Subject: Re: 100baseT ethernet card questions
To: Scott Bartram <email@example.com>
From: Hal Murray <firstname.lastname@example.org>
Date: 12/07/1998 16:35:06
I have another data point that might be interesting for this discussion...
I can't make the NetBSD Tulip driver work well at 100 megabits in
full duplex mode. That's with a 21143 on an Alpha. It just drops
packets. Not many of them, but enough to confuse things under heavy
load. telnet and ftp mostly work OK.
But if you try to run a tcp throughput test like netperf, it drops
a packet every time it gets up to speed, including on the retransmissions.
Each retransmission attempt gets another packet or 6 across but then
it drops one and goes through the long timeout path. (Neeless to
say, throughput isn't very impressive.)
Half duplex mode works fine.
I think the FreeBSD driver on an Intel box does the same thing.
I think the drivers are very similar so that's probably not very
I haven't looked at the sources. One of our guys spent a lot of
time working on the FreeBSD driver and he didn't find anything.
I also had some troubles at 10 megabits. I've forgotten the details.
It was the first time I tried to install a system so I was easily
confused. The problem went away when I switched to 100 megabits
and I didn't go back to investigate.
I do remember that the problem went away when I used ping on another
machine to bounce an occasional packet off the machine I was working
I think the symptom (without the ping running) was that nothing happened.