Wireless LANs use the IEEE 802.11 standard which defines the physical and MAC layers. The physical layer uses either frequency hopping spread spectrum or direct sequence spread spectrum to transmit over radio frequencies. The MAC layer uses CSMA/CA for channel access and defines frame formats for addressing between devices in a basic service set or extended service set. Bluetooth uses a piconet topology with a master-slave relationship between devices for communication at the baseband layer, and supports both single-slave and multiple-slave communication through its L2CAP layer.