For the traffic of UEs behind a RG, QoS differentiation in the RG's PDU Session can be provided on a per UE's IPsec Child Security Association basis. The UE's N3IWF/TNGF determines the IPsec child SAs as defined in clauses 4.12 and 4.12a of TS 23.502 as well as the DSCP value used in the outer IP header of that IPsec child SA. It is assumed that the same set of DSCP values and corresponding QoS are applicable independent of whether UE-requested or network-initiated QoS is used.
To support QoS differentiation for the UE's traffic, QoS mapping rules between the RG's 5GC and the UE's 5GC are governed by an SLA (or network configuration in case of single operator), which includes the mapping between the DSCP marking for the IPsec child SAs and the corresponding QoS parameters and also the N3IWF/TNGF IP address(es). The non-alteration of the DSCP field on NWu/NWt is also governed by the SLA and by transport-level arrangements that are outside of 3GPP scope. The SLA also governs the RG PDU session IP addresses.
The RG's PCF and SMF may provide PCC rules and QoS rules for the available mappings as determined by the SLA. The packet detection filters in the RG's UPF can be based on the N3IWF/TNGF IP address and the DSCP markings on NWu/NWt.
UE's SMF/PCF may use the UE's local IP address, which is the N6 address of the RG's PDU session, to enable differentiated QoS and charging when the UE is accessing N3IWF/TNGF via a W-5GAN.
Differentiated charging is enabled by the awareness of N3IWG/TNGF and RG PDU Session IP addresses and also the mapping between DSCP marking and QoS parameters included in the SLA.