10.2 Timers of 5GS mobility management

24.5013GPPNon-Access-Stratum (NAS) protocol for 5G System (5GS)Release 17Stage 3TS

Timers of 5GS mobility management are shown in table 10.2.1 and table 10.2.2.

NOTE: Timers T3324, T3346, T3245 and T3247 are defined in 3GPP TS 24.008 [12]. Timers T3444, T3445, T3447 and T3448 are defined in 3GPP TS 24.301 [15].

Table 10.2.1: Timers of 5GS mobility management – UE side

TIMER NUM.

TIMER VALUE

STATE

CAUSE OF START

NORMAL STOP

ON
EXPIRY

T3502

Default 12 min.

NOTE 1

5GMM-DEREGISTERED 5GMM-REGISTERED

At registration failure and the attempt counter is equal to 5

Transmission of REGISTRATION REQUEST message

Initiation of the registration procedure, if still required

T3510

15s

NOTE 7

NOTE 8

In WB-N1/CE mode, 85s

5GMM-REGISTERED-INITIATED

Transmission of REGISTRATION REQUEST message

REGISTRATION ACCEPT message received or REGISTRATION REJECT message received

Start T3511 or T3502 as specified in subclause 5.5.1.2.7 if T3510 expired during registration procedure for initial registration.

Start T3511 or T3502 as specified in subclause 5.5.1.3.7 if T3510 expired during the registration procedure for mobility and periodic registration update

T3511

10s

5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION

5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE

5GMM-REGISTERED.NORMAL-SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE

At registration failure due to lower layer failure, T3510 timeout or registration rejected with other 5GMM cause values than those treated in subclause 5.5.1.2.5 for initial registration or subclause 5.5.1.3.5 for mobility and periodic registration

Transmission of REGISTRATION REQUEST message

5GMM-CONNECTED mode entered (NOTE 5)

Retransmission of the REGISTRATION REQUEST, if still required

T3512

Default 54 min

NOTE 1

NOTE 2

5GMM-REGISTERED

In 5GMM-REGISTERED, when 5GMM-CONNECTED mode is left and if the NW does not indicate support for strictly periodic registration timer as specified in subclause 5.3.7.

If the network indicates support for strictly periodic registration timer, T3512 is started after the successful completion of registration update procedure. T3512 is restarted if it expires in 5GMM-CONNECTED mode as specified in subclause 5.3.7.

When entering state 5GMM-DEREGISTERED

When entering 5GMM-CONNECTED mode if the NW does not indicate support for strictly periodic registration timer as specified in subclause 5.3.7.

In 5GMM-IDLE mode, Initiation of the periodic registration procedure if the UE is not registered for emergency services.

In 5GMM-CONNECTED mode, restart the timer T3512.

Locally deregister if the UE is registered for emergency services

T3516

30s

NOTE 7

NOTE 8

In WB-N1/CE mode, 48s

5GMM-REGISTERED-INITIATED

5GMM-REGISTERED

5GMM-DEREGISTERED-INITIATED

5GMM-SERVICE-REQUEST-INITIATED

RAND and RES* stored as a result of an 5G authentication challenge

SECURITY MODE COMMAND received

SERVICE REJECT received

REGISTRATION ACCEPT received

AUTHENTICATION REJECT received

AUTHENTICATION FAILURE sent

5GMM-DEREGISTERED, 5GMM-NULL or

5GMM-IDLE mode entered

Delete the stored RAND and RES*

T3517

(a) 5s for case h) in subclause 5.6.1.1; or

(b) 15s for cases other than h) in subclause 5.6.1.1

NOTE 7

NOTE 8

NOTE 10

In WB-N1/CE mode, 61s

5GMM-SERVICE-REQUEST-INITIATED

Transmission of SERVICE REQUEST message, or CONTROL PLANE SERVICE REQUEST message

