Mobile Stream Control Transmission Protocol (mSCTP) has been proposed to support transport layer mobility management mostly based on the radio signal strength. It could result in aggregation of mobile stations accessed via a base station with the strongest signal in the same signal overlapped area and consequently decrease the transmission probability in wireless networks. In this paper, we propose a cross layer handoff mechanism based on mSCTP, named CL-mSCTP, which combines the layer 4 heartbeat successful contention probability with the link signal strength detection to accomplish the dynamic handoff management. The simulation results show that the CL-mSCTP achieves much better performance in terms of throughput and the balancing of traffic loading than mSCTP does.