I. Introduction
While the fourth generation (4G) of networks was designed for improving the smartphone experience mostly in terms of network throughput, the fifth generation (5G) is instead being designed with a much broader goal. 5G networks need to provide end-to-end connectivity, directly supporting verticals, including radio connectivity, wired connectivity and computing resource delivery and orchestration, exploiting system and network virtualization technologies [1]. 5G verticals include, e.g., e-health services, public safety systems, smart office, and connected vehicles, trains and aircrafts [2].