(a) Indication from the lower layers that the UE has changed to S1 mode or E-UTRA connected to 5GCN for case h) in subclause 5.6.1.1; or

(b) SERVICE ACCEPT message received, or

SERVICE REJECT message received for cases other than h) in subclause 5.6.1.1

see subclause 5.6.1.4.2

Abort the procedure

T3519

60s

NOTE 7

NOTE 8

In WB-N1/CE mode, 90s

5GMM-REGISTERED-INITIATED

5GMM-REGISTERED

5GMM-DEREGISTERED-INITIATED

5GMM-SERVICE-REQUEST-INITIATED (NOTE 6)

Transmission of IDENTITY RESPONSE message, REGISTRATION REQUEST message, or DEREGISTRATION REQUEST message with freshly generated SUCI

REGISTRATION ACCEPT message with new 5G-GUTI received

CONFIGURATION UPDATE COMMAND message with new 5G-GUTI received DEREGISTRATION ACCEPT message

Delete stored SUCI

T3520

15s

NOTE 7

NOTE 8

In WB-N1/CE mode, 33s

5GMM-REGISTERED-INITIATED

5GMM-REGISTERED

5GMM-DEREGISTERED-INITIATED

5GMM-SERVICE-REQUEST-INITIATED

Transmission of AUTHENTICATION FAILURE message with any of the 5GMM cause #20, #21, #26 or #71

Transmission of AUTHENTICATION RESPONSE message with an EAP-response message after detection of an error as described in subclause 5.4.1.2.2.4

AUTHENTICATION REQUEST message received or AUTHENTICATION REJECT message received

or

SECURITY MODE COMMAND message received

when entering 5GMM-IDLE mode

indication of transmission failure of AUTHENTICATION FAILURE message from lower layers

On first expiry during a 5G AKA based primary authentication and key agreement procedure, the UE should consider the network as false and follow item g of subclause 5.4.1.3.7, if the UE is not registered for emergency services.

On first expiry during a 5G AKA based primary authentication and key agreement procedure, the UE will follow subclause 5.4.1.3.7 under "For items c, d, e and f:", if the UE is registered for emergency services.

On first expiry during an EAP based primary authentication and key agreement procedure, the UE should consider the network as false and follow item e of subclause 5.4.1.2.4.5, if the UE is not registered for emergency services.

On first expiry during an EAP based primary authentication and key agreement procedure, the UE will follow subclause 5.4.1.2.4.5 under "For item e:", if the UE is registered for emergency services

T3521

15s

NOTE 7

NOTE 8

In WB-N1/CE mode, 45s

5GMM-DEREGISTERED-INITIATED

Transmission of DEREGISTRATION REQUEST message when de-registration procedure is not due to a "switch off"

DEREGISTRATION ACCEPT message received

Retransmission of DEREGISTRATION REQUEST message

T3525

Default 60s

NOTE 3

NOTE 7

NOTE 8

In WB-N1/CE mode, default 120s

5GMM-REGISTERED.NORMAL-SERVICE or 5GMM-REGISTERED.NON-ALLOWED-SERVICE

T3517 expires and service request attempt counter is greater than or equal to 5

When entering state other than 5GMM-REGISTERED.NORMAL-SERVICE state or 5GMM-REGISTERED.NON-ALLOWED-SERVICE,

or

UE camped on a new PLMN other than the PLMN on which timer started,

or

User-plane resources established with the network

The UE may initiate service request procedure

T3540

10s

NOTE 7 (applicable to case f) in subclause 5.3.1.3)

NOTE 8

In WB-N1/CE mode, 34s (applicable to case f) in subclause 5.3.1.3)

NOTE 11

5GMM-DEREGISTERED

5GMM-REGISTERED

REGISTRATION REJECT message or DEREGISTRATION REQUEST message received with any of the 5GMM cause #3, #6, #7, #11, #12, #13, #15, #27, #31, #62, #72, #73, #74, #75 or #76

SERVICE REJECT message received with any of the 5GMM cause #3, #6, #7, #11, #12, #13, #15, #27, #72, #73, #74, #75 or #76.

