SD-WAN Vs. SDN: Demystifying The Differences

By Michael Miller, EarthLink

Over the past 12 months the buzz around SD-WAN has exploded. It’s becoming to networking what the cloud became to infrastructure and applications. Yet, while the concept of a Software Defined WAN is generally understood, it’s often confused with its technology cousin, Software Defined Networking (SDN). Even by people who seem to be in-the-know.

So I thought it was about time someone explained the difference.

SDN and SD-WAN have more in common than “SD”

SD-WAN and SDN share a common heritage in that both are enabled by (excuse the technical jargon) the separation of the Control Plane and the Data Plane. Additionally, they’re both designed to run on commodity based x86 hardware, can both be virtualized, and can both support the integration of additional Virtual Network Functions (VNFs) such as security, or WAN acceleration.

SDN was designed to support the needs of modern computing environments inside Local Area Networks (LANs) and within a Service Provider’s networks. The goal was to create dynamic, flexible, and scalable connectivity to support changing demands in the data center and on core networks. SDNs are directly programmable, providing an agile and centrally managed network platform that decouples the Control Plane (which decides where traffic is routed) – from the Data Plane (which determines how traffic is forwarded).

These are the same underlying principles that power SD-WAN. However, it is important to note that SD-WAN and SDN are not the same thing.