5G System Learning - System Abnormalities (Failures)

1. System Abnormalities: Deviations from the design may occur during the normal operation of the 5G network. These include performance issues such as network security threats, signal interference, insufficient coverage, and potential failures in network software and hardware. These abnormalities can manifest as service interruptions, system crashes, slow network speeds, or dropped calls. They are typically identified by analyzing network data anomaly detection systems and can be categorized into the core network and radio network.

2. 5GC Abnormalities: If the NG RESET message includes the UE-associated Logical NG Connection List IE, but neither the AMF UE NGAP ID IE nor the RAN UE NGAP ID IE is present in the UE-associated Logical NG Connection Item IE, the AMF shall ignore the UE-associated Logical NG Connection Item IE. The AMF may return an empty UE-associated Logical NG Connection Item IE in the UE-associated Logical NG Connection List IE in the NG RESET ACKNOWLEDGE message.

3. NG-RAN Anomalies: If the NG RESET message contains the UE-Associated Logical NG Connection List IE, but neither the AMF UE NGAP ID IE nor the RAN UE NGAP ID IE is present in the UE-Associated Logical NG Connection Item IE, the NG-RAN node shall ignore the UE-Associated Logical NG Connection Item IE. The NG-RAN node may return an empty UE-Associated Logical NG Connection Item IE in the UE-Associated Logical NG Connection List IE in the NG RESET ACKNOWLEDGE message.

4. NG RESET message crossover typically occurs in the following two scenarios:

• If an NG reset procedure is in progress in an NG-RAN node and the NG-RAN node receives an NG RESET message from a peer entity on the same NG interface that is associated with one or more UE associations that were previously requested to be reset (as explicitly or implicitly indicated in the received NG RESET message), the NG-RAN node shall respond with an NG RESET ACKNOWLEDGE message as specified in clause 8.7.4.2.1.

• If an NG reset procedure is in progress in the AMF and the AMF receives an NG RESET message from a peer entity on the same NG interface that is related to one or more UE associations that were previously requested to be reset (indicated explicitly or implicitly in the received NG RESET message), the AMF shall respond with an NG RESET ACKNOWLEDGE message as specified in clause 8.7.4.2.