Section: 5.5.1.2.2a S1-based DAPS handover, normal
Content: This procedure describes the S1-based DAPS handover in the normal case. Figure 5.5.1.2.2a-1: S1-based DAPS handover 1. Step 1 to step 9b are performed as described in clause 5.5.1.2.2 with the following changes: The Source to Target Transparent Container which is included in Handover Required message in step 2 in clause 5.5.1.2.2 will contain the DAPS Information if DAPS HO is supported by source eNodeB and source MME and DAPS HO is requested for one or more DRBs as described in TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [5]. If DAPS HO is supported by the target eNodeB and target MME and the DAPS Information is received for one or more DRBs in the Source to Target transparent container, the target eNodeB provides the DAPS Response Information in the Target to Source transparent container in Handover Request Acknowledge message in step 5a in clause 5.5.1.2.2. 2. The source eNodeB sends the eNodeB Early Status Transfer message to the target eNodeB via the MME(s) to convey the PDCP and HFN status of the E-RABs for which PDCP status preservation applies, as specified in TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [5]. For the DRBs not subject to DAPS, step 10 to step 10c in clause 5.5.1.2.2 may be performed. If there is an MME relocation the source MME sends this information to the target MME via the Forward Access Context Notification message which the target MME acknowledges. The source MME or, if the MME is relocated, the target MME, sends the information to the target eNodeB via the MME Early Status Transfer message. 3. This step is the same as step 11 in clause 5.5.1.2.2. 4. This step is the same as step 12 in clause 5.5.1.2.2. 5. This step is the same as step 13 in clause 5.5.1.2.2 with the difference that the Notify Source eNodeB IE is included in the Handover Notify message. 6. This step is the same as step 14 in clause 5.5.1.2.2 with following changes: If there is an MME relocation and the target MME receives this Notify Source eNodeB information from the target eNodeB, the target MME provides the Notify Source eNodeB information via the Forward Relocation Complete Notification message. 7. If the Notify Source eNodeB IE is provided in either step 5 or step 6, the source MME sends the Handover Success message to source eNodeB to inform the source eNodeB that the UE has successfully accessed the target eNodeB. 8. The Source eNodeB initiates the eNodeB Status Transfer message for the DRB(s) subject to DAPS. This step is the same as step 10 in clause 5.5.1.2.2. 9. Steps 15 to 21b in clause 5.5.1.2.2 are performed.