versal subscriber identity module (USIM) of its universal integrated circuit card (UICC) and compares the seal (AUTN) received with that calculated; xxvi Wi-Fi Integration to the 4G Mobile Network - the mobile transmits its seal (RES) to the MME entity, which compares it to that received from the HSS entity; - the KASME key is used to protect the signaling exchanged between the mobile and the MME entity as well as the control and traffic data on the radio interface. I.1.3. Bearer establishment The EPS network transports the mobile data stream (IP packets) transparently to the PGW entity that is routing the packets. The IP packet is transported in bearers built between the entities of the EPS network (Figure I.2). EPS Bearer Radio Access Bearer Radio Bearer S1 Bearer S5 Bearer GTP-U GTP-U GTP-C Figure I.2. Bearer establishment The data radio bearer (DRB) is built between the mobile and the eNB entity. The RRC (Radio Resource Control) signaling, exchanged between the mobile and the eNB entity, is responsible for the construction of this bearer. The S1 bearer is built between the eNB and SGW entities. The S1-AP signaling, exchanged between the eNB and MME entities, and the GTPv2 (GPRS Tunneling Protocol-Control) signaling, exchanged between the MME and SGW entities, are responsible for the construction of this bearer. The S5 bearer is built between the SGW and PGW entities. The GTPv2- C signaling, exchanged between the SGW and PGW entities, is responsible for the construction of this bearer. Introduction xxvii The connection of the radio bearer and the S1 bearer, carried out by the eNB entity, constitutes the EPS radio access bearer (E-RAB). The connection of the E-RAB and S5 bearers, made by the SGW entity, constitutes the EPS bearer. The S1 and S5 bearers are GTP-U (GPRS Tunneling Protocol User) tunnels, which allow the IP packet of the mobile to be transported in the IP packet of the bearer transmitted between the entities of the EPS network. The PGW entity is the only entity in the EPS network that routes the mo