PDU Session Resource Modify Unsuccessful Transfer IE
For each PDU session resource with the failed modification, NG-RAN includes PDU Session Resource Modify Unsuccessful Transfer IE of the PDU Session Resource Modify Request message. This message includes the cause value, with the details on cause for the unsuccessful modification, for SMF.
The PDU Session Resource Modify Unsuccessful Transfer IE includes the following causes and their cause values:
Cause | Cause Value |
Details |
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Radio Network Layer |
Multiple PDU Session ID instances |
NG-RAN includes this cause value after receiving the PDU Session Resource Modify Request message. This message includes various PDU Session ID IEs in the PDU Session Resource Modify Request List IE, with the same configured value. |
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Collision with Handovers |
NG-RAN includes the following cause values after receiving the Handover request and continues with the Handover Preparation procedure:
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Unspecified |
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Unknown PDU Session ID |
NG-RAN includes this cause value after receiving the PDU Session Resource Modify Request message. This message includes PDU Session ID IEs, from the PDU Session Resource Modify Request List IE, which NG-RAN couldn't identify. These sessions are invalid PDU sessions. SMF releases the PDU Session of the PDU Session IDs that NG-RAN marks as invalid or unknown. NG-RAN maintains a N2 cause-based statistics in the N2 message type. |
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Transport group |
NG-RAN includes the transport cause value when the required transport resources are unavailable. SMF stops the PDU Session Modification procedure and continues to use the same value for all the fields as existed in the earlier modification procedure. SMF maintains an N2 cause-based statistics in the N2 message type. |
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NAS |
SMF stops the PDU Session Modification procedure and continues to use the same value for all the fields as existed in the earlier modification procedure. SMF maintains an N2 cause-based statistics in the N2 message type. |
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Protocol group |
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Miscellaneous |
SMF triggers the release of the PDU Session after receiving the PDU Session Resource Modify Request message. This message includes the following Miscellaneous causes in N2 SM information. SMF maintains a N2 cause-based statistics in the N2 message type.
Except for the cause value of the preceding causes, SMF stops the PDU Session Modification procedure and continues to use the same value for all the fields as existed in the earlier modification procedure. SMF maintains an N2 cause-based statistics in the N2 message type. |