Patent ID: 8345596

Claim:
A call control method for ensuring service continuity in a mobile communication service environment, which is performed by a service control unit to control a Session Initiation Protocol (SIP)-based service, comprising: receiving a call signal message including permanent IP addresses and transport IP addresses from a transmitter terminal and a receiver terminal, and acquiring the permanent IP addresses and the transport IP addresses of the transmitter terminal and the receiver terminal, wherein the permanent IP address does not participate in data transmission and is used as an identifier (ID) through which the location of the terminal is registered, and the transport IP address participates in actual data transmission; performing call control between the transmitter terminal and the receiver terminal on the basis of the transport IP addresses and the permanent IP addresses of the transmitter terminal and the receiver terminal, wherein the permanent IP address of a terminal is part of a payload of the call signal message; wherein the performing of the call control, comprises, in the service control unit, transmitting the permanent IP addresses and Quality of Service (QoS) information of the transmitter terminal and the receiver terminal to an IP mobility control unit; wherein in the IP mobility control unit, acquiring the transport IP addresses of the transmitter terminal and the receiver terminal from pre-stored information on the basis of the permanent IP addresses of the transmitter terminal and the receiver terminal; and transferring the transport IP addresses and the QoS information of the transmitter terminal and the receiver terminal to a network control unit.