ETSI TS 129 274 specifies the stage 3 of the control plane of the GPRS Tunnelling Protocol, Version 2 for Evolved Packet System interfaces (GTPv2-C). In this document, unless otherwise specified, the S2a, S2b, S5 and S8 interfaces refer always to the GTP-based S2a, S2b, S5 and S8 interfaces respectively . GTPv2-C shall be used across the following EPC signalling interfaces: S2a, S2b, S3, S4, S5, S8, S10, S11 and S16. GTPv2-C shall be used across the Sm and Sn interfaces for MBMS in EPS. GTPv2-C based protocols shall also be used across Sv (3GPP TS 29.280 [15]) and S101/S121 (3GPP TS 29.276 [14]) interfaces. The procedures supported between the TWAN and the PGW on the S2a interface, and between the ePDG and the PGW on the S2b interface are specified in 3GPP TS 23.402 [45]. The present document specifies functions, procedures and information which apply to GERAN Iu mode. However, functionality related to GERAN Iu mode is neither maintained nor enhanced.