ETSI TS 123 003 V19.6.0 (2026-03)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; 5G; Numbering, addressing and identification (3GPP TS 23.003 version 19.6.0 Release 19)

RTS/TSGC-0423003vj60

General Information

• Status: Not Published
• Technical Committee: 3GPP CT 4 - MAP/CAMEL/GTP/BCH/SS/TrFO/IMS/GUP/WLAN (formely CN4)
• Current Stage: 8 - Draft receipt by ETSI Secretariat
• Completion Date: 10-Mar-2026

Standards Content (Sample)

TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
Numbering, addressing and identification
(3GPP TS 23.003 version 19.6.0 Release 19)

3GPP TS 23.003 version 19.6.0 Release 19 1 ETSI TS 123 003 V19.6.0 (2026-03)

Reference
RTS/TSGC-0423003vj60
Keywords
5G,GSM,LTE,UMTS
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ETSI
3GPP TS 23.003 version 19.6.0 Release 19 2 ETSI TS 123 003 V19.6.0 (2026-03)
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ETSI
3GPP TS 23.003 version 19.6.0 Release 19 3 ETSI TS 123 003 V19.6.0 (2026-03)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 12
1 Scope . 14
1.1 References . 15
1.1.1 Normative references . 15
1.1.2 Informative references . 20
1.2 Abbreviations . 20
1.3 General comments to references . 21
1.4 Conventions on bit ordering . 21
2 Identification of mobile subscribers . 22
2.1 General . 22
2.2 Composition of IMSI. 22
2.2A Subscription Permanent Identifier (SUPI) . 23
2.2B Subscription Concealed Identifier (SUCI) . 23
2.3 Allocation and assignment principles . 26
2.4 Structure of TMSI . 26
2.5 Structure of LMSI . 27
2.6 Structure of TLLI . 27
2.7 Structure of P-TMSI Signature . 28
2.8 Globally Unique Temporary UE Identity (GUTI) . 28
2.8.1 Introduction. 28
2.8.2 Mapping between Temporary and Area Identities for the EUTRAN and the UTRAN/GERAN based
s yste ms . 29
2.8.2.0 Introduction . 29
2.8.2.1 Mapping from GUTI to RAI, P-TMSI and P-TMSI signature . 29
2.8.2.1.1 Introduction . 29
2.8.2.1.2 Mapping in the UE . 29
2.8.2.1.3 Mapping in the old MME . 30
2.8.2.2 Mapping from RAI and P-TMSI to GUTI . 30
2.8.2.2.1 Introduction . 30
2.8.2.2.2 Mapping in the UE . 30
2.8.2.2.3 Mapping in the new MME. 31
2.9 Structure of the S-Temporary Mobile Subscriber Identity (S-TMSI) . 31
2.10 5G Globally Unique Temporary UE Identity (5G-GUTI) . 31
2.10.1 Introduction. 31
2.10.2 Mapping between Temporary Identities for the 5GS and the E-UTRAN . 32
2.10.2.0 Introduction . 32
2.10.2.1 Mapping from 5G-GUTI to GUTI . 32
2.10.2.1.1 Introduction . 32
2.10.2.1.2 Mapping in the UE . 32
2.10.2.1.3 Mapping in the old AMF . 33
2.10.2.2 Mapping from GUTI to 5G-GUTI . 33
2.10.2.2.1 Introduction . 33
2.10.2.2.2 Mapping in the UE . 33
2.10.2.2.3 Mapping in the new AMF . 34
2.11 Structure of the 5G-S-Temporary Mobile Subscriber Identity (5G-S-TMSI) . 34
2.12 Structure of the Truncated 5G-S-Temporary Mobile Subscriber Identity (Truncated 5G-S-TMSI) . 34
3 Numbering plan for mobile stations . 35
3.1 General . 35
3.2 Numbering plan requirements . 35
3.3 Structure of Mobile Subscriber ISDN number (MSISDN) . 35
3.4 Mobile Station Roaming Number (MSRN) for PSTN/ISDN routeing . 36
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3.5 Structure of Mobile Station International Data Number . 37
3.6 Handover Number . 37
3.7 Structure of an IP v4 address . 37
3.8 Structure of an IP v6 address . 37
4 Identification of location areas and base stations . 37
4.1 Composition of the Location Area Identification (LAI) . 37
4.2 Composition of the Routing Area Identification (RAI) . 38
4.3 Base station identification . 38
4.3.1 Cell Identity (CI) and Cell Global Identification (CGI) . 38
4.3.2 Base Station Identify Code (BSIC) . 39
4.4 Regional Subscription Zone Identity (RSZI) . 39
4.5 Location Number . 40
4.6 Composition of the Service Area Identification (SAI) . 40
