An apparatus of a User Equipment, UE (602, 702), the apparatus comprising: a cellular transceiver (665, 765) to communicate (610, 710) with an Evolved Node B, eNB (604, 704), traffic of at least one Evolved Universal Mobile Telecommunications System, UMTS, Terrestrial Radio Access Network, E-UTRAN, Radio Access Bearer, E-RAB; a Wireless Local Area Network, WLAN, transceiver (663, 763) to receive (632, 732) a WLAN message comprising an Internet Protocol, IP, address assigned to the UE (602, 702); and a controller component (645, 745) configured to trigger the UE (602, 702) to use the IP address assigned to the UE (602, 702) in establishment (626, 628, 630; 726. 728, 730) of an IP security, IPSec, tunnel with the eNB (604, 704) via a WLAN node (606, 706), and to process an IPSec tunneling packet received via the IPSec tunnel, wherein the IPSec tunneling packet comprises an encapsulated IP payload comprising downlink traffic of the E-RAB; wherein said IPSec tunneling packet is encrypted and authenticated according to an IPSec protocol; characterized in that the cellular transceiver (665, 765) is configured to receive from the eNB (604, 704) a cellular message (614, 714) comprising a WLAN identifier of the WLAN node (606, 706), key information, and an IP address of the eNB (604, 704), the controller component (645, 745) is configured to trigger the WLAN transceiver (663, 763) to establish a WLAN connection with the WLAN node (606, 706) based on the WLAN identifier, to trigger the UE (602, 702) to perform a mutual authentication between the UE (602, 702) and the eNB (604, 704) using the key information contained in the cellular message (614, 714) received from the eNB (604, 704), and to establish an IPSec session with the eNB (604, 704) via the WLAN connection. a cellular transceiver (665, 765) to communicate (610, 710) with an Evolved Node B, eNB (604, 704), traffic of at least one Evolved Universal Mobile Telecommunications System, UMTS, Terrestrial Radio Access Network, E-UTRAN, Radio Access Bearer, E-RAB; a Wireless Local Area Network, WLAN, transceiver (663, 763) to receive (632, 732) a WLAN message comprising an Internet Protocol, IP, address assigned to the UE (602, 702); and a controller component (645, 745) configured to trigger the UE (602, 702) to use the IP address assigned to the UE (602, 702) in establishment (626, 628, 630; 726. 728, 730) of an IP security, IPSec, tunnel with the eNB (604, 704) via a WLAN node (606, 706), and to process an IPSec tunneling packet received via the IPSec tunnel, wherein the IPSec tunneling packet comprises an encapsulated IP payload comprising downlink traffic of the E-RAB; wherein said IPSec tunneling packet is encrypted and authenticated according to an IPSec protocol; characterized in that the cellular transceiver (665, 765) is configured to receive from the eNB (604, 704) a cellular message (614, 714) comprising a WLAN identifier of the WLAN node (606, 706), key information, and an IP address of the eNB (604, 704), the controller component (645, 745) is configured to trigger the WLAN transceiver (663, 763) to establish a WLAN connection with the WLAN node (606, 706) based on the WLAN identifier, to trigger the UE (602, 702) to perform a mutual authentication between the UE (602, 702) and the eNB (604, 704) using the key information contained in the cellular message (614, 714) received from the eNB (604, 704), and to establish an IPSec session with the eNB (604, 704) via the WLAN connection.