WLC40-2: An Experimental Evaluation of SCPS-TP over Lossy GEO-Space Links

Space communication protocol standards-transport protocol (SCPS-TP) is a set of extensions to transmission control protocol (TCP) aimed at improving TCP performance over space links. Some work has been done on performance evaluation of SCPS-TP based on its methodology, or by testing it as an isolated entity or over satellite that deploys performance enhancing proxies (PEPs). It is needed to have an experimental evaluation of SCPS-TP in coping with heavy noise using the complete SCPS protocol stack, especially by comparing it with state-of-the-art terrestrial TCP. This paper describes an experimental evaluation of SCPS-TP over congestion free, error-prone, high-latency, point-to-point space links, through file transfer experiment by running the actual SCPS protocol stacks via a testbed. The results reveal that SCPS-TP is more tolerant of heavy noise and has significant throughput advantages over TCP. The performance advantage of SCPS-TP in a lossy link is attributed to its novel SNACK scheme and the advantage in asymmetric channel is from the contributions of the channel rate control and acknowledgment reduction mechanisms.