Configuring High Availability

The high availability feature supports redundancy models with an active controller pair, or an active/standby deployment model with one backup controller supporting one or more active controllers. Each of these clusters of active and backup controllers comprises a high-availability group. All active and standby controllers within a single high-availability group must be deployed in independent masters topology. An independent masters topology requires all independent master controllers to have the same WLAN configuration.

Configuring High Availability

Configure the high availability feature in the WebUI or CLI using the high-availability and high-availability group profiles.

In the WebUI

To configure High Availability using the WebUI:

1. In Mobility Master > standalone, navigate to Configuration > Services > Redundancy.
2. Click the HA Groups accordion and click the + icon. A pop-up window appears.
3. In the Name field, enter a name for the new HA group.
4. Configure an IPv4 or IPv6 address for the controller.
a. Click the + icon in the HA Controller IPv4 or HA Controller IPv6 fields. The Add HA Controller IP window opens. Enter an IP address.


IPv4 and IPv6 controllers can be part of the same HA group profile. However, HA works only between controllers of same IP format.

b. Click the Role drop-down list to assign a role to the controller. The IP address of each controller must be reachable by APs and must be the IP address that appears in the Configuration > Controller > System settings tab of the controller WebUI, or in the output of the show controller-ip CLI command. The role can be one of the following options:

Active: Controller is active and serving APs.

Dual: Controller serves some APs and acts as a standby controller for other APs.

Standby: Controller does not serve APs and only acts as a standby in case of failover.

c. Click OK to add the controller to the group.
5. (Optional) Select the Pre-emption check boxto enable the failed over APs to attempt to connect back to its original active controller once the controller is reachable again. When you enable this setting, the AP waits for the time specified by the lms-hold-down-period parameter defined in the ap system profile before the AP attempts to switch back from the standby controller to the orginal controller.
6. (Optional) The standby controller over-subscription feature allows a standby controller to support connections to standby APs beyond the controller's original rated AP capacity. To enable this feature, select the Over subscription check box.
7. (Optional) Select the State synchronization check box to enable the feature. State synchronization improves failover performance by synchronizing client authentication state information from the active controller to the standby controller. (For more information about state synchronization, see  Client State Synchronization).


State synchronization is not applicable for IPv6 controllers.

8. (Optional) Select the Heartbeat check box to enable the high availability inter-controller heartbeat features, which enable faster AP failover from an active controller to a standby controller, especially in situations where the active controller reboots or loses connectivity to the network. To edit the default heartbeat threshold and interval values:

Enter a heartbeat threshold in the Heartbeat threshold field to define the number of heartbeats that must be missed before the APs are forced to failover to the standby controller. This value must be between 3 and 10, inclusive.

Enter a heartbeat interval in the Heartbeat interval (ms) field to define how often inter-controller heartbeats are sent. This value must be between 100 and 1000 ms, inclusive.

9. (Optional) If you enabled the state synchronization feature in Step 7, enter a pre-shared key into the Pre-shared key and Retype pre-shared key fields.
10. Click Submit.
11. Click Pending Changes.
12. In the Pending Changes window, select the check box and click Deploy changes.

In the CLI

To configure a High Availability group using the command-line interface, access the CLI in config mode and issue the following commands. The high availability group profile should be configured with a pair of IPv4 controller addresses and pair of IPv6 controller addresses to allow an IPv4 or IPv6 access point to establish a connection to a standby controller.

(host) [mynode] (config) #ha group-profile <profile>

(host) [mynode] (HA group information "default") #controller <ip> role [active/dual/standby]

A controller using the high availability features must be defined as a member of a high availability group. To add a controller to the new high availability group, issue following CLI command:

(host)[mynode] (config)#ha group-membership <ha-group>