Patent ID: 7986775

Claim:
A method for implementing a ring back tone in a communication system, wherein a packet core network of the communication system uses the Session Initiation Protocol as call control signaling, and a service control element provides various service logic control functions for a user, the method comprising: A) a service control element at a forward side, upon receiving a call request message from a caller user, issuing an instruction to reject a ring tone resource to a service control element at a backward side during interaction with the service control element at the backward side; B) the service control element at the backward side, upon receiving the call request message, if a user terminal is idle and permits a direct incoming call, sending a call request message to the user terminal, and requesting a ring tone resource from the media resource control element; and upon receiving a ring message from the user terminal and an answer response message indicative of a successful request for the ring tone resource, sending to the forward side a ring message representative of the ring tone resource; and C) the service control element at the forward side, upon receiving the ring message from the backward side, issuing an instruction to reject a ring tone resource to the service control element at the backward side, the instruction being an instruction to deactivate the ring tone resource from the backward side, and sending to the forward side a ring message.