Zephyr: First-person wireless analytics from high-density in-stadium deployments

Zephyr is a first-person wireless-performance data-collection approach to study the end-user's perspective of the wireless-network's performance using an OTT video-streaming service used in 35 mobile applications and 25 sports stadiums. We use Zephyr to provide insights into user behavior and user disengagement from production traces gathered over 2+ years. We identify the different types of failures that we've observed, and describe how frequently they occur. Finally, we correlate low-level Wi-Fi performance data with application-level failures and describe the trends that we observe. The data from Zephyr reveals that 50% of users disengage if video playback does not begin within 12 seconds, and also if video playback stalls, instream, for more than 6 seconds. The most dominant failure type for video playback is cancellation during the initial buffering phase, which accounts for 30% of all streams.