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Re: [ns] thrpughtput BUG??
--- Lloyd Wood <[email protected]> wrote:
> On Wed, 17 Jan 2001, Jacky Lee wrote:
>
> > I found that when I traced the trace file, the
> total
> > bytes sent indicated in the trace file was
> different
> > to [$tcp set ndatabytes_] (total bytes sent from
> tcp).
> > Anyone can tell me why?
>
> 1) Packet drops/reordering, leading to TCP resends.
I have counted the resend packets from the trace file
also.
Moreover, after I detach the tcp agent from the node
$ns at 10 "$ns detach-agent n0 tcp0"
[$tcp set ndatabytes_] at t=11 is not equal to
[$tcp set ndatabytes_] at t=20.
that's why?
> 2) Header overhead (depends on the TCP variant used;
> FullTcp simulates
> this most accurately.)
>
> If you snoop on data being delivered by the receiver
> sink to the
> application (I posted a simple recv() method a while
> back) you should
> see overall correspondence with ndatabytes_
>
> L.
>
>
<[email protected]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>
>
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