Re: On-Off flows

["Claudio E. Casetti" <casetti@polito.it>]

This is quite wierd... the same thing happened to me when I was trying to
simulate On-off flows too. (more or less 100/300 ms On/Off times).

Oddly enough, the problem showed up at around 250 seconds of simulated time in
my case as well. No hint as to what might be the cause, though. By the way, the
final output of the simulation was plainly wrong...

Claudio Casetti


>I am trying to simulate a topology where a great number 
>of On-Off flows (about a thousand) arrive at a 
>single bottleneck link.
>
>All the on-off sources are configured as follows:
>
>        $onoff($i) set rate_ 64Kb 
>        $onoff($i) set burst_time_ 720ms
>        $onoff($i) set idle_time_ 1080ms
>
>I got from ns a sequence of warnings like this one:
>
>ns: scheduler going backwards in time from 240.308663 to 240.306623.
>
>Is this a problem of accuracy at the time variable of the scheduler?
>Has anyone got a similar problem?
--
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   |                    Claudio Casetti, Ph.D.                           |
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