Direct Tunnel is an optional feature in Iu mode that allows the SGSN to establish a direct user plane tunnel between
RAN and GGSN within the PS domain.
The SGSN handles the control plane signalling and makes the decision when to establish a Direct Tunnel. In case of
Direct Tunnel, the SGSN provides the RAN with the TEID and user plane address of the GGSN, and provides the
GGSN with the TEID and user plane address of the RAN.
This TR contains deployment guidelines for the use of direct tunnelling of user plane data between the RNC and the GGSN (earlier known as the One Tunnel approach).
full Table of Contents for TR 23.919 Word version: 15.0.0