Most people have heard of SD-WAN but don't know what it actually is. The software-defined wide-area network (SD-WAN or SDWAN) is an application of SDN technology applied to certain WAN connections such as broadband internet, 4G, LTE, or MPLS. SD-WAN connects enterprise networks over large geographic distances.

SD-WAN offers your business advantage over traditional MPLS networks. Let's take a look at some of those:

Dramatically impact the entire enterprise networking ecosystem. Geographic boundaries are erasedVisibility, scalability, performance, and control are enhanced.SD-WAN comes with no bandwidth penalties.Ability to cost-effectively mix and match network links according to content type or priority.High level of security.End-to-end encryption across the entire network, including the Internet.All devices and endpoints are completely authenticated.

Source: SD WAN Pros and Cons