Ricerc@Sapienza

This paper proposes and investigates a reconfiguration policy of cloud and bandwidth resources in network function virtualization environments in which the network function virtualization infrastructure-point of presences are interconnected by an elastic optical network. The proposed policy is applied in dynamic traffic scenarios, it is based on virtual network function instances migrations and reconfiguration of optical circuits. The policy aims at minimizing the sum of three cost components: the cloud resource cost, the bandwidth cost, and the reconfiguration cost. The reconfiguration costs are characterized by the revenue loss of a network operator due to the bit loss occurring when the optical circuits are reconfigured. We formulate the optimization problem and because of its complexity we propose and investigate an effective heuristic. The achieved results show how the proposed heuristic allows, in typical traffic and network scenario, for a consistent cost reduction with respect to the solutions proposed in literature in which only the sum of cloud and bandwidth resource costs are considered and reconfiguration costs are not take into account.