REGISTRATION ACCEPT message received as described in subclause 5.3.1.3 case b) and case h)

SERVICE ACCEPT message received as described in subclause 5.3.1.3 case f)

AUTHENTICATION REJECT message received

N1 NAS signalling connection released

PDU sessions have been set up except for the case the UE has set Request type to "NAS signalling connection release" in the UE request type IE in the REGISTRATION REQUEST message as described in subclause 5.3.1.3 case b)

Other use cases see subclause 5.3.1.3

Release the NAS signalling connection for the cases a), b), f) and g) as described in subclause 5.3.1.3

5GMM-REGISTERED

CONFIGURATION UPDATE COMMAND message received as described in subclause 5.3.1.3 case e) and h)

SERVICE ACCEPT message received as described in subclause 5.3.1.3 case i)

N1 NAS signalling connection released Other use cases see subclause 5.3.1.3

Release the NAS signalling connection for the case e) and perform a new registration procedure as described in subclause 5.5.1.3.2

Release the NAS signalling connection for the case h) and i) as described in subclause 5.3.1.3

5GMM-DEREGISTERED

5GMM-DEREGISTERED.NORMAL-SERVICE

5GMM-REGISTERED.NON-ALLOWED-SERVICE

REGISTRATION REJECT message received with the 5GMM cause #9 or #10

SERVICE REJECT message received with the 5GMM cause #9, #10 or #28

Release the NAS signalling connection for the cases c) and d) as described in subclause 5.3.1.3 and initiation of the registration procedure as specified in subclause 5.5.1.2.2 or 5.5.1.3.2

Non-3GPP de-registration timer

Default 54 min.

NOTE 1

NOTE 2

NOTE 4

All 5GMM state over non-3GPP access except 5GMM-DEREGISTERED over non-3GPP access

Entering 5GMM-IDLE mode over non-3GPP access

N1 NAS signalling connection over non-3GPP access established or when entering state 5GMM-DEREGISTERED over non-3GPP access

Implicitly de-register the UE for non-3GPP access on 1st expiry

T3526

NOTE 9

5GMM-DEREGISTERED 5GMM-REGISTERED

Rejected S-NSSAI with rejection cause "maximum number of UEs per network slice reached" received.

None

Remove the S-NSSAI in the rejected NSSAI for the maximum number of UEs reached associated with the T3526 timer.

NOTE 1: The value of this timer is provided by the network operator during the registration procedure.

NOTE 2: The default value of this timer is used if the network does not indicate a value in the REGISTRATION ACCEPT message and the UE does not have a stored value for this timer.

NOTE 3: The value of this timer is UE implementation specific, with a minimum value of 60 seconds if not in NB-N1 mode and if not in WB-N1/CE mode.

NOTE 4: If the T3346 value received in the mobility management messages is greater than the value of the non-3GPP de-registration timer, the UE sets the non-3GPP de-registration timer value to be 4 minutes greater than the value of timer T3346.

NOTE 5: The conditions for which this applies are described in subclause 5.5.1.3.7.

NOTE 6: The conditions for which this applies to the 5GMM-SERVICE-REQUEST-INITIATED state are described in subclause 5.4.1.3.7 case c) and case d).

NOTE 7: In NB-N1 mode, the timer value shall be calculated as described in subclause 4.17.

NOTE 8: In WB-N1 mode, if the UE supports CE mode B and operates in either CE mode A or CE mode B, then the timer value is as described in this table for the case of WB-N1/CE mode (see subclause 4.19).

