5G Core SBA: Troubleshooting Service-Based Architecture
Practical guide to troubleshooting 5G Core SBA — NRF discovery, HTTP/2 failures, and AMF/SMF/UPF issues.
5G Core SBA: Troubleshooting Guide
What is SBA?
The Service-Based Architecture (SBA) is the defining feature of 5G Core. Network functions communicate via HTTP/2 REST APIs over a service bus, replacing legacy point-to-point interfaces.
Key Network Functions
| NF | Role |
|---|---|
| NRF | Service discovery and registration |
| AMF | Access and Mobility Management |
| SMF | Session Management |
| UPF | User Plane Function |
| UDM | Unified Data Management |
| PCF | Policy Control Function |
Common SBA Issues
1. NRF Discovery Failure
AMF cannot discover SMF. Check NRF database for registration. Verify SMF startup config and NRF URL.
2. HTTP/2 Connection Errors
Intermittent 503 errors. Usually TLS cert issues. Check cert validity and NTP sync.
3. Service Mesh Latency
PDU Session establishment takes too long. Trace HTTP/2 chain with tcpdump.
Debug Commands
display nrf nf-registration all
display amf peer-nf all
debugging http2 message allWireshark Filters
http2
http2.headers.path contains "/nsmf"
http2 || pfcp || ngap