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Access network design for branch, remote, outdoor and campus locations with Aruba access points, and mobility controllers.
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iPerf Wifi performance test settings

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  • 1.  iPerf Wifi performance test settings

    Posted Oct 12, 2021 11:46 AM

    I'm currently doing some test with iPerf and I'm wondering which options to set to receive the full wifi performance? I read that options -l and -w could improve performance, but I couldn't figure out a real improvement during my tests.
    I'm connecting a laptop via ethernet to the local switch where also the controller is connected to and run iPerf on it. On my wifi client I'm running "iperf 3 -c IP -p PORT".
    Does anyone know some tips & tricks to bring client and wifi to the limit?

    Many thanks!

  • 2.  RE: iPerf Wifi performance test settings
    Best Answer

    Posted Oct 19, 2021 04:30 AM
    First, let's be clear on 'wifi limit'. WiFi uses a shared radio medium om which only one station can transmit at the same time. That means first of all that the available capacity has to be shared between your client and AP transmitting (sending) and receiving data, secondly if you have multiple clients (or interference) the available airtime for your client will go down. This all, and the fact that there is additional overhead, results in that if you have, for example, a 600Mbps link, the maximum throughput with iPerf that you can expect is roughly half of that, so 300Mbps, and only if you have a strong signal, a not too busy network and little interference. On busy networks this number can go down significantely. Don't expect the marketing numbers that are on the box or datasheet of your AP, and also you will never get better throughput than your client can support with the AP. If you have a 2-stream client (most common), you can't leverage all 4 streams of an AP if that supports 4.

    Then on the iPerf settings, the most relevant settings to push as much as possible traffic are:
    -P : number of parallel sessions; you can put this to a number between 4 and 8 to prevent a hickup in a single tcp flow to bring down the measurements
    -w : tcp window; this is how much traffic can be sent without receiving an acknowledgement. I've seen numbers like 1000k, where the default maybe somewhere around 64k. The higher the speed, the higher your window size should be.

    Hope this helps..

    Herman Robers
    If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.

  • 3.  RE: iPerf Wifi performance test settings

    Posted Oct 19, 2021 04:43 AM
    Hi Herman,
    thank you very much. That was the information I was missing.