I currently have a arduino due with ethernet shield(w5100 chip) and i am trying to read packets and send acknowledgement packets, however i need this to work at 0.5 ms which i have not been able to do with this set up.
Are you aware that UDP.endPacket() call returns a value? You might want to evaluate the return value to see if the RPi is rejecting the packet. It returns 1 if the packet was accepted, and 0 if rejected.
It isn't in the reference, but it is documented in EthernetUdp.h.
aye another problem i am having which u have helped me with on another topic is the packets freezing after quite a few have been sent it seems the udp.write function write the function happens and udp.endpacket either doesnt get called, or it gets stuck in the while loop in the library because when it freeze it doesnt return anything it just seems to stop.
if the raspberrypi misses the packets, this is not an issue i just need to be able to send/acknowledge them quick enough. I am also not using a raspberry pi just yet, currently sending them to my computer.
Just to let you know i fixed all my UDP problems, the problem was the Buffers on the w5100 chip, so i changed to a wiz820io with w5200 chip, without all my packet manipulation i can send at 1 ms(with my packet manipulation goes to 3ms)