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Sep 26, 2013

LTE EPS mobility management timers - EMM timers

Lately many times I had to reach towards the EPS Mobility Management (EMM) timers, because it took me some time to google them here you go. Hope any one will find them as useful I did. 
In the two tables you can easily find the times name it's default or suggested value, what is triggering it and what happens in case it will finally expire.

EPS mobility management timers – UE side

TIMER NUM.
TIMER VALUE
STATE
CAUSE OF START
NORMAL STOP
ON
EXPIRY
T3402
Default 12 min.
NOTE 1
EMM-DEREGISTERED
EMM-REGISTERED
At attach failure and the attempt counter is equal to 5.
At tracking area updating failure and the attempt counter is equal to 5.
ATTACH REQUEST sent
TRACKING AREA UPDATE REQUEST sent
Initiation of the attach procedure or TAU procedure
T3410
15s
EMM-REGISTERED-INITIATED
ATTACH REQUEST sent
ATTACH ACCEPT received
ATTACH REJECT received
Start T3411 or T3402 as described in subclause 5.5.1.2.6
T3411
10s
EMM-DEREGISTERED. ATTEMPTING-TO-ATTACH

EMM-REGISTERED. ATTEMPTING-TO-UPDATE
At attach failure due to lower layer failure, T3410 timeout or attach rejected with other EMM cause values than those treated in subclause 5.5.1.2.5.

At tracking area updating failure due to lower layer failure, T3430 timeout or TAU rejected with other EMM cause values than those treated in subclause 5.5.3.2.5.
ATTACH REQUEST sent
TRACKING AREA UPDATE REQUEST sent
Retransmission of the ATTACH REQUEST or TRACKING AREA UPDATE REQUEST
T3412
Default 54 min.
NOTE 2
NOTE 5
EMM-REGISTERED
In EMM-REGISTERED, when EMM-CONNECTED mode is left.
When entering state EMM-DEREGISTERED or when entering EMM-CONNECTED mode.
Initiation of the periodic TAU procedure if the UE is not attached for emergency bearer services.

Implicit detach from network if the UE is attached for emergency bearer services.

T3416
30s
EMM-REGISTERED-INITIATED
EMM-REGISTERED
EMM-DEREGISTERED-INITIATED
EMM-TRACKING-AREA-UPDATING-INITIATED
EMM-SERVICE-REQUEST-INITIATED
RAND and RES stored as a result of a UMTS authentication challenge
SECURITY MODE COMMAND received
SERVICE REJECT received
TRACKING AREA UPDATE ACCEPT received
AUTHENTICATION REJECT received
AUTHENTICATION FAILURE sent
EMM-DEREGISTERED or EMM-NULL entered
Delete the stored RAND and RES
T3417
5s
EMM-SERVICE-REQUEST-INITIATED
SERVICE REQUEST sent
EXTENDED SERVICE REQUEST sent in case f, g, i and j in subclause 5.6.1.1
Bearers have been set up
SERVICE REJECT received
Abort the procedure
T3417ext
10s
EMM-SERVICE-REQUEST-INITIATED
EXTENDED SERVICE REQUEST sent in case d in subclause 5.6.1.1
EXTENDED SERVICE REQUEST sent in case e in subclause 5.6.1.1 and the CSFB response was set to "CS fallback accepted by the UE"
Inter-system change from S1 mode to A/Gb mode or Iu mode is completed
Inter-system change from S1 mode to A/Gb mode or Iu mode is failed
SERVICE REJECT received
Abort the procedure
T3418
20s
EMM-REGISTERED-INITIATED
EMM-REGISTERED
EMM-TRACKING-AREA-UPDATING-INITIATED
EMM-DEREGISTERED-INITIATED
EMM-SERVICE-REQUEST-INITIATED
AUTHENTICATION FAILURE (EMM cause = #20 "MAC failure" or #26 "non-EPS authentication unacceptable") sent
AUTHENTICATION REQUEST received
On first expiry, the UE should consider the network as false and follow item f of subclause 5.4.2.7, if the UE is not attached for emergency bearer services.

On first expiry, the UE will follow subclause 5.4.2.7 under “For items c, d, and e:”, if the UE is attached for emergency bearer services.
T3420
15s
EMM-REGISTERED-INITIATED
EMM-REGISTERED
EMM-DEREGISTERED-INITIATED
EMM-TRACKING-AREA-UPDATING-INITIATED
EMM-SERVICE-REQUEST-INITIATED
AUTHENTICATION FAILURE (cause = #21 "synch failure") sent
AUTHENTICATION REQUEST received
On first expiry, the UE should consider the network as false and follow item f of subclause 5.4.2.7, if the UE is not attached for emergency bearer services.

