MANAGEMENT OF SEAMLESS HANDOVER BETWEEN DIFFERENT COMMUNICATION SYSTEMS IN AN IP DUAL-MODE TERMINAL

摘要

Disclosed herein is a dual-mode terminal (T1) designed to connect to an IP-based network (IPN) via a first communication system (UMTS) and a second communication system (WLAN), the dual-mode terminal (T1 ) comprising a first physical network interface module (N11) adapted to establish a packet-based communication with the IP-based network (IPN) via the first communication system (UMTS), the first physical network interface module (N11) being accessible via a first physical network interface (ph11 ) having a first physical network address (IP1_P1 ); a second physical network interface module (N11 ) adapted to establish a packet-based communication with the IP-based network via the second communication system (WLAN), the second physical network interface module (N 12) being accessible via a second physical network interface (ph12) having a second physical network address (IP1_P2); an IP-based protocol stack (TCP/IP) adapted to operate between a software application (A2) in the dual-mode terminal (T1) and the first and second physical network interface modules (N 11, N 12); and a system for performing a seamless handover between the first communication system (UMTS) and the second communication system (WLAN) during a connection to the IP-based network; wherein the system for performing a seamless handover comprises a virtual network physical network interface module (M 1 ) accessible via a virtual network interface (virt11) having a virtual network address (IP1 V1), the virtual network physical network interface module (M1) being configured to operate between the IP-based protocol stack (TCP/IP) and the first and second physical network interface modules (N11, N 12) to receive and transmit incoming and outgoing data packets through the first and the second physical network interfaces (ph11, ph12); the IP-based protocol stack (TCP/IP) being configured to generate data packets having a source physical network address equal to the virtual network address (IP1_V1) of the virtual network interface (virt11) in the dual-mode terminal (T1 ); and the virtual network physical network interface module (M 1) being configured to change the source physical network address of data packets from the IP-based protocol stack (IPS1 ) to the physical network address (IP1_P1, IP1_P2) of the physical network interface (ph11, ph12) of the physical network interface module (N11, N12) in the dual-mode terminal (T1 ) used for the connection to the IP-based network.