Network virtualization is a key enabler for the 5G systems for supporting the novel use cases related to the vertical markets. In this context, we investigate the joint optimal deployment of Virtual Network Functions (VNFs) and the allocation of computational resources in a hybrid cloud infrastructure by taking into account the requirements of the 5G services and the characteristics of the cloud nodes. To achieve this goal, we analyze the relations between functional placement, computational requirements, and latency constraints, and formulate an integer linear programming problem, which can be solved by using a standard solver. Our results underline the advantages of a hybrid architecture over a standard solution with a central cloud, and show that the proposed mechanism to deploy VNFs leads to high resource utilization efficiency and large gains in terms of the number of slice chains that can be supported by the cloud-enhanced 5G networks.

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