Improvement of SCTP Performance in Vertical Handover

A heterogeneous wireless network integrating IEEE 802.11 WLAN and 3G/UMTS mobile phone system will be a common scenario in future mobile networking. The multi-homing feature of SCTP and the dynamic address configuration extension had made seamless vertical handover possible in heterogeneous mobile wireless networks. However, an ongoing SCTP association will experience the slow-start phase on the new path after a vertical handover, since the congestion window and slow-start threshold on the new path are reset to their initial values. For smoother handover, a new approach is developed and presented in this article. In the proposed scheme, we send out probing packets on the new path to estimate available bandwidth before actual handover. Obtained information can then use to preset the flow control parameters. By doing so, the slow-start phase can be effectively skipped. Simulation results reveal that the proposed scheme is a feasible and effective solution for the improvement of SCTP performance during vertical handover in heterogeneous mobile wireless networks.