Impact of queue size at bottleneck point on TCP protocol over 10G-bps networks

Currently, most research and educational backbone networks consist of 10 G-bps network and some hosts connect to this backbone with 10-Gbps. When the hosts try to transfer data with high speed, network often experiences congestion at the backbone due to a confliction with commodity traffic. In such situations, queue size at the bottleneck point has an impact on the throughput performance of TCP data transfer. However, the importance of queue size has not often been well mentioned during design of real R & E network. Network devices with small queue size have sometimes been placed at the bottleneck point. If hosts transfer data over a long distance path and the network device with small queue becomes bottleneck, TCP cannot utilize the available bandwidth effectively. In particular, when running a single TCP stream, the impact of queue size at bottleneck point is significant. In this paper, we will show the impact of queue size at possible bottleneck point on TCP protocols over a 10G-bps network experimentally. The results of our experiments indicate that a network device with small queue size at a bottleneck point decrease the TCP throughput performance on a 10 Gbps long distance path. We confirmed similar results among several advanced TCP protocols.