I'm developing a game that supports multiplayer via Game Center using Realtime Matches. The other day I noticed a different form of multiplayer that is being widely used where multiple players play on the Apple TV using their iDevices over Wifi.
What framework provides the ability to communicate between an iPhone and the Apple TV?
The version of IOS that run on an Apple TV is a cutdown one, all be it that the restrictions are somewhat artificial, WebKit for example is there and yet it is it a permitted frame work.
Blue tooth, not I beacons I mean core/pheripheral are the means I am using, which is permitted and works well although for a game you might find too slow.
Game kit which also there may be the answer, although I fear is quiet complex implement.
You have core networking so you could implement something using IP addresses and listening on ports, although I must confess I haven't managed to get that working on an IOS combo yet.
Hope that gives you some leads.