Spectrum-efficient anycast in elastic optical inter-datacenter networks

• We investigate the routing and spectrum assignment (RSA) problem for anycast requests in elastic optical inter-DC networks.
• We formulate an integer linear programming (ILP) model and propose several heuristics to solve the RSA problem.
• Simulation results indicate that our proposed algorithms can effectively reduce the blocking probability of anycast requests.

With the rapid development of cloud computing, optical inter-datacenter (inter-DC) networks have attracted intensive research attentions. Meanwhile, recent advances on the flexible-grid elastic optical networks (EONs) have demonstrated agile spectrum management in the optical layer. Therefore, we expect EONs to become a promising underlying infrastructure for optical inter-DC networks. In this paper, we investigate offline and online routing and spectrum assignment (RSA) problems for anycast requests in elastic optical inter-DC networks. For the offline problem, we formulate an integer linear programming (ILP) model and propose several heuristics based on single-DC destination selection. The optimal solutions for small-scale problems are obtained by solving the ILP, and we compare them with those from the heuristics for measuring the optimization gaps. For the online problem, we design several heuristics to consider the computing and bandwidth resources jointly for efficient service provisioning, including an algorithm that uses multi-DC destination selection. Our simulation results demonstrate that the anycast algorithm with multi-DC destination selection can fully utilize the bandwidth resources in the elastic optical inter-DC network, make computing resources become the bottleneck, and reduce the bandwidth blocking probability of anycast requests effectively.