TS 29.281 — General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)⚓︎
Release: Rel 17 · Version assessed: 17.4.0 · Network: 4G, 5G · Applies to: UPF, PGW · Interfaces: S1-U, N3, S5/S8
Mandatory items: 18, of which 12 supported and 6 partially supported. Conditional items: 39, of which 27 supported, 4 partially supported and 8 not supported. A further 28 clauses of the specification carry no conformance requirement and are not listed.
Mandatory items⚓︎
| Ref. | Item | Status | Support | Remarks |
|---|---|---|---|---|
| 4.1 | GTP Path | Mandatory | Supported | |
| 4.2.1 | GTP-U Tunnel description | Mandatory | Partial | IPv4 GTP-U tunnels; sequence numbers, N-PDU numbers and extension headers other than the PDU Session Container are not used. |
| 4.3.0 | General | Mandatory | Supported | GTP-U over UDP over IPv4. |
| 4.4.0 | GTP-PDU Stacks | Mandatory | Supported | |
| 4.4.1 | UDP/IP | Mandatory | Supported | |
| 4.4.2.1 | Echo Request Message | Mandatory | Supported | |
| 4.4.2.2 | Echo Response Message | Mandatory | Supported | |
| 4.4.3.1 | Echo Request Message | Mandatory | Supported | |
| 4.4.3.2 | Echo Response Message | Mandatory | Supported | |
| 4.5 | Transmission Order and Bit Definitions | Mandatory | Supported | |
| 5.1 | General format | Mandatory | Partial | S & PN are not supported |
| 5.2.2.7 | PDU Session Container | Mandatory | Partial | Delay UL/DL, Round trip time is not supported |
| 6.2 | Presence requirements of Information Elements | Mandatory | Supported | |
| 7.2.1 | Echo Request | Mandatory | Partial | Recovery Time Stamp is not supported |
| 7.2.2 | Echo Response | Mandatory | Partial | Recovery Time Stamp is not supported |
| 7.3.1 | Error Indication | Mandatory | Partial | Recovery Time Stamp is not supported |
| 8.3 | Tunnel Endpoint Identifier Data I | Mandatory | Supported | |
| 8.4 | GTP-U Peer Address | Mandatory | Supported |
Conditional items⚓︎
| Ref. | Item | Status | Support | Remarks |
|---|---|---|---|---|
| 4.2.2 | IP transport | Conditional | Supported | |
| 4.2.3 | GTP-U Tunnel IP transport | Conditional | Supported | |
| 4.2.4 | Ingress GTP tunnel (GTPv1-U sending endpoint) | Conditional | Supported | |
| 4.2.5 | Egress GTP tunnel (GTPv1-U receiving endpoint) | Conditional | Supported | |
| 4.4.2.0 | General | Conditional | Supported | |
| 4.4.2.3 | Encapsulated T-PDUs | Conditional | Supported | |
| 4.4.2.4 | Error Indication | Conditional | Supported | |
| 4.4.2.5 | Supported Extension Headers Notification | Conditional | Supported | |
| 4.4.2.6 | End Marker | Conditional | Supported | |
| 4.4.2.7 | Tunnel Status | Conditional | Not supported | |
| 4.4.3.3 | Encapsulated T-PDUs | Conditional | Supported | |
| 4.4.3.4 | Error Indication | Conditional | Supported | |
| 4.4.3.5 | Supported Extension Headers Notification | Conditional | Supported | |
| 4.4.3.6 | End Marker | Conditional | Supported | |
| 4.4.3.7 | Tunnel Status | Conditional | Not supported | |
| 4.6 | New Functionality | Conditional | Supported | |
| 5.2.1 | General format of the GTP-U Extension Header | Conditional | Partial | Functionality sepcific to bit 7 and 8 of next extension header is not supported |
| 5.2.2 | Extension Header types | Conditional | Supported | For UPF only following Extension Header Type support is required - PDU Session Container |
| 5.2.2.1 | UDP Port | Conditional | Supported | |
| 6.1 | General | Conditional | Partial | Tunnel Status is not supported |
| 7.1 | General | Conditional | Partial | MBMS is not supported |
| 7.2.3 | Supported Extension Headers Notification | Conditional | Not supported | |
| 7.3.2.1 | General | Conditional | Supported | |
| 7.3.2.2 | End Marker in EPS | Conditional | Supported | |
| 7.3.2.3 | End Marker in 5GS | Conditional | Supported | |
| 8.1 | Information Element Types | Conditional | Partial | All IE's are not supported, please refer subsequent sections for more details |
| 8.2 | Recovery | Conditional | Supported | |
| 8.5 | Extension Header Type List | Conditional | Supported | For UPF only following Extension Header Type support is required - PDU Session Container |
| 8.6 | Private Extension | Conditional | Not supported | No private extensions are used. |
| 8.7 | GTP-U Tunnel Status Information | Conditional | Not supported | |
| 8.8 | Recovery Time Stamp | Conditional | Not supported | |
| 9.1 | Protocol Errors | Conditional | Supported | |
| 9.2 | Path Failure | Conditional | Supported | |
| 10.0 | Security | Conditional | Not supported | GTP-U carries no security of its own; transport protection is a network-domain matter. |
| 11.0 | Reliable Delivery of Signalling Messages | Conditional | Supported | |
| 12.1 | General | Conditional | Supported | |
| 12.2 | Timers | Conditional | Supported | |
| 12.3 | Others | Conditional | Supported | |
| Annex A (Normative): | PDU session user plane protocol over N9, N3mb and N19mb | Conditional | Not supported |
Optional items⚓︎
The specification leaves these 2 items to the implementation; 0 are supported or partially supported. An item marked Not applicable belongs to an area the platform does not provide, named in the Support column. Expand for the full list.
2 optional items
| Ref. | Item | Support | Remarks |
|---|---|---|---|
| 4.3.1 | Handling of Sequence Numbers | Not supported | |
| 7.3.3 | Tunnel Status | Not supported |
Assessed 2026-09-15 against TS 29.281 version 17.4.0.