Remotely Gauging Upstream Bufferbloat Delays

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 response, 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 experienced by remote hosts, both those using LEDBAT, through LEDBAT’s native one-way delay measurements, and those using TCP (via the Timestamp Option).