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From: alan@mn-at1.UUCP (Alan Klietz)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Ethernet - Hyperchannel Gateway
Message-ID: <400@mn-at1.UUCP>
Date: Fri, 30-Oct-87 21:22:18 EST
Article-I.D.: mn-at1.400
Posted: Fri Oct 30 21:22:18 1987
Date-Received: Thu, 5-Nov-87 02:21:46 EST
References: <8710191505.AA06315@morgul.PSC.EDU> <784@gargoyle.UChicago.EDU>
Reply-To: alan@mn-at1.UUCP (0000-Alan Klietz)
Organization: Roseville, MN
Lines: 31

In article <784@gargoyle.UChicago.EDU> chris@gargoyle.uchicago.edu (Chris Johnston) writes:
<[Hyperchannel Ethernet router] performance is 2k packets/s per ethernet and 10k
<packets/s through the router backplane.
<
<All this information is from suits (salesman), reality may diverge...
<
<Anyone have any real life, hands on opinions of these things?

I've never seen a Hyperchannel deliver a thousand blocks per second,
much less two thousand.. 

From our experience, the actual sustained rate is 600/sec, assuming
no associated data and no contention on a dedicated trunk.  [Measured
between two Crays on a one meter coax trunk.]

The problem is that the internal adapter protocol puts in large
time-delays w.r.t. the transmission rate for collision avoidance. 
The salesman must have been taking about virtual ethernet packets
collected into larger Hyperchannel blocks.

(By the way, I've never seen 20 Mbit/sec either.)

--
Alan Klietz
Minnesota Supercomputer Center (*)
1200 Washington Avenue South
Minneapolis, MN  55415    UUCP:  ..rutgers!meccts!mn-at1!alan
Ph: +1 612 626 1836              ..ihnp4!dicome!mn-at1!alan (beware ihnp4)
                          ARPA:  alan@uc.msc.umn.edu  (was umn-rei-uc.arpa)

(*) An affiliate of the University of Minnesota