Separation of network features from hardware allows for their simpler administration and quicker deployment according to momentary needs. Ideally, we would need a communication infrastructure with an open programmable interface, and therefore NFV is combined with SDN. The open nature of SDN is an ideal platform to implement virtual network services.
NFV

Virtualization of network features represents an essential evolutionary step of modern networks. We have become accustomed to server-, application- or data centre virtualization, but the virtualization of network services on a large scale is still ahead of us. Nonetheless, there are already many technologies available, allowing for virtualization of network features. Similarly to separating applications from specific hardware in data centres, we can eliminate piles of specialised communications hardware, converting their functions into virtual instances.