An integrated WLAN/WWAN Radio Access Technology (“RAT”) architecture is described, in which signaling used to control the integration of the WLAN/WWAN architecture is performed over the Packet Data Convergence Protocol (“PDCP”) layer, and/or at other layers (e.g., a layer between the PDCP layer and the Internet Protocol (“IP”) layer). When involving the PDCP layer, non-standard PDCP packets, including variable length PDCP packets, may be used. The integrated architecture may provide a network controlled framework for performing traffic steering and radio resource management.