Master AP Failover
and Electing a New Master
Cisco Mobility Express
is supported on Cisco 1800 Access Points and the Master 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
Master AP and to elect a new Master.
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.
Only Cisco 1800
series Access Points can be elected as Master APs.
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
Master AP, another Cisco 1800 series AP is elected as a Master automatically.
The newly elected Master AP has the same IP and configuration as the original
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 Master AP election
The Master election
process of Cisco 1800 series APs is based on a set of priorities. An AP with
the highest priority is elected as the Master AP, running Mobility Express
The Master AP election
priorities are as follows:
Master— User can define a preferred Master 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 master, 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
user not to define the preferred Master AP unless it is required for debugging
or serviceability reasons.
Load—Cisco 1800 series Access Point with least client load is elected as the
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 Master AP.