Timer value
NOTE 18
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
3GPP Scout / Reference / EPS NAS timers / Timers T3451 and T3452
TS 24.301NAS timer
Timers T3451 and T3452: S&F wait time
Covers
TS 24.301 words these values in parallel, so they share this page. Each has its own section with the spec text and a plain explanation.
Timer T3451: EPS mobility management, UE side
In plain words
The UE starts T3451 on receiving ATTACH ACCEPT, TRACKING AREA UPDATE ACCEPT or SERVICE ACCEPT with a non-zero S&F wait time duration value. The UE may initiate NAS procedures over previously restricted S&F satellite E-UTRAN cells when T3451 expires.
Our summary of the spec text quoted below.
Started when
ATTACH ACCEPT message or TRACKING AREA UPDATE ACCEPT message or SERVICE ACCEPT message received with a non-zero S&F wait time duration value in the S&F satellite operation parameters IE.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
On expiry
Allowed to initiate NAS procedures over previously restricted S&F satellite E-UTRAN cells.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Stopped when
See clause 4.11.5.2
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
State
EMM-REGISTERED
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Note 18 of the table
NOTE 18: The value of this timer is set as described in clause 4.11.5.2.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Timer T3452: EPS mobility management, UE side
In plain words
The UE starts T3452 on receiving ATTACH REJECT, TRACKING AREA UPDATE REJECT or SERVICE REJECT with a non-zero S&F wait time duration value. The UE may initiate NAS procedures over previously restricted S&F satellite E-UTRAN cells when T3452 expires.
Our summary of the spec text quoted below.
Timer value
NOTE 18
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Started when
ATTACH REJECT message or TRACKING AREA UPDATE REJECT message or SERVICE REJECT message received with a non-zero S&F wait time duration value in the S&F satellite operation parameters IE.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
On expiry
Allowed to initiate NAS procedures over previously restricted S&F satellite E-UTRAN cells.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Stopped when
See clause 4.11.5.2
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
State
EMM-REGISTERED EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH EMM-REGISTERED.ATTEMPTING-TO-UPDATE
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
Note 18 of the table
NOTE 18: The value of this timer is set as described in clause 4.11.5.2.
Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.
How this page was made
3GPP Scout built this page from TS 24.301 V20.1.0 as indexed on 2026-10-15. The quotes are copied from the spec, and code checks each one against the stored text and the 3GPP archive file before publishing. The plain-words lines were written by an AI model (GPT-6 Sol) and checked against the quotes by a second AI model from another company (Claude Opus 5.5). The official 3GPP text governs.