Concurrent Multipath Transfer Using SCTP Multihoming

We propose CMT Concurrent Multipath Transfer using the Stream Control Transmission Protocol (SCTP). CMT uses SCTP’s multihoming feature to simultaneously transfer new data across multiple end-to-end paths to the receiver. Through ns-2 simulations, we observe significant reordering at the receiver due to CMT. We identify three negative side-effects of reordering introduced by CMT that must be managed before the full performance gains of parallel transfer can be achieved: (i) unnecessary fast retransmissions at the sender, (ii) reduced cwnd growth due to fewer cwnd updates at the sender, and (iii) more ack traffic due to fewer delayed acks. We propose three algorithms which augment and/or modify current SCTP to counter these side-effects and present initial simulations indicating correctness of the proposed solutions. In this work, we operate under the strong assumptions that the receiver’s advertised window does not constrain the sender, and that the bottleneck queues on the end-to-end paths used in CMT are independent of each other.