What is the difference between WAN and SD-WAN?

　　A Wide Area Network (WAN) is simply a computer network that covers a large geographical area – usually encompassing a series of Local Area Networks (LANs). The connections can be telephone systems, leased lines or satellites.

　　With the proliferation of cloud services based on private and public clouds – as well as services that are heavily dependent on reliable and high-performance applications – businesses are sometimes maxing out the limitations of available WAN services. Although it may be economically feasible to provide high bandwidth internet connectivity to the main office, providing the same speed connections to each branch office is prohibitively expensive. There may be many branch offices and the available internet services might be limited or costly.

　　A software defined wide area network is a departure from the way a WAN is typically deployed and managed. An SD-WAN is a software-based technology that overlays onto an existing network. With an SD-WAN, the physical network is separate from the logical network. It splits the network from the management plane and disconnects the traffic management and monitoring tasks from the hardware. For instance, traditional WANs can only handle so many incoming difference connections to multiple cloud platforms. SD-WANs are not limited by the underlying hardware that makes up the network.

　　SD-WAN technology can provide fast, reliable and relatively inexpensive data connectivity between the main office or data center of business with its branches. Compared to the alternative of using a single and expensive internet line, an SD-WAN can significantly cut WAN expenses. Beyond such cost savings, businesses can get reliable, general internet access for offices through the internet connection at the main office.