6 Jul
2003
6 Jul
'03
10:35 a.m.
Jay West wrote:
The basic gist of the problems was sporadically very
very poor throughput,
then suddenly great throughput. It SEEMED almost like a 10/100 duplex
mismatch, but it wasn't.
We had a client who, after spending ~$2000 on a firewall PC,
populated it with $9 Realtek cards. 1 outside interface and 4 inside.
It was running Linux, a v2.4.17 kernel. The thing ran all the internal
interfaces at near saturated levels, and was showing 1.2-2.5 system
loads (up to 2.5 processes waiting on CPU time). They were losing a lot
of packets.
After I talked them into replacing the Realtek cards with 3Com
3C905s, system load dropped to 0.1-0.6, and no more dropped packets. I
got curious and set up a Win2k testbed with 3 Realteks, and saw the same
behavior under load. You could literally see the CPU load in Task
Manager rise as the network traffic increased.
They're Win-NICs. It's not a driver issue, it's the way they're
designed.
Doc