On first expiry, the UE will follow subclause 5.4.2.7 under “For items c, d, and e:”, if the UE is attached for emergency bearer services.
T3421
15s
EMM-DEREGISTERED-INITIATED
DETACH REQUEST sent
DETACH ACCEPT received
Retransmission of DETACH REQUEST
T3423
NOTE 3
EMM-REGISTERED
T3412 expires while the UE is in EMM-REGISTERED.NO-CELL-AVAILABLE and ISR is activated.
When entering state EMM-DEREGISTERED or when entering EMM-CONNECTED mode.
Set TIN to "P‑TMSI"

T3430
15s
EMM-TRACKING-AREA-UPDATING-INITIATED
TRACKING AREA UPDATE REQUEST sent
TRACKING AREA UPDATE ACCEPT received
TRACKING AREA UPDATE REJECT received
Start T3411 or T3402 as described in subclause 5.5.3.2.6
T3440
10s
EMM-REGISTERED-INITIATED
EMM-TRACKING-AREA-UPDATING-INITIATED
EMM-DEREGISTERED-INITIATED
EMM-SERVICE-REQUEST-INITIATED
EMM-REGISTERED
ATTACH REJECT, DETACH REQUEST, TRACKING AREA UPDATE REJECT with any of the EMM cause #11, #12, #13, #14 or #15
SERVICE REJECT received with any of the EMM cause #11, #12, #13 or #15
TRACKING AREA UPDATE ACCEPT received after the UE sent TRACKING AREA UPDATE REQUEST in EMM-IDLE mode with no "active" flag
Signalling connection released
Bearers have been set up
Release the signalling connection and proceed as described in subclause 5.3.1.2
T3442
NOTE 4
EMM-REGISTERED
SERVICE REJECT received with EMM cause #39 "CS domain temporarily not available"
TRACKING AREA UPDATE REQUEST sent
None
NOTE 1: The default value of this timer is used if the network does not indicate another value in an EMM signalling procedure.
NOTE 2: The value of this timer is provided by the network operator during the attach and tracking area updating procedures.
NOTE 3: The value of this timer may be provided by the network in the ATTACH ACCEPT message and TRACKING AREA UPDATE ACCEPT message. The default value of this timer is identical to the value of T3412.
NOTE 4: The value of this timer is provided by the network operator when a service request for CS fallback is rejected by the network with EMM cause #39 "CS domain temporarily not available".
NOTE 5: The default value of this timer is used if the network does not indicate a value in the TRACKING AREA UPDATE ACCEPT message and the UE does not have a stored value for this timer.


EPS mobility management timers – network side

TIMER NUM.
TIMER VALUE
STATE
CAUSE OF START
NORMAL STOP
ON THE
1st, 2nd, 3rd, 4th EXPIRY (NOTE 1)
T3413
NOTE 2
EMM-REGISTERED
Paging procedure for EPS services initiated
Paging procedure for EPS services completed
Network dependent
T3422
6s
EMM-DEREGISTERED-INITIATED
DETACH REQUEST sent
DETACH ACCEPT received
Retransmission of DETACH REQUEST
T3450
6s
EMM-COMMON-PROC-INIT
ATTACH ACCEPT sent

TRACKING AREA UPDATE ACCEPT sent with GUTI

TRACKING AREA UPDATE ACCEPT sent with TMSI

GUTI REALLOCATION COMMAND sent
ATTACH COMPLETE received
TRACKING AREA UPDATE COMPLETE received
GUTI REALLOCATION COMPLETE received
Retransmission of the same message type, i.e. ATTACH ACCEPT, TRACKING AREA UPDATE ACCEPT or GUTI REALLOCATION COMMAND
T3460
6s
EMM-COMMON-PROC-INIT
AUTHENTICATION REQUEST sent

SECURITY MODE COMMAND sent
AUTHENTICATION RESPONSE received
AUTHENTICATION FAILURE received
SECURITY MODE COMPLETE received
SECURITY MODE REJECT received
Retransmission of the same message type, i.e. AUTHENTICATION REQUEST
or SECURITY MODE COMMAND
T3470
6s
EMM-COMMON-PROC-INIT
IDENTITY REQUEST sent
IDENTITY RESPONSE received
Retransmission of IDENTITY REQUEST
Mobile reachable
Default 4 min greater than T3412
All except EMM-DEREGISTERED
Entering EMM-IDLE mode
NAS signalling connection established
Network dependent, but typically paging is halted on 1st expiry if the UE is not attached for emergency bearer services.

Implicitly detach the UE which is attached for emergency bearer services.
Implicit detach timer
NOTE 3
All except EMM-DEREGISTERED
The mobile reachable timer expires while the network is in EMM-IDLE mode
NAS signalling connection established
Implicitly detach the UE on 1st expiry
NOTE 1: Typically, the procedures are aborted on the fifth expiry of the relevant timer. Exceptions are described in the corresponding procedure description.
NOTE 2: The value of this timer is network dependent.
NOTE 3: The value of this timer is network dependent. If ISR is activated, the default value of this timer is 4 minutes greater than T3423.


Source:

TS 23.401 3GPP