Content for TR 23.726 Word version: 16.0.0
5 Use cases and Key Issues
6 Solutions
7 Conclusions
A Summary of Solutions for KI#2
$ Change History
5 Use cases and Key Issues p. 9
5.1 Use Cases p. 9
5.1.1 Use Case #1: deployments where a SMF is not able / allowed to control UPF(s) throughout the whole PLMN p. 9
5.1.2 Use Case #2: inter PLMN mobility p. 10
5.1.3 Use Case #3: Third party (corporate) p. 10
5.2 Key Issues p. 11
5.2.1 Key Issue #1: IP address preservation and Control of UPFs in use cases #1,2,3 p. 11
5.2.2 Key Issue #2: IP Address and IP Address Prefix Allocation for Complex SMF/UPF Topologies p. 12
5.2.3 Key Issue #3: UPF resource management impact when UPF shared by multiple SMFs p. 12
5.2.4 Key issues #4: Intermediate SMF Insert/Relocation due to UE Mobility p. 13
5.2.5 Key Issue 5: Handling AF influence on traffic routing p. 13
5.2.6 Key Issue #: Latency to setup the user plane p. 13
6 Solutions p. 14
6.1 Solution #1: Mobility between service areas p. 14
6.1.1 Overview p. 14
6.1.2 Description of the solution p. 14
6.1.2.1 Overview p. 14
6.1.2.2 Non-roaming and LBO network architecture p. 14
6.1.2.3 Home-routed roaming architecture p. 15
6.1.2.4 Network architecture and relation to use cases p. 15
6.1.2.5 Procedure impacts p. 16
6.1.3 Impact of the solution to existing entities p. 27
6.1.4 Evaluation of the solution p. 27
6.2 Solution #2: Selection of I-SMF and V-SMF p. 28
6.2.1 Overview p. 28
6.2.2 Description of the solution p. 28
6.2.3 Impact of the solution to existing entities p. 29
6.2.4 Evaluation of the solution p. 30
6.3 Solution #3: Mobility between SMF service areas p. 30
6.3.1 Overview p. 30
6.3.2 Description of the solution p. 30
6.3.2.1 Network Architecture p. 30
6.3.2.2 Procedures p. 30
6.3.3 Impact of the solution to existing entities p. 32
6.3.4 Evaluation of the solution p. 32
6.4 Solution #4: I-SMF selection by the AMF p. 32
6.4.1 Overview p. 32
6.4.2 Description of the solution p. 32
6.4.3 Impact of the solution to existing entities p. 32
6.4.4 Evaluation of the solution p. 32
6.5 Solution #5: I-SMF as only a UPF Controller p. 32
6.5.1 Overview p. 32
6.5.2 Description of the solution p. 32
6.5.3 Network architecture and relation to use cases p. 33
6.5.4 Procedures p. 34
6.5.4.1 Handover with I-SMF insertion p. 34
6.5.4.2 AN Release p. 36
6.5.4.3 Service Request p. 36
6.5.4.4 Addition of additional PDU Session Anchor and Branching Point or UL CL p. 38
6.5.5 Impact of the solution to existing entities p. 39
6.5.6 Evaluation of the solution p. 39
6.6 Solution #6: SMF selection and reselection due to different region: p. 40
6.6.1 Overview p. 40
6.6.2 Description of the solution p. 40
6.6.2.1 General p. 40
6.6.2.2 SMF selection during PDU Session establishment p. 40
6.6.2.3 I-SMF reselection during UE mobility p. 41
6.6.2.4 Inter NG-RAN node N2 based handover with I-SMF Change p. 42
6.6.2.5 UE Triggered Service Request p. 46
6.6.2.6 Network Triggered Service Request p. 48
6.6.2.7 Registration Procedure p. 48
6.6.2.8 PDU Session Establishment p. 50
6.6.2.9 Xn based handover with I-SMF change p. 50
6.6.3 Impact of the solution to existing entities p. 53
6.6.4 Evaluation of the solution p. 53
6.7 Solution #7: UL-CL/BP Insertion p. 53
6.7.1 Overview p. 53
6.7.2 Description of the solution p. 54
6.7.2.1 General p. 54
6.7.2.2 UL-CL/BP in a same region as A-SMF p. 54
6.7.2.3 UL-CL/BP in a different region than A-SMF p. 58
6.7.3 Impact of the solution to existing entities p. 62
6.7.4 Evaluation of the solution p. 62
