Fabric Connected AP resiliency

[trickyg]

I have two Fabric connected WLCs (embedded on same switches that resilient Border/Control planes are running)

All APs are currently configured as Primary WLC Switch 1 and Secondary WLC Switch 2

I assume for complete resliency I will also need to add the secondary WLC IP address in DHCP Options sent back to AP on the off chance that the AP restarts after a loss of Switch 1 (which is already configured as Option 43 in DHCP server for WLC IP)

I guess my question is if, with all switches up, the AP  selects Switch 2 (Secondary) IP as the WLC to connect to from DHCP response is the fabric WLC intelligent enough to direct the AP to Switch 1 (Primary)

[balaji.bandi]

I do not believe that order works, it checks primary if not it will try other, this is Option43 only for onboarding AP. Once the AP register with WLC, it try directly with WLC, if the option provided secondary it will try second one. (but AP will not fall back after primary come back, you need to manually fail over AP to primary if you wish to)

is this what you looking or am i misunderstand your question or scenario.

[trickyg]

Thanks so if I have understood this correctly AP will always attempt to connect to the first WLC in the list of returned Options - This may or may not be the Primary Controller for the AP but it will connect anyway - If it connects to the Secondary WLC will this WLC then redirect it to the Primary WLC?

[balaji.bandi]

If it connects to the Secondary WLC will this WLC then redirect it to the Primary WLC?

If the primary not available, it connect to secondary, and it will be associated with secondary only (there is no redirection. until you fix the Primary WLC and reboot AP to join back to Primary WLC.

[trickyg]

Thanks for the response - Just to explain my query a little better:

I have two Fabric (Embedded) WLCs.  and  approx 45 APs. I have configured WLC A as the Primary WLC and  WLC B as the secondary. Currently the DHCP server is configured to only Serve the IP address of WLC A in the DHCP response. When I check the APs they see WLC A as Primary and WLC B as secondary as this is the config that has been served to them by WLC A. 

If i were to add WLC B to the DHCP server options then my query is how does the AP know which WLC is primary. It could select to connect to WLC B and if it did would it then be configured with WLC A as Primary and reconnect to that?