2.1 Transport
The Automatic Bluetooth Pairing Protocol MUST have a byte stream connection between the client and server. This connection MUST be established by using RFCOMM [BT-RFCOMM]. To identify an Automatic Bluetooth Pairing Protocol-capable server by using RFCOMM, the client MUST use the Bluetooth Service Discovery Protocol (SDP) [BT-SDP]. Tethering-capable servers MUST be identified through SDP by using the globally unique identifier (GUID) {D9009112-CD2B-4e7a-A463-437D71E14905}. The RFCOMM communication channel is created before a Bluetooth pairing relationship with the server is created and MUST be unauthenticated.