3GPP Scout / Reference / 5GS NAS timers / T3517
TS 24.501NAS timer
In plain words
The UE starts T3517 when it sends SERVICE REQUEST or CONTROL PLANE SERVICE REQUEST and aborts the procedure on expiry.
Our summary of the spec text quoted below.
(a) 5s for case h) in clause 5.6.1.1; or (b) 15s for cases other than h) in clause 5.6.1.1 NOTE 7 NOTE 8 NOTE 10 In WB-N1/CE mode, 61s For access via a satellite NG-RAN cell, 27s NOTE 12
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
Transmission of SERVICE REQUEST message, or CONTROL PLANE SERVICE REQUEST message
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
(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, or SERVICE REJECT message received for cases other than h) in clause 5.6.1.1 see clause 5.6.1.4.2
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
Abort the procedure
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
5GMM-SERVICE-REQUEST-INITIATED
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
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.
Source: 3GPP TS 24.501 V20.1.0, clause 10.2, table 10.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.
3GPP Scout built this page from TS 24.501 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.