“Software-defined” network enables an organization to virtualize their network, automate operations to enable efficient network configuration, and integrate network functions across dozens of switches creating a unified network architecture that is programmable and dynamically definable.
Network functions virtualization (NFV) offers a new way to design, deploy and manage networking services. NFV decouples the network functions, such as network address translation (NAT), firewall, intrusion detection, domain name service (DNS) ,caching and other network functions from proprietary hardware appliances so they can run in software.