Measurement-Based Wireless LAN Troubleshooting

Abstract — Wireless networks based on the IEEE 802.11 family of standards are becoming increasingly common. Their wide-scale deployment introduces a set of new operational problems concerning connectivity, security and quality-of-service. This pa-per describes a set of measurement tools for troubleshooting and securing a set of geographically overlapping wireless networks in infrastructure mode and in ad hoc mode. These tools improve on existing mechanisms by analyzing link-layer sequence numbers, deducing link congestion based on retransmission traces and by detecting cross-channel interference based on observing sets of neighboring or overlapping channels at the same time. The paper illustrates the effectiveness of these new measurement techniques through a series of short, real-world experiments. I