Section: 8.15.1.3 Multicast MRB type re-configuration with F1-U ptp-retransmission tunnel establishment
Content: Figure 8.15.1.3-1: Multicast MRB type re-configuration with F1-U ptp retransmission tunnel establishment 1. The gNB-DU decides to change the MRB type configuration for a UE and provides the new configuration to the gNB-CU-CP along with a per-MRB MRB type reconfiguration indication and the MRB Reconfigured RLC mode. 2. The gNB-CU-CP confirms the modification request and indicates this to the gNB-DU. The gNB-CU-CP may request the gNB-DU to establish F1-U ptp retransmission resources in order for the UE to perform PDCP Status Report and receive retransmitted PDCP PDUs for the reconfigured MRBs. 4. - 7. If necessary, the gNB-DU requests the establishment of F1-U resources for ptp retransmission by means of triggering the F1AP Multicast Distribution Setup procedure, which in turn triggers the E1AP MC Bearer Context Modification procedure to exchange F1-U tunnel end-point addresses. NOTE: Depending on MRB bearer type reconfiguration the gNB-DU may also request to release some F1-U resources. 8./9. The RRC Reconfiguration procedure is performed 10. PDCP Status Report and PDCP PDU retransmission can take place via the established F1-U ptp retransmission resources.