LEDGE S1-AP MME STATUS TRANSFER RRC ConnectionReconfigurationComplete S1 Bearer S5 Bearer Temporary Bearer Temporary Radio Bearer Temporary Bearer Radio Bearer S1 Bearer S5 Bearer Figure 7.8. Handover based on S1 with relocation execution phase 1) The source eNB entity starts the execution phase by sending to the mobile the RRC ConnectionReconfiguration message containing the information element handover command. Handover 2) The source eNB entity transmits to the former MME entity the sequence numbers of the PDCP protocol with the message SI-AP SN STATUS TRANSFER. 3) The former MME entity forwards the sequence numbers to the new MME entity in the message GTPv2-C FORWARD ACCESS CONTEXT NOTIFICATION. 4) The new MME entity responds to the former MME entity with the message GTPv2-C FORWARD ACCESS CONTEXT ACKNOWLEDGE to acknowledge the message received. 5) The new MME entity forwards the sequence numbers to the target eNB entity in the message SI-AP MME STATUS TRANSFER. Incoming data that have not been acknowledged by the mobile which the target eNB entity will store until the mobile is able to receive are transmitted in the temporary bearer. 6) When the RRC connection is established between the mobile and the target entity, mobile transmits ConnectionReconfigurationComplete message, which will trigger the transfer of incoming data stored by the target eNB entity to the mobile. 7.3.2.3. Completion phase The S1-based handover procedure with the relocation of the MME and SGW entities is shown in Figure 7.9 for the completion phase. 1) The completion phase starts when the target eNB entity notifies the new MME entity with the message S1-AP HANDOVER NOTIFY containing the ECGI identity of the cell. 2) The new MME entity informs the former MME entity that the handover is completed with the message GTPv2-C FORWARD RELOCATION COMPLETE NOTIFICATION. 3) Former MME entity responds to the new MME entity with the message GTPv2-C FORWARD RELOCATION COMPLETE ACKNOWLEDGE to acknowledge the message received. VoLTE and ViLTE 4) The new