PFCP vs GTP-C
GTP-C historically ran between core network entities (SGSN, SGW, PGW). CUPS (Control and User Plane Separation) and 5G introduce PFCP for the control-to-user-plane link between SMF and UPF, while GTP-C remains only on roaming/legacy interfaces.
| Attribute | PFCP | GTP-C |
|---|---|---|
| Role | SMF ↔ UPF control | Legacy inter-node control (S5/S8, S11) |
| Reference | 3GPP TS 29.244 | 3GPP TS 29.274 |
| Transport | UDP 8805 | UDP 2123 |
| Scope | Session rules, forwarding, QoS | Bearer creation, mobility |
| Exposure | Internal (should not cross operator) | Roaming border |
Verdict
PFCP should never leave the operator boundary. When it does — misconfigured cloud UPF or lift-and-shift deployments — it is trivially abusable. GTP-C remains the roaming-facing risk; PFCP is the internal risk.