While 802.11-based wireless hotspots are proliferating, users often have little recourse when the network does not work or performs poorly for them. They are left trying to manually debug the problem, which can be a frustrating and disruptive process. The users’ troubles are compounded by the absence of network administrators or an IT department to turn to in many 802.11 hotspot settings (e.g., cafes, airports, conferences).

We present WiFiProfiler, a system in which wireless hosts cooperate to diagnose and possibly resolve network problems in an automated manner, without requiring any infrastructural support. The key observation is that even if a host’s wireless link to an access point is not working, the host is often within the range of other wireless nodes and is in a position to communicate with them (a little) peer-to-peer. We leverage this ability to create a shared information plane, which enables wireless hosts to exchange a range of information about their network settings and the health of their network connectivity. By aggregating and correlating such information across multiple wireless hosts, we infer the likely cause of the problem. Our implementation on Windows XP shows that WiFiProfiler is effective in diagnosing a range of problems and imposes a low overhead on the participating hosts.