Is it possible to connect iPhones through NAT traversal techniques over 3G for peer 2 peer gaming

Question

Is it possible to connect an iPhone to another iPhone or any other network client talking that game's protocol.

I was thinking that I could use the same NAT Traversal technique used in the XBox 360 to host games on users XBox's through Firewalls.

For NAT traversal to work effectively I'd have to have a central server that would allow clients to "broadcast" that they were hosting so that another client could initiate the NAT connection. In the link provided this is called relaying.

Is there any inherent limitation of the US AT&T 3G network that will block the NAT traversal techniques (would you be limited to wifi firewall NAT traversal)?

NAT Traversal Projects: - PJSIP - providing NAT traversal functionalities by using standard based protocols such as STUN, TURN, and ICE. - Freecast using Apache MINA Java network library for NAT Traversal

Answer 1

iPhone OS 3.0 will have an API for multiplayer gaming and connectivity with over devices in your immediate area,

"You can find other iPhones and iPod Touches in a given area that are playing the same game as you; Forstall gives the example of two kids in the back of a car. iPhone 3.0 will automatically discover other applications over Bluetooth, and there's no pairing. "Completely seamless," he promises. Bonjour is the back-end technology behind this, and it's not just for games"

Sources: CNET Live Blog, and the Apple Special Event Quicktime Video It's about 20 minutes into the presentation.

If you are going for something more than playing with nearby devices, you will probably run into problems with bandwidth caps on the 3G network as well as latency issues depending on where users are located. Boonies with very sporadic 3G coverage vs. downtown major city USA with multiple cell towers concentrated in a small area. You may also run into a problem with AT&T depending on how much data the game is sending and receiving from the phone over the 3G network since multiplayer games require the players and the server (even if it's a player acting as one) to send information back and forth constantly. Interesting idea though!