Trajectory-based post-disaster content evacuation in inter-DC optical networks under cascading failures

In the post-pandemic era, global working patterns have been reshaped, and the demand for online network services has increased significantly. Therefore, cross-data-center content migration has become a relevant problem to address, leading to higher attention in data backup/recovery planning. Beyond traditional pre-disaster content redundancy approaches, this work focuses on the challenge of rapid post-disaster content evacuation under the threat of cascading failures. In fact, due to the interdependence of data centers (DCs), inter-DC optical networks, and power grid networks, disasters may have a domino effect on these infrastructures, with their impact gradually expanding over time and space. In this paper, we propose two trajectory models that capture the dynamic evolution of cascading failures, and we propose a trajectory-based content evacuation (TCE) strategy that considers the spatiotemporal evolution of cascading failures to minimize content loss. Numerical results show that, when each DC needs to evacuate about 200 TB of massive content, TCE can reduce content loss by up to 25% compared to baseline strategies.