6.8 Solution #8: UE IP address allocation by the UPF p. 62
6.8.1 Overview p. 62
6.8.2 Description of the solution p. 63
6.8.3 Impacts on existing Functions p. 63
6.9 Solution #9: One-time IP Address reservation for SMF by UPF p. 63
6.9.1 General p. 63
6.9.2 Architecture Aspects p. 64
6.9.2.1 UPF p. 64
6.9.2.2 SMF p. 64
6.9.2.3 User IP Reservation Procedure p. 65
6.9.2.4 IP De-Reservation Procedure p. 65
6.9.3 Impacts on existing nodes and functions p. 66
6.9.4 Solution Evaluation p. 66
6.10 Solution #10: IP address assignment by the SMF via IP Section allocation p. 67
6.10.1 Overview p. 67
6.10.2 Description of the solution p. 67
6.10.3 The impact of the solution p. 69
6.10.4 Evaluation of the solution p. 69
6.11 Solution #11: IP address assignment by the SMF via external Node coordination p. 70
6.11.1 Overview p. 70
6.11.2 Description of the solution p. 70
6.11.3 The impact of the solution p. 71
6.12 Solution #12: IP address assignment by the SMF via DN-AAA or DHCP Servers p. 71
6.12.1 Overview p. 71
6.12.2 Description of the solution p. 71
6.12.3 The impact of the solution p. 72
6.12.4 Evaluation p. 72
6.13 Solution #13: Handling AF influence on traffic routing - PCF aware of I-SMF insertion p. 73
6.13.1 Overview p. 73
6.13.2 Description of the solution p. 73
6.13.3 Procedures p. 74
6.13.3.1 AF policy processing - PCF aware of I-SMF insertion p. 74
6.13.3.2 Notification of User Plane Management Events p. 75
6.13.4 Impacts on existing nodes and functions p. 76
6.13.5 Solution Evaluation p. 76
6.14 Solution #14: TEID ranges assist CN tunnel Info allocation p. 77
6.14.1 Overview p. 77
6.14.2 Description of the solution p. 77
6.14.3 Impact of the solution to existing entities p. 77
6.14.4 Evaluation of the solution p. 77
6.15 Solution #15: Handling AF influence on traffic routing p. 77
6.15.1 Overview p. 77
6.15.2 Network Architecture p. 77
6.15.3 Procedures p. 78
6.15.3.1 AF policy processing at the A-SMF without PCF impact p. 78
6.15.3.2 Notification of User Plane Management Events p. 79
6.15.4 Impact of the solution to existing entities p. 80
6.15.5 Evaluation of the solution p. 80
6.16 Solution #16: I-UPF insertion and L-SMF/L-UPF selection p. 81
6.16.1 Overview p. 81
6.16.2 Description of the solution p. 81
6.16.2.1 Network Architecture p. 81
6.16.2.2 Procedures p. 82
6.16.3 Impact of the solution to existing entities p. 84
6.16.4 Evaluation of the solution p. 84
6.17 Solution #17: I-SMF insertion during EPS to 5GS handover using N26 p. 84
6.17.1 Overview p. 84
6.17.2 Description of the solution p. 84
6.17.3 Impact of the solution to existing entities p. 86
6.17.4 Evaluation of the solution p. 86
6.18 Solution 18: UL-CL/BP Insertion with UPF that is capable to flexibly interface any SMF p. 87
6.18.1 Overview p. 87
6.18.2 Description p. 87
6.18.2.1 General p. 87
6.18.2.2 Procedures p. 88
6.18.3 Impact of the solution to existing entities p. 88
6.18.4 Evaluation of the solution p. 89
6.19 Solution #19: Reduce latency to setup the user plane p. 89
6.19.1 Overview p. 89
6.19.2 Description of the solution p. 89
6.19.3 Impact of the solution to existing entities p. 90
6.19.4 Evaluation of the solution p. 90
6.20 Solution #20: UE IP address allocation by the UPF & UPF dealing with UP transfer to UE p. 90
7 Conclusions p. 92
7.1 Conclusions for Key issues #1, #4 and #5 p. 92
7.1.1 General p. 92
7.1.2 Information carried over Nxx p. 93
7.2 Conclusions for KI #2 p. 94
A Summary of Solutions for KI#2 p. 95
$ Change History p. 95
