Software-defined Networking (SDN) concepts and the OpenFlow protocol were introduced in 2011 to deliver increased agility, flexibility, operational efficiency and choice to data networking. Fundamental to SDN was the separation or disaggregation of the control or management function (plane) from the data forwarding function (plane) of the network. SDN proposed centralizing control while leaving the data forwarding function distributed amongst network elements (switches and routers).

The SD-WAN architectural model is similar to SDN in many ways:

Centralized management or orchestration – the control plane
Distributed data forwarding function – the data plane
Application-driven traffic routing policies
SD-WAN, similar to SDN solutions, do not support interoperability between vendors. However, various SDN and SD-WAN industry working groups continue to propose and debate the creation of industry standards.

Read more: Difference between SD-WAN and SDN

SD-WAN delivers value to enterprises of all sizes
In contrast, SD-WAN vendors focused on delivering production-worthy WANs and providing value to enterprises of all sizes. SD-WAN interoperability efforts focused on working with existing WAN infrastructure such as routers, firewalls and transport services and not on multi-vendor SD-WAN solutions.

SD-WAN delivers a tangible ROI
SD-WAN is being rapidly adopted in production by companies of all sizes and in all industry verticals because it delivers an easily attainable, tangible ROI. As of the second half of 2018, SD-WAN has moved beyond the early adopter market acceptance phase to the early majority, with more than 10,000 production SD-WAN deployments industry-wide.