SOFTWARE DEFINED WAN
The software-defined wide-area network (SD-WAN or SDWAN) is a specific application of software-defined networking (SDN) technology applied to WAN connections, which are used to connect enterprise networks – including branch offices and data centers – over large geographic distances.
A WAN might be used, for example, to connect branch offices to a central corporate network, or to connect data centers separated by distance. In the past, these WAN connections often used technology that required special proprietary hardware. The SD-WAN movement seeks to move more of the network control is moved into the "cloud," using a software approach.