me of the PDN connection to provide the UE with always-on IP connectivity to the PDN. This bearer is referred to as the default bearer. Any additional EPS bearer/E-RAB that is established to the same PDN is referred to as the dedicated bearer. The initial bearer-level QoS parameter values of the default bearer are assigned by the network, based on subscription information. The decision to establish or modify a dedicated bearer can only be taken by the EPC and the bearer-level QoS parameter values are always assigned by the EPC. An EPS bearer/E-RAB is referred to as a Guaranteed Bit Rate (GBR) bearer, if dedicated network resources related to a GBR value that is associated with the EPS bearer/E-RAB are permanently allocated by the admission control function in the eNB on bearer establishment/modification XX *An E-RAB uniquely identifies the concatenation of an S1 bearer and the corresponding data radio bearer. When an E-RAB exists, there is a one-to-one mapping between the E-RAB and an EPS bearer of the NAS. CHAPTER 6 The IEEE 802. 16m MAC CPS (Part I) E-UTRAN Internet- Entity End-to-end Service EPS Bearer External Bearer E-RAB S5/S8 Bearer Radio Bearer S1 Bearer Radio Link S5/S8 FIGURE 6-31 EPS bearer service architecture Otherwise, an EPS bearer/E-RAB is referred to as a Non-GBR bearer. A dedicated bearer can either be a GBR or a non-GBR bearer, while a default bearer is a non-GBR bearer. The EPS bearer service architecture is depicted in Figure 6-31, where: A UL Traffic Flow Template (TFT) binds a service data flow to an EPS bearer in the uplink direction. Multiple service data flows can be multiplexed into the same EPS bearer by including multiple uplink packet filters in the UL TFT. A DL TFT in the PDN GW binds a service data flow to an EPS bearer in the downlink direction. Multiple service data flows can be multiplexed into the same EPS bearer by including multiple downlink packet filters in the DL TFT. An E-RAB transports the packets of an EPS bearer between the UE and the EPC. When an E-RAB exists, there i