Google dead reckoning. Sending out updates for 4 players is not going to be significant. The amount of data sent is going to be on the order of bytes. So, that means frequent updates should be ok. With dead reckoning, you move the player on the client and the server. The server is the authority. When the clients position becomes too far out of synch from the server, it has to drift back into alignment. http://trac.bookofhook.com/bookofhook/trac.cgi/wiki/Quake3Networking Using UDP is the way to go. Bupdates will be sent to frequently that lost data will soon be replaced by incoming data anyway. The packet retransmit of TCP is not worth it for player position. Look at this article for more info on how to keep the client and server on synch.
