SEAMLESS HAND-OFF OF MOBILE NODE TO A WIRELESS LOCAL AREA NETWORK (WLAN)

摘要

A method and system for seamlessly handing off a Mobile Node (MN) equipped with a Wireless Local Area Network (WLAN) adaptor from a cellular network such as a GRPS/UMTS network to a WLAN network without interrupting the ongoing IP connection/session. When entering a WLAN coverage area, the roaming MN sends mobility information to a WLAN Integration Gateway (WIG) node allowing the WIG node to identify the source Service GPRS Support Node (SGSN). The WIG node contacts the source SGSN to obtain PDP Context information relative to the roaming MN, and establishes a new GTP tunnel with the servicing GGSN in order to complete the handoff. The WIG node may route data traffic for the MN by assigning a new IP address to the MN and by either performing IP-in-IP encapsulation or Network Address Translation (NAT).