Jul 12, 2020, 9:35:21 AM7/12/20
I am confused regarding TEID in GTPv1-C.
As per my understanding, GTP-C manages the creation, deletion of a GTP-U tunnel.
GTP-C can be managed from a user space program and it's not a tunnel at this stage, but GTP-U is a tunnel, and is set up at kernel level.
When GTP-C sends a request to the peer, he is sending:
- the Local TEID that he has reserved on his side for Data (user plane)
- upon receipt of such a request, the peer is saying it's ok, I will deliver you a Local TEID on my side, so that we can instruct GTP-U to setup a tunnel with these 2 TEID,
- The sequence of the messages are identified by Sequence Number.
At GTP-U level, there is no Sequence Number, but TEID is used.
So I have 2 questions please:
- Is it okay to say that GTP-C is only some GTP message sent through UDP, and the system can follow the sequence by using Sequence Number, thus there is no tunnel at all at this stage.
- GTP-C is using Sequence Number, why is there a TEID Control Plane in addition to TEID Data Plane in GTP-C message?
what is the purpose of this TEID Control plane, because Sequence Number is used to map and follow the subsequent messages and why a TEID Control because GTP-C is not a tunnel? or is it?