ETSI TS 133 128 V16.22.0 (2026-04)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; 5G; Security; Protocol and procedures for Lawful Interception (LI); Stage 3 (3GPP TS 33.128 version 16.22.0 Release 16)

RTS/TSGS-0333128vgm0

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 3 - Security
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 02-Apr-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
Security;
Protocol and procedures for Lawful Interception (LI);
Stage 3
(3GPP TS 33.128 version 16.22.0 Release 16)


3GPP TS 33.128 version 16.22.0 Release 16 1 ETSI TS 133 128 V16.22.0 (2026-04)

Reference
RTS/TSGS-0333128vgm0
Keywords
5G,GSM,LTE,UMTS
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ETSI
3GPP TS 33.128 version 16.22.0 Release 16 2 ETSI TS 133 128 V16.22.0 (2026-04)
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Legal Notice
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The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
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ETSI
3GPP TS 33.128 version 16.22.0 Release 16 3 ETSI TS 133 128 V16.22.0 (2026-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 8
Introduction . 8
1 Scope . 9
2 References . 9
3 Definitions, symbols and abbreviations . 11
3.1 Definitions . 11
3.2 Symbols . 11
3.3 Abbreviations . 11
4 General . 12
4.1 Introduction . 12
4.2 Basic principles for internal interfaces . 13
4.3 Basic principles for external handover interfaces . 14
4.4 Service scoping . 15
4.4.1 General . 15
4.4.2 CSP service type . 15
4.4.3 Delivery type . 15
4.4.4 Location Reporting . 15
4.4.5 LALS Triggering . 15
4.4.6 Roaming Interception . 16
5 Transport and Communications Protocol . 16
5.1 General . 16
5.2 Protocols for LI_X1 and LI_T interfaces . 16
5.2.1 General usage of ETSI TS 103 221-1 . 16
5.2.2 Usage for realising LI_X1 . 16
5.2.3 Usage for realising LI_X1 (management) . 17
5.2.4 Service scoping . 17
5.2.5 Usage for realising LI_T2 . 17
5.2.6 Usage for realising LI_T3 . 17
5.2.7 Usage for realising LI_XEM1 . 18
5.3 Protocols for LI_X2 and LI_X3 . 19
5.3.1 General usage of ETSI TS 103 221-2 . 19
5.3.2 Usage for realising LI_X2 . 19
5.3.3 Usage for realising LI_X3 . 19
5.3.4 Service scoping . 20
5.4 Protocols for LI_HI1 . 20
5.4.1 General . 20
5.4.2 Service scoping . 20
5.5 Protocols for LI_HI2 and LI_HI3 . 20
5.5.1 General . 20
5.5.2 Usage for realising LI_HI2 . 20
5.5.3 Usage for realising LI_HI3 . 21
5.5.4 Service scoping . 21
5.5.5 IRI Target Identifiers . 21
5.6 Protocols for LI_HI4 . 21
5.6.1 General . 21
5.6.2 Usage for realising LI_HI4 . 21
5.7 Protocols for LI_HIQR . 22
5.7.1 General . 22
5.7.2 Usage for realising LI_HIQR. 22
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5.7.2.1 Request structure . 22
5.7.2.2 Request parameters . 23
5.7.2.3 Response structure . 24
5.8 Protocols for LI_XQR . 25
5.8.1 General . 25
5.8.2 Identity association requests . 25
5.8.3 Ongoing identity association requests. 25
5.9 Protocols for LI_XER . 26
5.10 Protocols for LI_ST interface . 26
5.10.1 Overview . 26
5.10.2 Storage . 26
5.10.3 Retrieval . 26
5.10.4 Removal . 27
6 Network Layer Based Interception . 27
6.1 Introduction . 27
6.2 5G . 27
6.2.1 General . 27
6.2.2 LI at AMF . 27
