A hybrid WAN is a WAN architecture connecting geographically distant sites by combining two or more disparate network links at each site. One connection may be a private MPLS circuit. Another connection might be some type of broadband internet link such as internet, cable, DSL, or 4G/LTE/5G. The routing protocols used in traditional WANs do not natively provide application-aware networking for granular control of application flows across different paths. Implementing policies to engineer traffic over multiple disparate links for granular control, even in a small-scale environment, will only further complicate the management and maintenance of a traditional WAN.
A hybrid WAN offers availability and cost advantages over a traditional MPLS-only WAN. It can also offer performance and quality of experience (QoE) advantages over an MPLS-only WAN, if used with the right SD-WAN offering. With an appropriate SD-WAN solution, a hybrid WAN can utilize multiple links simultaneously. If used with a failsafe SD-WAN solution, organizations can improve reliability and application QoE and performance, and even support a single, large application flow across all available links, all while lowering WAN costs. While some use the terms hybrid WAN and SD-WAN interchangeably, they are not the same. An SD-WAN simplifies the management of a hybrid WAN, offers the possibility of branch office consolidation and simplification, and delivers a solution that is centrally managed and provides policy-based orchestration and visibility into the entire WAN from a single pane of glass.