ETSI TS 123 502 V19.7.0 (2026-03)

5G; Procedures for the 5G System (5GS) (3GPP TS 23.502 version 19.7.0 Release 19)

RTS/TSGS-0223502vj70

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 2 - Architecture
• Current Stage: 8 - Draft receipt by ETSI Secretariat
• Completion Date: 13-Mar-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
Procedures for the 5G System (5GS)
(3GPP TS 23.502 version 19.7.0 Release 19)

3GPP TS 23.502 version 19.7.0 Release 19 1 ETSI TS 123 502 V19.7.0 (2026-03)

Reference
RTS/TSGS-0223502vj70
Keywords
5G
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ETSI
3GPP TS 23.502 version 19.7.0 Release 19 2 ETSI TS 123 502 V19.7.0 (2026-03)
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ETSI
3GPP TS 23.502 version 19.7.0 Release 19 3 ETSI TS 123 502 V19.7.0 (2026-03)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 27
1 Scope . 28
2 References . 28
3 Definitions, symbols and abbreviations . 31
3.1 Definitions . 31
3.2 Abbreviations . 32
4 System procedures . 32
4.1 General . 32
4.2 Connection, Registration and Mobility Management procedures . 32
4.2.1 General . 32
4.2.2 Registration Management procedures . 32
4.2.2.1 General . 32
4.2.2.2 Registration procedures . 32
4.2.2.2.1 General . 32
4.2.2.2.2 General Registration . 35
4.2.2.2.3 Registration with AMF re-allocation . 56
4.2.2.2.4 Registration with Onboarding SNPN . 60
4.2.2.3 Deregistration procedures . 62
4.2.2.3.1 General . 62
4.2.2.3.2 UE-initiated Deregistration . 62
4.2.2.3.3 Network-initiated Deregistration . 64
4.2.3 Service Request procedures . 65
4.2.3.1 General . 65
4.2.3.2 UE Triggered Service Request . 66
4.2.3.3 Network Triggered Service Request . 79
4.2.4 UE Configuration Update . 87
4.2.4.1 General . 87
4.2.4.2 UE Configuration Update procedure for access and mobility management related parameters . 88
4.2.4.3 UE Configuration Update procedure for transparent UE Policy delivery . 92
4.2.5 Reachability procedures . 94
4.2.5.1 General . 94
4.2.5.2 UE Reachability Notification Request procedure . 94
4.2.5.3 UE Activity Notification procedure . 96
4.2.6 AN Release . 97
4.2.7 N2 procedures . 100
4.2.7.1 N2 Configuration . 100
4.2.7.2 NGAP UE-TNLA-binding related procedures . 100
4.2.7.2.1 Creating NGAP UE-TNLA-bindings during Registration and Service Request . 100
4.2.7.2.2 Creating NGAP UE-TNLA-bindings during handovers . 101
4.2.7.2.3 Re-Creating NGAP UE-TNLA-bindings subsequent to NGAP UE-TNLA-binding release . 101
4.2.7.2.4 NGAP UE-TNLA-binding update procedure . 102
4.2.7.2.5 NGAP UE-TNLA-binding per UE Release procedure . 102
4.2.7.3 AMF Failure or Planned Maintenance handling procedure . 102
4.2.7.4 Additional User Location Information with Mobile Base Station Relay (MBSR) . 103
4.2.7.5 Additional User Location Information with Mobile gNB with wireless access backhauling
(MWAB) . 103
4.2.8 Void . 103
4.2.8a UE Capability Match Request procedure . 103
4.2.9 Network Slice-Specific Authentication and Authorization procedure . 105
4.2.9.1 General . 105
4.2.9.2 Network Slice-Specific Authentication and Authorization . 106
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4.2.9.3 AAA Server triggered Network Slice-Specific Re-authentication and Re-authorization procedure . 108
4.2.9.4 AAA Server triggered Slice-Specific Authorization Revocation . 109
4.2.10 N3 data transfer establishment procedure when Control Plane CIoT 5GS Optimisation is enabled . 110
4.2.10.1 UE triggered N3 data transfer establishment procedure . 110
4.2.10.2 SMF triggered N3 data transfer establishment procedure . 110
4.2.11 Network Slice Admission Control Function (NSACF) procedures . 111
4.2.11.1 General . 111
4.2.11.2 Number of UEs per network slice availability check and update procedure . 111
4.2.11.2a Hierarchical NSACF-based number of UEs per network slice availability check and update
procedure . 114
4.2.11.3 Configuration for Early Admission Control (EAC) update procedure . 116
4.2.11.4 Number of PDU Sessions per network slice availability check and update procedure . 117
4.2.11.4a Hierarchical NSACF-based Number of PDU Sessions per network slice availability check and
update procedure . 120
4.2.11.5 Network Slice Admission Control Support for Roaming . 121
4.2.11.5.1 Network Slice Admission Control Support for Roaming by VPLMN . 121
4.2.11.5.2 Network Slice Admission Control Support for Roaming by HPLMN . 122
4.2.11.6 Update of local maximum number in Hierarchical NSAC Architecture . 127
4.3 Session Management procedures . 128
4.3.1 General . 128
4.3.2 PDU Session Establishment . 129
4.3.2.1 General . 129
4.3.2.2 UE Requested PDU Session Establishment . 129
4.3.2.2.1 Non-roaming and Roaming with Local Breakout . 129
4.3.2.2.2 Home-routed Roaming . 147
4.3.2.2.3 SMF selection . 152
4.3.2.2.4 Multiple PDU Sessions towards the same DNN and S-NSSAI . 157
4.3.2.3 Secondary authorization/authentication by an DN-AAA Server during the PDU Session
establishment . 157
4.3.2.4 Support of L2TP . 160
4.3.3 PDU Session Modification . 162
4.3.3.1 General . 162
4.3.3.2 UE or network requested PDU Session Modification (non-roaming and roaming with local
breakout) . 162
4.3.3.3 UE or network requested PDU Session Modification (home-routed roaming) . 173
4.3.4 PDU Session Release . 177
4.3.4.1 General . 177
4.3.4.2 UE or network requested PDU Session Release for Non-Roaming and Roaming with Local

