Primary AP Failover and Electing a New Primary

Cisco Mobility Express is supported on Cisco 1800 Access Points and the primary AP election process determines which Cisco 1800 AP will be elected to run Mobility Express controller function in case of a Failover. VRRP is used to detect a failure of primary AP and to elect a new primary.


Note
Mobility Express uses MAC 00-00-5E-00-01-VRID where VRID is 1 so if there are other instances of VRRP running in the environment, use VRID other than 1 for those instances.

Note

Only Cisco 1800 series Access Points can be elected as primary APs.

Primary AP Failover

To have redundancy in the Mobility Express network, it must have two or more Cisco 1800 series Access Points. These Access Points should have AP Image type as MOBILITY EXPRESS IMAGE and AP Configuration as MOBILITY EXPRESS CAPABLE. In an event of a failure of primary AP, another Cisco 1800 series AP is elected as a primary automatically. The newly elected primary AP has the same IP and configuration as the original primary AP.


Note

Cisco 1800 series Access points which have the Mobility Express Image but AP Configuration is NOT MOBILITY EXPRESS CAPABLE, they will not participate in the primary AP election process.

Primary Election

The primary election process of Cisco 1800 series APs is based on a set of priorities. An AP with the highest priority is elected as the primary AP, running Mobility Express controller function.

The primary AP election priorities are as follows:

  1. User Defined Primary— User can define a preferred primary AP to be elected incase of a failover. The following command can be entered on the controller CLI : 

    (Cisco Controller) >config ap next-preferred-master <Cisco AP>
<Cisco AP>     Enter the name of the Cisco AP
    To view the preferred primary, use the following command: 
    (Cisco Controller) >show ap next-preferred-master
    To clear the user defined priority from an AP, use the following command: 
    Cisco Controller) >clear ap next-preferred-master

    Note

    We recommend user not to define the preferred primary AP unless it is required for debugging or serviceability reasons.

  2. Least Client Load—Cisco 1800 series Access Point with least client load is elected as the primary AP.

  3. Lowest MAC Address—If the User defined priority is not configured and everything else is the same, then Access Point with the lowest MAC gets elected as the primary AP.