UE8

1. UE8 UE7 R4 R3 R2 R1 UE5 UE6 UE1 UE3 UE2 UE4

2. Old MME SGSN A UE eNodeB New MME S-GW P-GW PCRF HSS 1. Attach request EIR 2. Attach request 3. Identification request 3. Identification response 4. Identity request 4. Identity response 5a. Authentication / Security 5b. Identity request /response 6. Ciphered option response 7. PCEF initiated IP CAN Session Termination (A) 7. Delete bearer request 7. Delete bearer response 8. Update location request 9. Cancel location 9. Cancel location ack. 10. PCEF initiated IP CAN Session Termination (B) 10. Delete bearer request 10. Delete bearer response 11. Update location acknowledgment 12. Create default bearer request 13. Create default bearer request 14. PCEF initiated IP CAN Session Termination (C) 15. Create default bearer response First downlink data if not handover 16. Create default bearer response 17. Initial context setup request / attach request 18. RRC connection reconfiguration 19. RRC connection reconfiguration complete 20. Initial context setup response 22. Attach complete First uplink data 23. Update bearer request 23a.Update bearer request 23b. Update bearer response (B) 24. Update bearer response First downlink data 25. Notify request 26. Notify response

3. LTE Uu S1 MME S11 S6 a S-GW P-GW UE eNodeB MME HSS DL DATA UE EMM-REGISTERED and ECM-IDLE D L2 SCTP : DL DATA NOTIFICATION Paging Procedure BN RRC CONNECTION REQUEST Begin measurement BUE RRC CONNECTION SETUP Setup SRB1 RRC CONNECTION SETUP COMPLETE L3 NAS : SERVICE REQUEST S1 – AP INITIAL UE MESSAGE L3 NAS : SERVICE REQUEST L2 SCTP : Create Bearer Request Activate EPS bearer setup in ePC L2 SCTP : Create Bearer Response MAP Send Authentication Info If authentication vectors are not available in MME, authenticate UE MAP Send Authentication Info ACK S1-AP: UL NAS TRANSPORT (L3: AUTHENTICATION AND CIPHERING REQUEST) RRC: DL INFORMATION TRANSFER (L3: AUTHENTICATION AND CIPHERING REQUEST) If authentication timer has expired, setup security association for user plane RB RRC: UL INFORMATION TRANSFER (L3: AUTHENTICATION AND CIPHERING RESPONSE S1-AP: DL NAS TRANSPORT (L3: AUTHENTICATION AND CIPHERING RESPONSE)

4. LTE Uu S1 MME S11 S6 a S-GW P-GW UE eNodeB MME HSS DL DATA UE EMM-REGISTERED and ECM-CONNECTED BN Delay L2 SCTP : DL DATA NOTIFICATION Paging Attempt T1 L2 SCTP : DL DATA NOTIFICATION Ack. S1-AP: DL NAS TRANSPORT (L3 NAS: PAGING) RRC: DL INFORMATION TRANSFER (L3 NAS: PAGING) Timer Retry (optionally) To all cells of all TAs L2 SCTP : DL DATA NOTIFICATION Reject Paging Failure T2 UE Triggered Service Request Procedure [3GPP TS 23.401] UE EMM-REGISTERED and ECM-CONNECTED L2 SCTP: Stop Paging Forward DL Packet to UE EN

5. LTE Uu S1 MME S11 S6 a S-GW P-GW UE eNodeB MME HSS S1-AP: INITIAL CONTEXT SETUP REQUEST PM Counter: EPS_SETUP_ATT T1 S1-AP: INITIAL CONTEXT SETUP FAILURE RRC SECURITY MODE COMMAND EUE RRC CONNECTION RECONFIGURATION Setup user plan RB RRC SECUIRTY MODE COMMAND COMPLETE RRC CONNECTION RECONFIGURATION COMPLETE End measurement Means “Delay DL Packet Notification Request” to stop/ enable DL data transfer First UL PDU S1-AP: INITIAL CONTEXT SETUP COMPLETE PM Counter: EPS_SETUP_SUCC T2 L2 SCTP : Create Bearer Request L2 SCTP : Create Bearer Response EN First DL PDU

6. UE Source eNodeB Target eNodeB MME S-GW 0. Area restriction provided 1. Measurement control Packet data Packet data UL Allocation LEGEND L1 / L2 signaling 2. Measurement reports L3 signaling 3. HO Decision User Data 4. HO request 4. Admission control 6. HO request Ack. DL Allocation HO Preparation 7. HO Command Dettach from old cell synch. to new cell Deliver buffered and in transit packets to target eNodeB 8. SN stats request Buffer packets from source eNodeB HO execution 9. Synchronisation 10. UL allocation + TA for UE 11. Handover confirm 12. Path switch request 13. User plane update request End marker 14. Switch DL path 15. User plane update response 16. Path switch request Ack. 17. UE conterxt release Flush DL buffer , continue delivering in-transit packets HO completion Data Forwarding End market 18. Release resources Packet data Packet data