6.2.2.1 Provisioning over LI_X1 . 27
6.2.2.2 Generation of xIRI over LI_X2 . 28
6.2.2.2.1 General . 28
6.2.2.2.2 Registration . 28
6.2.2.2.3 Deregistration . 29
6.2.2.2.4 Location update . 30
6.2.2.2.5 Start of interception with registered UE . 31
6.2.2.2.6 AMF unsuccessful procedure . 32
6.2.2.2.7 AMF identifier association . 33
6.2.2.3 Generation of IRI over LI_HI2 . 33
6.2.2.4 Identity privacy . 34
6.2.2A Identifier Reporting for AMF . 34
6.2.2A.1 Activation of reporting over LI_XEM1 . 34
6.2.2A.2 Generation of records over LI_XER . 34
6.2.2A.2.2 Association Events . 35
6.2.2A.2.3 Transmission to the ICF . 36
6.2.3 LI for SMF/UPF . 36
6.2.3.1 Provisioning over LI_X1 . 36
6.2.3.1.1 General . 36
6.2.3.1.2 Provisioning of the IRI-POI, IRI-TF and CC-TF in the SMF . 36
6.2.3.1.3 Provisioning of the MDF2 . 37
6.2.3.1.4 Provisioning of the MDF3 . 38
6.2.3.2 Generation of xIRI at IRI-POI in SMF over LI_X2 . 39
6.2.3.2.1 General . 39
6.2.3.2.2 PDU session establishment . 39
6.2.3.2.3 PDU session modification . 40
6.2.3.2.4 PDU session release . 42
6.2.3.2.5 Start of interception with an established PDU session . 42
6.2.3.2.6 SMF unsuccessful procedure . 44
6.2.3.2.7 MA PDU sessions. 45
6.2.3.2.8 PDU to MA PDU session modification . 55
6.2.3.3 Triggering of the CC-POI from CC-TF over LI_T3 . 56
6.2.3.3.1 LI_T3 interface specifics . 56
6.2.3.3.2 CC interception with multi-homed PDU session . 57
6.2.3.3.3 CC Interception only at PDU Session Anchor UPFs . 58
6.2.3.4 IRI-POI in UPF triggering over LI_T2 . 58
6.2.3.5 Generation of xIRI at UPF over LI_X2. 59
6.2.3.5.1 Packet data header reporting . 59
6.2.3.5.2 Fragmentation . 60
6.2.3.5.3 Packet Data Header Reporting (PDHR) . 60
6.2.3.5.4 Packet Data Summary Reporting (PDSR) . 62
6.2.3.6 Generation of xCC at CC-POI in the UPF over LI_X3 . 64
6.2.3.7 Generation of IRI over LI_HI2 . 64
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6.2.3.8 Generation of CC over LI_HI3 . 65
6.2.3.9 Packet Data Information Reporting . 65
6.2.3.10 Sharing LI state information over LI_ST . 66
6.2.3.10.1 Overview . 66
6.2.3.10.2 Storing LI state . 66
6.2.3.10.3 Retrieving LI state . 67
6.2.3.10.4 Removing LI state . 67
6.2.4 LI at UDM for 5G . 68
6.2.4.1 General description . 68
6.2.5 LI at SMSF . 68
6.2.5.1 Provisioning over LI_X1 . 68
6.2.5.2 Generation of xIRI over LI_X2 . 69
6.2.5.3 SMS Message . 69
6.2.5.4 Generation of IRI over LI_HI2 . 72
6.2.6 LI support at NRF . 72
6.3 4G . 72
6.3.1 General . 72
6.3.2 LI at MME . 73
6.3.2.1 Provisioning over LI_X1 . 73
6.3.2.2 Generation of xIRI over LI_X2 . 73
6.3.2.2.1 General . 73
6.3.2.2.2 MME identifier association . 73
6.3.2.3 Generation of IRI over LI_HI2 . 74
6.3.3 LI at SGW/PGW and ePDG . 74
6.3.3.1 Provisioning over LI_X1 . 74
6.3.3.2 Generation of xIRI over LI_X2 . 74
6.3.3.3 Generation of xCC at CC-POI in the SGW/PGW and ePDG over LI_X3 . 75
6.3.3.4 Generation of IRI over LI_HI2 . 75
6.3.3.5 Generation of CC over LI_HI3 . 75
6.4 3G . 75
7 Service Layer Based Interception . 76
7.1 Introduction . 76
7.2 Central Subscriber Management . 76
7.2.1 General description . 76
7.2.2 LI at UDM . 76
7.2.2.1 General description . 76
7.2.2.2 Provisioning over LI_X1 . 76
7.2.2.3 Generation of xIRI over LI_X2 . 76
7.2.2.3.1 General description . 76
