While Ron was correct prior to V9, in V9 we added a new feature called license pooling. Essentially this allows AP and/or Radar licenses to be shared within an HA pair. As part of this feature we also added the ability to move an AP from one controller to the other controller more easily. The combination of both features will allow customers to be able to load-balance their AP / Radar connections as their deployment or needs grow. Please note that the Radar analysis engine still only runs on one controller in the HA pair.