3GPP 24.501 v20.0.0 — the document's own text
10.2 Timers of 5GS mobility management
Taught in 6. Getting on the network, and getting a connection through it (CT1 — the group that writes what your phone says, in depth), 2. Architecture and protocol — what stage 2 and stage 3 mean (CT1 — the group that writes what your phone says, overview), 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview), 7. Following the group yourself, and what the record cannot tell you (CT1 — the group that writes what your phone says, overview).
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]. Timers TF, TG, TS are defined in 3GPP TS 23.122 [5].
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 | 15sNOTE 7NOTE 8In WB-N1/CE mode, 85sFor access via a satellite NG-RAN cell, 27sNOTE 12 | 5GMM-REGISTERED-INITIATED | Transmission of REGISTRATION REQUEST message | REGISTRATION ACCEPT message received or REGISTRATION REJECT message received | Start T3511 or T3502 as specified in clause 5.5.1.2.7 if T3510 expired during registration procedure for initial registration.Start T3511 or T3502 as specified in clause 5.5.1.3.7 if T3510 expired during the registration procedure for mobility and periodic registration update |
| T3511 | 10s | 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE5GMM-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 clause 5.5.1.2.5 for initial registration or clause 5.5.1.3.5 for mobility and periodic registration | Transmission of REGISTRATION REQUEST message5GMM-CONNECTED mode entered (NOTE 5) | Retransmission of the REGISTRATION REQUEST message, if still required |
| T3512 | Default 54 minNOTE 1NOTE 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 clause 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 clause 5.3.7. | When entering state 5GMM-DEREGISTEREDWhen entering 5GMM-CONNECTED mode if the NW does not indicate support for strictly periodic registration timer as specified in clause 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 | 30sNOTE 7NOTE 8In WB-N1/CE mode, 48s For access via a satellite NG-RAN cell, 35sNOTE 12 | 5GMM-REGISTERED-INITIATED5GMM-REGISTERED5GMM-DEREGISTERED-INITIATED5GMM-SERVICE-REQUEST-INITIATED | RAND and RES* stored as a result of an 5G authentication challenge | SECURITY MODE COMMAND message receivedSERVICE REJECT message receivedREGISTRATION ACCEPT message receivedAUTHENTICATION REJECT message receivedAUTHENTICATION FAILURE message sent5GMM-DEREGISTERED, 5GMM-NULL or5GMM-IDLE mode entered | Delete the stored RAND and RES* |
| T3517 | (a) 5s for case h) in clause 5.6.1.1; or(b) 15s for cases other than h) in clause 5.6.1.1NOTE 7NOTE 8NOTE 10In WB-N1/CE mode, 61s For access via a satellite NG-RAN cell, 27sNOTE 12 | 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 clause 5.6.1.1; or(b) SERVICE ACCEPT message received, orSERVICE REJECT message received for cases other than h) in clause 5.6.1.1see clause 5.6.1.4.2 | Abort the procedure |
| T3519 | 60sNOTE 7NOTE 8In WB-N1/CE mode, 90s For access via a satellite NG-RAN cell, 65sNOTE 12 | 5GMM-REGISTERED-INITIATED5GMM-REGISTERED5GMM-DEREGISTERED-INITIATED5GMM-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 receivedCONFIGURATION UPDATE COMMAND message with new 5G-GUTI received DEREGISTRATION ACCEPT message | Delete stored SUCI |
| T3520 | 15sNOTE 7NOTE 8In WB-N1/CE mode, 33s For access via a satellite NG-RAN cell, 20sNOTE 12 | 5GMM-REGISTERED-INITIATED5GMM-REGISTERED5GMM-DEREGISTERED-INITIATED5GMM-SERVICE-REQUEST-INITIATED | Transmission of AUTHENTICATION FAILURE message with any of the 5GMM cause #20, #21, #26 or #71Transmission of AUTHENTICATION RESPONSE message with an EAP-response message after detection of an error as described in clause 5.4.1.2.2.4 | AUTHENTICATION REQUEST message received or AUTHENTICATION REJECT message receivedorSECURITY MODE COMMAND message receivedwhen entering 5GMM-IDLE modeindication 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 clause 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 clause 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 clause 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 clause 5.4.1.2.4.5 under "For item e:", if the UE is registered for emergency services |
