Benoit PAPILLAULT a écrit :
> TX rate is dropping a lot (like 20 MBits down to 200 kbits/s). Using
> another card in monitor mode, I still see packets sent at 54 Mbits rate 
> however.
I found out what is wrong with the TX throughput. In fact, when a packet 
is transmitted at 54 Mbits, the destination send back a 802.11 ACK which 
is ignored!!! As such, the packet is transmitted at 54 Mbits once again, 
then twice at 48 Mbits, then twice at 36 Mbits ... and so on down to 1 
Mbits. Of course, this divide the throughput by 18 (twice for each 9 
rates), leading to 200 - 300 kbits.

When implementing proper TX status reporting, needed by minstrel rate 
control, I also found out that some 802.11 ACK where not received by the 
driver, but received by the card, leading to inconsistencies in the rate 
control code.

Are there some registers that are responsible for ACK behavior?


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