On Cost-Efficient Integrated Multilayer Protection Planning in IP-Over-EONs

In this work, we investigate the problem of integrated multilayer protection planning in IP over elastic optical networks (IP-over-EONs). We consider a single-failure scenario where either a router outage or a fiber cut would occur in any time period. To protect against a router outage, we formulate the backup router planning problem as a mixed linear programming (MILP) model in which the optical-layer spare capacity can be reused by the IP-layer spare capacity and the total cost consisting of the extra spare capacity and the IP-layer backup lightpaths is to be minimized. According to the time complexity of the weighted set-covering problem, we prove the NP-hardness of the backup router planning problem and, therefore, propose a heuristic algorithm. To protect against fiber cuts, we employ shared “1 + 1” path protection and propose a lightpath establishment algorithm that can not only clarify the types of the spare capacity but also perform spectrum sharing among them adaptively. Extensive numerical simulations show that our proposed backup router algorithm can achieve 96.88% similar results to the MILP model, and requires about 43.78% less IP-layer lightpaths than the benchmark algorithm based on dedicated backup routers. Meanwhile, our proposed lightpath establishment algorithm can reduce the planned spectrum resources by 35.67%.