| T3521 | 15sNOTE 7NOTE 8In WB-N1/CE mode, 45s For access via a satellite NG-RAN cell, 27sNOTE 12 | 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 60sNOTE 3NOTE 7NOTE 8In WB-N1/CE mode, default 120sFor access via a satellite NG-RAN cell, default 72sNOTE 12 | 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,orUE camped on a new PLMN other than the PLMN on which timer started,OrUE camped on a new SNPN other than the SNPN on which timer was started,orUser-plane resources established with the network | The UE may initiate service request procedure |
| T3540 | 10sNOTE 7 (applicable to case f) in clause 5.3.1.3)NOTE 8In WB-N1/CE mode, 34s (applicable to case f) in clause 5.3.1.3)NOTE 11For access via a satellite NG-RAN cell, default 22s (applicable to case f) in clause 5.3.1.3)NOTE 12NOTE 13NOTE 14 | 5GMM-DEREGISTERED5GMM-REGISTERED | REGISTRATION REJECT message or DEREGISTRATION REQUEST message received with any of the 5GMM cause #3, #6, #7, #11, #12, #13, #15, #27, #31, #36, #62, #72, #73, #74, #75, #76, #78 or #80.SERVICE REJECT message received with any of the 5GMM cause #3, #6, #7, #11, #12, #13, #15, #27, #36, #72, #73, #74, #75, #76, #78 or #80.REGISTRATION ACCEPT message received as described in clause 5.3.1.3 case b) and case h)SERVICE ACCEPT message received as described in clause 5.3.1.3 case f)AUTHENTICATION REJECT message receivedDEREGISTRATION ACCEPT message received as described in clause 5.3.1.3 case k) | N1 NAS signalling connection releasedPDU 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 clause 5.3.1.3 case b)Other use cases see clause 5.3.1.3 | Release the NAS signalling connection for the cases a), a1), b), c), d), e), f), g), h), i), j), k), l) as described in clause 5.3.1.3 |
| 5GMM-REGISTERED | CONFIGURATION UPDATE COMMAND message received as described in clause 5.3.1.3 case e) and h)SERVICE ACCEPT message received as described in clause 5.3.1.3 case i) | N1 NAS signalling connection released Other use cases see clause 5.3.1.3 | Release the NAS signalling connection for the case e) as described in clause 5.3.1.3 and perform a new registration procedure as described in clause 5.5.1.3.2Release the NAS signalling connection for the case h) and i) as described in clause 5.3.1.3 | ||
| 5GMM-DEREGISTERED5GMM-DEREGISTERED.NORMAL-SERVICE5GMM-REGISTERED.NON-ALLOWED-SERVICE | REGISTRATION REJECT message received with the 5GMM cause #9 or #10SERVICE 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 clause 5.3.1.3 and initiation of the registration procedure as specified in clause 5.5.1.2.2 or 5.5.1.3.2 | |||
| Non-3GPP de-registration timer | Default 54 min.NOTE 1NOTE 2NOTE 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 "S-NSSAI not available due to maximum number of UEs reached" received. | Associated S-NSSAI in the rejected NSSAI for the maximum number of UEs reached as specified in clause 4.6.2.2 deleted. | Remove the S-NSSAI in the rejected NSSAI for the maximum number of UEs reached associated with the T3526 timer. |
| T3527 | 15s | 5GMM-REGISTERED.NORMAL-SERVICE | Transmission of RELAY KEY REQUEST messageTransmission of RELAY AUTHENTICATION RESPONSE message | RELAY KEY REJECT message received orRELAY AUTHENTICATION REQUEST message received orRELAY KEY ACCEPT message received | Retransmission of RELAY KEY REQUEST message |
| 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 default value of this timer is used when the UE is not configured with the implementation specific value. The minimum value of this timer is 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 clause 5.5.1.3.7.NOTE 6: The conditions for which this applies to the 5GMM-SERVICE-REQUEST-INITIATED state are described in clause 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 clause 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 clause 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 "S-NSSAI not available due to maximum number of UEs 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 "S-NSSAI not available due to maximum number of UEs reached".NOTE 10: Based on implementation, the timer may be set to a value between 250ms and 15s when the MUSIM 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 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.NOTE 12: In satellite NG-RAN access, this value shall only be selected when satellite NG-RAN RAT type is NR(MEO) or NR(GEO).NOTE 13: If the timer is started due the reception of a 5GMM reject cause triggering a PLMN selection according to 3GPP TS 23.122 [5] or a search for a suitable cell in another tracking area according to 3GPP TS 38.304 [28], the UE may start the timer with an implementation specific value which is lower than the value described in this table.NOTE 14: For a UE configured for high priority access in selected PLMN or SNPN, the timer value shall be implementation specific which shall be greater than 1 second and less than 5 seconds. |
