Not much more than 10mbps?

Gerhard Sittig G.Sittig@abo.FreiePresse.DE
Wed Sep 30 15:13:14 1998

On Wed, 30 Sep 1998, Rogier Wolff wrote:
> I have two computers connected by a crossover cable, and I don't see
> the expected 100mbps performance.
> [ ... ]
> Yesterday I got ping delays of about 0.3 ms. Nice. But sometimes (say
> about 20%) I got about 10ms or even 20ms. ftp would do about 1.2 to
> 1.7 Mb per second. Even copying a raw disk (i.e. no seeks!) didn't
> give the expected performance.

SHOULD these protocols show such a performance ?  AFAIR I never had
more than 450KB/s over NFS and never more than 4MB/s when using FTP.
The cards are connected by two 100Mbit hubs and the computers were
the only active ones at that time.  Maybe the protocol overhead
reduces the speed that COULD be reached ?  Although ftp was faster
than possible using 10Mbit hardware NFS ist REALLY SLOW.  But maybe
I missed the chance for tuning it -- I never really cared, who
uses NFS when not migrating disks :) ?

What about other mechanisms (ssh redirected from a file or producing
very much output at no computing cost -- but w/o compression!; scp;
telnet host chargen; flood ping; ...) ?

What about collisions on the cable / hub, drops due to buffer
shortage or slow computers / high load in general ?

> Today all three lights come on. 

That's what they do even when not connected at all -- seems to be
their first approximation to reality and might change when they
are "sure" :)  I had to learn that activity is when the LED is
blinking.  Anything else can be a reflection or "sympathy for the
neighbourhood LED" when having just a quick look :>


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