SCTP efficient flow control during handover

Stream control transmission protocol (SCTP) is a transport protocol similar to TCP and UDP. It has a multihoming feature that a node equipped with multiple network interfaces connects to several separate networks concurrently. Multi-homing is a useful feature for a handover process since a mobile terminal can prepare a new path before a breakdown of using path. When a terminal performs a handover using SCTP, it experiences a reduction of traffic rates immediately after handover. This phenomenon is due to a flow control mechanism. Congestion window and slow-start threshold are managed on a per destination address basis in SCTP. After handover, the ongoing SCTP association is switched to a slow-start phase because the congestion window and the slow-start threshold are on an initial state at new path. This paper presents a SCTP efficient flow control (SCTP EFC) mechanism during handover. SCTP EFC minimizes a change of traffic rates during handover. SCTP EFC mechanism has a three-step-procedure: (1) pre-storing flow control parameters before a handover, (2) setting flow control parameters on a handover, and (3) adjusting flow control parameters after a handover. We simulate and analyze the performance using NS-2 simulation tool. The result shows that SCTP EFC adapts to a network environment after a handover. SCTP EFC shows a throughput improvement for several seconds after a handover. In addition, SCTP EFC uses an available network resource efficiently during handover. SCTP EFC is also appropriate for QoS (quality-of-service) because it keeps the traffic rates regularly during handover