We are using this AP, AIR-LAP1142N-A-K9 and WLCs at v18.104.22.168. We use WPA2 w/AES and TKIP. We never see more than a 54 Mbps link. Even within a few feet of the AP. We had an Aruba controller and the same clients reported 270 Mbps. Is there an issue with this system not doing 802.11n speeds?