em in order of their prece- dence. The UPF passes on the classification of user data traffic which belongs to a QoS flow through the interface between the UPF and 5G RAN (radio access network, i.e. radio AN) based on user plane marking with QFI. Further, the AN does binding of QoS flows to AN resources, which are the data radio bearers (DRBs) in the RAN. However, 5 QoS for Mobile Ultra-Broadband the relationship between QoS flows and AN resources is not strictly one-to-one. Further, AN establishes and releases the AN resources and in the case of QoS flows indicates that to the SMF. In summary, the main novelty (regarding the 3GPP mobile networks) in the 5G QoS approach is the possibility for differentiation of data flows, which provides means for differentiation of traffic from different applications/services with diverse QoS requirements while at the same maximizing the resource utilization in the AN. Also, 5G (starting with 3GPP Release 15) is designed to support different types of AN, including fixed ANs. QoS provisioning is symmetric because it is provided in the same manner in both directions, downlink and uplink, which is possible with the reflective QoS approach (copying the downlink QoS rules for the uplink). Finally, while in UMTS and LTE/LTE-Advanced the QoS support is based on bearers, the 5G mobile core is designed to have flow-based QoS rather than bearer-based one. 5.8 Mobile Broadband Spectrum Management and QoS The spectrum management in mobile broadband networks is crucial for QoS support. Why? Because the most important parameter for the mobile broadband (e.g. 3G and 4G) and mobile ultra-broadband (5G) is to have more bits per second. And that can be accomplished by using more frequency spectrum bands for a given RAN, either 3G, 4G, or 5G, and by using wider frequency carriers (e.g. 20 MHz was the maximum width of a frequency carrier in LTE, 5 MHz in UMTS, and 0.2 MHz in GSM/GPRS). To provide higher aggregate bitrates in a given cell it is also required to have bigger width of fre- quency carrie