GTP-C
GPRS Tunneling Protocol - Control Plane: the signaling protocol used in EPC (and some 5GC interworking scenarios) for tunnel management between S-GW, P-GW, and MME.
GTP-C is the control-plane sibling of GTP-U. Where GTP-U carries the user's data through tunnels, GTP-C is the signalling that creates, modifies and deletes those tunnels and manages the sessions behind them. In EPC it runs on interfaces like S11 (MME to S-GW) and S5/S8 (S-GW to P-GW), handling bearer setup, updates during mobility, and teardown. It's how the control plane tells the gateways "build this user a tunnel with these QoS parameters."
In pure 5G SA the equivalent job is done differently — PFCP programs the user plane and the SBI handles session control — so native 5G doesn't use GTP-C between core functions. Where it stays relevant is interworking: when a device moves between 5G and 4G, or when an operator runs the two together, GTP-C appears on the EPC side and at the interworking interfaces (such as the S5/S8-based path used by the SMF+PGW-C and UPF+PGW-U combined nodes). So even in a 5G-centric shop, GTP-C is a protocol you keep around for the 4G estate and the seams between generations.
Related terms
Want to truly understand GTP-C? Learn it in context.
A free account opens all 13 courses — 404 video lessons, labs and full practice exams — for 7 days, no card. Prime Membership keeps them and adds the certification exam and a verifiable certificate.
- 7 days of every course
- Then the first module, free
- No card needed
- TELCOMA since 2009
Get one 5G/LTE engineering deep-dive a fortnight
One thing explained properly every other Tuesday — a real failure, and the lab or trace where you work it yourself. No spam, no marketing, just engineering. Unsubscribe in one click.