PDU Session Resource Setup Unsuccessful Transfer IE
For each PDU session resource with the failed configuration, the NG-RAN includes PDU Session Resource Setup Unsuccessful Transfer IE of the PDU Session Resource Setup Request message. This message includes the cause value, with the details on cause for the unsuccessful establishment, for SMF.
In case the serving NG-RAN doesn't accept the partial QoS Flow failures of a PDU Session, the SMF initiates the PDU Session Modification procedure. This procedure removes the non-accepted QoS flows from the PDU Session after PDU Setup procedure is completed.
Note | SMF supports the decoding of "Criticality Diagnostics" IE that it receives as part of the N2 message only. For example, PDU Session Resource Setup Unsuccessful Transfer message and PDU Session Resource Modify Unsuccessful Transfer message. SMF doesn't fully support the "Criticality Diagnostics" IE for other messages. |
The PDU Session Resource Setup Unsuccessful Transfer IE includes the following causes and their cause values:
Cause | Cause Value |
Description |
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Radio Network Layer |
Multiple PDU Session ID instances |
NG-RAN includes this cause value after receiving the PDU Session Resource Setup Request message. This message includes various PDU Session ID IEs in the PDU Session Resource Setup Request List IE, which is configured to the same value. |
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User Plane Security Enforcement |
NG-RAN includes the following cause values in case the User Plane Security Enforcement information is unfulfilled. These cause values have either the Required or Preferred value:
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Collision with Handovers |
NG-RAN includes the following cause value after receiving the Handover request and continues with the Handover Preparation procedure:
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Unspecified |
In case the NG-RAN failure is unspecified, SMF triggers the release of this PDU Session. NG-RAN maintains a N2 cause-based statistics in the N2 message type. |
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Protocol Group |
Erroneous errors in Protocol data |
NG-RAN includes the following cause values when it couldn't decode the received message:
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Unforeseen or Unknown information in Protocol data |
NG-RAN includes the following cause value when it is unable to decode the received message:
When the NG-RAN is unable to decode the message, SMF triggers the release of the PDU Session. NG-RAN maintains an N2 cause-based statistics in the N2 message type. |
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Transport Group |
Inaccessible transport resources |
NG-RAN includes the following cause values when required transport resources are unavailable:
When the NG-RAN is unable to access the transport resources, SMF triggers the release of the PDU Session. NG-RAN maintains an N2 cause-based statistics in the N2 message type. |
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Miscellaneous |
Not enough user plane processing resources |
NG-RAN includes this cause value when insufficient resources are available for the User Plane processing. When the NG-RAN is unable to access the User Plane processing resources, SMF triggers the release of the PDU Session. NG-RAN maintains an N2 cause-based statistics in the N2 message type. |