Hello Experts.
In a private 5G standalone (SA) network where only data PDU sessions are supported (no voice PDU), we are encountering an issue where the data PDU session remains stable for only 2 minutes before the device enters network search mode. What could be causing this issue?
This is likely due to a combination of factors, including network configuration, device settings, and potential protocol issues.
Potential Causes and Troubleshooting Steps:
Inactivity Timer:
Check the network’s inactivity timer settings. This timer determines how long a connection can remain idle before being automatically terminated. If it’s set to 2 minutes, it could be causing the issue.
2.* Security Policy:
Ensure that the security policy is configured correctly and that the device is properly authenticated and authorized. Incorrect security settings can lead to premature session termination.
Verify the Quality of Service (QoS) parameters assigned to the PDU session. Insufficient QoS can result in dropped sessions, especially under heavy load.
Ensure that the device’s power saving modes are not aggressively configured. Some power-saving features can cause the device to disconnect from the network after a certain period of inactivity.
Check for any known issues or bugs in the device’s firmware or software that might be affecting network connectivity. Update to the latest versions if available.
Monitor the network for any signaling errors or anomalies that might be causing the PDU session to drop. Use network monitoring tools to analyze the signaling traffic.
Ensure that the radio link between the device and the gNB is stable and reliable. Poor radio conditions can lead to frequent reconnections and dropped sessions.
Troubleshooting Tips:
Examine the logs of the gNB, SMF, and UPF for any error messages or unusual behavior.
Look for specific error codes related to PDU session establishment or maintenance.
Use network monitoring tools to track key performance indicators (KPIs) such as RRC connection duration, PDU session duration, and error rates.
Identify any trends or anomalies that might be contributing to the issue.
Conduct controlled tests in a controlled environment to isolate the root cause.
Try different device configurations, network settings, and traffic patterns to see if they affect the behavior.
Use protocol analyzers to capture and analyze network traffic.
If the UE is a voice-centric device, it will attempt to establish an IMS PDU session and register with the IMS. If this attempt fails, the UE will fall back to 4G, 3G, or 2G networks. In a private 5G network without voice services, all UEs must be data-centric devices.