A Measurement-based Study of End-to-End Internet Traffic Dynamics

We present findings from a multiple week study of Internet traffic dynamics using link throughput as the primary metric. Many traces were conducted through a four node, mesh-connected, “real world” Internet testbed. We generate different types of traffic (single TCP flows, multiple TCP flows, and single UDP flows) using a generic, multipurpose, sockets program. We discuss 1) link asymmetry for TCP and UDP traffic; 2) effects of different transfer sizes on throughput when using TCP and UDP; 3) link throughput when sending multiple simultaneous TCP flows, comparing their total throughput with a single TCP flow’s throughput; 4) link throughput achieved when using different transport protocols; and 5) the changing trend of diurnal traffic patterns. We find that there continues to be significant asymmetry between sending and receiving paths. Also, we show that TCP throughput is significantly affected by transfer size, however UDP traffic throughput is impervious to transfer size variations. We further find that larger (longer duration) TCP flows share bandwidth more fairly than smaller TCP flows; also, no significant throughput improvement was noted when using larger flows, however multiple small flows can achieve a significantly higher throughput than a single small flow. Finally, we show that UDP traffic always attains the available bandwidth, which is significantly higher than that attained by TCP traffic.