Specification
3GPP TS 24.501: Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3
At a glance
- Title
- Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3
- Newest version
- V20.1.0 (Rel-20)
- Versions indexed
- 10
- Newest per release
- Rel-16: V16.15.0 (2025-07-01); Rel-17: V17.18.1 (2025-07-11); Rel-18: V18.14.0 (2026-09-22); Rel-19: V19.8.0 (2026-09-23); Rel-20: V20.1.0 (2026-09-23)
In plain words
TS 24.501 defines 5GS session management (5GSM), which "provides procedures for the handling of 5GS PDU sessions.". Its 5GS mobility management (5GMM) controls mobility when the UE uses NG-RAN, non-3GPP access, or both, and controls security for NAS protocols. V20.1.0 includes change requests (CRs) on SIP Location support, disaster roaming rejection handling, and extended 802.1Q packet filters for PDU session modification procedures.
Source: 3GPP TS 24.501 V20.1.0, clause 1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.501/24501-k10.zip
Newest version in each release
| Release | Newest version | In the archive | TSG meeting |
|---|---|---|---|
| Rel-20 | V20.1.0 | 2026-09-23 | TSG CT #113 |
| Rel-19 | V19.8.0 | 2026-09-23 | TSG CT #113 |
| Rel-18 | V18.14.0 | 2026-09-22 | TSG CT #113 |
| Rel-17 | V17.18.1 | 2025-07-11 | TSG CT #108 |
| Rel-16 | V16.15.0 | 2025-07-01 | TSG CT #108 |
| Rel-15 | V15.7.0 | 2022-06-24 | TSG CT #96 |
Source: 3GPP specification archive, versions indexed by 3GPP Scout. Each version links its official file.
Change requests in V20.1.0
V20.1.0 of TS 24.501 includes 28 CRs. The first 12 by CR number are listed.
| CR | Category | Subject | Source | Working group meeting | TSG TDoc |
|---|---|---|---|---|---|
| CR 7116 rev 4 | B | Indicating support for SIP Location | Apple, AT&T, Deutsche Telekom, Bouygues Telecom, Nokia, Huawei, HiSilicon | CT1 #162 | CP-262073 |
| CR 7190 rev 1 | B | NSSRG handling for requested NSSAI considering PDN connection(s) in EPS | LG Electronics, Apple, Samsung, Nokia | CT1 #162 | CP-262096 |
| CR 7198 rev 4 | F | Handling of forbidden TAI and restricted access technology when attempt for disaster roaming is rejected | MediaTek Inc. | CT1 #162 | CP-262073 |
| CR 7203 rev 1 | F | Corrections for the abnormal cases on the network side of the CONTROL PLANE SERVICE REQUEST procedure | Nokia | CT1 #162 | CP-262078 |
| CR 7204 rev 1 | F | Reset of the UE implementation specific attempt counter triggered by abnormal cases | Apple | CT1 #162 | CP-262073 |
| CR 7208 rev 1 | F | Adding extended 802.1Q C-TAG/S-TAG PCP/DEI packet filter to PDU session modification procedures | Qualcomm Incorporated, Ericsson | CT1 #162 | CP-262078 |
| CR 7209 | F | Correction to reference numbers in 3GPP TS 24.501. | Ericsson | CT1 #162 | CP-262078 |
| CR 7213 | F | Correction of 5G ProSe-l2end in 5GMM capability IE | ZTE | CT1 #162 | CP-262078 |
| CR 7214 | F | Correction to the references for PDCP specifications | ZTE | CT1 #162 | CP-262078 |
| CR 7216 rev 1 | F | Correction of security key name | ZTE | CT1 #162 | CP-262078 |
| CR 7218 rev 3 | F | Clarification on T3510 timer | Samsung, Huawei, HiSilicon | CT1 #162 | CP-262073 |
| CR 7219 rev 2 | F | Clarification of alternative S-NSSAI handling | SHARP | CT1 #162 | CP-262078 |
Source: 3GPP CR database.
Meetings behind the latest versions
Working group meetings that agreed the CRs in V20.1.0, V19.8.0, V18.14.0:
- CT1 #162: 32 CRs
Plenary meetings:
- TSG CT #113 approved V20.1.0 (Rel-20)
- TSG CT #112 approved V20.0.0 (Rel-20)
- TSG CT #113 approved V19.8.0 (Rel-19)
Source: 3GPP CR database and specification archive, as indexed by 3GPP Scout.
Clauses changed in V20.1.0
42 clauses changed or added in V20.1.0. The 10 with the largest edits are listed. Each clause number opens Scout on that clause.
| Clause | Title | Change | CRs |
|---|---|---|---|
| 5.5.1.3.6A | Mobility and periodic registration update for an emergency services fallback not accepted by the network | changed | CR 7244 |
| 6.3.1A.4 | Abnormal cases on the network side | changed | CR 7237 |
| 2 | References | changed | CR 7116, CR 7214, CR 7227 |
| 5.4.5.3.3 | Network-initiated NAS transport of messages accepted by the UE | changed | CR 7238, CR 7239 |
| 5.4.7.2.3 | Abnormal cases on the network side | changed | CR 7240 |
| 5.5.1.1 | General | changed | CR 7204 |
| 5.5.1.2.2 | Initial registration initiation | changed | CR 7220, CR 7225 |
| 5.5.1.2.5 | Initial registration not accepted by the network | changed | CR 7198 |
| 5.5.1.2.6A | Initial registration for initiating an emergency PDU session not accepted by the network | changed | CR 7236 |
| 5.5.1.3.2 | Mobility and periodic registration update initiation | changed | CR 7220, CR 7225 |
Source: 3GPP Scout comparison of this version with the one before it.
Sources
- 3GPP TS 24.501 V20.1.0, clause 1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.501/24501-k10.zip
- 3GPP specification archive, versions indexed by 3GPP Scout.
- 3GPP CR database.
How this page was made
The facts box and the tables come straight from the 3GPP specification archive and CR database as indexed by 3GPP Scout. An AI model (GPT-6 Luna) wrote the paragraph and named the source of each sentence. Code checked every quote word for word against the stored source text and every number against the cited source. A second AI model from another company (Claude Opus 5.5) reviewed the paragraph against the same sources. The 3GPP documents themselves govern.