ZL modules/controllers that do not support the nonstop switching feature include the following:
During a nonstop switching failover, unsupported modules will not failover seamlessly to the standby module. A nonstop switching failover causes a forced reboot on these modules. After rebooting, these modules then sync with the newly active management module and begin operation again. Module traffic is disconnected until the module completes the reboot process.
Use the MM Shutdown button on the front of the management module before removal. The Shutdown button ensures that the management module is shut down properly. If nonstop switching is enabled, using the Shutdown button prior to removal ensures failover to the standby module will be successful.
With K.15.01.0031, nonstop switching supports only Layer 2 functions on the switch. During a failover, traffic routed through the switch at Layer 3 will see an interruption. When a failover from active to standby occurs, the routing table is "frozen." All routes that existed at the time of the failover are marked as "stale." While dynamic routing protocols running at the time may act as if the routing protocol has been restarted and rebuilds the table, the switch on which the failover occurred continues to rout traffic using the ‘stale routes.'
The "stale timer" begins counting when the switchover occurs. When the "stale timer" expires, any routes that are still marked as stale are purged from the routing table. Because of the nature of rapid routing switchover, if there are multiple simultaneous failures, network loops could occur or traffic could flow through unpredictable paths.
Use caution if setting the "rapid-switchover" timer higher than the default. To disable "rapid routing switchover" and to ensure that all routing is based on the most current routing protocol information, set the "rapid-switchover" timer to 0.