The promises of Network Functions Virtualization (NFV) complemented with Software Defined Networking (SDN) can be simply stated as: get much more, pay much less. Adopting such paradigms, Service Operators expect to achieve high reductions in capital investments and greater operational agility. However, applying these concepts to existing networks will require challenging architectural updates, as well as deep changes in service models and operating procedures. To analyze such aspects, in this paper we provide an overview of the experience gathered at Italtel R&D labs in this field, and discuss state-of-the-art and future perspectives of these technologies. In particular, we describe how NFV was applied to a specific network function, the Session Border Controller, solving some related technical issues of general interest, and providing scalability and flexibility. Finally, we discuss the evolution of this virtualized network function, and its integration into an SDN-based network.
