This is the "controllerless" mode. One AP-505 acts as a virtual controller for the rest. If you aren't using a physical appliance, you’ll likely be looking for InstantOS firmware.
Essential for modern security, ensuring guest networks are encrypted without needing a complex password. aruba ap 505 firmware top
Updating to the latest stable firmware unlocks several key benefits for the 500 series: This is the "controllerless" mode