Impact of Access Bandwidth on Packet Loss: A Flow-level Analysis

High-speed Internet connectivity is becoming more ubiquitous due to advances in access technologies. On the one hand, the increased access speed allows flows to consume the larger available bandwidth. On the other hand, large aggressive flows lead to more bursty traffic. In this paper, we study the impact of higher broadband access speeds on the resulting packet losses, and dissect those losses into their constituent flows. Based on tightly controlled experiments using open source tools, we show that as ISPs are increasing the access bandwidth of their residential customers, the effects on flow-level properties are non-trivial. Surprisingly, the average number of flows that participate in a packet loss burst remains small, as compared to the burst size. As expected, higher access bandwidth translates into larger packet loss bursts. Furthermore, large flows dominate packet losses, and even more so as access bandwidth increases. In contrast, irrespective of the access bandwidth, a few small flows systematically participate in loss episodes, and suffer significantly due to their limited size.