7.2.2.3.2 Serving system . 76
7.2.2.3.3 Subscriber record change. 77
7.2.2.3.4 Cancel location . 78
7.2.2.3.5 Location information request . 79
7.2.2.4 Generation of IRI over LI_HI2 . 79
7.2.3 LI at HSS . 79
7.2.3.1 General . 79
7.2.3.2 Provisioning over LI_X1 . 80
7.2.3.3 Generation of xIRI over LI_X2 . 80
7.2.3.4 Generation of IRI over LI_HI2 . 80
7.3 Location . 80
7.3.1 Lawful Access Location Services (LALS) . 80
7.3.1.1 General description . 80
7.3.1.2 Provisioning over LI_X1 . 81
7.3.1.2.1 Target positioning service . 81
7.3.1.2.2 Triggered location service . 81
7.3.1.3 Triggering over LI_T2 . 82
7.3.1.4 Generation of xIRI over LI_X2 . 83
7.3.1.5 Generation of IRI over LI_HI2 . 84
7.3.2 Cell database information reporting . 84
7.3.2.1 General description . 84
7.3.2.2 Delivery of cell site information over LI_HI2 . 84
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7.3.3 Use of the Location structure . 84
7.3.3.1 General description . 84
7.4 Messaging. 85
7.4.1 Introduction. 85
7.4.2 LI at the MMS Proxy-Relay . 85
7.4.2.1 Provisioning over LI_X1 . 85
7.4.2.2 Generation of xIRI over LI_X2 . 85
7.4.2.3 Generation of xCC over LI_X3 . 85
7.4.2.4 MMS Record Generation Cases . 85
7.4.3 MMS Records . 86
7.4.3.1 MMSSend . 86
7.4.3.2 MMSSendByNonLocalTarget . 88
7.4.3.2A MMSConvertedFromEmail . 90
7.4.3.3 MMSNotification . 90
7.4.3.4 MMSSendToNonLocalTarget . 91
7.4.3.4A MMSConvertedToEmail . 93
7.4.3.5 MMSNotificationResponse . 94
7.4.3.6 MMSRetrieval . 95
7.4.3.7 MMSDeliveryAck . 97
7.4.3.8 MMSForward . 97
7.4.3.9 MMSDeleteFromRelay . 99
7.4.3.10 MMSMBoxStore . 100
7.4.3.11 MMSMBoxUpload . 100
7.4.3.12 MMSMBoxDelete . 101
7.4.3.13 MMSDeliveryReport. 101
7.4.3.14 MMSDeliveryReportNonLocalTarget . 102
7.4.3.15 MMSReadReport . 103
7.4.3.16 MMSReadReportNonLocalTarget . 104
7.4.3.17 MMSCancel . 105
7.4.3.18 MMSMBoxViewRequest . 105
7.4.3.19 MMSMBoxViewResponse . 106
7.4.3.20 MMBoxDescription . 107
7.4.3.21 MMS Content . 109
7.4.4 IRI and CC Generation . 109
7.4.4.1 Generation of IRI over LI_HI2 . 109
7.4.4.2 Generation of CC over LI_HI3 . 109
7.5 PTC service . 109
7.5.1 Introduction. 109
7.5.1.1 Provisioning over LI_X1 . 110
7.5.1.2 Generating xIRI over LI_X2 . 110
7.5.1.3 Generation of xCC over LI_X3 . 110
7.5.2 IRI events . 110
7.5.2.1 PTC registration . 110
7.5.2.2 PTC session initiation . 110
7.5.2.3 PTC session abandon attempt . 111
7.5.2.4 PTC session start . 112
7.5.2.5 PTC session end . 113
7.5.2.6 PTC start of interception . 114
7.5.2.7 PTC preestablished session . 115
7.5.2.8 PTC instant personal alert . 115
7.5.2.9 PTC party join . 116
7.5.2.10 PTC party drop . 116
7.5.2.11 PTC party hold . 117
7.5.2.12 PTC media modification . 117
7.5.2.13 PTC group advertisement . 118
7.5.2.14 PTC floor control . 118
7.5.2.15 PTC target presence . 120
7.5.2.16 PTC participant presence . 121
7.5.2.17 PTC list management . 121
7.5.2.18 PTC access policy . 122
7.5.3 IRI and CC Generation . 123
7.5.3.1 Generation of IRI over LI_HI2 . 123
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7.5.3.2 Generation of CC over LI_HI3 . 124
7.6 Identifier Association Reporting . 124
7.6.1 General . 124
7.6.2 ICF . 124
7.6.2.1 General .
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