Acer ALN-315 (tulip) card

Mon Sep 20 11:10:47 1999

I'm having trouble with a Acer ALN-315 card.  This card has an Intel 21143
chip on it with no MII transceiver.  The tulip driver recognizes the cards,
and does not complain about them at all.  The trouble I'm having is with
full-duplex operation.  When I have the cards connected to a switch, they
negotiate full duplex operation, which is what I had expected.  However, the
switch drops most of the packets, since I believe that they are somehow
garbled and fail the checksumming that the switch is doing (and obviously
get dropped).  The net result is that I get a netperf of about 1.3 Mbit/sec.
When I force the cards into half duplex, they work fine, and I get about 67
Mbit/sec (due to the switch backpressure).

Initially I thought that the switch had a problem with is full duplex
firmware, but I have tested it with another beowulf using Intel eepro100's
and the full duplex operation is fine.

An interesting anomaly is that when I connect 2 machines with a crossover
cable, the cards negotiate full duplex, and when I run netperf
simultaneously in both directions, I get 87 Mbit/sec in one direction and
approximately 400Mbit/sec (not a misprint) in the other.  I suspect that
this is due to the packets somehow getting garbled and the crossover cable
not dropping the invalid packets.

I've tried both the 0.89 and the 0.91 tulip drivers, and both give the same
results.  I am interested to hear any advice anybody can offer.  I really
don't know alot about the device driver, and would appreciate any input.


Thomas Lovie.