Content for TR 23.879 Word version: 9.0.0
5 Architecture Alternatives p. 9
5.1 Alternative 1 - Evolved MSC p. 9
5.1.1 Reference architecture p. 9
5.1.1.1 Non-roaming architecture p. 9
5.1.1.2 Roaming architecture p. 9
5.1.1.3 Required functionality in network elements p. 10
5.1.1.4 Reference points p. 10
5.1.1.5 Protocol Stacks p. 11
5.1.2 Procedures p. 11
5.1.2.1 Registration p. 11
5.1.2.2 Location Update p. 13
5.1.2.3 Deregistration p. 13
5.1.2.4 eMSC Discovery p. 13
5.1.2.5 MO and MT Call Setup p. 14
5.1.2.6 MO and MT SMS p. 14
5.1.2.7 HO from E-UTRAN to GSM/UMTS CS p. 15
5.1.2.8 HO from GSM/UMTS CS to E-UTRAN p. 16
5.1.3 Co-existence with IMS based services p. 17
5.1.4 Roaming aspects p. 17
5.1.5 Security aspects p. 17
5.1.6 Charging aspects p. 17
5.1.7 Legal requirements aspects p. 18
5.1.7.1 Emergency calls p. 18
5.1.7.2 Lawful interception p. 18
5.1.8 Assessment p. 18
5.2 Alternative 2 - IWF between EPS and MSC p. 18
5.2.1 Reference architecture p. 18
5.2.1.1 Non-roaming architecture p. 19
5.2.1.2 Roaming architecture p. 19
5.2.1.3 Required functionality in network elements p. 20
5.2.1.4 Reference points p. 21
5.2.1.5 Protocol Stacks p. 22
5.2.2 Procedures p. 23
5.2.2.1 IWF Discovery p. 23
5.2.2.2 Registration p. 24
5.2.2.3 Periodic Location Update p. 26
5.2.2.4 EPS Detach procedure p. 26
5.2.2.5 Handling of IWF or MSC failure p. 26
5.2.2.6 Deregistration p. 26
5.2.2.7 Establishment of IWF-MME communication for the UE p. 26
5.2.2.8 MO and MT Call Setup p. 27
5.2.2.9 MO and MT SMS p. 28
5.2.2.10 HO from E-UTRAN to GSM/UMTS CS p. 29
5.2.2.11 HO from GSM/UMTS CS to E-UTRAN p. 31
5.2.3 Co-existence with IMS based services p. 31
5.2.4 Roaming aspects p. 32
5.2.4.1 CSoPS support in the VPLMN p. 32
5.2.4.2 No CSoPS support in the VPLMN p. 32
5.2.4.3 Co-existence with SRVCC p. 32
5.2.4.4 Support for inbound roaming IMS subscribers p. 32
5.2.4.5 Voice mode selection in VPLMN for UEs Supporting Combinations of Voice Modes p. 32
5.2.5 Security aspects p. 34
5.2.6 Charging aspects p. 34
5.2.7 Legal requirements aspects p. 34
5.2.7.1 Emergency calls p. 34
5.2.7.2 Lawful interception p. 34
5.2.7a CSoPS interaction with ISR p. 34
5.2.7a.1 General p. 34
5.2.7a.2 Mobile Terminating Call when ISR is active and SGs is active between MSC/VLR and MME p. 36
5.2.8 Assessment p. 37
5.3 Alternative 3 - Iu-CS based solution p. 38
5.3.1 Reference architecture p. 38
5.3.2 Procedures p. 39
5.3.3 Co-existence with IMS based services p. 39
5.3.4 Roaming aspects p. 39
5.3.5 Security aspects p. 40
5.3.6 Charging aspects p. 40
5.3.7 Legal requirements aspects p. 40
5.3.8 Assessment p. 40
5.4 Alternative 4 - Page in eUTRAN, Call in GSM/WCDMA p. 40
5.4.1 Reference architecture p. 40
5.4.2 Procedures p. 41
5.4.2.1 Mobility Management p. 41
5.4.2.2 EPS Relocation p. 42
5.4.2.3 Mobile Terminating Call p. 42
5.4.2.4 MT CS Call in Active Mode - Preparation Phase p. 44
5.4.2.5 MT CS Call in Active Mode - Execution Phase p. 46
5.4.2.6 MO CS Call in Active Mode - Preparation Phase p. 48
5.4.2.7 MO CS Call in Active Mode - Execution Phase p. 50
5.4.2.8 MT CS Call in Idle Mode p. 52
5.4.2.9 MO CS Call in Idle Mode p. 52
5.4.3 Co-existence with IMS based services p. 52
5.4.4 Roaming aspects p. 52
5.4.5 Security aspects p. 52
5.4.6 Charging aspects p. 53
5.4.7 Legal requirements aspects p. 53
5.4.8 Assessment p. 53
5.5 Alternative 5 - SIP based approach p. 53
5.5.1 Key aspects of delivering a successful solution p. 53
5.5.2 Conclusion and recommendation p. 53
5.6 Alternative 6 - Combined solution p. 54
5.6.0 General p. 54
5.6.1 Reference architecture p. 54
5.6.1.1 General p. 54
5.6.1.2 Required functionality in network elements p. 55
5.6.1.3 Reference points p. 55
5.6.1.4 Protocol Stacks p. 56
5.6.2 Procedures p. 56
5.6.2.1 CS attachment p. 56
5.6.2.2 Location Update p. 56
5.6.2.3 Deregistration p. 57
5.6.2.4 eMSC Discovery p. 57
5.6.2.5 Gs-like Paging p. 57
5.6.2.6 MT Call Setup p. 57
5.6.2.7 MO Call Setup p. 57
5.6.2.8 MO and MT SMS p. 57
5.6.2.9 HO from E-UTRAN to GSM/UMTS CS p. 57
5.6.2.10 HO from GSM/UMTS CS to E-UTRAN p. 57
5.6.3 Co-existence with IMS based services p. 57
5.6.4 Roaming aspects p. 58
5.6.4.1 'CS domain call and SMS control signalling over EPS' support in the VPLMN and UE p. 58
5.6.4.2 No 'CS domain call and SMS control signalling over EPS' support in the VPLMN or UE p. 58
5.6.5 Security aspects p. 58
5.6.6 Charging aspects p. 58
5.6.7 Legal requirements aspects p. 58
5.6.8 Assessment p. 58
6 Conclusion p. 58
$ Change history p. 60
