help on multiplayer server for mobile games

[sankars]

We are developing a multiplayer game server in php. here since the clients are not ip based, we are developing pull based data transfer. so the server acts like a router and assignes ip etc. now Iwould like to know what all should I do to optimize my server. like now we use php, is java better for this. or we use mysql, is it better to have mssql or having a file based db. plz give your suggestions.

Mobile Game Developer (http://www.smackall.com)