In chipflip example given with SIP installer, they r using ACK for each message(In-game for example.sending what player moved..Not SIP message) players send.

Is it really fruitful ? As once game become n player, waiting for ACK for each move is ......

Does socket connection that handsets estaiblish between them after SIP invitation acceptance never loose data or what's frequency of loosing data ?

What about bluethooth connection ?