Socket UDP + same port number

W5500 configured as UDP server or client?
Re-reading your other post like this [url]Step-by-Step UDP implementation] I saw that you used DHCP libraries so if you are using the W5500 as a client you can use the part of prepare, send and receiving packets of the same example.
UDP streams do not need a connection and contain the caller’s information in the first few bytes of the stream so you can open multiple socket for receiving (W5500 with single IP / MAC with one or more socket on the same port ) and you know who’s calling and on what (client side) port answer.
Using W5500 as UDP multisocket server is possible for small one-shot stream and very difficult for countinuos stream.
UDP is made to individual packages of small dimensions because is not guaranteed the packets reception order.
So in case of UDP flows in addition to mark each package uniquely (using other type of protocols for continuous streaming ex RDP ) you must manage them in memory before you can use.
Everything depends on the size flow you want to achieve.