NOTE 9: The value of this timer is provided by the network operator during the registration procedure or the generic UE configuration update procedure along with the rejected S-NSSAI with rejection cause "maximum number of UEs per network slice reached". The default value of this timer is implementation specific with a minimum value of 12 minutes and used if the network does not provide a value in the REGISTRATION ACCEPT message, the REGISTRATION REJECT message, or the CONFIGURATION UPDATE COMMAND message along with the rejected S-NSSAI with rejection cause "maximum number of UEs per network slice reached".

NOTE 10: Based on implementation, the timer may be set to a value between 250ms and 15s when the MUSIM-capable UE indicates "NAS signalling connection release" in the UE request type IE of the SERVICE REQUEST message or CONTROL PLANE SERVICE REQUEST message.

NOTE 11: Based on implementation, the timer may be set to a value between 250ms and 10s when the MUSIM capable UE not in NB-N1 mode or WB-N1 mode indicated "NAS signalling connection release" or "Rejection of paging" in the UE request type IE of the SERVICE REQUEST message or CONTROL PLANE SERVICE REQUEST message; or indicated "NAS signalling connection release" in the UE request type IE of the REGISTRATION REQUEST message.

Table 10.2.2: Timers of 5GS mobility management – AMF side

TIMER NUM.

TIMER VALUE

STATE

CAUSE OF START

NORMAL STOP

ON
EXPIRY

T3513

NOTE 7

NOTE 9

NOTE 4

5GMM-REGISTERED

Paging procedure initiated

Paging procedure completed as specified in subclause 5.6.2.2.1

Network dependent

T3522

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 24s

5GMM-DEREGISTERED-INITIATED

Transmission of DEREGISTRATION REQUEST message

DEREGISTRATION ACCEPT message received

Retransmission of DEREGISTRATION REQUEST message

T3550

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 18s

5GMM-COMMON-PROCEDURE-INITIATED

Transmission of REGISTRATION ACCEPT message as specified in subclause 5.5.1.2.4 and 5.5.1.3.4

REGISTRATION COMPLETE message received

Retransmission of REGISTRATION ACCEPT message

T3555

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 24s

5GMM-REGISTERED

Transmission of CONFIGURATION UPDATE COMMAND message with "acknowledgement requested" set in the Acknowldgement bit of the Configuration update indication IE

CONFIGURATION UPDATE COMPLETE message received

Retransmission of CONFIGURATION UPDATE COMMAND message

T3560

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 24s

5GMM-COMMON-PROCEDURE-INITIATED

Transmission of AUTHENTICATION REQUEST message

Transmission of SECURITY MODE COMMAND message

AUTHENTICATION RESPONSE message received

AUTHENTICATION FAILURE message received

SECURITY MODE COMPLETE message received

SECURITY MODE REJECT message received

Retransmission of AUTHENTICATION REQUEST message or SECURITY MODE COMMAND message

T3565

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 24s

5GMM-REGISTERED

Transmission of NOTIFICATION message

SERVICE REQUEST message received

CONTROL PLANE SERVICE REQUEST message received

NOTIFICATION RESPONSE message received

REGISTRATION REQUEST

Message received

DEREGISTRATION REQUEST message received

NGAP UE context resume request message as specified in 3GPP TS 38.413 [31] received

Retransmission of NOTIFICATION message

T3570

NOTE 6

NOTE 8

6s

In WB-N1/CE mode, 24s

5GMM-COMMON-PROCEDURE-INITIATED

Transmission of IDENTITY REQUEST message

IDENTITY RESPONSE message received

Retransmission of IDENTITY REQUEST message

T3575

NOTE 6

NOTE 8

15s

In WB-N1/CE mode, 60s

5GMM-REGISTERED

Transmission of NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message

NETWORK SLICE-SPECIFIC AUTHENTICATION COMPLETE message received

Retransmission of NETWORK SLICE-SPECIFIC AUTHENTICATION COMMAND message

Active timer

NOTE 10

All except 5GMM-DEREGISTERED

Entering 5GMM-IDLE mode after indicating MICO mode activation to the UE with an active timer value.

