Abstract: In general, the present invention provides for a direct inter-subsystem transfer of an active communication session, such as a call, between a packet subsystem (PS) and a circuit-switched subsystem (CS) in an efficient and effective manner while maintaining service control and continuity. Further, the inter-subsystem transfer may take place between a PS of one generation and a CS of another generation.

Abstract: In general, the present invention provides for a direct inter-subsystem transfer of an active communication session, such as a call, between a packet subsystem (PS) and a circuit-switched subsystem (CS) in an efficient and effective manner while maintaining service control and continuity. Further, the inter-subsystem transfer may take place between a PS of one generation and a CS of another generation.

Abstract: To provide expedited ringback at an originating terminal, a call request is sent from the originating terminal to a destination device over an Internet Protocol (IP) network. Local resource reservation is performed by the originating terminal after sending the call request. A first message is received by the originating terminal prior to the originating terminal sending a second message indicating that local resource reservation has been performed, the first message for indicating that alerting is being performed at the destination device. In response to receiving the first message and determining that the local resource reservation has been performed, a ringback indicator is generated by the originating terminal.

Abstract: A call request is sent to establish a telephony session over an Internet Protocol (IP) network between an originating terminal and a destination device. A message responsive to the call request is received from a node connected to the IP network. In response to receiving the message, local generation of a comfort indicator at the originating terminal is performed.