Question

How the PDU session to QOS flow to DRB mapping handled and which IEs in the relevant protocol stacks facilitate the multiplexing and demultiplexing these sessions/flows?

Thanks for your help

Answer 1

Each bearer at core network has its associated data radio bearer at radio side. Downlink traffic flow templates configured at PGW do this job. Each bearer at the PGW is associated with a TFT and each TFT may contain many packet filters.
Each IP packet destined to UE, passes through these packet filters and PGW chooses relevant bearer to transmit packets.
Required QoS treatment for an IP packet is taken care from PGW till eNodeB.

Comments

@Vimal: Thankyou very much for the answer. Sorry but may be I was not very clear, the question is  how the 5G Core and gNB handle the mappings ?

I am interested in knowing how the "Single-Network Slice Selection Assistance Information (S-NSSAI)" and "Network Slice Selection Assistance Information (NSSAI)" are mapped to PDU sessions. And if possible want to know how the App data from n/w get split into GTP sessions,  PDU sessions, QOS flows and finally the DRBs.