PDU session troubleshooting: Why can't the user get data?

Data Connectivity Failures

When a user reports no data connectivity, the root cause could be anywhere in the PDU session lifecycle. The session may have failed to establish entirely, the IP address allocation may have failed, the GTP-U tunnel between gNB and UPF may be broken, the PFCP forwarding rules at the UPF may be incorrect, or DNS resolution may be failing. Systematic troubleshooting starts with checking whether the PDU Session Establishment Accept was received by the UE, then working through each layer of the data path.