Research on TCP Flavors Performance over TDRS Link

Because of support the real time and continual relay for the tracking, telemetry and command information, and also data, video and audio of the LEO and MEO spacecrafts, the Tracking and Data Relay Satellite (TDRS) becomes very important. With the increasing needs for complicated space missions applications, the TDSR requires achievement of seamless interoperability with terrestrial networks as both evolve to provide end-to-end services. It is known that TCP has been a robust and efficient protocol for terrestrial networks and have excellent extensions, so the paper do some research on the performance that TCP works in the GEO TDRS space/ground link, including variants such as TCP Tahoe, TCP Reno, TCP NewReno, TCP SACK and TCP Vegas. Based on the works on the TDRS, the paper compares TCP flavors at first, and then analyses some challenges in space links when using TCP flavors, that are high bit error rate, asymmetric channels, large bandwidth-delay product, and intermittent connectivity and variable round trip time that impede reliable data communication, etc. At last, the paper analyses the performance of TCP flavors in the TDRS space link, focuses on their throughput, link utilization, and congestion window size. From the simulation results, it may draw conclusion that TCP Vegas has the best performance in regular TCP flavors when using in the TDRS space link, but even this, the regular TCP flavors are not totally appropriate for the TDRS space/ground end-to-end communication in any circumstance, they need to be modified and improved.