I. Introduction
To cope with the ever-growing mobile traffic, mobile operators have been looking into the decentralization of their core network, along with devising traffic offload-based solutions [1] [2]. On the other hand, the fast growing business of clouding computing is pushing for the deployment of regional Data Centers (DCs) [3] [4]. Internet Service Providers (ISPs) are also pushing micro DCs closer to customers, enabling third parties to rent them out [11]. Connecting these geographically distributed micro DCs as well as macro DCs, together into a common resource pool, to deliver a variety of cloud services forms the so-called federated cloud. The distribution of cloud computing resources over different locations in the network is beneficial for different reasons such as increasing availability, reducing bandwidth cost, and reducing latency by locating resources nearby users.