How it Works
The RAN-initiated QoS flow is offloaded from Primary Node (PN) to Secondary Node (SN). After the flow is created, PN may switch the traffic to SN. SN allocates new DL TEID and sends it to PN. Then, PN initiates the PDU Session resource modify request with that DL TEID. SMF updates only the DL FAR to switch the traffic to SN. The switch from SN to PN can happen. However, SMF has no behavioral change.