Assortativity Decreases the Robustness of Interdependent Networks

TL;DR

This paper investigates how the internal network topology, specifically assortativity, affects the robustness of interdependent networks, revealing that higher assortativity decreases system resilience against cascading failures.

Contribution

It demonstrates that assortativity within individual networks reduces the overall robustness of interdependent systems, providing new insights into network design for improved resilience.

Findings

Assortativity decreases the critical failure threshold.

Internal node correlations significantly impact failure propagation.

Results suggest designing less assortative networks for better robustness.

Abstract

It was recently recognized that interdependencies among different networks can play a crucial role in triggering cascading failures and hence system-wide disasters. A recent model shows how pairs of interdependent networks can exhibit an abrupt percolation transition as failures accumulate. We report on the effects of topology on failure propagation for a model system consisting of two interdependent networks. We find that the internal node correlations in each of the two interdependent networks significantly changes the critical density of failures that triggers the total disruption of the two-network system. Specifically, we find that the assortativity (i.e. the likelihood of nodes with similar degree to be connected) within a single network decreases the robustness of the entire system. The results of this study on the influence of assortativity may provide insights into ways of improving the robustness of network architecture, and thus enhances the level of protection of critical infrastructures.