Events and Actions in Session Availability

In the event of a primary controller outage, or the network connectivity failure to the primary controller, the wireless AP:

• Sends a ‘tunnel-active-req‘ request message to the secondary controller.
• The secondary controller accepts the request by sending the ‘tunnel-activate-response‘ message.
• The AP applies the backup configuration and starts sending the data. The client devices‘ authentication state is not preserved during failover.

When the fast failover takes place, a critical message is displayed in the information log of the secondary controller.

Note

In session availability, the maximum number of failover APs that the secondary controller can accommodate is equal to the maximum number of APs supported by the hardware platform.

When the failed controller recovers, each controller in the pair goes back to normal mode. They exchange information that includes the latest lists of registered APs. The administrator must release the APs manually on the second controller, so that they may re-register with their home controller. Foreign APs can now all be released at once by using the Approve as Foreign button on the Access Approval screen to select all foreign APs, and then clicking Released.

To support the availability feature during a failover event, administrators need to do the following:

1. Monitor the critical messages for the failover mode message, in the information log of the secondary controller (in the Logs & Traces section of the Wireless Assistant).
2. After recovery, on the secondary controller, select the foreign APs, and then click Release on the Access Approval screen.

After the APs are released, they establish the active tunnel to their home controller and backup tunnel to the secondary controller.