Question about test results

[Dan Watts <dwatts --at-- g4.net>]

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
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