Breakout . 177
4.3.4.3 UE or network requested PDU Session Release for Home-routed Roaming . 183
4.3.5 Session continuity, service continuity and UP path management . 186
4.3.5.1 Change of SSC mode 2 PDU Session Anchor with different PDU Sessions . 186
4.3.5.2 Change of SSC mode 3 PDU Session Anchor with multiple PDU Sessions . 187
4.3.5.3 Change of SSC mode 3 PDU Session Anchor with IPv6 Multi-homed PDU Session . 190
4.3.5.4 Addition of additional PDU Session Anchor and Branching Point or UL CL . 193
4.3.5.5 Removal of additional PDU Session Anchor and Branching Point or UL CL . 194
4.3.5.6 Change of additional PDU Session Anchor for IPv6 multi-homing or UL CL . 196
4.3.5.7 Simultaneous change of Branching Point or UL CL and additional PSA for a PDU Session. 197
4.3.5.8 Ethernet PDU Session Anchor Relocation . 200
4.3.6 Application Function influence on traffic routing, service function chaining and handling of payload

headers . 202
4.3.6.1 General . 202
4.3.6.2 Processing AF requests to influence traffic routing and/or Service Function Chaining and/or for
Handling of Payload Headers for Sessions not identified by an UE address . 205
4.3.6.3 Notification of User Plane Management Events . 207
4.3.6.4 Transferring an AF request targeting an individual UE address to the relevant PCF. 212
4.3.6.5 Processing AF requests to influence traffic routing for HR-SBO session . 213
4.3.6.5.1 General . 213
4.3.6.5.2 AF traffic influence request includes HPLMN DNN, HPLMN S-NSSAI . 214
4.3.6.5.3 AF traffic influence request without HPLMN DNN, S-NSSAI information for a single UE,
with private IP address or public IP address owned by VPLMN . 216
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4.3.6.5.4 AF traffic influence request without HPLMN DNN, S-NSSAI information for a single UE,
with UE IP address owned and assigned by HPLMN . 217
4.3.6.5.5 AF traffic influence request for GPSI or any UE . 218
4.3.7 CN-initiated selective deactivation of UP connection of an existing PDU Session . 219
4.3.8 Change of Network Slice instance for PDU Sessions . 221
4.4 SMF and UPF interactions . 221
4.4.1 N4 session management procedures . 221
4.4.1.1 General . 221
4.4.1.2 N4 Session Establishment procedure . 221
4.4.1.3 N4 Session Modification procedure . 222
4.4.1.4 N4 Session Release procedure . 222
4.4.2 N4 Reporting Procedures . 223
4.4.2.1 General . 223
4.4.2.2 N4 Session Level Reporting Procedure . 223
4.4.3 N4 Node Level Procedures . 225
4.4.3.1 N4 Association Setup Procedure . 225
4.4.3.2 N4 Association Update Procedure . 226
4.4.3.3 N4 Association Release Procedure . 226
4.4.3.4 N4 Report Procedure . 227
4.4.3.5 N4 PFD management Procedure . 227
4.4.4 SMF Pause of Charging procedure . 228
4.5 User Profile management procedures . 229
4.5.1 Subscriber Data Update Notification to AMF . 229
4.5.2 Session Management Subscriber Data Update Notification to SMF . 230
4.5.3 Purge of subscriber data in AMF . 230
4.6 Security procedures . 231
4.7 ME Identity check procedure . 231
4.8 RAN-CN interactions . 231
4.8.1 Connection Inactive and Suspend procedure . 231
4.8.1.1 Connection Inactive procedure . 231
4.8.1.1a Connection Inactive procedure with CN based MT communication handling . 231
4.8.1.2 Connection Suspend procedure . 233
4.8.2 Connection Resume procedure . 234
4.8.2.1 General . 234
4.8.2.2 UE Triggered Connection Resume in RRC_INACTIVE procedure . 234
4.8.2.2a Network Triggered Connection Resume in RRC_INACTIVE procedure . 236
4.8.2.2b Network Triggered Connection Resume in RRC_INACTIVE with CN based MT communication
handli ng . 237
4.8.2.3 Connection Resume in CM-IDLE with Suspend procedure . 239
4.8.2.4 Connection Resume in CM-IDLE with Suspend and MO EDT procedure . 240
4.8.3 N2 Notification procedure . 242
4.9 Handover procedures . 243
4.9.1 Handover procedures in 3GPP access . 243
4.9.1.1 General . 243
4.9.1.2 Xn based inter NG-RAN handover . 243
4.9.1.2.1 General . 243
4.9.1.2.2 Xn based inter NG-RAN handover without User Plane function re-allocation . 244
4.9.1.2.3 Xn based inter NG-RAN handover with insertion of intermediate UPF . 248
4.9.1.2.4 Xn based inter NG-RAN handover with re-allocation of intermediate UPF . 249
