4.17 5GS mobility management in NB-N1 mode

A UE in NB-N1 mode (see 3GPP TS 36.331 [25A]) shall calculate the value of the applicable NAS timer indicated in table 10.2.1 plus 240s.

The timer value obtained is used as described in the appropriate procedure clause of this specification. The NAS timer value shall be calculated at start of a NAS procedure and shall not re-calculate the use of the NAS timer value until the NAS procedure is completed, restarted or aborted.

When an AMF that supports NB-N1 mode performs NAS signalling with a UE, which is using NB-N1 mode, the AMF shall calculate the value of the applicable NAS timer indicated in table 10.2.2 plus 240s.

The timer value obtained is used as described in the appropriate procedure clause of this specification. The NAS timer value shall be calculated at start of a NAS procedure and shall not re-calculate the use of the NAS timer value until the NAS procedure is completed, restarted or aborted.