High Availability Active and Standby
The Cisco Embedded Wireless Controller on Catalyst Access Points (EWC), is supported on the Cisco Catalyst 9100 series APs. The active AP election process determines which of the Cisco Catalyst 9100 series APs is elected to run the EWC controller function. Once the active AP is elected and other subordinate EWC-capable Cisco Catalyst 9100 series APs join the active AP, it selects a standby AP and redundancy is formed.
This High Availability (HA) architecture is based on the Cisco Catalyst 9800 HA architecture, with a few additions:
HA pairing is different in EWC. For the initial bring-up, the EWC active AP waits until all the APs join the controller. The active AP then selects the designated standby AP (either by auto-selection or configuration), and communicates the role and the HA parameters (local/peer IP, keepalive interval, priority) to the selected AP, through a CAPWAP control message.
After a power outage, the standby AP does not come up in the EWC HA pair. The standby AP tries to come up but fails. Then another EWC capable AP is selected as standby, which fails to come up. To avoid this situation, ensure that the APs have the same IP version to be elected as a HA pair.
The selected standby AP starts and dynamically configures the HA parameters without manual intervention.
Monitoring Redundancy between Active and Standby Access Points
To view the redundancy between active AP and standby APs, follow the steps given below:
Open the Cisco Embedded Wireless Controller for Catalyst Access Points GUI.
Choose Monitoring > General > System.
Click the Redundancy tab.
In the General tab, you can view the current state, peer state, redundancy modes, and the chassis details of the active and standyby APs.