386 UNIX on OpenNet

[George michaelson]

>From article <1988Sep20.183604.2240 at utzoo.uucp>, by henry at utzoo.uucp (Henry Spencer):
> In article <1537 at ficc.uu.net> peter at ficc.uu.net (Peter da Silva) writes:
>>As an aside, what is the history between the split between OSI and DOD?
> 
> Well, *very* concisely, the TCP/IP protocols are a bit old and have some

the split predates even TCP/IP I suggest. ARPA was designed as a datagram
service but the CCITT provided services in Europe were/are virtual-circuit
based. IMP and the like were being taught as "nasty U.S. ideas we don't want
to run" when I learned about X.25 in York. [as an experimental service, in 
1980ish]

When you rent a leased line, whan you run above it is probably your own
buisness, but in the absence of good host-level software you'll take what
the PTT provides. If PTT's had pushed datagram at their customers renting
leased lines, perhaps we'd all be in the same bathtub. By the time public
networks got off the ground, the split was already history.

ISO/CCITT transport must be post-1982 because I recall working with
ECMA specs for transport, and then seeing them massaged into the BSI/IEEE
submission (to DP state I guess). At that stage, very few people in the UK
had ethernet, what was available was researchy and slow and nasty. There
was already in place a GEC based packet switching VC network (SERCnet
later to become JANET) running X.25 and like-minded protocols on top.
-this was only just starting to squeeze out the old point-to-point links
from various uni's to computer centres and the like. 

for ISO class 4, the early documents may have had some discussion about why 
they used time based rather than hop based TTL. are there more important 
differences?

Many people were either using VMS version 2.x or V7 unix, and neither come
as-is with TCP/IP, but did have free/cheap X.25 solutions available. perhaps
if TCP had been visible on 360's, ICL 2900's, and DEC-10's around the 70's it 
would have looked a better option, but when people in the UK started writing
network code for their central facilities, X.25 aligned stuff came out.

So a combination of lack of availability, funded nets with non DoD protocols,
PTT intransigence and NIH seem to be likely.

Why then did the PTT's (who tend to dominate the standards process, certainly
for the CCITT and I would expect also the ISO committees outside of the US/UK)
reject the datagram model?

did they see an easier path to doing VC stuff, and a better initial
return on their investment in H/W and S/W?

I was told they opposed multiplexing at the network level because of the
established charging pattern (per VC, as well as volume-per-VC) so perhaps
money was the final motive, and not architectural preferences.


	-george

-- 
        George Michaelson, CSIRO Division of Information Technology

ACSnet: G.Michaelson at ditmela.oz                      Phone: +61 3 347 8644
Postal: CSIRO, 55 Barry St, Carlton, Vic 3053 Oz       Fax: +61 3 347 8987