[ns] Another question about mac802_11.cc

[glitch74]

Hi user!
I've another question for you.
In mac 802.11 I understood that every station need to sense the medium idle for  a difs+backoff before transmitting A SINGLE packet. Isn't it? The question is : ns2 it makes it in this way?
I suppose the answer in NO!
Explanation :
For a trasmission in wich there's only a station transmitting packets udp/cbr, ns2 works well;
BUT in a simulation in wich there's only a station transmitting packets tcp/ftp, only a few packets waits a difs+ backoff before transmitting. It seems to me that there isn't a shared medium but a reservation of the medium for a long long time. I mean that i've transmitted 80 packets tcp/ftp and only 3!!!!!!! of them awiats difs+backoff, the others are sent in burst after (respectively) one of the previous 3!
It's right or wrong that ns2 works in this way?
Thank you.

P.s. : A very special thanks to Alper Kamil for previous explanations.

BYE





____________________________________________________________
Navighi a 4 MEGA e i primi 3 mesi sono GRATIS. 
Scegli Libero Adsl Flat senza limiti su http://www.libero.it