Re: A further question on using the -l option


Jim:

Jim Mozley wrote:

> A further question on using the -l option.
> 
> If I use the command below (on a 100 Mb/s link):
> 
> iperf -u -c 172.18.1.1 -b 90m -t 300 -l 100B

you also used "-i 1"... ;)

> 
> After a time I see the following from the server output:
> 
> [  6] 154.0-155.0 sec  7.01 MBytes  58.8 Mbits/sec  0.013 ms 
> 46088/119609 (39%)
> [  6] 155.0-156.0 sec  7.00 MBytes  58.7 Mbits/sec  0.018 ms 
> 43404/116817 (37%)
> [  6] 156.0-157.0 sec  6.31 MBytes  52.9 Mbits/sec  0.016 ms    0/66157 
> (0%)
> [  6] 157.0-158.0 sec  6.33 MBytes  53.1 Mbits/sec  0.017 ms    0/66423 
> (0%)
> 
> The number of datagrams/s seems to lower and packets stop being dropped 
> or at least only a few get lost. The time to reach this point seems to 
> vary but it appears to be consistent behaviour if I repeat the test. Is 
> there any reason why the Iperf client would start to send fewer packets, 
> as this is what appears to happen, or am I mistaken about what is 
> happening?

The standard test should be 60 seconds according to RFC 2544,
but this behaviour means that something is "stabilizing" or that
Iperf is not reporting correct numbers..

contrast with 1 second query to your SNMP switch (loss counters)..

regards,


> 
> Thanks,
> 
> Jim Mozley
> 
> 

-- 
Marcelo Maraboli Rosselott
Jefe Area de Redes           (Network & UNIX Systems Administrator)
Ingeniero Civil Electronico                   (Electronic Engineer)

Direccion Central de Servicios Computacionales (DCSC)
Universidad Tecnica Federico Santa Maria, Chile.
phone: +56 32 654237
mailto:marcelo.maraboli --at-- dcsc.utfsm.cl	http://elqui.dcsc.utfsm.cl/



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