[Fwd: [ns] Tracing RTS/CTS in 802.11, how?]

[Xavier]

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Message-ID: <3BC6FCF1.854028CD@ccrle.nec.de>
Date: Fri, 12 Oct 2001 16:23:45 +0200
From: Xavier <Xavier.Perez-Costa@ccrle.nec.de>
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To: Joe Andersson <joe_se01@yahoo.com>
Subject: Re: [ns] Tracing RTS/CTS in 802.11, how?
References: <20011012140138.32476.qmail@web20406.mail.yahoo.com>
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Joe,

It's some time ago that I had this problem. I think that I checked the
tracefile in the MAC level looking for rts/cts and I realize that in the
place where the RTS/CTS where supposed to be I found these MAC 44/38.
These messages, you can check it, where repeated for each transmission
of a data packet between the bs and the station, so I'm quite sure that
these are the RTS/CTS. To know which one is the RTS/CTS you have to
check just who sends the packet, the one who sends the packet should
send the RTS. 

Anyway I think that for checking that I was right I added a
'cout/printf' in the mac-802_11.cc file in sendRTS, etc... with the time
of the event and then I compared these results with the tracefile. If
you want to make statistics with it I would modify the message that
appears in the tracefile, I wouldn't rely in the size of the header

Xavi

Joe Andersson wrote:
> 
> Thanks for your quick reply!
> 
> Could I ask you one more question regarding the same?
> 
> How can one know that 44 refers to RTS and 38 to CTS? I have been looking at
> cmu-trace.cc, and if I understand correctly the 44 and 38 are specifically ch->size(), so
> basically the size for the packets exchanged, is only by chance that they are different
> and that using the size you can guess what they are?
> 
> Thanks,
> 
> /J
> 
> --- Xavier <Xavier.Perez-Costa@ccrle.nec.de> wrote:
> > Hi Joe,
> >
> > If you look carefully to the tracefile you will realize that when you
> > use the RTS/CTS mechanism before the transmission of the data packet
> > there's a signaling exchange between the bs and the station. These
> > messages are printed as: MAC 44 and MAC 38
> > If you want to see it clearer you can modify cmu-trace.cc in order to
> > print rts/cts in the tracefile
> >
> > Xavi
> 
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