Improving Throughput in SCTP via Dynamic Optimization of Retransmission Bounds

The Stream Control Transmission Proto- col (SCTP) is a relatively new transport protocol. It has several underlying mechanisms that are similar to the Transmission Control Protocol (TCP), as well as several improvements that are important in certain classes of applications. The timeout scheme of SCTP, however, is almost identical to that used in TCP. With the dynamics of today’s Internet, that timeout scheme may be too passive. This paper presents an al- gorithm which dynamically adjusts the overall context of the retransmission timeout process without chang- ing the fundamental retransmission mechanisms. This approach manages the impact of fast retransmissions and timeouts to significantly improve the throughput of SCTP applications. The algorithm has been im- plemented and tested in real network environments. Experimental results show that the algorithm avoids spurious retransmissions and provides better through- put by intelligently managing RTO boundaries and allowing conventional timeout schemes to participate more actively in the retransmission process.