AN APPARATUS AND A METHOD FOR SERVICE CONTINUITY BETWEEN UMTS NETWORK AND WLAN

An apparatus and a method for service continuity between a UMTS(Universal Mobile Telecommunication System) network and a WLAN(Wireless LAN) are provided to enable an IWG(InterWorking Gateway), interworking with the SGSN(Serving GPRS Support Node) or GGSN(Gateway GPRS Support Node) of a 3GPP(Third Generation Partnership Project) network, to seamlessly provide a service to a mobile station in case the mobile station moves from the 3GPP network to a non-3GPP network or returns to the 3GPP network from the non-3GPP network. An apparatus for service continuity between a UMTS network and a WLAN comprises the first node, the second node, and an IWG(250). The first node, or an SGSN(220), executes packet data transfer with a mobile station(100) within service area of the UMTS network. The second node, or a GGSN(230), serves as a wireless gateway between the SGSN(220) and a packet data network(400), and allocates the first address to the mobile station(100) through the SGSN(220) for data communication with the packet data network(400). The IWG (250), when the mobile station(100) moves from the UMTS network to the WLAN, receives the first address, allocated to the mobile station(100), through the first interface from the GGSN (230) and provides a seamless service to the mobile station(100) by using the first address. Also the IWG(250) forms a tunnel with the mobile station(100) by using the first address.