[mod.protocols.tcp-ip] Congestion in the Arpanet

GOWER@D.ISI.EDU (Neil E. Gower) (10/02/86)

Dennis, thanks for the copy of BBNs progress and plan of attack.  We are
having trouble understanding why the busiest nodes are not in the middle
of the cross-country paths (SAC, TEXAS and COLLINS (ours)).  Or at the
entrances to those paths.  The only one of the four mentioned by BBN,
which seems to fit the "cross-country bottleneck" is UWISC.

There also seems to be no explanation why a PSN cannot give reasonable
response between two of its own nodes.  We see just as poor (or worse)
service between equipment in the same room here as we do between here
and D.ISI.EDU (ISI27).  Maybe its because our packets are going to ISI27
or somewhere else first.

It does seem that all four of the PSNs mentioned are in areas where
heavy (not necessarily cross-country) traffic would occur.  This would
indicate problems in the areas of shortages of packet buffers and/or
virtual circuits and/or slowness in setting up virtual circuits.

I agree that we have an ONION of problems, but wouldn't it make sense to
resolve the ones that are "localized" to one PSN first?

Regards,
Neil Gower
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jqj@GVAX.CS.CORNELL.EDU (J Q Johnson) (10/04/86)

Has anyone done any modelling of the likely effect of the new NSF sites
and of NSFnet on ARPAnet traffic/performance?  Offhand, I would expect
that the changes (supercomputers with scientists all over the country
using telnet or tn3270 to get to them by ARPAnet, many more
NSF-supported hosts, and a new alternative backbone) are likely to have
massive effects on ARPAnet traffic patterns.  It would be nice to know
that someone had given some thought before the fact to the potential
effects!

Similarly, has anyone modelled the effect of widearea and wideband
regional nets such as the planned NY-wide 1Mbit network (NYSERNET)?