Is the clustering coefficient a measure for fault tolerance in wireless sensor networks?

Distributed systems such as the Internet and wireless sensor networks must provide a high degree of resilience against errors and attacks. Besides steps that increase reliability of data and resources of the network, the topology structure itself plays a crucial role in the efficacy of the fault-tolerance behavior. The network topology is a supportive factor to reduce or avoid malfunction behavior of the system after a strike on a strategic node or a random failure of a node. For a self-organizing topology with numerous nodes, it is necessary to have a local fault tolerance measure instead of collecting information of the entire network to adjust the topology locally when needed. The local clustering coefficient determines the degree of the connectedness of the node´s neighbors. The correlation between the clustering coefficient and fault tolerance is an open research problem. In this paper, we propose the clustering coefficient as a local metric for fault tolerance, in particular for wireless sensor networks. We describe how to increase the clustering coefficient by (a) exclusively adding and (b) exclusively removing links to a wireless sensor network topology. Simulation results indicate that the clustering coefficient is correlated to the fault tolerance of the system.