Virtual Infrastructures (VIs) have recently emerged as result of the combined on-demand provisioning of Information Technology (IT) resources (consolidated by Cloud Computing) and dynamic virtual networks (introduced by Cloud Networking). By combining IT and network virtualization to realize dynamic service provisioning, the VI concept is turning the Internet into a world-wide reservoir of interconnected resources, where computational, storage, and communication services are available on-demand for different users and applications. A VI is fully virtualized, provisioned and managed by an...