Enabling Smart Redundancy
When Unleashed is switched to Dedicated Master mode, Unleashed supports "Smart Redundancy" feature like ZoneDirector.
Unleashed Dedicated Master's Smart Redundancy feature allows two Dedicated Masters to be configured as a redundant pair, with one unit actively managing your network while the other serves as a backup in standby mode, ready to take over if the first unit fails or loses power.
Each Dedicated Master will either be in active or standby state. If the active Dedicated Master fails, the standby device becomes active. When the original active device recovers, it automatically assumes the standby state as it discovers an already active Dedicated Master on the network.
The Dedicated Master in active state manages all APs and client connections. The Dedicated Master in standby state is responsible for monitoring the health of the active unit and periodically synchronizing its settings to match those of the active device. The Dedicated Master in standby state will not respond to Discovery requests from APs and changing from active to standby state will release all associated APs.
When failover occurs, all associated APs will continue to provide wireless service to clients during the transition, and will associate to the newly active Dedicated Master within approximately one minute.
When two Dedicated Masters are connected in a Smart Redundancy configuration, the standby Dedicated Master will send heartbeats and the active will send discover messages at 6 second intervals. If after 15 seconds no reply is seen, each controller will assume disconnection from its peer, and the standby Dedicated Master will change to active state. At this point both devices are in active state and will accept join requests from APs.
When the two Dedicated Masters are communicating again, one active Dedicated Master will change to standby state and an auto-synchronization process will be started. A timestamp is used to determine which Dedicated Master should sync its latest configuration changes to those of its peer. They will continue trying to communicate, sending discover messages every 6 seconds, until the Dedicated Masters are communicating again, at which point they will determine active/standby roles based on: 1) most managed APs, and/or 2) lower MAC address.