This TS defines the user plane of GTP used on:
interfaces of the General Packet Radio Service (GPRS);
interfaces of the UMTS system;
interfaces of the Evolved Packet System (EPS);
interfaces of the 5G System (5GS);
GTP-U Tunnels are used to carry encapsulated T-PDUs and signalling messages between a given pair of GTP-U Tunnel Endpoints. The Tunnel Endpoint ID (TEID) which is present in the GTP header shall indicate which tunnel a particular T-PDU belongs to. In this manner, packets are multiplexed and de-multiplexed by GTP-U between a given pair of Tunnel Endpoints. The TEID value to be used in the TEID field shall be signalled to the peer GTP-U entity using a control plane protocol like GTPv1-C, GTPv2-C, RANAP or S1-AP.
full Table of Contents for TS 29.281 Word version: 15.5.0