4.7 Closed Subscriber Group . 40
4.8 HNB Name . 40
4.9 CSG Type . 41
4.10 HNB Unique Identity . 41
4.11 HRNN . 41
5 Identification of MSCs, GSNs, location registers and CSSs . 41
5.1 Identification for routeing purposes . 41
5.2 Identification of HLR for HLR restoration application . 42
5.3 Identification of the HSS for SMS . 42
6 International Mobile Station Equipment Identity, Software Version Number and Permanent
Equipment Identifier. 42
6.1 General . 42
6.2 Composition of IMEI and IMEISV . 43
6.2.1 Composition of IMEI . 43
6.2.2 Composition of IMEISV . 43
6.3 Allocation principles . 44
6.4 Permanent Equipment Identifier (PEI) . 44
7 Identification of Voice Group Call and Voice Broadcast Call Entities . 44
7.1 Group Identities . 44
7.2 Group Call Area Identification . 45
7.3 Voice Group Call and Voice Broadcast Call References . 45
8 SCCP subsystem numbers . 45
8.1 Globally standardized subsystem numbers used for GSM/UMTS . 46
8.2 National network subsystem numbers used for GSM/UMTS . 46
9 Definition of Access Point Name . 46
9A Definition of Data Network Name . 47
9.0 General . 47
9.1 Structure of APN . 47
9.1.1 Format of APN Network Identifier . 47
9.1.2 Format of APN Operator Identifier . 48
9.2 Definition of the Wild Card APN . 49
9.2.1 Coding of the Wild Card APN . 49
9.3 Definition of Emergency APN . 49
10 Identification of the Cordless Telephony System entities . 49
10.1 General description of CTS-MS and CTS-FP Identities . 49
10.2 CTS Mobile Subscriber Identities . 49
10.2.1 General . 49
10.2.2 Composition of the CTSMSI . 49
10.2.3 Allocation principles . 50
10.2.4 CTSMSI hexadecimal representation . 50
10.3 Fixed Part Beacon Identity . 50
10.3.1 General . 50
10.3.2 Composition of the FPBI . 50
10.3.2.1 FPBI general structure . 50
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10.3.2.2 FPBI class A. 51
10.3.2.3 FPBI class B . 51
10.3.3 Allocation principles . 52
10.4 International Fixed Part Equipment Identity . 52
10.4.1 General . 52
10.4.2 Composition of the IFPEI . 52
10.4.3 Allocation and assignment principles . 52
10.5 International Fixed Part Subscription Identity . 53
10.5.1 General . 53
10.5.2 Composition of the IFPSI . 53
10.5.3 Allocation and assignment principles . 53
11 Identification of Localised Service Area . 53
12 Identification of PLMN, RNC, Service Area, CN domain and Shared Network Area . 54
12.1 PLMN Identifier . 54
12.2 CN Domain Identifier . 54
12.3 CN Identifier . 54
12.4 RNC Identifier . 55
12.5 Service Area Identifier . 55
12.6 Shared Network Area Identifier . 55
12.7 Stand-Alone Non-Public Network Identifier . 55
12.7.1 Network Identifier (NID) . 55
12.7.2 NID of assignment mode 0 . 56
12.7.3 Group ID for Network Selection (GIN) . 56
13 Numbering, addressing and identification within the IP multimedia core network subsystem . 57
13.1 Introduction . 57
13.2 Home network domain name. 57
13.3 Private User Identity . 58
13.4 Public User Identity . 58
13.4A Wildcarded Public User Identity . 59
13.4B Temporary Public User Identity . 59
13.5 Public Service Identity (PSI) . 60
13.5A Private Service Identity . 60
13.6 Anonymous User Identity . 61
13.7 Unavailable User Identity . 61
13.8 Instance-ID . 61
13.9 XCAP Root URI . 61
13.9.1 XCAP Root URI on Ut interface . 61
13.9.1.1 General . 61
13.9.1.2 Format of XCAP Root URI . 61
13.10 Default Conference Factory URI for MMTel . 62
13.11 Unknown User Identity . 62
13.12 Default WWSF URI . 63
13.12.1 General . 63
13.12.2 Format of the Default WWSF URI . 63
13.13 IMEI based identity . 63
14 Numbering, addressing and identification for 3GPP System to WLAN Interworking . 64
14.1 Introduction . 64
14.2 Home network realm . 64
14.3 Root NAI . 65
14.4 Decorated NAI . 65
14.4A Fast Re-authentication NAI . 65
14.5 Temporary identities. 66
