Section: 5.2.3.2.2 ATTEMPTING-TO-UPDATE
Content: The UE: - shall not send any user data; - shall initiate tracking area updating on the expiry of timers T3411, T3402 or T3346; - shall initiate tracking area updating when entering a new PLMN, if timer T3346 is running and the new PLMN is not equivalent to the PLMN where the UE started timer T3346, the PLMN identity of the new cell is not in one of the forbidden PLMN lists, and the tracking area is not in one of the lists of forbidden tracking areas; - shall initiate tracking area updating when the tracking area of the serving cell has changed, if timer T3346 is not running, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the tracking area is not in one of the lists of forbidden tracking areas; - may initiate a tracking area updating procedure upon request of the upper layers to establish a PDN connection for emergency bearer services; - shall initiate tracking area updating procedure upon request of the upper layers to establish a PDN connection without the NAS signalling low priority indication as specified in clause 5.5.3.2.6, item l), if timer T3346 is running due to a NAS request message (TRACKING AREA UPDATE REQUEST, CONTROL PLANE SERVICE REQUEST or EXTENDED SERVICE REQUEST) which contained the low priority indicator set to "MS is configured for NAS signalling low priority" and timer T3402 and timer T3411 are not running; - may detach locally and initiate an attach for emergency bearer services even if timer T3346 is running; - shall use requests for non-EPS services from CM layers to trigger a combined tracking area updating procedure, if timer T3346 is not running (see clause 5.5.3.3), or to attempt to select GERAN, UTRAN or cdma2000® 1xRTT radio access technology and proceed with the appropriate MM and CC specific procedures; - may use requests for an MMTEL voice call or MMTEL video call from the upper layers to initiate tracking area updating, if timer T3346 is not running; - shall initiate tracking area updating when the UE performs inter-system change from N1 mode to S1 mode, even if timer T3402 is running; - shall initiate tracking area updating in response to paging with S-TMSI or paging with IMSI and domain indicator set to ″CS″; NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication. - shall initiate tracking area updating if the EPS update status is set to EU2 NOT UPDATED, and timers T3411, T3402 and T3346 are not running; - if configured for eCall only mode as specified in 3GPP TS 31.102[ Characteristics of the Universal Subscriber Identity Module (USIM) application ]  [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4); - may initiate tracking area updating upon receiving a request from upper layers to transmit user data related to an exceptional event and the UE is allowed to use exception data reporting (see the ExceptionDataReportingAllowed leaf of the NAS configuration MO in 3GPP TS 24.368[ Non-Access Stratum (NAS) configuration Management Object (MO) ]  [15A]) if timer T3346 is not already running for "MO exception data" and even if timer T3402 or timer T3411 is running; - may initiate tracking area updating if the UE is a UE configured to use AC11 – 15 in the selected PLMN, even if timer T3402, T3346 or timer T3447 is running; and - shall not initiate the detach signalling procedure unless the current TAI is part of the TAI list.