Enabling "preferred master" on Instant AP (IAP) does not work if "Instant" is broadcast.
WLAN administrator can enforce a particular Instant AP to act as a Master.
Starting from InstantOS version 188.8.131.52-184.108.40.206 we can selectively choose one of the member in the cluster and set it as "Preferred Master".
Provisioning of IAP as a master can be done by using the Instant UI or CLI.
But enabling this option in a specific AP will not take effect if factory default SSID "Instant" is still being broadcasted.
Two APs in cluster (AP1 & AP2) with AP1 initially acting as master. Factory-default SSID "Instant" is seen broadcasted.
Set "preferred master" to enable for AP-2 and then reboot the specific AP for the changes to take effect.
Once the AP reboots and comes up you could see the AP being set to "Init ---> slave" during the boot process and the AP-2 continues to act as slave irrespective of preferred master being set.
To verify that the config is present please execute #show ap-env on AP-2
AP2# show ap-env Antenna Type:Internal name:AP2 wifi0_arm_channel:52 wifi0_arm_power:3 wifi1_arm_channel:6 wifi1_arm_power:3 iap_master:1 ---------> this indicates that the preferred master has been set to "enable" AP2#
To make the specific AP act as preferred master we have to configure a non-factory default SSID so that the "instant" SSID gets removed.
Now go to AP2 --- 'Edit' and enable "preferred master". Reboot the specific AP for changes to take effect.
AP2 comes up as a master AP and then the AP1 reboot itself and joins the cluster as a slave.