Re: Question about test results
Dan,
At first blush, I don't know why you can't get the dualmode test to work in
this configuration. I'm fairly certain we've never tested Iperf using a
crossover cable, but I don't see why that should be different.
I'm certain we can think of some excuses for non-symmetrical results you're
seeing, but you may eliminate several of them if you have more info about
you end workstations besides the fact they are both running FreeBSD
4.9. Are they identical in their hardware configuration? How much
different are the two directions?
-Jim Ferguson
At 05:21 PM 4/2/2004 -0500, you wrote:
>Hello,
>
> I'm a new user of Iperf and a customer of mine is using Iperf to try
>and validate their available bandwidth.
>
>Using command lines of:
>
> server: iperf -s
> client: iperf -c #.#.#.# -d
>
>we see results that are not symmetrical. If we use UDP:
>
> server: iperf -s -u
> client: iperf -c #.#.#.# -d -u -b 1500k
>
>we get symmetrical results. These tests were run on the equivalent of a
>point-to-point T1 data circuit.
>
>If we connect two computers together (FreeBSD 4.9) via a switch, we see
>similar results. Oddly, when the two FreeBSD systems are connected
>together with a crossover cable we are unable to get the dualmode test
>to run. It always run in tradeoff mode. We've yet to dig into the source
>code to see what would trigger this condition. We built our executables
>from the source that was available at:
>
> http://dast.nlanr.net/Projects/Iperf/
>
>My question is whether this is normal. Should we see a non-symmetrical
>test result using TCP when trying to perform a test that would use all
>available bandwidth?
>
>Dan
>--
>Dan Watts
>G4 Communications
>One Sundial Avenue
>Manchester, NH 03103
>(603) 296-4422 voice direct
>(603) 625-0555 voice
>(603) 647-7576 fax
>www.G4communications.com
>
>"High-Speed Intelligence... Business Internet & Voice Solutions."
J. W. Ferguson (ferguson --at-- nlanr.net)
Distributed Applications Support Team
National Laboratory for Applied Network Research (NLANR)
NCSA - University of Illinois
Ph. (217) 244-1974