[eepro100] High collision rate

[Bernd Stahlbock]

Hello all,

I've recognised a problem in the internal network of our industrial
machines: We use a NT workstation control PC with GUI (normally SMC
Etherpower II or 3Com NICs) and one or two Linux embedded PCs with Intel
82558B Chip and Donald Beckers driver "eepro100.c:v1.11 7/19/2000 Donald
Becker <becker@scyld.com>\n";.
If the machine has one embedded PC, it's a direct cross connection to
the NT PC. If there are two embedded PCs, we use a small 100MB Hub. The
Problem is on all machines the same:

If we produce network traffic (with not more than 800kbyte/sec) on a TCP
stream while the machine is operating, we got a collision rate up to
55%. Nearly no matter if one or two embedded pcs are written to at the
same time.

Now, I read something about a Interframe Gap, which may be set to small
by the driver, for reasons of performance. The NT Intel-Etherpower
driver for the 82558 chip has a special registry setting for this.
(normal gap is 9.6 microseconds)
Too small gaps leads to high collision rate.

Now my question: is Donalds driver written according to the IEEE rule
for 100TX? Is it possible to adjust this value to archive a better
throughtput/collision ratio?

I remember that in earlier times we didn't have this problems. We
already changed the SMC drivers back to the old ones and also used old
cards, with no effect. So I assume that there has been a change in the
linux side drivers.

best regards
Bernd Stahlbock


--
stahlbock@basysprint.de, http://www.basysprint.de
basysPrint GmbH, Guelzer Str. 15, 19258 Boizenburg, Germany
Tel.: ++49-38847-99-150, Fax:++49-38847-99-192