Traditional networks are no more suitable for the increasing traffic demand of the recent years. Indeed, they were based on coupling the data and the control plane in each device of the network. This approach is old and poorly flexible because it is strictly related to hardware vendors and is too much pricey nowadays. For satisfying the high bandwidth request and the switchover to cloud-based applications, the traditional approach would imply purchasing a lot of new devices, that is costly and energy-consuming. Thus, a transition towards the Software Defined Networking (SDN) is occurring. SDN is a new network paradigm that reverses the previous approach by decoupling the data and the control plane, implementing the first into the dummy switches of the network, and the second into a specialized hardware usually known as SDN controller or orchestrator.