GTPv2 message reference
The GTPv2-C protocol creates, manages, and deletes SGW and PGW tunnels on Sx interfaces. GTPv2-C is used for the control plane path management, tunnel management and mobility management. It also controls forwarding relocation messages; SRNS context and creating forward tunnels during inter LTE handovers.
GTP-C message types include Path Management Messages, Location Management Messages, and Mobility Management Messages.
3GPP TS 29.274 lists and describes GTPv2 messages.