Hi,
Just to recap what you have and what your requirements are:
HQ:
- Master Controller
- APs
Remote
- Local Controller
- APs
Requirement
- APs at each site should connect to their respective controller - i.e. APs at HQ should connect to the HQ controller and APs at the remote site should connect to the Local controller. In case of failover of the Master controller, APs should connect to Local controller.
This is doable by using the LMS function. All APs will need to initially connect to the master controller, which can be accomplish either by DNS or DHCP options so the APs can find the master controller.
You will need to create 2 AP groups - one for HQ and one for Remote site. Under the AP Group controller, you will need to modify the AP System profile to set the LMS IPs. For HQ, set the primary LMS to the HQ controller, backup LMS to the remote site. If desired, you can do the same for remote: For Remote, set the primary LMS to the Local controller and backup LMS to the Master controller. When the AP first comes online, provision the AP and change the group accordingly.
The above is a VERY simple explanation and I'm sure you would benefit from understanding the Aruba architecture a bit more. I would highly recommend you take a look at the following Reference Design Guides:
- Campus Wireless VRD
- Aruba Mobility Controllers And Deployment Models VRD
- Location for other VRDs
I hope my "simple" explanation guide you in the right direction. If you have follow-up questions let me know.
-Mike