ETSI TS 124 501 V15.5.0 (2019-10)

ETSI TS 124 501 V15.5.0 (2019-10)






TECHNICAL SPECIFICATION
5G;
Non-Access-Stratum (NAS) protocol for 5G System (5GS)
Stage 3
(3GPP TS 24.501 version 15.5.0 Release 15)

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1 ETSI TS 124 501 V15.5.0 (2019-10)



Reference
RTS/TSGC-0124501vf50
Keywords
5G
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2 ETSI TS 124 501 V15.5.0 (2019-10)
Intellectual Property Rights
Essential patents
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pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
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Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
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Modal verbs terminology
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"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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3 ETSI TS 124 501 V15.5.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 18
1 Scope . 19
2 References . 19
3 Definitions and abbreviations . 21
3.1 Definitions . 21
3.2 Abbreviations . 25
4 General . 27
4.1 Overview . 27
4.2 Coordination between the protocols for 5GS mobility management and 5GS session management . 27
4.3 UE domain selection . 28
4.3.1 UE's usage setting . 28
4.3.2 Domain selection for UE originating sessions / calls . 28
4.3.3 Change of UE's usage setting . 30
4.3.4 Change or determination of IMS voice availability . 30
4.4 NAS security . 31
4.4.1 General . 31
4.4.2 Handling of 5G NAS security contexts. 31
4.4.2.1 General . 31
4.4.2.2 Establishment of a mapped 5G NAS security context during inter-system change from S1 mode
to N1 mode in 5GMM-CONNECTED mode . 33
4.4.2.3 Establishment of a 5G NAS security context during N1 mode to N1 mode handover . 34
4.4.2.4 Establishment of an EPS security context during inter-system change from N1 mode to S1 mode
in 5GMM-CONNECTED mode . 35
4.4.2.5 Establishment of secure exchange of NAS messages . 35
4.4.2.6 Change of security keys . 37
4.4.3 Handling of NAS COUNT and NAS sequence number . 37
4.4.3.1 General . 37
4.4.3.2 Replay protection . 38
4.4.3.3 Integrity protection and verification . 38
4.4.3.4 Ciphering and deciphering . 38
4.4.3.5 NAS COUNT wrap around . 39
4.4.4 Integrity protection of NAS signalling messages. 39
4.4.4.1 General . 39
4.4.4.2 Integrity checking of NAS signalling messages in the UE . 40
4.4.4.3 Integrity checking of NAS signalling messages in the AMF . 40
4.4.5 Ciphering of NAS signalling messages . 42
4.4.6 Protection of initial NAS signalling messages . 42
4.5 Unified access control . 44
4.5.1 General . 44
4.5.2 Determination of the access identities and access category associated with a request for access . 45
4.5.3 Operator-defined access categories . 49
4.5.4 Access control and checking . 50
4.5.4.1 Access control and checking in 5GMM-IDLE mode . 50
4.5.4.2 Access control and checking in 5GMM-CONNECTED mode and in 5GMM-CONNECTED
mode with RRC inactive indication . 51
4.5.5 Exception handling and avoiding double barring . 53
4.5.6 Mapping between access categories/access identities and RRC establishment cause . 56
4.6 Network slicing . 57
4.6.1 General . 57
4.6.2 Mobility management aspects. 58
4.6.2.1 General . 58
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4 ETSI TS 124 501 V15.5.0 (2019-10)
4.6.2.2 NSSAI storage . 58
4.6.2.3 Provision of NSSAI to lower layers in 5GMM-IDLE mode . 59
4.6.3 Session management aspects . 61
4.7 NAS over non-3GPP access . 61
4.7.1 General . 61
4.7.2 5GS mobility management aspects . 61
4.7.2.1 General . 61
4.7.2.2 Establishment cause for non-3GPP access . 62
4.7.3 5GS session management aspects . 62
4.7.4 Limited service state over non-3GPP access . 62
4.8 Interworking with E-UTRAN connected to EPC . 63
4.8.1 General . 63
4.8.2 Single-registration mode . 63
4.8.2.1 General . 63
4.8.2.2 Single-registration mode with N26 interface . 63
4.8.2.3 Single-registration mode without N26 interface . 63
4.8.2.3.1 Interworking between NG-RAN and E-UTRAN . 63
4.8.2.3.2 Interworking between N3IWF connected to 5GCN and E-UTRAN . 64
4.8.3 Dual-registration mode . 65
4.8.4 Core Network selection . 66
4.9 Disabling and re-enabling of UE's N1 mode capability . 66
4.9.1 General . 66
4.9.2 Disabling and re-enabling of UE's N1 mode capability for 3GPP access . 67
4.9.3 Disabling and re-enabling of UE's N1 mode capability for non-3GPP access. 67
