Section: 5.4.7.2.3 Abnormal cases on the network side
Content: The following abnormal cases can be identified: a) T3575 expiry The AMF shall, on the first expiry of the timer T3575, retransmit the NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message and shall reset and start timer T3575. This retransmission is repeated four times, i.e. on the fifth expiry of timer T3575, the AMF shall abort the network slice-specific authentication and authorization procedure for the S-NSSAI. The AMF shall consider that the network slice-specific authentication and authorization procedure for the S-NSSAI is completed as a failure. b) Lower layers indication of non-delivered NAS PDU due to handover If the NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message could not be delivered due to an intra AMF handover and the target TAI is included in the TAI list, then upon successful completion of the intra AMF handover the AMF shall retransmit the NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message. If a failure of handover procedure is reported by the lower layer and the N1 NAS signalling connection exists, the AMF shall retransmit the NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message. c) Network slice-specific authentication and authorization procedure and de-registration procedure collision If the network receives a DEREGISTRATION REQUEST message before the ongoing network slice-specific authentication and authorization procedure has been completed and the access type included in the DEREGISTRATION REQUEST message is the same as the one for which the network slice-specific authentication and authorization procedure is ongoing, the network shall abort the network slice-specific authentication and authorization procedure and shall progress the UE-initiated de-registration procedure. The AMF may initiate the network slice-specific authentication and authorization procedure for the S-NSSAI which is completed as a failure, if available. If the access type included in the DEREGISTRATION REQUEST message is different from the one for which the network slice-specific authentication and authorization procedure is ongoing, the network shall proceed with both procedures. d) Network slice-specific authentication and authorization procedure and service request procedure collision If the network receives a SERVICE REQUEST message before the ongoing network slice-specific authentication and authorization procedure has been completed and the SERVICE REQUEST message includes the UE request type IE with the Request type value set to "NAS signalling connection release", the network shall abort the network slice-specific authentication and authorization procedure and shall progress the service request procedure. If the network receives a SERVICE REQUEST message before the ongoing network slice-specific authentication and authorization procedure has been completed and the SERVICE REQUEST message does not include UE request type IE with the Request type value set to "NAS signalling connection release", both procedures shall be progressed. e) Network slice-specific authentication and authorization procedure and registration procedure for mobility and periodic registration update collision If the network receives a REGISTRATION REQUEST message before the ongoing network slice-specific authentication and authorization procedure has been completed and the REGISTRATION REQUEST message includes the Unavailability information IE, the network shall abort the network slice-specific authentication and authorization procedure and shall progress the registration procedure for mobility and periodic registration update procedure. If the network receives a REGISTRATION REQUEST message before the ongoing network slice-specific authentication and authorization procedure has been completed and the REGISTRATION REQUEST message does not include the Unavailability information IE, both procedures shall be progressed.