o the UE. The principle of classification and marking of user-plane traf- fic and mapping of QoS flows to AN resources is illustrated in Fig. 1.88 [3]. A packet filter set is used in the quality of service rules or service data flow template to identify a quality of service flow. The packet filter set may contain packet filters for the downlink direction, the uplink direction, or packet filters that are applicable to both directions. There are two types of packet filter set, that is, IP packet filter set and Ethernet packet filter set, corresponding to those protocol data unit session types. The quality of service rule precedence value and the service data flow template precedence value determine the order in which a quality of service rule or a service data flow template, respectively, is evaluated. The evaluation of the quality of service rules or service data flow templates is performed in the increasing order of their precedence value. The averaging window is defined only for guaranteed bit rate quality of service flows and represents the duration over which the guaranteed flow bit rate and maximum flow bit rate are calculated. The averaging window may be signaled along with 5 QoS identifiers to the access network and user-plane function, and if it is not received, a predefined value will be applied. Policy control function provides policy framework incorporating network slicing, roaming and mobility man- agement and is equivalent to policy and charging rules function in evolved packet core. Application/Service Layer Data packets from applications QoS Rules (Mapping UL packets to QoS flows and apply QoS flow marking) QoS Flow (All packets marked with the same QoS flow ID) Mapping QoS flows to AN Resources Packet Detection Rule (PDR) (classify packets for QoS AN Resources PDU Session flow marking and other AN Resources actions) Figure 1.88 Classification and user-plane marking of QoS flows and mapping to access network resources [3]. 180 Chapter 1 In the downlink direction, the incoming data packets are classi