Abstract: Cascaded TCP: BIG Throughput for BIG DATA Applications in Distributed HPC

Saturating high capacity and high latency paths is a challenge with vanilla TCP implementations. This is primarily due to congestion-control algorithms which adapt window sizes when acknowledgements are received. With large latencies, the congestion-control algorithms have to wait longer to respond to network conditions (e.g., congestion), and thus result in less aggregate throughput. We argue that throughput can be improved if we reduce the impact of large end-to-end latencies by introducing layer-4 relays along the path. Such relays would enable a cascade of TCP connections, each with lower latency, resulting in better aggregate throughput. This would directly benefit typical applications as well as BIG DATA applications in distributed HPC. We present empirical results supporting our hypothesis.