4.6.3.5 Session management for optimized handling of temporarily available network slices

A network slice can be available temporarily. Clause 4.6.2.8 addresses how the allowed NSSAI and partially allowed NSSAI are managed based on the S-NSSAI time validity information.

If the S-NSSAI time validity information indicates that the S-NSSAI is available, the UE may initiate a UE-requested PDU session establishment procedure to establish a PDU session associated with the S-NSSAI.

If the S-NSSAI time validity information indicates that the S-NSSAI is not available, then the UE shall:

• initiate UE-requested PDU session release procedure to release any PDU session associated with the S-NSSAI, if the UE is in 5GMM-CONNECTED mode or in 5GMM-CONNECTED mode with RRC inactive indication; or
• locally release any PDU session associated with the S-NSSAI, if the UE is in 5GMM-IDLE mode.

When the S-NSSAI time validity information in the AMF indicates that the S-NSSAI is not available, independent of whether the UE is in 5GMM-CONNECTED mode, 5GMM-CONNECTED mode with RRC inactive indication or in 5GMM-IDLE mode, the AMF shall request the SMF to release any PDU session associated with the S-NSSAI.