3GPP Scout / Reference / EPS NAS timers / T3450

TS 24.301NAS timer

Timer T3450: EPS mobility management, network side

TS 24.301 V20.1.0Clause 10.2Table 10.2.2Checked 2026-10-15

In plain words

The network starts T3450 after sending ATTACH ACCEPT, TRACKING AREA UPDATE ACCEPT with GUTI or TMSI, or GUTI REALLOCATION COMMAND. When T3450 expires, the network retransmits the same message type.

Our summary of the spec text quoted below.

What the spec says

Timer value

6s In WB-S1/CE mode, 18s NOTE 11

Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.

Started when

ATTACH ACCEPT sent TRACKING AREA UPDATE ACCEPT sent with GUTI TRACKING AREA UPDATE ACCEPT sent with TMSI GUTI REALLOCATION COMMAND sent

Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.

Stopped when

ATTACH COMPLETE received TRACKING AREA UPDATE COMPLETE received GUTI REALLOCATION COMPLETE received

Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.

On expiry

Retransmission of the same message type, i.e. ATTACH ACCEPT, TRACKING AREA UPDATE ACCEPT or GUTI REALLOCATION COMMAND

Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.

State

EMM-COMMON-PROC-INIT

Source: 3GPP TS 24.301 V20.1.0, clause 10.2, table 10.2.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24301-k10.zip in the 3GPP archive.

Same timer in 5GS (TS 24.501)

TS 24.501 defines the corresponding timer for 5GS. Its page quotes the 5GS wording.

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 line was 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.