Congestion Control

SCTP congestion control mechanism is similar to that provided by TCP, and includes slow start, congestion avoidance, and fast retransmit. In SCTP, the initial congestion window ( cwnd ) is set to the double of the maximum transmission unit (MTU) while in TCP, it is usually set to one MTU. In SCTP, cwnd increases based on the number of acknowledged bytes, rather than the number of acknowledgements in TCP. The larger initial cwnd and the more aggressive cwnd adjustment provided by SCTP result in a larger average congestion window and, hence, better throughput performance than TCP.