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Re: cwnd bug?
Thanx a lot! When I added the following line:
$tcp($i) set window_ 50000000
the TCP worked perfectly. Am I right that this is a bug in ns?
My assumption was that if I do not set window_ myself, then it is either
set to a reasonable value as a default or it means that the reciver
window
is not a limitation for the TCP.
The behavior it produced can not be explained by any setting.of the
window.
(If I change the buffer size to 1 or a few packets it works fine, but I
wanted to
investigate large buffers)
Maybe this warning could be added to the documentation?
Again, thank you very much!
Andras
Chris Parsa wrote:
>
> Hmm. That doesn't happen to my sims. First I'd set the net. queues to
> hold only 1 packet and see if you still get it. Also make sure
> you set window_ to something reasonable.
>
> Hope that helps.
>
> Chris
>
> On Tue, 25 May 1999, Andras Veres wrote:
>
> > I tried the following little script to log the cwnd of two competing
> > TCPs. They share a single buffer:
> >
> > $ns duplex-link $na $nb 0.2Mb 10ms DropTail
> >
> > Surprisingly the cwnd increases continuously which is quite
> > strange. Even after simulating it for 1 hour simulation time.
> >
> > Is it a bug or a 'feature' :) ?
> >
> > The program logs the windows into 'byte.log'. After 3600s of simulation,
> > the tail of the file looks like:
> >
> > Time cwnd1 cwnd2
> >
> > 3598.5999999989181 300.577296 300.517404
> > 3598.7999999989179 300.577296 300.534042
> > 3598.9999999989177 300.577296 300.550679
> > 3599.1999999989175 300.577296 300.567315
> > 3599.3999999989173 300.583949 300.577296
> > 3599.5999999989172 300.600583 300.577296
> > 3599.799999998917 300.617216 300.577296
> > 3599.9999999989168 300.633848 300.577296
> >
> > So the amount of packets in the system is >600? It is impossible!
> >
> >
> > \Andras
--
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Andras Veres [email protected]
TrafficLab ETH/LT Tel: +36-1-437-7735
Ericsson Kft. Fax: +36-1-437-7219
P.O.B. 107, 1300 Budapest, Hungary
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