Applying Speculative Technique to Improve TCP Throughput over Lossy Links

Abstract — The throughput degradation of Transport Control Protocol (TCP) over lossy links due to the coexistence of congestion losses and link corruption losses is very similar to the degradation of processor performance due to control hazards in CPU design. First, two types of loss events in networks with lossy links can be considered as two possibilities of a branching result (correct speculation vs. incorrect speculation) in a CPU. Secondly, both problems result in performance degradations in their application environments, i.e., penalties (in clock cycles) in a processor, and throughput degradation (in bit per second) in TCP networks. This has motivated us to apply speculative techniques (i.e., speculating on the outcome of branch predictions), used to overcome control dependencies in a processor, to TCP improvements when lossy links are involved in TCP connections. The objective of this paper is to propose a protocol-level speculation based TCP modification to improve its throughput over lossy links. Simulation results show that, compared to other prior research, our proposed algorithm significantly improves TCP throughput in a network with satellite links