Characterizing Home Network Performance Problems

We design, develop, validate, and deployWTF (Where’s The Fault?), a system that determines whether a performance problem in a home network lies with the ISP or inside the home network. WTF uses four independent maximum likelihood detectors to detect both access link bottlenecks and wireless network pathologies with high detection rates and low false positive rates; we use extensive controlled experiments to determine the appropriate thresholds for each parameter that we measure. We implemented WTF as custom firmware that runs in an off-the-shelf home router and deployed it in 64 home networks across 15 countries. The real-world deployment sheds light on common pathologies that occur in home networks. We find that wireless bottlenecks are significantly more common than access link bottlenecks, that the 5 GHz spectrum consistently outperforms the 2.4 GHz spectrum, that many homes experience high TCP round-trip latencies between wireless clients and the access point, and that performance can vary dramatically across wireless devices, even within a single home network.