Research On UMTS/WLAN Vertical Handoff Based On MIP And MSCTP

The co-existance of multiple wireless access networks is the development trend of future networks. Therefore, the study on interworking among heterogeneous access technologies will be one of the key research issues of the future networks. Because UMTS and WLAN are the two most popular wireless access networks, lots of research work are done in the UMTS/WLAN integrated environments.To satisfy the mobility requirement and provide seamless services for users accross ubiquitous and heterogeneous access networks, mobility management has evolved as one of the key techniques in the interworking among heterogeneous access technologies. As one of the most indispensable techniques in mobility management, vertical handoff aims at the communications continuity when a user moves from one network to another different network.Mobile IP (MIP) and mobile Stream Control Transport Protocol (mSCTP) are the two important vertical handoff solutions. MIP and its extensions, which are network layer vertical handoff solutions, have been proposed and standardized by IETF (Internet Engineering Task Force), whereas mSCTP is used as a transport layer vertical handoff solution being standardized by IETF.Based on the analysis of MIP and mSCTP, this paper focused on the UMTS/WLAN vertical handoff based on the MIP and mSCTP. Two simulations of UMTS/WLAN vertical handoff are implemented using NS-2. Furthermore, this paper analyzed and compared the results of the simulations through throughput, handoff delay and packet loss. The conclusion are drawn that the UMTS/WLAN vertical handoff based on mSCTP is better than that based on MIP considering throughput, handoff delay, packet loss and the condition of extra functional entity needed. Finally, a study on the SCTP Load Sharing is explained. Due to its efficiency in using free network resources, the use of the SCTP Load Sharing in the UMTS/WLAN vertical handoff is suggested.