I was reviewing the "Cisco Wireless Controller Configuration Guide, Release 8.0". Under the Management of the WLC section , and more specifically the High Availability section , I found this below information in bold.
A redundancy VLAN should be a nonroutable VLAN in which a Layer 3 interface should not be created for the VLAN, and the interface should be allowed on the trunk port to extend an HA setup between multiple chassis. Redundancy VLAN should be created like any other data VLAN on Cisco IOS-based switching software. A redundancy VLAN is connected to the redundant port on Cisco WiSM2 through the backplane. It is not necessary to configure the IP address for the redundancy VLAN because the IP address is automatically generated. Also, ensure that the redundancy VLAN is not the same as the management VLAN.
Is this specific to the WiSM or all platforms? I have used the configuration in the past where the Mgmt interface for the WLC and the RMI have been on the same VLAN. I haven't experienced any issues with that , but it seems from the above that its not Best Practice? Can someone please help clarify?