> WKT QFI is used to identify QoS flow.
> QoS flow is the finest granularity of QoS differentiated services in a PDU session.
> Multiple services can have the same QoS flow if they are having the same QoS service level.
> QFI is unique and its value range from 0 to 63.
> A QoS flow is controlled by SMF and can be configured in PDUSessionEstablishment/PDUSession Modification.
> QFI is used to identify a QoS flow.
Features of QoS flow:
1. They have a QoS profile.
2. One or more uplink and downlink PDR.
5G NR QoS flow mapping
SMF is responsible for QoS control.
wWhen a PDU session is established, SMF will configure the required WoS parameters for UPF, AN and UE.
SMF will provide below information about QoS flow to RAN:
> QoS profile.
> optionally, Alternative QoS Profile(s).
Below shows the steps of mapping of QoS flow to AN:
> For DownLink, the incoming data packets are classified by the UPF based on the packet filter of DL PDR in order of precedence.
> The AN binds QoS Flows to AN resources
> If no matching DL PDR is found, the UPF shall discard the DL data packet.
> For UL, the UE will match the data packets according to the QoS rules and the data packet is transmitted upward from the matched QoS flow to its corresponding AN channel.
Source TS 23 501