Evaluation of reconfiguration cost and energy aware virtual network embedding policies

Network virtualization techniques allow for the coexistence of many virtual networks hosted in a same substrate network. Virtual router migrations allow for resource consolidation with the consequence to reduce the power consumption in low traffic periods. Unfortunately virtual router migrations have the effect of degrading the Quality of Service during the downtime in which the router is not able to carry on its forwarding function. For this reason, despite the advantages in power consumption saving, the migration technique should be applied with parsimony to avoid an excessive QoS degradation. The objective of this paper is to study Virtual Network Embedding problems aware of both operation and reconfiguration costs that are characterized by the energy consumption and the revenue loss due to QoS degradation. An Embedding Optimization Problem formulation will be given in which the objective is to minimize an objective function taking into account both the operation and reconfiguration costs. Because the problem is NP-hard, we propose a feasible solution to the problem in cycle-stationary traffic scenario and when the possible embeddings are a-priory determined. The solution consists in determining the optimal policy of a Markov Decision Process. The results obtained show how the application of the introduced solution allows for cost reduction in the order of 30% as well as to limit the reconfiguration costs with respect to traditional migration policies.