The Cisco 3900-AX includes licenses for IP Base, Data, Security, AVC, WAAS Express (WAASX), and a RTU for 2500 WAAS or vWAAS connections and a 1300 WAAS or vWAAS RTU license for the Cisco 2911-AX Series platforms and later. You can use this RTU on any combination or multiples of modules for WAAS and/or vWAAS connections on the Cisco 2900-AX or 3900-AX Series Routers, respectively. The Cisco 1900-AX Series includes licenses for IP Base, Data, Security, AVC, and WAASX