ETSI TS 124 502 V15.4.0 (2019-07)

ETSI TS 124 502 V15.4.0 (2019-07)






TECHNICAL SPECIFICATION
5G;
Access to the 3GPP 5G Core Network (5GCN) via non-3GPP
access networks
(3GPP TS 24.502 version 15.4.0 Release 15)

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3GPP TS 24.502 version 15.4.0 Release 15 1 ETSI TS 124 502 V15.4.0 (2019-07)



Reference
RTS/TSGC-0124502vf40
Keywords
5G

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3GPP TS 24.502 version 15.4.0 Release 15 2 ETSI TS 124 502 V15.4.0 (2019-07)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is 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 ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
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Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
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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 24.502 version 15.4.0 Release 15 3 ETSI TS 124 502 V15.4.0 (2019-07)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 7
1 Scope . 8
2 References . 8
3 Definitions, symbols and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 General . 10
4.1 Overview . 10
4.2 Untrusted access . 10
4.3 Identities . 11
4.3.1 User identities . 11
4.3.2 FQDN for N3IWF Selection . 11
4.4 Quality of service support . 11
4.4.1 General . 11
4.4.2 QoS differentiation in untrusted non-3GPP access . 11
4.4.2.1 General . 11
4.4.2.2 QoS signalling . 11
4.4.2.3 QoS differentiation in user plane . 12
4.4.2.4 Reflective QoS . 12
4.4.2.5 QoS enforcement . 12
5 Network discovery and selection . 12
5.1 General . 12
5.2 Access network discovery procedure . 12
5.2.1 General . 12
5.2.2 Discovering availability of WLAN access networks . 12
5.3 Access network selection procedure. 13
5.3.1 General . 13
5.3.2 WLAN selection procedure . 13
5.3.2.1 General . 13
5.3.2.2 Manual mode WLAN selection. 13
5.3.2.3 Automatic mode WLAN selection . 13
5.4 Access network reselection procedure . 14
5.4.1 General . 14
5.4.2 WLAN reselection procedure . 14
6 UE - 5GC network protocols . 15
6.1 General . 15
6.2 Untrusted Accesses. 15
6.3 Authentication and authorization for accessing 5GS via an untrusted non-3GPP access network . 15
6.3.1 General . 15
6.4 Handling of ANDSP Information . 15
6.4.1 General . 15
6.4.2 UE procedures . 16
6.4.2.1 General . 16
6.4.2.2 Use of WLAN selection information . 16
6.4.2.3 Use of N3AN node configuration information . 16
6.4.3 ANDSP information from the network . 16
7 Security association management procedures . 16
7.1 General . 16
7.2 N3AN node selection procedure . 17
ETSI

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3GPP TS 24.502 version 15.4.0 Release 15 4 ETSI TS 124 502 V15.4.0 (2019-07)
7.2.1 General . 17
7.2.2 N3AN node configuration information . 17
7.2.3 Determination of the country the UE is located in . 17
7.2.4 N3AN node selection . 17
7.2.4.1 General . 17
7.2.4.2 Determine if the visited country mandates the selection of N3IWF in this country. 18
7.2.4.3 UE procedure when the UE only supports connectivity with N3IWF . 18
7.2.4.4 UE procedure when the UE supports connectivity with N3IWF and ePDG . 20
7.2.4.4.1 General . 20
7.2.4.4.2 N3AN node selection for IMS service . 20
7.2.4.4.3 N3AN node selection for Non-IMS service . 23
7.3 IKE SA establishment procedure . 26
7.3.1 General . 26
7.3.2 IKE SA and signalling IPsec SA establishment procedure . 26
7.3.2.1 IKE SA and signalling IPsec SA establishment initiation . 26
7.3.2.2 IKE SA and signalling IPsec SA establishment accepted by the network . 26
7.3.2.3 IKE SA and signalling IPsec SA establishment not accepted by the network . 28
7.3.3 EAP-5G session over non-3GPP access . 29
7.3.3.1 General . 29
7.3.3.2 EAP-5G session completion initiated by the network . 30
7.3.3.3 EAP-5G session completion initiated by the UE . 30
7.3.4 Abnormal cases in the UE . 31
7.3.5 Abnormal cases in the N3IWF . 31
7.4 IKEv2 SA deletion procedure . 31
7.4.1 General . 31
7.4.2 IKE SA deletion procedure initiated by the N3IWF . 32
7.4.2.1 IKE SA deletion initiation . 32
7.4.2.2 IKE SA deletion accepted by the UE . 32
7.4.2.3 Abnormal cases in the N3IWF . 32
7.4.3 IKE SA deletion procedure initiated by the UE . 32
7.4.3.1 IKE SA deletion initiation . 32
7.4.3.2 IKE SA deletion accepted by the N3IWF . 32
7.4.3.3 Abnormal cases in the UE . 33
7.5 User plane IPsec SA creation procedure . 33
7.5.1 General . 33
7.5.2 Child SA creation procedure initiation . 33
7.5.3 Child SA creation procedure accepted by the UE . 33
7.5.4 Child SA creation procedure not accepted by the UE . 33
7.5.5 Abnormal cases in the UE . 34
7.5.6 Abnormal cases in the N3IWF . 34
7.6 IPsec SA modification procedure . 34
7.6.1 General . 34
7.6.2 N3IWF procedure for IPsec child SA modification . 34
7.6.3 UE procedure for IPsec child SA modification. 34
7.7 IPSec SA deletion procedure . 35
7.7.1 General . 35
7.7.2 N3IWF-initated child SA deletion procedure . 35
7.7.2.1 N3IWF-initiated child SA deletion procedure initiation . 35
7.7.2.2 N3IWF-initiated child SA deletion procedure accepted by the UE . 35
7.7.2.3 Abnormal cases in the N3IWF . 35
7.7.3 UE-initiated child SA deletion procedure . 35
7.7.3.1 UE-initiated child SA deletion procedure initiation . 35
7.7.3.2 UE-initiated child SA deletion procedure accepted by the N3IWF . 36
7.7.3.3 Abnormal cases in the UE . 36
7.7.4 Abnormal cases in the UE . 36
7.7.5 Abnormal cases in the N3IWF . 36
7.8 UE-initiated liveness check procedure . 36
7.8.1 General . 36
7.8.2 UE-initiated liveness check procedure initiation . 36
7.8.3 UE-initiated liveness check procedure completion . 36
7.8.4 Abnormal cases . 37
7.9 Network-initiated liveness check procedure . 37
ETSI

