Technical reference hub for telecom engineers
Structured protocol references, message databases, call flows, troubleshooting guides, releases, and engineering tools for wireless and telecom engineers.
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Troubleshooting Guides
5G Initial Access Troubleshooting
Isolate failures in cell search, PBCH decode, SIB1 acquisition, suitability checks, camping, and pre-random-access gating.
TAI and Tracking Area Mismatch Troubleshooting
Troubleshoot TAC broadcast errors, tracking-area restrictions, roaming-area mismatch, and area-related registration reject causes.
AMF Selection and GUAMI Issues
Troubleshoot wrong AMF targeting, stale GUAMI or 5G-GUTI context, and broken AMF-selection hints across RRC and NGAP.
5G Registration Failure Troubleshooting
End-to-end guide for registration reject, incomplete registration, AMF selection issues, and first-access failures.
Initial Context Setup Failure Analysis
Diagnose failures during Initial Context Setup and isolate core, policy, or radio-side blockers.
PDU Session Establishment Failure
Diagnose failed session setup, 5GSM reject causes, policy gaps, and missing path creation.
Latest Updates
UE Context Resume Failure is the NGAP UE Context Management message sent by the AMF to the NG-RAN node when the AMF cannot accept a UE Context Resume Request. It is the unsuccessful outcome of the UE Context Resume procedure and indicates that the previously suspended UE context could not be resumed.
UE Context Suspend FailureUE Context Suspend Failure is the NGAP UE Context Management message sent by the AMF to the NG-RAN node when the AMF cannot accept a UE Context Suspend Request. It is the unsuccessful outcome of the UE Context Suspend procedure and provides the reason through a mandatory Cause IE.
Uplink RAN Status TransferUplink RAN Status Transfer is an NGAP Mobility Management message sent by the source NG-RAN node to the AMF during handover. It transfers RAN/PDCP status information so that the target NG-RAN can continue data transmission without loss, supporting lossless or seamless handover.
RAN Paging RequestRAN Paging Request is an NGAP paging-related message used to support RAN-side paging in 5G. It is used when the network needs the NG-RAN to page a UE in a RAN-managed state, especially around RRC Inactive handling and UE reachability.
5G NGAP - PWS Cancel RequestPWS Cancel Request is the NGAP warning message sent by the AMF to the NG-RAN node to cancel an active public warning broadcast identified by Message Identifier and Serial Number.
5G NGAP - PWS Cancel ResponsePWS Cancel Response is the NGAP warning message sent by the NG-RAN node to the AMF to report the result of a PWS Cancel Request, including completed and failed warning cancellation areas.