If all the devices are virtualized, how about the Networking will be done in an virtualized environment. Present Networking technology mainly focused on Physical devices, so there is a need for network configuration in virtualized environment is there always, SDN i.e. Software Defined network is an a open source networking where programmed Networking is possible.
Our traditional network physical devices are mostly Hardawar based, growing computer change leads to a driving network change, Even cisco a major network giant in industries had came virtualization network with its own technology . So Now let us lookup how the concept is implemented .
Infrastructure layer or Data Plane : its a non -intelligence end layer ,where network switches and routers where the data forward to need layer.
Control layer 0r Control plane : it’s the intelligence layer, its the place determine how the traffic should be forwarded.
Application layer or Application Plane : services, application utilities with control level available in Application layer