: the Chaosnet
Message-ID: <8903142340.AA24333@gaak.LCS.MIT.EDU>
Date: 14 Mar 89 23:40:47 GMT
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John, that was a very nice and fairly complete reply on the ChaosNet.
I have a few minor clarifications of historical (or hysterical :-)
fact.  I had already been in communication with Mr. Murayama in answer
to his original query so these comments are mostly intended as a
follow up to you and the wider distribution to which your message was
addressed.  As you know, but others may not, I was involved in the
early days of the ChaosNet (in 1979 I worked on one of the first
implementations).  Later I worked with Dave Clark (and you, when you
showed up :-) on early TCP/IP development (1981-1982).  As you noted,
a comparison of the two architectures is very interesting indeed.

>>	[...]  The host address space was smaller, 16 bits.
This was in fact a conscious decision.  The design of the protocols
was known to be biased towards campus sized networks and was
explicitly intended to be internetworked with gateways above the
network layer, rather than routers as the IP protocols are.  Several
of these gateways exist, it's possible to transparently telnet from a
ChaosNet host to a host on the Internet, the reverse was never
implemented because TCP opens don't have arguments, someone later
proposed a way to do it with address mapping, but this was never
implemented to my knowledge.

>>  Internally, it didn't differentiate between the transport and network
>>  layers as much as TCP/IP does (smush TCP, UDP and IP together into one
>>  protocol and you get something similar to the layering of Chaosnet).
One of the features that I liked about the protocol stack was the
ability to have one "connection" with a fully error-checked and
sequenced byte stream, with out-of-band packets.  This allowed
terminal applications to send interrupt characters that would succeed
in interrupting type-ahead.

>>	[...] Symbolics and LMI both supported Chaosnet [...] I think
>>  TI might have on the Explorer.
Right, TI did have it, on both the Explorer and the Nu.
>>  Eventually LMI went boom and Symbolics brought up TCP.
Actually all varieties of LispMachine I know of speak both Chaos and
TCP/IP.  The code frequently is arranged to try one and then fall back
to the other for various services.
>>  [...] I believe there are still a few systems around MIT running it,
>>  and probably some at Symbolics, but by and large, it's faded away.
At this instant 28 Chaos subnets are reachable at MIT (vs 47 IP
subnets), with 441 hosts registered and over 300 on-line now.  It
hasn't quite faded away yet it's just that TCP/IP has been growing so
much faster around here.

>>  There's a document called "Chaosnet" by David Moon (if I remember
>>  correctly) available from the AI Lab, [...]
Yes, I believe the latest version is AI Lab Memo #628, June 1981, it
is sometimes referred to as the "Amber" document (from "9 Princes in
Amber", also where the name Chaos comes from).  I also recommend it
for people looking for a different perspective on how to do local area
networking.  The AI Lab Publications office is at +1-(617)-253-6773
and by E-Mail at pub@Wheaties.AI.MIT.Edu (I think).

	    __
  /|  /|  /|  \		Mike Patton, Network Hacker
 / | / | /_|__/		Laboratory for Computer Science
/  |/  |/  |atton	Massachusetts Institute of Technology

Disclaimer: The opinions expressed above are a figment of the phosphor
on your screen and do not represent the views of MIT, LCS, or MAP. :-)