4.9.1.3 Inter NG-RAN node N2 based handover . 251
4.9.1.3.1 General . 251
4.9.1.3.2 Preparation phase. 252
4.9.1.3.3 Execution phase . 259
4.9.1.3.3a Execution phase for DAPS handover . 263
4.9.1.4 Inter NG-RAN node N2 based handover, Cancel . 264
4.9.2 Handover of a PDU Session procedure between 3GPP and untrusted non-3GPP access . 264
4.9.2.0 General . 264
4.9.2.1 Handover of a PDU Session procedure from untrusted non-3GPP to 3GPP access (non-roaming
and roaming with local breakout) . 264
4.9.2.2 Handover of a PDU Session procedure from 3GPP to untrusted non-3GPP access (non-roaming
and roaming with local breakout) . 265
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4.9.2.3 Handover of a PDU Session procedure from untrusted non-3GPP to 3GPP access (home routed
roaming) . 266
4.9.2.3.1 The target AMF is in the PLMN of the N3IWF . 266
4.9.2.3.2 The target AMF is not in the PLMN of the N3IWF (i.e. N3IWF in HPLMN) . 267
4.9.2.4 Handover of a PDU Session procedure from 3GPP to untrusted non-3GPP access (home routed
roaming) . 268
4.9.2.4.1 The selected N3IWF is in the registered PLMN . 268
4.9.2.4.2 The UE is roaming and the selected N3IWF is in the home PLMN . 268
4.9.3 Handover of a PDU Session procedure between 3GPP and trusted non-3GPP access . 269
4.9.3.0 General . 269
4.10 NG-RAN Location reporting procedures . 269
4.11 System interworking procedures with EPC . 271
4.11.0 General . 271
4.11.0a Impacts to EPS Procedures . 272
4.11.0a.1 General . 272
4.11.0a.2 Interaction with PCC . 272
4.11.0a.2a Interaction with PCC for URSP delivery via EPS . 272
4.11.0a.2a.0 General . 272
4.11.0a.2a.1 SM Policy Association Establishment . 273
4.11.0a.2a.1a SM Policy Association Establishment in EPS . 274
4.11.0a.2a.2 SMF initiated SM Policy Association Modificatio n . 274
4.11.0a.2a.3 PCF initiated SM Policy Association Modification . 275
4.11.0a.2a.4 Void . 275
4.11.0a.2a.5 UE Policy Association establishment . 275
4.11.0a.2a.6 UE Policy Association Modification initiated by the PCF for the UE . 277
4.11.0a.2a.7 UE Policy Association Modification initiated by the PCF for the PDU Session . 278
4.11.0a.2a.8 UE Policy Association Termination initiated by PCF for PDU session . 279
4.11.0a.2a.9 UE Policy Association termination initiated by the PCF for the UE . 279
4.11.0a.2a.10 UE Policy Container delivery via EPS . 280
4.11.0a.3 Mobility Restrictions . 281
4.11.0a.4 PGW Selection . 281
4.11.0a.5 PDN Connection Establishment . 282
4.11.0a.6 Network Configuration . 284
4.11.0a.7 Interactions with DN-AAA Server . 284
4.11.0a.8 5GC NAS capability (re-)enabled and disabled . 284
4.11.0a.9 PDN Connection Release . 284
4.11.0a.10 UE requested bearer resource modification procedure. 284
4.11.0a.11 SMF+PGW-C initiated bearer modification without bearer QoS update . 285
4.11.1 N26 based Interworking Procedures . 285
4.11.1.1 General . 285
4.11.1.2 Handover procedures . 287
4.11.1.2.1 5GS to EPS handover using N26 interface . 287
4.11.1.2.2 EPS to 5GS handover using N26 interface . 293
4.11.1.2.3 Handover Cancel . 301
4.11.1.3 Idle Mode Mobility procedures . 303
4.11.1.3.1 General . 303
4.11.1.3.2 5GS to EPS Idle mode mobility using N26 interface . 303
4.11.1.3.2A 5GS to EPS Idle mode mobility using N26 interface with data forwarding . 306
4.11.1.3.3 EPS to 5GS Mobility Registration Procedure (Idle and Connected State) using N26 interface . 307
4.11.1.3.3A EPS to 5GS Idle mode mobility using N26 interface with data forwarding . 313
4.11.1.3.4 EPS to 5GS Mobility Registration Procedure (Idle) using N26 interface with AMF
reallocation . 314
4.11.1.4 Procedures for EPS bearer ID allocation . 315
4.11.1.4.1 EPS bearer ID allocation . 315
4.11.1.4.2 EPS bearer ID transfer . 318
4.11.1.4.3 EPS bearer ID revocation . 319
4.11.1.5 Impacts to EPS Procedures . 320
4.11.1.5.1 General . 320
4.11.1.5.2 E-UTRAN Initial Attach . 320
4.11.1.5.3 Tracking Area Update . 321
4.11.1.5.4 Session Management . 322
4.11.1.5.5 5GS to EPS handover using N26 interface . 324
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4.11.1.5.6 UE triggered Service Request . 324
4.11.1.5.7 Establishment of S1-U bearer during Data Transport in Control Plane CIoT EPS

