AP Load Balancing behaviour in Aruba OS 8.x
How does AP Load Balancing work in Aruba OS 8.x?
AP load balancing feature in Clustering ensure that APs are distributed evenly between all controllers. One of the controller is selected as the Cluster Leader and it is responsible for identifying the AAC and S-AAC for each AP. Prior to ArubaOS 126.96.36.199, the cluster leader considered the total AP load (Active APs + Standby APs) for load balancing. This resulted in unequal load balancing with active APs especially with clusters of two controllers.
If one of the controllers goes down and comes back up all the active APs will be on one node & the other node will take all the standby APs. Cluster manager will assume that the APs are equally distributed as the total load is the same on both the controllers.
To overcome this short coming, starting from ArubaOS 188.8.131.52, during AP load balancing, the cluster leader considers only the Active AP load and assigns the target with the least active AP load as the AAC.