The robust-yet-fragile nature of interdependent networks

Interdependent networks have been shown to be extremely vulnerable based on the percolation model. Parshani et. al further indicated that the more inter-similar networks are, the more robust they are to random failure. Our understanding of how coupling patterns shape and impact the cascading failures of loads in interdependent networks is limited, but is essential for the design and optimization of the real-world interdependent networked systems. This question, however, is largely unexplored. In this paper, we address this question by investigating the robustness of interdependent ER random graphs and BA scale-free networks under both random failure and intentional attack. It is found that interdependent ER random graphs are robust-yet-fragile under both random failures and intentional attack. Interdependent BA scale-free networks, however, are only robust-yet-fragile under random failure but fragile under intentional attack. These results advance our understanding of the robustness of interdependent networks significantly.