Optimisation . 324
4.11.1.5.8 Radio Resource Management functions and Information Storage . 324
4.11.1.6 EPS interworking information storing Procedure . 325
4.11.2 Interworking procedures without N26 interface . 325
4.11.2.1 General . 325
4.11.2.2 5GS to EPS Mobility . 325
4.11.2.3 EPS to 5GS Mobility . 328
4.11.2.4 Impacts to EPS Procedures . 330
4.11.2.4.1 E-UTRAN Attach . 330
4.11.2.4.2 Session Management . 332
4.11.2.4.3 Void . 332
4.11.3 Handover procedures between EPS and 5GC-N3IWF . 333
4.11.3.1 Handover from EPS to 5GC-N3IWF . 333
4.11.3.2 Handover from 5GC-N3IWF to EPS . 333
4.11.3a Handover procedures between EPS and 5GC-TNGF . 334
4.11.3a.1 Handover from EPS to 5GC-TNGF . 334
4.11.3a.2 Handover from 5GC-TNGF to EPS . 334
4.11.4 Handover procedures between EPC/ePDG and 5GS . 335
4.11.4.1 Handover from EPC/ePDG to 5GS . 335
4.11.4.2 Handover from 5GS to EPC/ePDG . 336
4.11.4.3 Impacts to EPC/ePDG Procedures . 336
4.11.4.3.1 General . 336
4.11.4.3.2 ePDG FQDN construction . 336
4.11.4.3.3 Initial Attach with GTP on S2b . 337
4.11.4.3.3a Initial Attach for emergency session (GTP on S2b) . 337
4.11.4.3.4 Interaction with PCC . 337
4.11.4.3.5 UE initiated Connectivity to Additional PDN with GTP on S2b .
...