ETSI TS 123 122 V17.9.0 (2023-01)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; 5G; Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode (3GPP TS 23.122 version 17.9.0 Release 17)

RTS/TSGC-0123122vh90

General Information

• Status: Not Published
• Technical Committee: 3GPP CT 1 - MM/CC/SM [lu] (formely CN1)
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 10-Jan-2023

Standards Content (Sample)

ETSI TS 123 122 V17.9.0 (2023-01)






TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
Non-Access-Stratum (NAS) functions related
to Mobile Station (MS) in idle mode
(3GPP TS 23.122 version 17.9.0 Release 17)

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3GPP TS 23.122 version 17.9.0 Release 17 1 ETSI TS 123 122 V17.9.0 (2023-01)

Reference
RTS/TSGC-0123122vh90
Keywords
5G,GSM,LTE,UMTS
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© ETSI 2023.
All rights reserved.

ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 2 ETSI TS 123 122 V17.9.0 (2023-01)
Intellectual Property Rights
Essential patents
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pertaining to these essential IPRs, if any, are publicly available for ETSI members and non-members, and can be
found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to
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Trademarks
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ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP
Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the
®
oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.
Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
interpreted as being references to the corresponding ETSI deliverables.
The cross reference between 3GPP and ETSI identities can be found under http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 3 ETSI TS 123 122 V17.9.0 (2023-01)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 7
1.1 References . 7
1.2 Definitions and abbreviations . 10
2 General description of idle mode . 16
3 Requirements and technical solutions . 17
3.0 General . 17
3.1 PLMN selection and roaming . 17
3.1A CSG selection / restriction . 22
3.1B PLMN selection triggered by ProSe communications . 22
3.1C PLMN selection triggered by V2X communication over PC5 . 25
3.2 Regional provision of service . 27
3.3 Borders between registration areas . 28
3.4 Access control . 28
3.4.1 Access control . 28
3.4.2 Forbidden LA or TA for regional provision of service . 29
3.5 No suitable cell (limited service state) . 29
3.6 CTS fixed part selection (A/Gb mode only) . 31
3.7 NAS behaviour configuration. 31
3.8 CAG selection (N1 mode only) . 31
3.9 SNPN selection . 32
3.10 Minimization of service interruption . 32
4 Overall process structure . 35
4.1 Process goal . 35
4.2 States description . 35
4.3 List of states . 35
4.3.1 List of states for the PLMN selection process . 35
4.3.1.1 List of states for automatic mode (figure 2a) . 35
4.3.1.2 List of states for manual mode (figure 2b) . 36
4.3.2 Void . 36
4.3.3 List of states for location registration (figure 3) . 36
4.4 PLMN selection process . 37
4.4.1 Introduction. 37
4.4.2 Registration on a PLMN . 37
4.4.3 PLMN selection . 38
4.4.3.1 At switch-on or recovery from lack of coverage . 39
4.4.3.1.1 Automatic Network Selection Mode Procedure . 40
4.4.3.1.2 Manual Network Selection Mode Procedure . 44
4.4.3.1.3 Manual CSG selection . 47
4.4.3.2 User reselection . 49
4.4.3.2.1 Automatic Network Selection Mode . 49
4.4.3.2.2 Manual Network Selection Mode . 49
4.4.3.2.3 Manual CSG selection . 49
4.4.3.3 In VPLMN . 50
4.4.3.3.1 Automatic and manual network selection modes . 50
4.4.3.3.2 Manual CSG selection . 53
4.4.3.4 Investigation Scan for higher prioritized PLMN . 53
4.4.4 Abnormal cases . 54
4.4.5 Roaming not allowed in this LA or TA . 54
4.4.6 Steering of roaming . 54
4.5 Location registration process . 54
ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 4 ETSI TS 123 122 V17.9.0 (2023-01)
4.5.1 General . 54
4.5.2 Initiation of Location Registration . 55
4.5.3 Periodic Location Registration . 57
4.5.4 IMSI attach/detach operation . 57
4.5.5 No Suitable Cells In Location Area . 58
4.6 Service indication (A/Gb mode only) . 58
4.7 Pageability of the mobile subscriber . 58
4.8 MM Restart Procedure . 59
4.9 SNPN selection process . 59
4.9.1 General . 59
4.9.2 Registration on an SNPN . 59
4.9.3 SNPN selection . 59
4.9.3.0 General . 59
4.9.3.1 At switch-on or recovery from lack of coverage . 64
4.9.3.1.0 General . 64
4.9.3.1.1 Automatic SNPN selection mode procedure . 65
4.9.3.1.2 Manual SNPN selection mode procedure . 66
4.9.3.1.3 Automatic SNPN selection mode procedure for onboarding services in SNPN. 67
4.9.3.1.4 Manual SNPN selection mode procedure for onboarding services in SNPN . 68
4.9.3.2 User reselection . 68
4.9.3.2.0 General . 68
4.9.3.2.1 Automatic SNPN selection mode . 68
4.9.3.2.2 Manual SNPN selection mode procedure . 69
4.9.4 Abnormal cases . 69
5 Tables and Figures . 71
6 MS supporting access technologies defined both by 3GPP and 3GPP2 . 77
6.1 General . 77
Annex A (normative): HPLMN Matching Criteria . 79
Annex B (normative): PLMN matching criteria to be of same country as VPLMN . 83
Annex C (normative): Control plane solution for steering of roaming in 5GS . 84
C.0 Requirements for 5G steering of roaming over the control plane . 84
C.1 General . 84
C.1.1 Steering of roaming over the control plane in a PLMN . 84
C.1.2 Steering of roaming over the control plane in an SNPN . 86
C.2 Stage-2 flow for steering of UE in VPLMN during registration . 88
C.3 Stage-2 flow for steering of UE in HPLMN or VPLMN after registration . 96
C.4 Enhanced 5G control plane steering of roaming for the UE in connected mode . 100
C.4.1 General . 100
C.4.2 Applying SOR-CMCI in the UE . 102
C.4.3 Stage-2 flow for providing UE with SOR-CMCI in HPLMN, VPLMN, subscribed SNPN or non-
subscribed SNPN after registration . 105
C.5 Stage-2 flow for steering of UE in SNPN during registration . 108
C.6 Stage-2 flow for steering of UE in SNPN after registration . 114
C.7 Stage-2 flow for providing UE with SOR-SNPN-SI in HPLMN or VPLMN after registration . 117
C.8 Stage-2 flow for providing UE with list of preferred PLMN/access technology combinations in
SNPN after registration . 120
Annex D (informative): Change history . 123
History . 139

ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 5 ETSI TS 123 122 V17.9.0 (2023-01)
Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
In the present document, modal verbs have the following meanings:
shall indicates a mandatory requirement to do something
shall not indicates an interdiction (prohibition) to do something
The constructions "shall" and "shall not" are confined to the context of normative provisions, and do not appear in
Technical Reports.
The constructions "must" and "must not" are not used as substitutes for "shall" and "shall not". Their use is avoided
insofar as possible, and they are not used in a normative context except in a direct citation from an external, referenced,
non-3GPP document, or so as to maintain continuity of style when extending or modifying the provisions of such a
referenced document.
should indicates a recommendation to do something
should not indicates a recommendation not to do something
may indicates permission to do something
need not indicates permission not to do something
The construction "may not" is ambiguous and is not used in normative elements. The unambiguous constructions
"might not" or "shall not" are used instead, depending upon the meaning intended.
can indicates that something is possible
cannot indicates that something is impossible
The constructions "can" and "cannot" are not substitutes for "may" and "need not".
will indicates that something is certain or expected to happen as a result of action taken by an agency
the behaviour of which is outside the scope of the present document
will not indicates that something is certain or expected not to happen as a result of action taken by an
agency the behaviour of which is outside the scope of the present document
might indicates a likelihood that something will happen as a result of action taken by some agency the
behaviour of which is outside the scope of the present document
ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 6 ETSI TS 123 122 V17.9.0 (2023-01)
might not indicates a likelihood that something will not happen as a result of action taken by some agency
the behaviour of which is outside the scope of the present document
In addition:
is (or any other verb in the indicative mood) indicates a statement of fact
is not (or any other negative verb in the indicative mood) indicates a statement of fact
The constructions "is" and "is not" do not indicate requirements.

ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 7 ETSI TS 123 122 V17.9.0 (2023-01)
1 Scope
The present document gives an overview of the tasks undertaken by the Core network protocols of a Mobile Station
(MS) when in idle mode, that is, switched on but typically not having a dedicated channel allocated. It also describes the
corresponding network functions. The idle mode functions are also performed by a GPRS MS as long as no dedicated
channel is allocated to the MS. The conditions when the idle mode functions are performed by an MS in the UTRA
RRC connected mode states are specified in 3GPP TS 25.331 [33]. The conditions when the idle mode functions are
performed by an MS in the E-UTRAN are specified in 3GPP TS 36.304 [43]. The conditions when the idle mode
functions are performed by an MS in the NG-RAN are specified in 3GPP TS 36.304 [43] and 3GPP TS 38.304 [61].
The conditions when the idle mode functions are performed by an MS in the NG-RAN RRC inactive state are specified
in 3GPP TS 36.331 [42] and 3GPP TS 38.331 [65].
The present document defines the PLMN selection for a multi mode MS that supports both 3GPP and 3GPP2 systems.
The common PLMN selection logic covers also PLMNs that are available in 3GPP2 system, but the present document
®
makes no changes on the cdma2000 signalling towards networks that are available via 3GPP2 system.
The present document gives procedures for using the CSG cells, whenever such use is permitted.
The present document gives procedures for using the CAG cells, when the MS supports CAG.
The present document specifies the SNPN selection.
This 3GPP TS outlines how the requirements of the 22 series Technical Specifications (especially 3GPP TS 22.011 [9])
on idle mode operation shall be implemented. Further details are given in 3GPP TS 24.008 [23].
Clause 2 of this 3GPP TS gives a general description of the idle mode process. Clause 3 outlines the main requirements
and technical solutions of those requirements. Clause 4 describes the processes used in idle mode. There is inevitably
some overlap between these clauses.
®
NOTE: cdma2000 is a registered trademark of the Telecommunications Industry Association (TIA-USA).
The present document describes the procedures for control plane solution of steering of roaming in 5GS in annex C.
Annex C is applicable to the MS, the AMF, the UDM and the SOR-AF in the 5GS.
The present document does not consider GERAN Iu mode.
1.1 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] Void.
[2] Void.
[3] Void.
[4] Void.
[5] Void.
[6] Void.
[7] Void
ETSI

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3GPP TS 23.122 version 17.9.0 Release 17 8 ETSI TS 123 122 V17.9.0 (2023-01)
[8] Void.
[9] 3GPP TS 22.011: "Service accessibility".
[10] Void.
[11] Void.
[12] Void.
[13] Void.
[14] Void.
[15] Void.
[16] Void.
[17] Void.
[18] Void.
[19] Void.
[20] Void.
[21] Void.
[22] Void.
[22A] 3GPP TS 23.003: "Numbering, addressing and identification".
[23] 3GPP TS 24.008: "Mobile Radio Interface Layer 3 specification, Core Network Protocols -
Stage 3".
[23A] 3GPP TS 24.301: "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS);
Stage 3".
[24] 3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
[25] 3GPP TS 45.008: "Radio subsystem link control".
[26] Void.
[27] 3GPP TS 23.060: "General Packet Radio Service (GPRS); Service description; Stage 2".
[27A] 3GPP TS 23.682: "Architecture enhancements to facilitate communications with packet data
networks and applications".
[28] Void.
[29] Void.
[30] Void.
[31] Void.
[32] 3GPP TS 25.304: "UE Procedures in Idle Mode and Procedures for Cell Reselection in Connected
Mode".
[33] 3GPP TS 25.331: "RRC Protocol Specif
...