The Bluetooth architecture, showing all the major layers in the Bluetooth system, are depicted in the Fig. The layers below can be considered to be different hurdles in an obstacle course. This is because all the layers function one after the other. One layer comes into play only after the data has been through the previous layer.

                                      Figure 5.8.3 The Bluetooth architecture

·         Radio: The Radio layer defines the requirements for a Bluetooth transceiver operating in the 2.4 GHz ISM band.

·         Baseband: The Baseband layer describes the specification of the Bluetooth Link Controller (LC), which carries out the baseband protocols and other low-level link routines. It specifies Piconet/Channel definition, “Low-level” packet definition, Channel sharing

·         LMP: The Link Manager Protocol (LMP) is used by the Link Managers (on either side) for link set-up and control.

·         HCI: The Host Controller Interface (HCI) provides a command interface to the Baseband Link Controller and Link Manager, and access to hardware status and control registers.

·         L2CAP: Logical Link Control and Adaptation Protocol (L2CAP) supports higher level protocol multiplexing, packet segmentation and reassembly, and the conveying of quality of service information.

·         RFCOMM: The RFCOMM protocol provides emulation of serial ports over the L2CAP protocol. The protocol is based on the ETSI standard TS 07.10.

·         SDP: The Service Discovery Protocol (SDP) provides a means for applications to discover, which services are provided by or available through a Bluetooth device. It also allows applications to determine the characteristics of those available services.

Now we shall be study each layer in detail (in next few sections) so that we come to know the function of each layer.