tity and the AAA server provide the following functions: - mutual authentication of the mobile and the AAA server, via the SWx and SWa interfaces. This authentication has the effect of opening Wi-Fi access to the mobile; - mutual authentication related to the establishment of the SWu tunnel, via the SWx and SWm interfaces; - transfer of the mobile profile comprising a list of access point names (APN) and the quality of service (QoS) level of the S2b tunnel, to the PGW entity via the interface S6b, to the ePDG entity via the SWm interface and to the untrusted Wi-Fi access via the SWa interface. The PCRF entity provides the QoS level of the S2b tunnel to the PGW via the Gx interface and the ePDG via the Gxb interface. The PCRF entity provides the QoS level of the SWu tunnel to the ePDG entity via the Gxb interface. In this case, the ePDG entity provides the QoS level to be applied on the Wi-Fi radio interface via the SWn interface. The mobile must establish a SWu instance for each PDN connection. When the mobile connects to the PDN network, a default bearer must be established on the S2b interface. This connection is maintained for the duration of the connection. Dedicated bearers can be built for the same PDN connection, based on the rules provided by the PCRF. An SWu instance transports the packets of all the S2b bearers for the same connection to the PDN network between the mobile and the ePDG entity. The ePDG entity shall release the SWu instance when the S2b default bearer of the associated connection to the PDN network is released. Wi-Fi Integration to the 4G Mobile Network Two IPv4 and/or IPv6 addresses are assigned to the mobile: - an address for the SWu tunnel built between the mobile and the ePDG entity, provided by the untrusted Wi-Fi access; - an address for the flow transiting in this tunnel, provided by the PGW entity. The connection to the PDN network is described in Figure 1.4. Flows (IP packets) Correspondance SWu instance S2b identifier Tunnel filter Bearer Correspondance SWu instance filter Figur