Over the last years, networks have changed in size, traffic, and requirements. There are more nodes, the traffic has increased, and there are frequent requests that imply modifications to the underlying infrastructure. Some examples of these requirements are cloud computing, virtualized environments, and data centers. SDN has been developed to address some of these issues. By separating control and data planes, SDN enables the programming of the control plane and the dynamic reconfiguration of the data plane thus making it possible to automatize some tasks.