[c-nsp] {Disarmed} Re: IPerf alternative

Raymond Burkholder ray at oneunified.net
Sat Aug 12 11:21:07 EDT 2017

On 08/09/17 06:35, CiscoNSP List wrote:
> Hi Raymond (Apologies re top post, Hotmail is a pain) - Reliability 
> concerns primarily with bidirectional simultaneous test mode - Single 
> direction test (UDP), we are able to achieve close to a links capacity 
> (1Gb), bidirectional (-r) (Sends one direction first, then the other), 
> also achieves links capacity...but simultaneous bidirectional (-d), we 
> see 50% in both directions (i.e ~450-500Mb) - I dont know if this is a 
> limitation of iperf, but have tried on multiple boxes, back-to-back, and 
> can not get the bidirectional simultaneous test to achieve 1Gb 
> synchronously - Its like IPERF sees the link as only 1Gb, and therefore 
> only sends as a total (500Mb in both directons...Ive also tried multiple 
> threads, but it refuses to go above 50% - If this is a limitation within 
> the software, or theirs another flag I should be using, Id love to hear 
> it :)

Have you tried in back to back mode to eliminate network issues?  When a 
test is complete, what do the statistics say?  .... any drops, etc?

I have successfully run iperf bidirectionally in tcp as well as udp and 
hit link limits, even on smaller, lower capacity linux based boxes.

As another poster has said, you can run two iperf sessions on each side, 
one to tx and one to rx.  tx1 -> rx2, tx2 -> rx1.

You are testing without rate-limiting, firewalls, tunnels, .... ?

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