Ok, this might just be a dumb question, but I was wondering if Bluetooth follows TCP or UDP protocol? From my knowledge of network protocols (which isn't much), I would say that it doesn't follow either of those two and that there is some kind of specific bluetooth protocol that exist. I have one more question...what protocol does the bluetooth functionality in the GameKit in the new iPhone OS 3.0 follow? I haven't looked through every single word of the apple documents yet, but so far, I haven't been able to find it.
TCP and UDP are transport level protocols whereas Bluetooth would be a lower level protocol. Thus you could use TCP or UDP on top of Bluetooth just as you use TCP and UDP on top of Ethernet.
The Bluetooth protocol stack includes its own transport protocols: L2CAP and RFCOMM, where RFCOMM links use the L2CAP layer. You can work some IP tunneling over Bluetooth encapsulating UDP packets over RFCOMM links.
Gamekit hides the Bluetooth stack from you but my guess is that it uses SDP for peer discovery and RFCOMM links for communication between them.
Neither. I can't say which protocol of those that the iPhone uses by default, but I've had some work experience in communicating PCs and cell phones via the RFCOMM protocol at least.
The normal communication between two devices is by using RFCOMM (Radio Frequency Communication) and L2Cap. Upto my guess the protocols used by the iphone would be A2DP or AVRCP
Think of Bluetooth stack comparable to the typical TCP/IP based OSI stack. If you read further on the Bluetooth protocol stack and architecture, you would see the similarities of the OSI stack mappings. As in the traditional OSI layer that you're probably aware of, you have L2 equivalent layer, transport layer, session and application and so on.
If you're thinking of TCP layer, you're looking at L2CAP layer on Bluetooth. Please follow up with the Bluetooth wiki to give you a better understanding.
Further, I referred this book years ago - http://www.amazon.com/Bluetooth-Operation-Use-Robert-Morrow/dp/007138779X
来源：https://stackoverflow.com/questions/1046669/bluetooth-protocol