On the other hand, infrastructure virtualiza- tion is key in cloud computing, as it allows effi- cient sharing of physical resources (i.e., computing, storage, and network), while provid- ing deterministic QoS through infrastructure iso- lation. Virtualization techniques have been commercially exploited by many cloud service providers, and it is expected that future cloud services will be based on globally distributed DCs interconnected through network infrastruc-
tures deploying cross-domain coordinated virtu- alization.