Content for TR 29.892 Word version: 16.0.0
2 References
3 Definitions, symbols and abbreviations
4 Introduction
5 User Plane Architecture in 5GC
6 Candidate User Plane Protocols
7 Evaluations and Comparison
8 Conclusion
$ Change History
2 References p. 8
3 Definitions, symbols and abbreviations p. 9
3.1 Definitions p. 9
3.2 Abbreviations p. 10
4 Introduction p. 10
5 User Plane Architecture in 5GC p. 10
5.1 Architectural Requirements for User Plane p. 10
5.1.1 General p. 10
5.1.2 User Plane Functionality p. 13
5.1.3 Support for Error Recovery and Restoration p. 13
5.2 Key Issues for User Plane Protocol p. 14
6 Candidate User Plane Protocols p. 15
6.1 GTP-U p. 15
6.1.1 Description p. 15
6.1.1.1 General p. 15
6.1.1.2 IP Transport for GTP-U p. 15
6.1.1.3 Path/Tunnel Management functions p. 15
6.1.1.4 Load Balancing p. 16
6.1.1.5 Multicast p. 16
6.1.2 Analysis of IETF RFC 8200 Impacts p. 16
6.1.3 Solutions for Impacts due to IETF RFC 8200 p. 20
6.1.4 System Impacts p. 21
6.2 Segment Routing IPv6 (SRv6) p. 21
6.2.1 General SRv6 Description p. 21
6.2.2 Description of SRv6 solution in 5GC p. 23
6.2.2.1 General p. 23
6.2.2.2 Principles p. 23
6.2.2.3 SRv6 SID Encoding p. 24
6.2.2.3.1 General p. 24
6.2.2.3.2 Discussion p. 24
6.2.2.4 User Plane packet flow p. 25
6.2.2.4.1 SRv6 in Traditional Mode p. 25
6.2.2.4.2 SRv6 in Enhanced mode p. 26
6.2.2.4.2.1 Uplink p. 27
6.2.2.4.2.2 Downlink p. 28
6.2.2.4.3 Hand-over p. 28
6.2.2.5 Discovery of SRv6 supported UPF p. 29
6.2.2.5.1 General p. 29
6.2.2.5.2 Use PFCP protocol at N4 to pass SRv6 Capability p. 29
6.2.2.5.3 Use Local Configuration at SMF p. 30
6.2.2.5.4 Discovery of UPF using NRF p. 30
6.2.2.6 IPv4 Transport Support for SRv6 User Plane p. 30
6.2.2.6.1 General p. 30
6.2.2.6.2 IPv4 Encapsulation and Decapsulation for IPv6 packet p. 30
6.2.2.6.3 Routing IPv6 packet over IPv4 Transport Network p. 30
6.2.2.6.4 Mapping SRv6 User Plane IP Resource to IPv4 Transport p. 31
6.2.2.7 Security Considerations for SRv6 p. 31
6.2.2.8 Using SRH for User Plane Messages p. 31
6.2.2.8.1 General p. 31
6.2.2.8.2 Tag Encoding p. 31
6.2.2.9 Packet forwarding between SMF and UPF p. 32
6.2.2.10 Roaming Support p. 32
6.2.2.11 Failure Detection and Recovery p. 32
6.2.2.11.1 General p. 32
6.2.2.11.2 Failure Detection p. 32
6.2.2.11.3 Restoration Procedure p. 32
6.2.2.11.3.1 SRv6 Error Indication received by another UPF p. 32
6.2.2.11.3.2 Restoration Procedures upon User Plane Path Failure p. 33
6.2.2.11.4 Restoration Procedure for User Plane Related Entities p. 33
6.2.2.12 SRv6 Guaranteed Packet Delivery p. 33
6.2.2.12.1 General p. 33
6.2.2.12.2 Redundant packet transmission for downlink traffic p. 33
6.2.2.12.3 Removal of Redundant packet for uplink traffic p. 34
6.2.2.13 SRv6 extensibility using SRH TLVs p. 35
6.2.3 System Impacts p. 35
6.2.3.1 General p. 35
6.2.3.2 Common System Impacts of SRv6 p. 35
6.2.3.2.1 System Impact on N4 interface p. 35
6.2.3.2.1.1 General p. 35
6.2.3.2.1.2 Impact on PFCP procedure p. 35
6.2.3.2.1.3 Impact on PFCP IEs p. 36
6.2.3.2.2 System Impact on N16/N16a/N38 interfaces p. 36
6.2.3.3 System Impacts of Traditional Mode p. 37
6.2.3.4 System Impacts of Enhanced Mode p. 37
7 Evaluations and Comparison p. 37
7.1 Evaluation p. 37
7.1.1 Evaluation Points p. 37
7.1.2 GTP-U p. 37
7.1.2.1 General p. 37
7.1.2.2 Architectural requirements for User Plane p. 37
7.1.2.3 Key issues p. 37
7.1.2.4 System impacts p. 38
7.1.3 SRv6 p. 38
7.1.3.1 Traditional Mode p. 38
7.1.3.1.1 General p. 38
7.1.3.1.2 Architectural requirements for User Plane p. 38
7.1.3.1.3 Key issues p. 38
7.1.3.1.4 System impacts p. 38
7.1.3.2 Enhanced Mode p. 39
7.2 Additional Considerations p. 40
7.3 Comparison p. 47
8 Conclusion p. 48
8.1 General p. 48
8.2 GTP-U over IP-based transport (including SRv6) p. 48
8.3 SRv6 user plane protocol (without GTP-U) p. 49
$ Change History p. 50
