In the Bluetooth protocol stack, the Service Discovery Protocol (SDP), also known as Bluetooth SDP, provides special means for applications in the Bluetooth environment to discover which services are available and to determine the characteristics of those available services. The SDP defines how a Bluetooth client’s application shell acts to discover available Bluetooth servers’ services and their characteristics. The protocol defines how client can search for a service based on specific attributes without the client knowing anything of the available services. The SDP provides means for discovery of new services becoming available when the client enters an area where a Bluetooth server is operating. The SDP also provides functionality for detecting when a service is no longer available.