duplicate udp packets: how often it happens?

Question

I am developing a protocol over UDP to be used in a local network, there will be only a switch (cisco, 3com, etc) between source and destination, both Linux systems, same MTU. How often should I expect udp packets to be duplicated (obviously not by me but by the switch or maybe the server) at the destination in this case? I need this to know if to implement a duplication check in my code or not.

Answer 1

Switches will send packets to all interfaces when using broadcasts or under extreme conditions (full MAC Address Table). This can lead to duplication if there is a loop between two or more switches and if the Spanning Tree Protocol is not used. So the answer is rarely.