- On premise only
The first is on premise only, meaning, the SD-WAN Box (router) is installed at each site, it only connects between sites, there is no connection to the cloud gateway.
- Cloud enabled
Cloud enabled means, SD WAN Box at each site connects to a cloud gateway, for example you have an application in the cloud, then access to the application is through a cloud gateway (virtual) that connects directly to the cloud provider (for example: AWS, GCP, Azure etc.).
- Cloud enabled plus backbone
Plus, the backbone here means that the SD-WAN Box is installed on the connection site to the SD-WAN Box provider which is part of the backbone provider, so the connection is private. For access to applications in the cloud through a backbone provider that connects directly to the cloud provider.