This document discusses software-defined networking (SDN), network functions virtualization (NFV), network virtualization (NV), and open networking. It provides definitions of these concepts and compares the hardware-defined data center and software-defined data center approaches. Diagrams show the network overlay and underlay in NV. Open networking organizations and initiatives like OpenFlow, Open Network Install Environment (ONIE), Open Network Linux (ONL), OpenNSL, and OPNFV are also mentioned. Lastly, the benefits of different approaches are noted.