We wanted to replace Aruba with TP-Link Omada, but a major point prevents us from achieving this : since the guests are not in the same VLAN as the controller, we cannot redirect them to an external radius. (And inter-vlan routing is not possible on all of our sites).
The solution would be for the AP itself to give the information to the guests (which Aruba does).
No need to make a very advanced system like them and their virtual controllers, just that the APs can give this information to the guests.

The most frustrating thing is that according to the documentation, the AP can already do this, but only if the controller is down (https://www.tp-link.com/us/support/faq/2051/).
So it seems that they can store this information...
Please add an option in Omada for the AP to respond directly to guests even if the controller is UP, this way you will kill Aruba and triple your sales 

Or another possible solution, perhaps even simpler, would be to tell the guests to contact the controller via a hostname rather than the IP, this way by tricking the DNS it would be possible to send them to a controller which is accessible from the Internet (in the DMZ of our central site for example).

Thanks !