14.6 Alternative NAI . 66
14.7 W-APN . 66
14.7.1 Format of W-APN Network Identifier . 67
14.7.2 Format of W-APN Operator Identifier. 67
14.7.3 Alternative Format of W-APN Operator Identifier . 68
14.8 Emergency Realm and Emergency NAI for Emergency Cases . 68
15 Identification of Multimedia Broadcast/Multicast Service . 69
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15.1 Introduction . 69
15.2 Structure of TMGI . 69
15.3 Structure of MBMS SAI . 70
15.4 Home Network Realm . 70
15.5 Addressing and identification for Bootstrapping MBMS Service Announcement . 71
16 Numbering, addressing and identification within the GAA subsystem . 71
16.1 Introduction . 71
16.2 BSF address . 71
17 Numbering, addressing and identification within the Generic Access Network . 72
17.1 Introduction . 72
17.2 Network Access Identifiers . 72
17.2.1 Home network realm . 72
17.2.2 Full Authentication NAI . 73
17.2.3 Fast Re-authentication NAI . 73
17.3 Node Identifiers . 74
17.3.1 Home network domain name . 74
17.3.2 Provisioning GANC-SEGW identifier. 74
17.3.3 Provisioning GANC identifier . 75
18 Addressing and Identification for IMS Service Continuity and Single-Radio Voice Call
Continuity . 75
18.1 Introduction . 75
18.2 CS Domain Routeing Number (CSRN). 75
18.3 IP Multimedia Routeing Number (IMRN) . 76
18.4 Session Transfer Number (STN) . 76
18.5 Session Transfer Identifier (STI) . 76
18.6 Session Transfer Number for Single Radio Voice Call Continuity (STN-SR). 76
18.7 Correlation MSISDN . 76
18.8 Transfer Identifier for CS to PS Single Radio Voice Call Continuity (STI-rSR) . 76
18.9 Additional MSISDN . 76
19 Numbering, addressing and identification for the Evolved Packet Core (EPC). 77
19.1 Introduction . 77
19.2 Home Network Realm/Domain . 77
19.3 3GPP access to non-3GPP access interworking . 77
19.3.1 Introduction. 77
19.3.2 Root NAI . 78
19.3.3 Decorated NAI . 78
19.3.4 Fast Re-authentication NAI . 80
19.3.5 Pseudonym Identities . 80
19.3.6 Emergency NAI for Limited Service State . 81
19.3.7 Alternative NAI . 81
19.3.8 Keyname NAI . 81
19.3.9 IMSI-based Emergency NAI . 82
19.3.10 High Priority Access NAI . 82
19.4 Identifiers for Domain Name System procedures . 82
19.4.1 Introduction. 82
19.4.2 Fully Qualified Domain Names (FQDNs) . 83
19.4.2.1 General . 83
19.4.2.2 Access Point Name FQDN (APN-FQDN) . 83
19.4.2.2.1 Structure . 83
19.4.2.2.2 Void . 84
19.4.2.2.3 Void . 84
19.4.2.2.4 Void . 84
19.4.2.3 Tracking Area Identity (TAI) . 84
19.4.2.4 Mobility Management Entity (MME) . 84
19.4.2.5 Routing Area Identity (RAI) - EPC . 85
19.4.2.6 Serving GPRS Support Node (SGSN) within SGSN pool . 85
19.4.2.7 Target RNC-ID for U-TRAN . 85
19.4.2.8 DNS subdomain for operator usage in EPC . 86
19.4.2.9 ePDG FQDN and Visited Country FQDN for non-emergency bearer services . 86
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19.4.2.9.1 General . 86
19.4.2.9.2 Operator Identifier based ePDG FQDN . 86
19.4.2.9.3 Tracking/Location Area Identity based ePDG FQDN . 87
19.4.2.9.4 Visited Country FQDN . 88
19.4.2.9.5 Replacement field used in DNS-based Discovery of regulatory requirements . 88
19.4.2.9A ePDG FQDN for emergency bearer services . 89
19.4.2.9A.1 General . 89
19.4.2.9A.2 Operator Identifier based Emergency ePDG FQDN . 89
19.4.2.9A.3 Tracking/Location Area Identity based Emergency ePDG FQDN . 89
19.4.2.9A.4 Visited Country Emergency FQDN. 90
19.4.2.9A.5 Replacement field used in DNS-based Discovery of regulatory requirements for emergency
services . 90
19.4.2.9A.6 Country based Emergency Numbers FQDN . 90
19.4.2.9A.7 Replacement field used in DNS-based Discovery of Emergency Numbers . 91
19.4.2.10 Global eNodeB-ID for eNodeB. 91
19.4.2.11 Local Home Network identifier . 91
19.4.2.12 UCMF .
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