In this case, you can deploy your controllers on-premise. As long as edge routers can reach vBond through your private network you should be good. Internet connection is mandatory only when sdwan controllers are deployed in public cloud.
You can download virtual images (OVA, qcow2) from CCO for controllers and vEdge and create your own lab topology.
https://software.cisco.com/download/home/286320995/type
You can also create device serial numbers in PnP portal and upload same to v...
You can set "device rollback timer" while attaching a template. When you attach a vEdge router to a device configuration template, if the router is unable to successfully start after 5 minutes, it returns to, or rolls back to, the previous configurat...
