5G NR QoS Profile
A QoS flow may be either GBR or non-GBR depending on QoS profile.
The QoS profile for a QoS flow is sent to RAN with below QoS parameters:
For both GBR and non-GBR, QoS profile shall include below parameters:
– 5G QoS Identifier (5QI); and
– Allocation and Retention Priority (ARP)
For each Non-GBR QoS Flow, the QoS profile may also include:
– Reflective QoS Attribute (RQA).
In Case of GBR QoS flow, the QoS profile may include:
– Notification control;
– Maximum Packet Loss Rate – UL and DL.
5G QoS Rules
UE performs the association of UL traffic to QoS flows based on QoS rules.
These ruled can be explicitly provided to UE during PDU Session Establishment/Modification procedure or it can be pre-configured in UE by applying Reflective QoS.
A QoS rule contains the QFI of the associated QoS Flow, a Packet
Filter Set and a precedence value.
There can be more than one QoS rule associated with the same QoS Flow.
A default QoS rule is required to be sent to the UE for every PDU Session establishment and it is associated with a QoS
Flow. TS 24.501 [47]
Characteristics DL traffic
> UPF maps User Plane Traffic to QoS flow based on PDR (Packet Detection Rule)
> UPF will perform sessionAMBR enforcement and performs counting of packets for charging.
> UPF will transmit PDUs in a single tunnel between 5GC and RAN.
> UPF performs transport level packet marking in DL as per QoS flow basis.
Characteristics UL traffic
> UE uses the stored QoS rules to determine mapping between UL User Plane traffic and QoS Flows
> RAN transmits the PDU over N3 tunnel towards UPF.
> RAN performs transport level packet marking in the UL on a per QoS Flow basis
Source TS 23 501