How to recognize ACK event

Hongwei Zhang zhangho
Sun Aug 1 15:20:16 PDT 2004

Hi Juan,

Thanks for your reply.

>>Just to share my recent experience with hostap-ver-0.1.3, I found that
>>multiple TX interrupts seem to pop up for the transmission of a single
>>short UDP packet. This happens to unicast packets, but does not happen
>>to broadcast packets. I wonder what may be the cause for this
>I have no clue about your actual test environment, but...
I used two Linux boxes (Stargates 7.1 from Intel Research), with kernel 
2.4.19 patched with wireless exetension 14. One node keeps sending 
packets to the other node at some frequencies. I changed iwevent.c and 
hostap_hw.c to check the number of TX as well as TXEXC interrupts from 
the the firmware, then I compared this number to that of the short 
packets sent in the application.

I wonder if the driver sends some control packets for certain 

>Perhaps it's just that you're seeing the ARP request + the UDP
>transmission for unicast transmissions, while there's no ARP request for
>broadcast transmissions...
In my program, I used MAC address when calling UDP socket functions, so 
there should not be any involvement of ARP even for unicast. Please 
correct me if I missed anything obvious here?



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