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3GPP TS 24.502 version 15.4.0 Release 15 5 ETSI TS 124 502 V15.4.0 (2019-07)
7.9.1 General . 37
7.9.2 Network-initiated liveness check procedure initiation . 37
7.9.3 Network-initiated liveness check procedure completion . 37
7.9.4 Abnormal cases . 37
7.10 IKE SA rekeying procedure . 37
7.10.1 General . 37
7.10.2 N3IWF-initiated IKE SA rekeying procedure . 37
7.10.2.1 N3IWF-initiated IKE SA rekeying procedure initiation . 37
7.10.2.2 N3IWF-initiated IKE SA rekeying procedure completion . 38
7.10.2.3 Abnormal cases . 38
7.10.3 UE-initiated IKE SA rekeying procedure . 38
7.10.3.1 UE-initiated IKE SA rekeying procedure initiation . 38
7.10.3.2 UE-initiated IKE SA rekeying procedure completion . 38
7.10.3.3 Abnormal cases . 38
7.11 IPsec SA rekeying procedure . 38
7.11.1 General . 38
7.11.2 N3IWF-initiated IPsec SA rekeying procedure . 39
7.11.2.1 N3IWF-initiated IPsec SA rekeying procedure initiation . 39
7.11.2.2 N3IWF-initiated IPsec SA rekeying procedure completion . 39
7.11.2.3 Abnormal cases . 39
7.11.3 UE-initiated IPsec SA rekeying procedure . 39
7.11.3.1 UE-initiated IPsec SA rekeying procedure initiation . 39
7.11.3.2 UE-initiated IPsec SA rekeying procedure completion . 39
7.11.3.3 Abnormal cases . 39
8 Message transport procedures . 39
8.1 General . 39
8.2 Transport of NAS messages over control plane . 40
8.2.1 General . 40
8.2.2 TCP packet encapsulation . 40
8.2.3 Establishment of TCP connection for transport of NAS messages . 42
8.2.4 Transport of NAS messages over TCP connection . 42
8.2.5 Release of TCP connection for transport of NAS messages . 42
8.3 Transport of messages over user plane . 42
8.3.1 General . 42
8.3.2 Generic routing encapsulation (GRE) . 43
9 Parameters and coding. 44
9.1 General . 44
9.2 3GPP specific coding information . 44
9.2.1 GUAMI . 44
9.2.2 Establishment cause for non-3GPP access . 45
9.2.3 PLMN ID . 45
9.2.4 IKEv2 Notify Message Type value . 46
9.2.4.1 General . 46
9.2.4.2 Private Notify Message - Error Types . 46
9.2.4.3 Private Notify Message - Status Types . 47
9.3 IETF RFC coding information . 48
9.3.1 IKEv2 Notify payloads .
...