SmSCTP: SIP-Based MSCTP Scheme for Session Mobility over WLAN/3G Heterogeneous Networks

In this paper, a new cross-layer protocol was developed, called as SmSCTP protocol, for session mobility over WLAN and 3G UMTS heterogeneous networks. Two key issues investigated in this work are the connection broken problem and fleeting-location-collapse problem. The connection broken problem indicates that a connection is broken when a mobile device is roaming to a different network. The connection broken problem incurs the long handoff delay time and cannot provide the seamlessly handoff result for session mobility. Traditional session mobility schemes, such as SIP (layer-7 solution) and MSCTP (layer-4 solution) protocols, only provide non-real time registration when third party user is calling up mobile user. The non-real time registration incurs the well-known fleeting-location-collapse problem and causes additional location update overhead. This paper presents a SIP-based MSCTP (SmSCTP) protocol which is a cross-layer, combination of layer-4 and layer-7, approach. The SmSCTP protocol utilizes the multi-homing mechanism to reduce hand-off delay time and to provide the more seamless handoff scheme. In the SmSCTP protocol, two new SIP signalings for the SmSCTP protocol are designed to simplify the initial handoff procedure and solve fleeting-location-collapse problem. Finally, simulation results are conducted to illustrate the performance achievements of the proposed SmSCTP protocol by improving the signaling cost, the hand-off delay time.