The core functionalities of Fortinet's SD-WAN solution are built into the FortiGate. Whether the environment contains one FortiGate, or one hundred, you can use SD-WAN by enabling it on the individual FortiGates.
At a basic level, SD-WAN can be deployed on a single device in a single site environment:
At a more advanced level, SD-WAN can be deployed in a multi-site, hub and spoke environment:
At an enterprise or MSSP level, the network can include multiple hubs, possibly across multiple regions:
For more details, see the SD-WAN / SD-Branch Architecture for MSSPs guide.