For question 1 , that dependent of how you connect to your server
if u use it like this (session_connect(app_name,"internet ip")), that mean the engine send the data over internet to this client , if you connect like this (session_connect(app_name,"") or session_connect(app_name,"127.0.0.1")) or trough router (session_connect(app_name,"192.168.....") + opned port) that mean the engine send the data over lan.