| Edition 31 | 7 October 2026 |
CT4’s two 6G core protocol studies already have long solution lists. The control-plane study lists ten SBI solutions, from HTTP/3 to agent-to-agent communication. The user-plane study puts GTP-U against SRv6 and QUIC, and the final choice is now expected in September 2027.
In 60 seconds
Four key issues, one per candidate: GTP-U kept, SRv6 replacing GTP-U, QUIC under GTP-U, and QUIC replacing GTP-U. The solutions divide the same way:
| Direction | Solutions |
|---|---|
| Enhance GTP-U | A: GTP-U as candidate · B: IE encoding in header · C: path via UP list · D: message bundling · E: GTP-U source routing · F: in-band tunnel management · G: path-ID mapped UP list · H: on-path tunnel creation · I: SRv6-aware GTP-U |
| Replace with SRv6 | J |
| QUIC | K: QUIC under GTP-U · L: plain QUIC · M: QUIC with CONNECT-IP |
Nine of the thirteen solutions enhance GTP-U rather than replace it. Rapporteur: Yong Yang (Ericsson). Work item FS_6G_UPCN_CT.
The control-plane report starts from five limitations of today’s SBI: the parameter passthrough bottleneck, static execution logic, filtering of resource representations on reads, API versioning in practice, and feature negotiation. Its ten solutions:
Rapporteur: Hao Jing (Huawei). Work item FS_6G_CPCN_CT. The scope ties the study to TR 22.870, TR 23.801-01 and TR 33.801-01.
Postponed
Guy Daniels reports the user-plane protocol decision was deferred from end-2026 to September 2027, the same date the CT studies end.
RAN also depends on this choice: the RAN–core user-plane interface (today N3 over GTP-U) has to match whatever CT4 picks.
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Sources
Report contents are read from FriendlySpec renders of the draft TRs. Drafts change at every meeting; nothing in a draft TR is agreed until its conclusions are.