Assessing the impact of geographically correlated network failures

Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to human attacks, such as an electromagnetic pulse (EMP) attack. Such real-world events have geographical locations, and therefore, the geographical structure of the network graph affects the impact of these events. In this paper we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the location of a disaster that would have the maximum effect on network capacity. We consider a geometric graph model in which nodes and links are geographically located on a plane. Specifically, we model the physical network as a bipartite graph (in the topological and geographical sense) and consider the set of all vertical line segment cuts. For that model, we develop a polynomial time algorithm for finding a worst possible cut. Our approach has the potential to be extended to general graphs and provides a promising new direction for network design to avert geographical disasters or attacks.