Role of GTP-C in LTE?

Question

Sorry for asking basic question, want to know the role of GTP-C in LTE. Can some describe the need, and high level functionality of GTP-C in LTE.

Answer 1

GTP-C stands for "GRPS Tunneling Protocol".
In LTE, GTP-C is used for signalling between MME to SGW and SGW to PGW for an UE session establishment/modification/release.

Please refer 3GPP 29.274 for more details. If you have any query after going through this specification then post a query.

Answer 2

GTP-C message flows between different interface to setup the signalling connection. The interfaces are S11, S5, S8 and S4.

There are two type of GTP-C messages are there.
1. Path management messages
2. Tunnel management messages.

1. Path Management Messages
ECHO request/response will be used to ping destination GTP end point as well handle the restart procedure of a GTP endpoint.
Please refer ECHO message handling in GTP-C

2. Tunnel Management Messages
Different GTP-C messages are used to manage a Tunnel. The GTP-C messages are Create Session Request/Response, Create Bearer Request/Response, Modify Bearer Request/Response, Update Bearer Request/Response, Delete Session Request/Response, Delete Bearer Request/Response etc.