Bluetooth® Low Energy (BLE) devices can operate in one or more Generic Access Profile (GAP) roles at the same time (provided the Link Layer supports this):
The role imposes restrictions and enforces behavior, so it is generally fixed in the design stage of the device.
Two role pairs are defined, allowing devices to communicate with each other.
This role pair implements unidirectional, connection-less communications.
- Scans for broadcasters, listening for advertising data
- Uses the Link Layer Scanner role
This role pair implements bidirectional, connection-oriented communications.
- Link Layer Slave role
- Advertises by using connectable advertising packets
- Optimized to consume the least amount of processing power and memory
- Enables a low-cost design
- Link Layer Master role
- Capable of establishing and managing a connection
- May be connected to various devices simultaneously
For data transfer operations in BLE connections, different roles are defined by the Generic Attribute Profile layer.