[ns] TCP and packet drop: where are the retransmitted packets?
arne.lie at item.ntnu.no
Tue Jun 27 06:47:01 PDT 2006
Thanks, I will have a look and see if full TCP header is possible; however,
I need only a unique sequence number series.
> -----Opprinnelig melding-----
> Fra: Ethan Giordano [mailto:giordano at cis.udel.edu]
> Sendt: 27. juni 2006 12:49
> Til: Arne Lie
> Emne: Re: [ns] TCP and packet drop: where are the
> retransmitted packets?
> There are two different sequence numbers...the TCP sequence
> number and the internal unique id for each packet. I think
> you have to turn on tcp header output for the trace to see
> the tcp sequence number.
> Arne Lie wrote:
> > Hi all,
> > For some time I have only been interested in the congestion
> > of the different TCP congestion control algorithms, and the way it
> > balances flow throughput to available capacity, packet drop
> statistics, etc.
> > However, now I need to see how well TCP tackles
> retransmissions, e.g.
> > with SACK. When I inspect the event trace file, dropped
> packets are "never"
> > retransmitted, in that ns-2 seems to increment the sequence numbers
> > (both per flow and per simulation) all the time,
> >>>>>>>> making it impossible to know WHEN a retransmission
> is performed.
> > <<<<<<<<<
> > Is this a correct observation? If yes, are there any
> workarounds? If
> > incorrect, how *do* I find the retransmission event, and e.g. how
> > *many* packets are duplicated/retransmitted (SACK vs. non-SACK)?
> > best regards
> > Arne
More information about the Ns-users