Hi,
How to identify a particular packet in a protocol sent over the air that gets dropped on the Receiving side ?
Packets will be segmented into many tiny packets so, how to identify that particular packet that gets dropped ?
Thx in advans, Karthik Balaguru
Put a unique identifier in each packet.
By giving them an identification number, advanced 1 at a time, modulo a number large enough to cover the appropriate delays.
Use sequence numbers. The number of sequence numbers you need depends on your protocol. iirc USB just has the one bit that implements this functionality, because it's a master slave protocol. But you might want to use a 4-bit number, 8-bit, 32-bit number or a-another. What you can get away with depends on your protocol.
HTH
Paul.
Isn't that what sequence numbers are for?
This particular problem already exists and has been addressed in the TCP/IP protocol stack for ethernet. You might want to look at how UDP (broadcasting, don't care about packet loss) and TCP (no data loss) work. TCP has various mechanisms to detect lost packets, such as sequence numbers, but also handles problems like fragmented packets. Jack Peacock
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