I've got a few questions how to implement my Unity 3D game server. First of all some information of my game:

•It's a ARPG diablo style game.
•Must support multiple clients.
•Must support multiple games with 1 to 5 players.
•Game chat.

I have basic C++ UDP socket server (using one port) that receives a message and response to the client. Now I need to implement the multiple clients. My idea was when the server receives the messege from the client, create new thread (leaving the socket free to listen) and process the message (player position, events, etc..) then broadcast the response to the other clients in the same game, finaly close the thread.

1.Do I need to use threads when I'm using UDP socket to process the client message?
2.It's good my logic for the server?
3.The chat must be in separeted socket and port number?
4.The client will need to use threads to process the received message?
5.Any other suggestions how to implement the server?