Early-Warning-Driven Approach for Network Protection Against Earthquakes

Abstract

Natural disasters can significantly disturb communication networks. There are examples of events causing massive connectivity failures in the past, such as the Great East Japan Earthquake. Network protection mechanisms have been developed to cope with the destructive power of natural disasters and mitigate their impact on connections availability, but in terms of accuracy, they are far from perfect.

Some natural disasters are predictable and can be detected hours or even days in advance. In that case, an adequate protection strategy can be applied. Nevertheless, other types of disasters, such as earthquakes, are classified as unpredictable; thus, protecting the network becomes challenging. Fortunately, early warning systems can detect ground motion and provide a few seconds of warning before the shaking is actually felt. In our work, we utilize early warnings and other disaster data to develop a network protection approach against earthquakes, which operates under rigorous time constraints. Our goal is to minimize the number of disrupted connections in the network by rerouting as many connections as possible out of the disaster zone, such that their availability is maximized. At the same time, the sum of the bandwidth of the connections in the network is also maximized.

We create a realistic disaster model using an early warning system and disaster information. We tackle the uncertainties related to unpredictable disasters by introducing the concept of multiple disaster scenarios. We define the problem of finding paths with maximized availability considering the multiple scenarios. The problem is extended further by adding bandwidth constraints. We propose heuristics to solve the formulated problems and provide an SDN implementation. We validate the effectiveness of our solutions by conducting a series of experiments and creating a custom metric to evaluate our results. The results show that our approach improves the availability of the endangered connections; using the proposed multi-scenario strategy is more beneficial than a single scenario. The results also show that our bandwidth algorithm can optimize the bandwidth utilization of the network. Finally, we compare our solution to an exact solution and find out that our results are very close to optimal. This work provides a mechanism for network operators to ensure the protection of critical network communication in the event of a natural disaster and prevent the potential loss of human lives.