Content for TR 23.714 Word version: 14.0.0
4 Architectural considerations
5 Key issues
6 Solutions
7 Overall evaluation
8 Conclusions
A Example for interaction between CP and UP function
B Example for attributes exchanged between the CP and UP function
$ Change History
4 Architectural considerations p. 8
4.1 Architectural assumptions and requirements p. 8
4.2 Baseline architecture p. 8
4.3 Existing functionality of S-GW, P-GW and TDF p. 9
5 Key issues p. 12
5.1 Key issue 1 - Functionality split into user plane and control plane functions p. 12
5.1.1 Description p. 12
5.2 Key Issue 2 - Selection mechanism for user plane functional entities p. 12
5.3 Key Issue 3 - Change of user plane session identity (due to other than UE mobility scenarios) p. 12
5.3.1 Description p. 12
5.3.2 Solution requirements p. 12
5.4 Key Issue 4 - Relocation of user plane functional entity due to UE mobility p. 13
6 Solutions p. 13
6.1 Solutions to key issue 1 p. 13
6.1.1 Solution 1: Functional split for SGW, PGW and TDF p. 13
6.1.1.1 Overview p. 13
6.1.1.2 Functional split of SGW p. 13
6.1.1.3 Functional split of PGW p. 16
6.1.1.4 Functional split of TDF p. 18
6.1.1.5 Considerations for GTP-U IP address and TEID allocation p. 20
6.1.1.5.1 Description p. 20
6.1.1.5.2 Solution 1: F-TEID-u allocation / release in the user plane function p. 20
6.1.1.5.3 Solution 2: F-TEID-u allocation / release in the control plane function p. 20
6.1.1.5.4 Solution 3: Control plane function providing pre-allocated GTP-U IP address and TEID to the user plane function (during restoration scenario) p. 20
6.1.1.5.5 Evaluations p. 21
6.1.1.5.6 Conclusions p. 21
6.1.1.6 Considerations for online charging, offline charging and usage monitoring p. 21
6.1.1.6.1 Description p. 21
6.1.1.6.2 Solution 1: Charging and usage monitoring handling in the control plane function p. 22
6.1.1.7 Consideration for SGW Service Area and TAI list alignment due to control plane and user plane split of SGW p. 23
6.1.1.7.1 Description p. 23
6.1.1.7.2 Solutions p. 23
6.1.1.7.3 Evaluation p. 25
6.1.1.7.4 Conclusion p. 26
6.1.1.8 Considerations for UE IP address management p. 26
6.1.1.8.1 Description p. 26
6.1.1.8.2 Solution 1: UE IP address management performed by the control plane function p. 26
6.1.1.8.3 Evaluation p. 28
6.1.1.8.4 Conclusion p. 28
6.1.1.9 Considerations for the functionality supported by the user plane function p. 28
6.1.1.9.1 Description p. 28
6.1.1.9.2 Solution 1: Protocol based advertisement of supported functionality by the user plane function p. 29
6.1.1.10 Considerations for supporting extended buffering for the UE in power saving mode p. 29
6.1.1.10.1 Description p. 29
6.1.1.10.2 Solution 1: Supporting extended buffering for the UE in power saving mode in the control plane function p. 29
6.1.1.10.3 Solution 2: Supporting extended buffering for the UE in power saving mode in the user plane function p. 30
6.1.1.10.4 Evaluation p. 31
6.1.1.10.5 Conclusion p. 32
6.1.1.11 Considerations for 3GPP specific information at the user plane function p. 33
6.1.1.11.1 Description p. 33
6.1.1.11.2 Solution 1: Not providing subscriber's or UE's permanent identity to the user plane function p. 33
6.1.1.12 Considerations for performing LI functionality p. 34
6.1.1.12.1 Description p. 34
6.1.1.12.2 Solution 1: Terminating the LI related reference points in the control plane function p. 34
6.1.1.12.3 Solution 2: Lawful interception architecture with the X3 reference points terminating at the user plane function p. 36
6.1.1.12.4 Evaluation p. 37
6.1.1.12.5 Conclusion p. 38
6.1.1.13 Considerations for control of user plane forwarding p. 39
6.1.1.13.1 Description p. 39
6.1.1.13.2 Solution 1: Uniform handling of user plane forwarding to cater for multiple forwarding scenarios p. 39
6.1.1.14 Procedures over Sx Reference Points p. 43
6.1.1.14.1 Sx Management Procedures p. 43
6.1.1.14.2 Sx Session Management Procedures p. 44
