link manager protocol (Bluetooth) (LMP)
Like the Logical Link Control and Adaptation Protocol (L2CAP), the Service Discovery Protocol( SDP) and the Baseband Protocol, the Link Manager Protocol( LMP) is one of the core protocols of Bluetooth.
The LMP protocol interfaces with the HostController Interface( HCI) and connects the higher layers of the protocol stack with the transmission-related baseband protocol.
Using the LMP protocol, Bluetooth devices independently agree on the appropriate connection parameters when establishing contact. In addition to establishing the connection, the Link Manager Protocol negotiates the packet size for the baseband protocol, controls the RF transmit power, informs the Protocol Description Units( PDU) about switching on economy modes, and performs security functions in the form of authentication and encryption using security codes. Authentication uses a 128-bit key on the link.