All too often SD-WAN and hybrid WAN are used interchangeably—mistakenly.
SD-WANs extend software-defined networking (SDN) technologies to the WAN. As with SDNs, SD-WANs build an “overlay” or a virtual abstraction of the underlying physical network that can then be reconfigured and optimized for the applications traveling across the overlay. It’s this property that allows SD-WANs to give one application a hub-and-spoke WAN configuration, while another application a meshed WAN configuration each with their own IP addressing spaces, traffic policies and more.
Hybrid WANs combine a mix of data services to interconnect geographically dispersed locations. A network that combines MPLS and carrier Ethernet services is a hybrid WAN, so too is a WAN that combines 4G and MPLS. When you have some sites connected via MPLS and others via IP VPNs, this too was a hybrid WAN. When you have sites connected to an MPLS backbone with a secondary Internet connection, you also have a hybrid WAN.
SD-WANs speak about the overlay; hybrid WANs speak about the underlay. The two are not exclusionary. You can build a hybrid WAN without an SD-WAN, and you could build an SD-WAN that’s a hybrid WAN…..
(To read the complete post see the Network World blog: http://www.networkworld.com/article/3156172/lan-wan/death-to-the-hybrid-wan.html