Toward Understanding the Behavior of BGP During Large-Scale Power Outages

While the Internet continues to thrive, the resiliency of its fundamental routing infrastructure is not fully understood. In this paper, we analyze the behavior of the de facto inter-domain routing protocol, BGP, during a large-scale power outage that affected the connectivity of 3, 175 networks in dozens of cities in the eastern USA and Canada. By observing proper metrics of BGP, we study BGP behavior from both the global level and the prefix level. At the global level, our results show that many global BGP metrics remained stable during the blackout event; importantly, we do not find an increase in the number of BGP announcements, a metric that has been primarily used to indicate significant changes in routing. However, we observe an apparent increase in the number of withdrawals. At the prefix level, we introduce per-prefix AS-path graphs and study their evolution for affected prefixes during the blackout; we have found that in such graphs there is a sharp decrease in the number of edges and nodes as well as changes in node degrees.