What part of BLE is GAP concerned with?

Answer

GAP, the generic access profile, is concerned with how devices advertise, broadcast, discover, and connect with each other. GAP defines the following roles: Broadcaster - transmit only Observer - receive only Central - scans for and initiates connections with advertising peripherals Peripheral - advertises and invites connections from central role devices In reality most BLE devices use the terms central or peripheral, but an iBeacon could be described as a broadcaster for example.