Cascading failures in interdependent networks due to insufficient received support capability

We propose a capability based dependency model of interdependent network that takes two node dependency properties into account. One is support capability and the other is required capability. The redundancy degree of an interdependent network is also defined, whose value is the ratio of its total support capability and total required capability. Through the numerical simulations, we found that: (1) Interdependent networks without redundant support-dependence links are extremely vulnerable, even the failure of one node could cause the collapse of whole network; (2) Increasing support-dependence links and redistributing the nodes' dependency properties can enhance the robustness of network without changing its redundancy degree; (3) Improving the redundancy degree could enhance network robustness without adding support-dependence links. These conclusions enlighten the design of interdependent networks: when network's redundancy degree is fixed, we can take strategy from results (2), and when network structure is settled, we can apply strategy from results (3).