How to recognize ACK event

[Hongwei Zhang]

>>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? 

I am sorry. I must have mis-spoken. I am using IP addresses in my 
program, so it semms highly likely that the extra TXs are for ARP 
related packet transmission. I wonder where is ARP done? Is it somewhere 
in the driver code? (I am quite new to Linux networking internal, and 
any information would be quite helpful and greatly appreciated.)

Thanks and best,

Hongwei