6.1.1.14.3 Sx reporting procedure p. 46
6.1.1.14.4 Conclusion p. 47
6.1.1.15 Parameters for Sx Reference Points p. 47
6.1.1.15.1 Parameters related to general UP function management p. 48
6.1.1.15.2 Parameters related to Sx session management p. 48
6.1.1.15.3 Conclusion p. 52
6.1.1.16 Application of Sx session management procedures to existing procedures p. 52
6.1.1.17 Consideration for activation/deactivation of predefined PCC/ADC rules p. 57
6.1.2 Solution 2: Functional split for combined S/P-GW (key issue #1) p. 58
6.2 Solutions to key issue 2: Selection mechanism for user plane functional entities p. 59
6.2.1 Solution 1 - User plane selection by the control plane of the corresponding functional entity p. 59
6.2.1.1 Description p. 59
6.2.1.1.1 General p. 59
6.2.1.1.2 Entity performing user plane selection p. 59
6.2.1.1.3 Parameters considered during selection mechanism p. 59
6.2.1.1.4 How to realize the selection mechanism p. 60
6.2.1.1.5 Triggers for selection of user plane p. 60
6.2.1.2 Impacts on existing nodes and functionality p. 60
6.2.1.3 Solution Evaluation p. 61
6.2.2 Solution 2 - Combined control plane function selects combined user plane function p. 61
6.2.2.1 Description p. 61
6.2.2.1.1 General p. 61
6.2.2.1.2 Entity performing user plane selection p. 62
6.2.2.1.3 Parameters considered during selection mechanism p. 62
6.2.2.1.4 How to realize the selection mechanism p. 62
6.2.2.1.5 Triggers for selection of user plane p. 63
6.2.2.2 Impacts on existing nodes and functionality p. 63
6.2.2.3 Solution Evaluation p. 63
6.2.3 Evaluation p. 63
6.2.4 Conclusion p. 63
6.3 Solutions to key issue 3: Change of user plane session identity (due to other than UE mobility scenarios) p. 64
6.3.1 Solution 1 - Control plane changing the user plane session identity p. 64
6.3.1.1 Description p. 64
6.3.1.1.1 General p. 64
6.3.1.1.2 Change of user plane session identity p. 64
6.3.1.1.3 SGW: Call flows for control plane changing user plane session identity p. 64
6.3.1.1.4 PGW: Call flows for control plane changing user plane session identity p. 66
6.3.1.1.5 TDF: Call flows for control plane changing user plane session identity p. 66
6.3.1.2 Impacts on existing nodes and functionality p. 66
6.3.1.3 Solution Evaluation p. 66
6.3.2 Solution 2 - SGW-C triggers MME to perform UP session identity change p. 67
6.3.2.1 Description p. 67
6.3.2.2 Impacts on existing nodes and functionality p. 68
6.3.2.3 Solution Evaluation p. 68
6.3.3 Evaluation p. 68
6.3.4 Conclusion p. 68
6.4 Solutions to key issue 4 - Relocation of user plane functional entity due to UE mobility p. 68
6.4.1 Solution 1- Service area alignment of SGW control plane with SGW user plane p. 68
6.4.1.1 General p. 68
6.4.1.2 Descriptions p. 69
6.4.1.3 Call flows p. 70
6.4.1.4 Solution Evaluation p. 72
6.4.2 Solution 2 - SGW user plane change triggered during two subsequent procedures p. 72
6.4.2.1 Service Request p. 72
6.4.3 Solution 3 - SGW user plane change during mobility procedure p. 73
6.4.3.1 Service Request p. 73
6.4.3.2 X2-based handover p. 74
6.4.3.2.1 Without Serving GW control plane relocation p. 74
6.4.3.2.2 With Serving GW control plane relocation p. 74
6.4.3.3 S1-based handover p. 74
6.4.3.3.1 Without Serving GW control plane relocation p. 74
6.4.3.3.2 With Serving GW control plane relocation p. 75
6.4.3.4 Impacts on existing nodes and functionality p. 75
6.4.3.5 Solution Evaluation p. 75
6.4.4 Evaluation p. 75
6.4.5 Conclusion p. 76
7 Overall evaluation p. 76
8 Conclusions p. 76
A Example for interaction between CP and UP function p. 78
B Example for attributes exchanged between the CP and UP function p. 81
B.1 During the UPlane Session Establishment procedure p. 81
B.1.1 UPlane Session Establishment Request p. 81
B.1.2 Policy Rule p. 81
B.1.3 Bearer Info p. 82
B.1.4 Usage Reporting Rule p. 84
B.2 During the Usage Report generated by UP function p. 85
$ Change History p. 87
