Re: tcptrace Slow Start Duration

From: Shawn Ostermann (ostermann@cs.ohiou.edu)
Date: 03/11/03

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    Message-Id: <200303111635.h2BGZN4N007462@picard2.cs.ohiou.edu>
    From: "Shawn Ostermann" <ostermann@cs.ohiou.edu>
    Subject: Re: tcptrace Slow Start Duration 
    Date: Tue, 11 Mar 2003 11:35:23 -0500
    
    

    > given a certain tcp transfer, is it possible with tcptrace to
    > calculate the slow start duration?
    >
    > Thanks,
    > Gianluca

    It's generally pretty easy to deduce by looking at the time sequence
    graph (-S). Printing the value out numerically would require a
    heuristic. I imagine that you could watch the outstanding data (sent
    but not ACKed; a good estimator of congestion window) and look for it to
    "flatten out". Alternately, you could try to match outgoing segments
    with incoming ACKs and watch for a 1-to-1 correspondence to start, but
    that's an even less robust heuristic.

    I guess my answer would be that one could put in a heuristic to
    calculate it, but the heuristic would be sufficiently error-prone that
    it would be deceiving in many cases.

    Any other thoughts??

    Shawn
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