Interface protocol stacks

Protocol Stacks by Interface Type

The 5GC uses three distinct protocol stack patterns matched to the requirements of each interface type. Service-based interfaces between core NFs use HTTP/2 over TLS 1.3 over TCP over IP, enabling RESTful APIs with JSON payloads and strong encryption. User plane interfaces N3 and N9 use the inner user IP packet encapsulated in GTP-U over UDP port 2152 over IP, optimized for high throughput with minimal processing overhead. The N4 PFCP interface uses PFCP messages over UDP port 8805 over IP with built-in reliability through sequence numbers and retransmission timers.