SD-WAN First, let’s see what WAN is. Compared to LAN, which is Local Area Network, WAN is a world-wide interconnection of these smaller networks, hence called: Wide Area Network. LAN is more like driving a car and LAN is similar to flying by plane. Keeping the same example, flying a plane is so complex that is has to be at least partially automated: it follows a radio beacon to fly to the right direction, also a computer helps navigation and controls the plane. Furthermore, traffic is managed from centralized places: flight control towers. Similarly, SD (Software Defined) - WAN, by heavily relying on software, helps to automate routine tasks on a large scale: when a complex and versatile large set of network devices have to be configured behind a global network. This helps reduce number of errors and costs as well, and provides greater agility, especially because of the centrally managed nature. Similarly to a flight control tower it will oversee, control or limit traffic to certain areas. It is pretty much like aviation, but instead of carrying real payload, information is carried through the existing global network mediums, but with a better management which is easier to sustain and maintain.
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