4.10 Interworking with ePDG connected to EPC . 68
4.11 UE configuration parameter updates . 68
5 Elementary procedures for 5GS mobility management . 68
5.1 Overview . 68
5.1.1 General . 68
5.1.2 Types of 5GMM procedures . 68
5.1.3 5GMM sublayer states . 70
5.1.3.1 General . 70
5.1.3.2 5GMM sublayer states . 70
5.1.3.2.1 5GMM sublayer states in the UE. 70
5.1.3.2.1.1 General . 70
5.1.3.2.1.2 Main states . 70
5.1.3.2.1.2.1 5GMM-NULL . 70
5.1.3.2.1.2.2 5GMM-DEREGISTERED . 70
5.1.3.2.1.2.3 5GMM-REGISTERED-INITIATED . 71
5.1.3.2.1.2.4 5GMM-REGISTERED . 71
5.1.3.2.1.2.5 5GMM-DEREGISTERED-INITIATED . 71
5.1.3.2.1.2.6 5GMM-SERVICE-REQUEST-INITIATED. 71
5.1.3.2.1.3 Substates of state 5GMM-DEREGISTERED . 71
5.1.3.2.1.3.1 General . 71
5.1.3.2.1.3.2 5GMM-DEREGISTERED.NORMAL-SERVICE . 71
5.1.3.2.1.3.3 5GMM-DEREGISTERED.LIMITED-SERVICE . 71
5.1.3.2.1.3.4 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION . 71
5.1.3.2.1.3.5 5GMM-DEREGISTERED.PLMN-SEARCH . 71
5.1.3.2.1.3.6 5GMM-DEREGISTERED.NO-SUPI . 72
5.1.3.2.1.3.7 5GMM-DEREGISTERED.NO-CELL-AVAILABLE . 72
5.1.3.2.1.3.8 5GMM-DEREGISTERED.eCALL-INACTIVE . 72
5.1.3.2.1.3.9 5GMM-DEREGISTERED.INITIAL-REGISTRATION-NEEDED . 72
5.1.3.2.1.4 Substates of state 5GMM-REGISTERED . 72
5.1.3.2.1.4.1 General . 72
5.1.3.2.1.4.2 5GMM-REGISTERED.NORMAL-SERVICE . 72
5.1.3.2.1.4.3 5GMM-REGISTERED.NON-ALLOWED-SERVICE . 72
5.1.3.2.1.4.4 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE . 73
5.1.3.2.1.4.5 5GMM-REGISTERED.LIMITED-SERVICE . 73
5.1.3.2.1.4.6 5GMM-REGISTERED.PLMN-SEARCH . 73
5.1.3.2.1.4.7 5GMM-REGISTERED.NO-CELL-AVAILABLE . 73
5.1.3.2.1.4.8 5GMM-REGISTERED.UPDATE-NEEDED . 73
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5 ETSI TS 124 501 V15.5.0 (2019-10)
5.1.3.2.2 5GS update status in the UE . 73
5.1.3.2.3 5GMM sublayer states in the network side . 74
5.1.3.2.3.1 General . 74
5.1.3.2.3.2 5GMM-DEREGISTERED . 74
5.1.3.2.3.3 5GMM-COMMON-PROCEDURE-INITIATED . 74
5.1.3.2.3.4 5GMM-REGISTERED . 74
5.1.3.2.3.5 5GMM-DEREGISTERED-INITIATED . 74
5.1.4 Coordination between 5GMM and EMM . 75
5.1.4.1 General . 75
5.1.4.2 Coordination between 5GMM and EMM with N26 interface . 75
5.1.4.3 Coordination between 5GMM and EMM without N26 interface . 75
5.2 Behaviour of the UE in state 5GMM-DEREGISTERED and state 5GMM-REGISTERED . 76
5.2.1 General . 76
5.2.2 UE behaviour in state 5GMM-DEREGISTERED . 76
5.2.2.1 General . 76
5.2.2.2 Primary substate selection . 76
5.2.2.2.1 Selection of the substate after power on . 76
5.2.2.3 Detailed description of UE behaviour in state 5GMM-DEREGISTERED . 76
5.2.2.3.1 NORMAL-SERVICE . 76
5.2.2.3.2 LIMITED-SERVICE . 77
5.2.2.3.3 ATTEMPTING-REGISTRATION . 77
5.2.2.3.4 PLMN-SEARCH . 77
5.2.2.3.5 NO-SUPI . 77
5.2.2.3.6 NO-CELL-AVAILABLE . 77
5.2.2.3.7 eCALL-INACTIVE . 77
5.2.2.4 Substate when back to state 5GMM-DEREGISTERED from another 5GMM state . 78
5.2.3 UE behaviour in state 5GMM-REGISTERED . 78
5.2.3.1 General . 78
5.2.3.2 Detailed description of UE behaviour in state 5GMM-REGISTERED . 78
5.2.3.2.1 NORMAL-SERVICE . 78
5.2.3.2.2 NON-ALLOWED-SERVICE . 79
5.2.3.2.3 ATTEMPTING-REGISTRATION-UPDATE . 79
5.2.3.2.4 LIMITED-SERVICE . 80
5.2.3.2.5 PLMN-SEARCH . 80
5.2.3.2.6 NO-CELL-AVAILABLE . 80
5.3 General on elementary 5GMM procedures . 80
5.3.1 5GMM modes and N1 NAS signalling connection . 80
5.3.1.1 Establishment of the N1 NAS signalling connection . 80
5.3.1.2 Re-establishment of the N1 NAS signalling connection . 81
5.3.1.3 Release of the N1 NAS signalling connection . 82
5.3.1.4 5GMM-CONNECTED mode with RRC inactive indication . 85
5.3.2 Permanent identifiers . 87
5.3.3 Temporary identities . 87
5.3.4 Registration areas . 88
5.3.5 Service area restrictions . 89
5.3.6 Mobile initiated connection only mode . 90
5.3.7 Handling of the periodic registration update timer and mobile reachable timer . 91
5.3.8 Handling of timer T3502 . 93
5.3.9 Handling of NAS level mobility management congestion control . 93
5.3.10 Handling of DNN based congestion control . 94
5.3.11 Handling of S-NSSAI based congestion control . 94
5.3.12 Handling of local emergency numbers . 94
5.3.12A Handling of local emergency numbers received via 3GPP access and non-3GPP access . 95
5.3.12A.1 General . 95
5.3.12A.2 Receiving a REGISTRATION ACCEPT message via non-3GPP access . 96
5.3.13 Lists of 5GS forbidden tracking areas. 96
5.3.14 List of equivalent PLMNs . 97
5.3.15 Transmission failure abnormal case in the UE .
...