Traditional Enterprise WAN connectivity requires L2/L3 (L2.5) type protocols like MPLS to guarantee bandwidth between sites. The speeds selected from product offers for MPLS were guaranteed by the network based on QoS settings in the network. A form of security is provided by the MPLS network in the sense that the network is separate from the Internet and forms a VPN between enterprise sites.
However, maintaining such networks is costly for Enterprise Business, and SD-WAN has emerged as a possible less costly alternative. With SD-WAN, the control and data plane are separated, with the routing decisions centralized in the controller and forwarding done at the edge.
SD-WAN has been described extensively by MEF, and the service components there have been identified as
- SD-WAN Edge – SD-WAN provider to SD-WAN subscriber interface
- SD-WAN Controller – For Service Management
- Service Orchestrator – which I consider a Domain Orchestrator Orchestrator
- SD-WAN Gateway – for interconnect of transport service
- Subscriber – web Portal – for Service Management and Service Operations
While the service and service management models have been described extensively, the “operate” model that connects to IT systems has also to be considered.
In a similar vein as such operate models are being considered for 5G slicing, an “operate” model of SD-WAN is considered here. Additional details are in my contribution to TMForum IG1224 for NaaS.
The following figures are based on the MEF models and illustrate
A logical representation of the SD-WAN net,

And a logical representation of SD-WAN related circuits.

The “operate” model utilizes this by exposing SD-WAN services to the IT layer, which is the core commerce layer in TMForum’s open digital architecture.
Such a model is described in detail in my contribution to IG1224 Release 13 (currently in draft).