TCP-HORUS: A Dynamic Splitting TCP Utilizing Packet Loss Rate and Latency

With recent improvements in wireless communication technology, the proportion of high-loss and high-latency wireless links such as satellite communication links has increased. Conventional TCP communication based on the end-to-end principle suffers from significant throughput degradation owing to the inefficiency of retransmission control when relatively high loss rates and high-latency wireless links are included. To solve this problem, we previously proposed a dynamic splitting TCP method called TCP-DOPPEL+ (TCP-Dynamically Opt for Proxy to achieve Performance Enhancement based on Link state PLUS), which is based on the product of the packet loss rate and latency. However, TCP-DOPPEL+ uses the product of the packet loss rate and latency as the splitting threshold. If one of the measured values deviates from the actual situation, it becomes difficult to place the splitting devices appropriately. Therefore, we propose a dynamic splitting TCP method, TCP-HORUS (TCP-proxy Hack and Optimize Retransmission by Utilizing link State), based on the packet loss rate and latency with parameters used independently. To evaluate the characteristics of TCP-HORUS, we conducted experiments to evaluate the throughput environments where links with different packet loss rates and latencies between links are mixed on the route, and their locations are varied. The results show that TCP-HORUS improves throughput by at most 20.6 % compared to TCP-DOPPEL+.