alt text 

Stanford University Networking Seminar


Aaron Schulman (Stanford University)
Pingin’ in the Rain: How Weather Correlates with Residential Internet Failures

12:15pm, Thursday, April 3, 2014
Packard 202

About the Talk

Residential links are vulnerable to all types of weather, including wind, heat, and rain. This is because residential equipment and wiring are often installed outdoors: wind can blow trees onto overhead wires, heat can cause equipment to fail, and rain can seep into deteriorating cables. To investigate the connectivity of residential Internet hosts before, during, and after periods of severe weather forecast by the National Weather Service, we collected 4 billion pings from 3.5 million IP addresses over 400 days of probing from PlanetLab hosts.

The diversity of the weather, residential link types, and residential locations in this data creates an opportunity to discover rare pathologies, but also creates substantial challenges in focusing the analysis on failures of the residential link due to weather. We overcome these challenges with a suite of processing techniques: (1) We groom the pings to remove false positive failures caused by PlanetLab faults; (2) We determine the probability that a complete loss of pings indicates a failure based on past behavior of the host; (3) We apply an edge detection algorithm to determine when hosts completely or partially lose connectivity; and (4) We characterize and remove potential power distribution failures by correlating pings with a list of self-reported power distribution failures from the Department of Energy. We apply these techniques to our large corpus of data and present a broad study of the effect of weather on last-mile Internet links. Our study reveals interesting nonlinear effects of various types of weather on various last-mile link technologies.

About the Speaker

Aaron Schulman is a Postdoctoral Scholar at Stanford working with Sachin Katti. His research interests are in wireless communication, network measurement, and low-power embedded systems. He enjoys finding problems with the Internet's last-mile link infrastructure and coming up with practical solutions. He earned his PhD in Computer Science from University of Maryland in August 2013 under the supervision of Neil Spring. From 2010 to 2011, he was a Visiting Scholar with Prabal Dutta at the University of Michigan. He interned at Microsoft Research Redmond in 2008 and India in 2009. Aaron won the 2013 ACM SIGCOMM Doctoral Dissertation Award