Table 10.2.2: Timers of 5GS mobility management – AMF side
| TIMER NUM. | TIMER VALUE | STATE | CAUSE OF START | NORMAL STOP | ON EXPIRY |
|---|---|---|---|---|---|
| T3513NOTE 7NOTE 9 | NOTE 4 | 5GMM-REGISTERED | Paging procedure initiated | Paging procedure completed as specified in clause 5.6.2.2.1 | Network dependent |
| T3522NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 24sFor access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-DEREGISTERED-INITIATED | Transmission of DEREGISTRATION REQUEST message | DEREGISTRATION ACCEPT message received | Retransmission of DEREGISTRATION REQUEST message |
| T3550NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 18sFor access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-COMMON-PROCEDURE-INITIATED | Transmission of REGISTRATION ACCEPT message as specified in clause 5.5.1.2.4 and 5.5.1.3.4 | REGISTRATION COMPLETE message received | Retransmission of REGISTRATION ACCEPT message |
| T3555NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 24sFor access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-REGISTERED | Transmission of CONFIGURATION UPDATE COMMAND message with "acknowledgement requested" set in the Acknowledgement bit of the Configuration update indication IE | CONFIGURATION UPDATE COMPLETE message received | Retransmission of CONFIGURATION UPDATE COMMAND message |
| T3560NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 24sFor access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-COMMON-PROCEDURE-INITIATED | Transmission of AUTHENTICATION REQUEST messageTransmission of SECURITY MODE COMMAND message | AUTHENTICATION RESPONSE message receivedAUTHENTICATION FAILURE message receivedSECURITY MODE COMPLETE message receivedSECURITY MODE REJECT message received | Retransmission of AUTHENTICATION REQUEST message or SECURITY MODE COMMAND message |
| T3565NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 24s For access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-REGISTERED | Transmission of NOTIFICATION message | SERVICE REQUEST message receivedCONTROL PLANE SERVICE REQUEST message receivedNOTIFICATION RESPONSE message receivedREGISTRATION REQUESTMessage receivedDEREGISTRATION REQUEST message receivedNGAP UE context resume request message as specified in 3GPP TS 38.413 [31] received | Retransmission of NOTIFICATION message |
| T3570NOTE 6NOTE 8 | 6sIn WB-N1/CE mode, 24sFor access via a satellite NG-RAN cell, 11sNOTE 12 | 5GMM-COMMON-PROCEDURE-INITIATED | Transmission of IDENTITY REQUEST message | IDENTITY RESPONSE message received | Retransmission of IDENTITY REQUEST message |
| T3575NOTE 6NOTE 8 | 15sIn WB-N1/CE mode, 60sFor access via a satellite NG-RAN cell, 27sNOTE 12 | 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 signallingconnection 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 modeEntering 5GMM-IDLE mode over 3GPP access if the MICO mode is activated and strictly periodic monitoring timer is not runningThe 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 clause 5.3.7. | Entering 5GMM-DEREGISTERED. | In 5GMM-IDLE mode, start implicit de-registration timer as specified in clause 5.3.7.In 5GMM-CONNECTED mode, Strictly periodic monitoring timer is started again as specified in clause 5.3.7. |
| Implementation specific timer for onboarding services | NOTE 11 | 5GMM-REGISTERED | At the successful completion of initial 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 or successful completion of registration procedure for mobility and periodic registration update if the implementation specific timer for onboarding services is not running and:- the UE is registered for onboarding services in SNPN; or- the UE's subscription only allows 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 clause 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 clause 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.NOTE 12: In satellite NG-RAN access, this value shall only be selected when satellite NG-RAN RAT type is NR(MEO) or NR(GEO). |