ABSTRACT
Nowadays, cloud computing is considered an emerging computation paradigm able to pursue new levels of efficiency in service delivering, and could represent, at the same time, a tempting business opportunity for IT operators of increasing their revenues. Until now, the trend of the cloud computing ecosystem has been characterized by the steady rising of hundreds of independent, heterogeneous cloud providers, managed by private subjects, yielding various types of cloud-based services to their clients (e.g., IT societies, organizations, universities, desktop and mobile end-users, etc.). Currently, most of such clouds can be considered as “islands in the ocean of the cloud computing” and do not presents any form of federation. At the same time a few clouds are beginning to use the cloud-based services of other clouds, but there is still a long way to go toward the establishment of a worldwide Intercloud ecosystem including thousands of cooperating clouds. In such a perspective, the latest trend toward cloud computing is dominated by the idea to federate heterogeneous clouds. This means not to think about independent private clouds any more, but to consider a new Intercloud scenario where different clouds, belonging to different administrative domains, interact with each other, sharing and gaining access to physical resources, and becoming themselves at the same time both “users” and “resource providers.”
