Section: 8.11.3 RRC Connection Reestablishment – separate PLMN signalling
Content: The signalling flow for RRC Connection Reestablishment for network sharing with multiple cell-ID broadcast with separate per-PLMN signalling is shown in Figure 8.11.3-1. In this example message flow - each F1-C/Xn-C interface instance uses either a separate signalling transport or a share signalling transport with other interface instances. - the New gNB-DUA/B entity shown in Figure 8.11.3-1 is a simplified representation of the New gNB-DUA of PLMN A, the New gNB DUB of PLMN B and respective radio resources of the shared cell. Figure 8.11.3-1: RRC Connection Reestablishment and network sharing with multiple cell-ID broadcast 1. The UE sends the RRCReestablishmentRequest. 2A-5A. Depicts the case where the UE context could not be retrieved by the new gNB-CUA. In step 2A, the NR CGI associated to PLMNA is indicated. In step 5A, the gNB-CUA would prepare the possibility to revert back to normal RRC Connection Establishment, indicating that the UE Context was not retrieveable and may include the re-directed RRC message as received in step 1. After step 5A, the gNB-DUA may redirect the UE towards the PLMN indicated in DL RRC MESSAGE TRANSFER message, if the PLMN assistance information is provided by the gNB-CUA. If the New gNB-DUA/B was not able to deduce the RRC message from step 1, this indicator triggers step 2B. The New gNB-DUA is supposed to trigger the release the UE-associated signalling connection (not shown). 2B-5B. Depicts the case where the UE context was retrieveable by the New gNB-CUB. In step 2B, the NR CGI associated to PLMNB is indicated. Step 2B also includes the C-RNTI allocated at reception of step 1. 6-8. The RRC Connection Reestablishment continues with the New gNB-CUB. NOTE: If all gNB-CUs indicate that the UE context is not retrievable, the RRC connection reestablishment falls back to RRC Connection setup, as described in clause 8.11.2. NOTE: Initiating procedures from gNB-DUA towards gNB-CUA and from gNB-DUB to gNB-CUB in parallel is not precluded.