Section: 4.9.1.3.3a Execution phase for DAPS handover
Content: This procedure applies only if at the end of the Preparation phase it has been determined that at least one DRB of the UE is subject to a DAPS related Handover. Figure 4.9.1.3.3a-1: inter NG-RAN node N2 based DAPS handover, execution phase 1 to 2. Same as step 1 to step 2 in clause 4.9.1.3.3 with the following difference. DAPS Response information received in the Target to Source Transparent Container indicates the DAPS handover is accepted for one or more DRBs. 2a to 2c. The S-RAN sends the Uplink RAN Early Status Transfer message to the S-AMF as specified in TS 38.413[ NG-RAN; NG Application Protocol (NGAP) ]  [10]. For the DRBs not subjecting to DAPS, steps 2a to 2c in clause 4.9.1.3.3 may be performed. If there is an AMF change, the S-AMF sends this information to the T-AMF via the Namf_Communication_N1N2MessageTransfer service operation and the T-AMF acknowledges. The S-AMF or, if the AMF is relocated, the T-AMF, sends the information to the T-RAN via the Downlink RAN Early Status Transfer message, as specified in TS 38.413[ NG-RAN; NG Application Protocol (NGAP) ]  [10]. 3. Same as step 3 in clause 4.9.1.3.3. 4. Same as step 4 in clause 4.9.1.3.3. 5. T-RAN to T-AMF: same as step 5 in clause 4.9.1.3.3 with the difference that the Handover Notify includes a Notify Source NG-RAN node information which is used to notify the S-RAN that the UE has successfully accessed the T-RAN. 6a. [Conditional] T-AMF to S-AMF: Namf_Communication_N2InfoNotify. The T-AMF notifies the S-AMF as in step 6a in clause 4.9.1.3.3 with the difference that Notify Source NG-RAN node information is included. 6b. [Conditional] S-AMF to T-AMF: Namf_Communication_N2InfoNotify ACK. The S-AMF acknowledges by sending the Namf_Communication_N2InfoNotify ACK to the T-AMF as in step 6b in clause 4.9.1.3.3. 7. S-AMF to S-RAN: Handover Success. The S-AMF informs the S-RAN node that the UE has successfully accessed the T-RAN as described in TS 38.413[ NG-RAN; NG Application Protocol (NGAP) ]  [10], S-RAN stops the UL data transfer for the UE. 8a to 8c. The S-RAN initiates step 8a. Step 8a to 8c are the same as step 2a to 2c in clause 4.9.1.3.3 for the DRB(s) subject to DAPS. 9. Step 6c to step 15 in clause 4.9.1.3.3 are performed.