In local mode, an AP creates two CAPWAP tunnels to the WLC. One is for management, the other is data traffic. This behavior is known as "centrally switched" because the data traffic is switched(bridged) from the ap to the controller where it is then routed by some routing device. https://community.cisco.com/t5/wireless-and-mobility/what-s-the-difference-between-local-mode- and-flex-connect-mode/td-p/2532657