Measuring transmission time - Linux

This is a discussion on Measuring transmission time - Linux ; Hi folks, I'm looking for a way to know the time required by a wireless interface to push out a certain number of packets (with a certain size, at a certain rate, on a certain channel (hence interference)). What I've ...

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Thread: Measuring transmission time

  1. Measuring transmission time

    Hi folks,
    I'm looking for a way to know the time required by a wireless
    interface to push out a certain number of packets (with a certain
    size, at a certain rate, on a certain channel (hence interference)).

    What I've been doing so far, is setting a fake arp table entry and use
    ICMP (ping) to get this time ... BUT... what is exactly ICMP
    measuring?

    Another point is that I would like to cut off the retransmission
    mechanism AND timeout.. but I can't act directly at the MAC layer, so
    I thought to send broadcast packets... which points out the second
    question:
    What can I use in place of ICMP (as I need broadcast)?... I was
    thinking to develop a simple UDP socket application, but I don't
    really know how to measure the timings (what to probe for..)... I've
    seen a previous post where people were trying to use queue_xmit or
    something like that, and get direct access to the outgoing interface..
    assuming that transmission would start right away, there would still
    be a queue in the middle... hence I

    Is there any fast solution aside using tcpdump ?

  2. Re: Measuring transmission time

    InuY4sha wrote:
    >
    >Hi folks,
    >I'm looking for a way to know the time required by a wireless
    >interface to push out a certain number of packets (with a certain
    >size, at a certain rate, on a certain channel (hence interference)).


    Are you hoping to compute the elapsed time after the transfer happens, or
    are you hoping to get a number you can use to predict future transfers?

    I suspect you're after prediction, but I'm not convinced that is reliably
    computable from user mode. Further, because wireless is so wildly
    variable, as soon as you got a number, it wouldn't be applicable any more.
    --
    Tim Roberts, timr@probo.com
    Providenza & Boekelheide, Inc.

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