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Time and Bandwidth-Aware Virtual Network Embedding and Migration in Hybrid Optical-Electrical Data Centers

The advances in fiber-optic technology and wavelength division multiplexing technique have led to the adoption of optical networks into cloud data centers to meet the ever-growing traffic demands. The hybrid optical-electrical data center network architecture becomes a transition solution from the all-electrical network architecture to the all-optical one since it is efficient in terms of the operational cost and resource efficiency in data centers. Network traffic can be routed through either the electrical network or optical network or migrated between the networks. Selection of the target network (optical or electrical) for embedding and decision of migration are challenging problems for providers since it depends on multiple inter-related constraints such as wavelength availability, computing resource availability and residual bandwidth on the links. A sub-optimal decision will affect the overall performance of data centers in terms of blocking ratio and bandwidth efficiency. We address the problem of virtual network embedding and migration in hybrid data centers in this paper. We first develop an optimization programming formulation that gives the embedding solution with target networks for a given set of virtual networks while maximizing the total bandwidth utilized. Since the formulation is computationally prohibitive, we then propose a heuristic algorithm, namely Time and Bandwidth-Aware Virtual Network Embedding and Migration (TBA-VNEM), that efficiently embeds and migrates virtual networks in hybrid data centers so as to improve bandwidth efficiency. We evaluate the proposed algorithm through comprehensive simulations. The results show that the proposed algorithm outperforms baseline algorithms by reducing the rejection ratio by up to 52% and increasing the bandwidth efficiency of the optical network alone by up to 20%.