hello again,
i upgraded the 3com switch to firmware 2.62. since then everything
works just fine!!! thanks for your help.
it took me a long time to figure out that it had actually worked,
because the program i use to measure network speed was broken
for speeds > 10 mbit/s. it seems it always shows a throughput of
around 1 mbit/s if the real speed gets above 10 mbit/s. i did the
following to figure it out:
time cat /dev/zero | netcat -v ...
then i used the following formula to calculate throughput in kbit/s:
number_of_bytes * 8 / 1024 / number_of_seconds
this gave me about 70-80 mbit/s after the firmware upgrade. this is
a good value, since the tcp/ip-overhead is not included in this figure.
i found out that the program version i used was completely
outdated ("iptraf" version 1.2.0, recent version: 2.3.1). i complained
to suse about distributing outdated, broken software.
greetings,
johannes ballé
Am 12 Feb 2001, um 11:36 schrieb Johannes Ballé:
> Hello everybody,
>
> I have a strange problem with two 3c905b NICs and a 3Com Switch
> 3300. The two NICs belong to a file server and a web server.
>
> The thing is, when I test the network speed on the file server with
> "iptraf", it never gets above about 8 or 9 Mbit/s, no matter how
> much load I put on it. (In order not to confuse network bandwith
> with filesystem bandwith, I also tried to netcat /dev/zero from the
> file server to the webserver and vice versa, but with the same
> results.)
>
> The switch as well as the NICs were set to auto-detect, so I tried
> setting all of them explicitly to 100Mbit/s full duplex (I set the
> switch via telnet, and the nics by booting into dos and running the
> 3com tool), but it didn't work either.
>
> Cable length from the web server to the switch to the file server is
> approx. 5 metres, so that cannot be the problem either.
>
> I don't get any error messages; it seems to work all fine if you just
> look at the logs. But the throughput is just too slow if you figure
> that the file server is running samba, sometimes serving up to 30
> NT workstations at once with multimedia data. Some of our
> applications seem to hang because the throughput is too slow, so I
> need to find some kind of solution.
>
> I'm running Linux 2.2.18 (with no patches installed) on both of the
> machines. I compiled the 3com driver as a module.
>
> I hope someone at least has an idea where I could look.
>
> Thank you for your attention.
>
> Johannes Ballé
> Gymnasium zum Altenforst, Troisdorf
> Germany
>
> -
> : send the line "unsubscribe linux-net" in
> the body of a message to majordomo@vger.kernel.org
-
: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.kernel.org
