The oversubscription of intra-Data Center links and the high volatility of Virtual Machine deployments require a flexible and agile control of the Data Center network infrastructure, possibly coordinated with computing and storage resources control. In this scenario, the Software-Defined Networking paradigm opens up new opportunities to design orchestrated resources control strategies able to meet the dynamically-changing traffic demands of instantiated Virtual Machines. This paper presents the architectural design of an SDN-based orchestrator for dynamic computing and communication resources chaining, able to assure better than best effort VMs data exchanges across Cloud Data Centers. Moreover, the paper evaluates a number of different cha...