Re: iperf -n option with udp

[Lawrence S. <lst...@ro...>]

Hi Gokul,

I can confirm this behaviour on FreeBSD 6.2 using Iperf v2.0.2 for both 
UDP and TCP modes of operation. The "-n" option appears to have no 
effect in the scenario you described. A quick scan of the sourceforge 
bug tracker 
(http://sourceforge.net/tracker/?atid=711371&group_id=128336&func=browse) 
doesn't reveal any filed bugs relating to this issue.

Playing around with it a bit, I did discover that the option does work 
as expected with TCP if you use the "M" suffix on the number of bytes 
i.e. limit the test to x megabytes e.g. on server run "iperf -s" and on 
client run "iperf -c 127.0.0.1 -n 20M" and that works correctly. It does 
not work in TCP mode if I use the "K" suffix or no suffix at all, and 
the option does not appear to work at all when running in UDP mode, 
regardless of the suffix.

Perhaps you should log a bug unless someone out there has some info on 
why the "-n" option does not appear to function as expected?

Cheers,
Lawrence

gokul wrote:
> Hi,
> I am a new user of iperf trying to test our network by passing a given 
> amount of UDP traffic across. In order to do so, I run the following 
> commands:
> iperf -s -u
> iperf -u  -c 192.168.18.3 -n 20000
>
> The -n option should limit the traffic passed to 20000 bytes however I 
> seem to find that data transfer seems to occur indefinitely. I am 
> using iperf 2.0.2 on  ubuntu. Could someone shed some light on the 
> behavior of the "-n" option ?
> Thanks,
> Gokul
>