Remotely Gauging Upstream Bufferbloat Delays
Chiara Chirichella, D. Rossi, C. Testa, Timur Friedman, Antonio Pescapè · 2013
Abstract. “Bufferbloat ” is the growth in buffer size that has led Internet delays to occasionally exceed the light propagation delay from the Earth to the Moon. Manufacturers have built in large buffers to prevent losses on Wi-Fi, cable and ADSL links. But the combination of some links ’ limited bandwidth with TCP’s tendency to saturate that bandwidth results in excessive queuing delays. In re-sponse, new congestion control protocols such as BitTorrent’s uTP/LEDBAT aim at explicitly limiting the delay that they add over the bottleneck link. This work proposes and validate a methodology to monitor the upstream queuing delay ex-perienced by remote hosts, both those using LEDBAT, through LEDBAT’s native one-way delay measurements, and those using TCP (via the Timestamp Option). 1 Problem statement As a recent CACM article points out, “Internet delays now are as common as they are maddening ” [3]. Currently, the combination of excessive buffer sizes (aka bufferbloat), with TCP’s congestion control mechanism (which forces a bottleneck buffer to fill and generate a loss before the sender reduces its rate), queuing delays can potentially reach