N1 NAS signalling

connection established

Activate MICO mode for the UE.

Implicit de-registration timer

NOTE 2

All except 5GMM-DEREGISTERED

The mobile reachable timer expires while the network is in 5GMM-IDLE mode

Entering 5GMM-IDLE mode over 3GPP access if the MICO mode is activated and strictly periodic monitoring timer is not running

The strictly periodic monitoring timer expires while the network is in 5GMM-IDLE mode

N1 NAS signalling connection established

Implicitly de-register the UE on 1st expiry

Mobile reachable timer

NOTE 1

All except 5GMM-DEREGISTERED

Entering 5GMM-IDLE mode

N1 NAS signalling connection established

Network dependent, but typically paging is halted on 1st expiry, and start implicit de-registration timer, if the UE is not registered for emergency services.

Implicitly de-register the UE which is registered for emergency services

Non-3GPP implicit de-registration timer

NOTE 3

All except 5GMM-DEREGISTERED

Entering 5GMM-IDLE mode over non-3GPP access

N1 NAS signalling connection over non-3GPP access established

Implicitly de-register the UE for non-3GPP access on 1s expiry

Strictly periodic monitoring timer

NOTE 5

All except 5GMM-DEREGISTERED

At the successful completion of registration update procedure if strictly periodic registration timer indication is supported as specified in subclause 5.3.7.

Entering 5GMM-DEREGISTERED.

In 5GMM-IDLE mode, start implicit de-registration timer as specified in subclause 5.3.7.

In 5GMM-CONNECTED mode, Strictly periodic monitoring timer is started again as specified in subclause 5.3.7.

Timer for onboarding services

NOTE 11

5GMM-REGISTERED

At the successful completion of registration for onboarding services in SNPN or initial registration for the UE which the subscription is only for configuration of SNPN subscription parameters in PLMN via the user plane.

DEREGISTRATION REQUEST message received.

Network-initiated de-registration procedure performed

NOTE 1: The default value of this timer is 4 minutes greater than the value of timer T3512. If the UE is registered for emergency services, the value of this timer is set equal to the value of timer T3512. If the T3346 value provided in the mobility management messages is greater than the value of the timer T3512, the AMF sets the mobile reachable timer and the implicit de-registration timer such that the sum of the timer values is greater than the value of timer T3346.

NOTE 2: The value of this timer is network dependent. If MICO is activated, the default value of this timer is 4 minutes greater than the value of timer T3512.

NOTE 3: The value of this timer is network dependent. The default value of this timer is 4 minutes greater than the non-3GPP de-registration timer. If the T3346 value provided in the mobility management messages is greater than the value of the non-3GPP de-registration timer, the AMF sets the non-3GPP implicit de-registration timer value to be 8 minutes greater than the value of timer T3346.

NOTE 4: The value of this timer is network dependent.

NOTE 5: The value of this timer is the same as the value of timer T3512.

NOTE 6: In NB-N1 mode, the timer value shall be calculated as described in subclause 4.17.

NOTE 7: In NB-N1 mode, the timer value shall be calculated by using an NAS timer value which is network dependent.

NOTE 8: In WB-N1 mode, if the UE supports CE mode B and operates in either CE mode A or CE mode B, then the timer value is as described in this table for the case of WB-N1/CE mode (see subclause 4.19).

NOTE 9: In WB-N1 mode, if the UE supports CE mode B, then the timer value shall be calculated by using an NAS timer value which value is network dependent.

NOTE 10: If the AMF includes timer T3324 in the REGISTRATION ACCEPT message and if the UE is not registered for emergency services, the value of this timer is equal to the value of timer T3324.

NOTE 11: The value of this timer needs to be large enough to allow a UE to complete the configuration of one or more entries of the "list of subscriber data" and considering that configuration of SNPN subscription parameters in PLMN via the user plane or onboarding services in SNPN involves third party entities outside of the operator’s network.