Section: 4.7 EPS mobility management and EPS session management in NB-S1 mode
Content: A UE in NB-S1 mode (see 3GPP TS 36.331[ Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification ]  [22]) shall calculate the value of the applicable NAS timer: - indicated in table 10.2.1 plus 240s; and - indicated in table 10.3.1 plus 180s. 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 MME that supports NB-S1 mode performs NAS signalling with a UE, which is using NB-S1 mode, the MME shall calculate the value of the applicable NAS timer: - indicated in table 10.2.2 plus 240s; and - indicated in table 10.3.2 plus 180s. 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. NOTE 1: If the tracking area updating procedure is initiated in EMM-CONNECTED mode, the MME can stop any running implementation specific supervision timer if it is started when sending an ESM DATA TRANSPORT message to the UE. NOTE 2: As NB-S1 mode includes the case when satellite access is used in EPS, the values for applicable NAS timers specified in this clause apply also for satellite access.