RTT Based Congestion Control and Path Switching Scheme for SCTP

SCTP is an emerging transport protocol that has TCP like congestion control mechanism. The occurrence of packet loss due to congestion is part of SCTP as its congestion control mechanisms rely on packet loss. Loss of packets leads to retransmissions causing excessive delay jitters and increasing traffic burden on the network reducing the throughput. As a result the packets suffer more delays. We have employed a RTT based congestion control technique [5] on SCTP which avoids occurrence of extreme congestion situations. With this scheme the queue-occupancy of the packets and unnecessary packet losses can be controlled. As a result the packet latency and jitter decreases and the utilization efficiency of the links improve. Further, SCTP uses the alternate path only for the retransmission of the packets and failover cases. We propose use of the alternate path for diversion of the traffic based on detection of congestion in the primary path using RTT. This allows good control over queue occupancy of the packets. Result is significantly improved throughput and fairness and reduced latency and packet loss. Experimental results have been obtained to that effect.