Netgear WC7500-Wireless User Manual - Page 298

ProSAFE Wireless Controller When the primary controller that went down and for which the redundant controller took over comes back up and is stable, a switchback occurs automatically, in which case ownership of the controller IP address is returned to the primary controller that came back up. The redundant controller reassumes its passive position, and redundancy is once again available for all primary controllers in the redundancy group. Note: When a redundancy failover occurs, WiFi clients might experience a service interruption of a few seconds. Requirements and Restrictions for N:1 Redundancy These are the requirements and restrictions for N:1 redundancy to function correctly: • All controllers in a redundancy group must be in the same management VLAN and IP subnet. • The primary controllers must be stacked. • If three or four controllers are in the same redundancy group, you must configure one controller as the redundant controller and all other controllers as primary controllers. • All controllers in the redundancy group must run the same firmware version. If the firmware versions do not match, redundancy does not work. • The licenses on the redundant controller must match those on the primary controller that supports the largest number of licenses. For example, in a redundancy group with two primary controllers, if one primary controller supports a license for 10 access points and the other primary controller supports a license for 50 access points, the redundant controller must support a license for 50 access points. If the licenses do not match, redundancy does not work. • For the relationship of each primary controller with the redundant controller, you must configure a unique VRRP ID that is also different from any other VRRP IDs that might be used for other purposes in the network. You also must configure a unique local controller IP address for each controller in the redundancy group. • When a failover occurs and the redundant controller takes over for a primary controller, redundancy is no longer available for the other primary controllers in the redundancy group. Example of an N:1 Redundancy Configuration The following figure shows an N:1 configuration with three stacked controllers and one redundant controller before a failover occurs. Manage Stacking and Redundancy 298