Hi Alan Tam
The secondary management IP is shared between both controllers and can be used for this purpose. It must be on the same VLAN/network for both controllers. When the standby controller becomes active it sends out a gratuitous ARP so that the MAC table of the local gateway and other devices on L2 network will be updated. It is good idea to test this by manually failing over the controllers and checking the router and local PC ARP tables to make sure the correct MC is learned. The network between the two peer redundant controllers must be very reliable to prevent the standby from becoming active while the active is still working, this can cause the gratuitous ARP to mess up the router tables and cause loss of management messages. A local DNS entry can be used to assign a URL to the management IP or just use the actual IP for management systems to respond with.
Please note - Ruckus Captive Portal, Guest Pass and Wispr implementations do not need to use this management IP as they will include a "sip" variable in the redirect url that changes to the Active Zone Directors IP .
I hope this information is helpful