Configure and Troubleshoot WLC Redundancy

Without any additional configuration, a lightweight AP will select the controllers to join based on the result of the CAPWAP discovery, and it will select the least-loaded WLC. The AP will also learn the management IP addresses of the controllers on the same mobility group, and it will be able to fall back to one of these WLCs if it loses connectivity to the current controller.

If you need to make the WLC selection process more predictable, you can specify for each AP a primary, secondary, and tertiary WLC. This configuration requires you to specify the controllers using the system names. As of version 4.2, it’s possible to also specify an IP address in addition to the system name to allow the APs to join WLCs outside the local mobility group.