The UE shall re-enable the N1 mode capability when the UE powers off and powers on again, the USIM is removed or an entry of the "list of subscriber data" with the SNPN identity of the SNPN is updated.
The UE shall only disable the N1 mode capability for 3GPP access when in 5GMM-IDLE mode.
When the UE is disabling the N1 mode capability for 3GPP access for a PLMN not due to redirection to EPC, it should proceed as follows:
select an E-UTRA cell, which is not a restricted RAT as specified in clauses 4.2A, connected to EPC, or for the UE which supports CIoT EPS optimization select a satellite E-UTRA cell connected to EPC via "WB-E-UTRAN(LEO)", "WB-E-UTRAN(MEO)", or "WB-E-UTRAN(GEO)", of the registered PLMN or a PLMN from the list of equivalent PLMNs, if the UE supports S1 mode and the UE has not disabled its E-UTRA capability as specified in TS 24.301;
if an E-UTRA cell, connected to EPC, or for the UE which supports CIoT EPS optimization if a satellite E-UTRA cell connected to EPC via "WB-E-UTRAN(LEO)", "WB-E-UTRAN(MEO)", or "WB-E-UTRAN(GEO)", of the registered PLMN or a PLMN from the list of equivalent PLMNs cannot be found, the UE does not support S1 mode or the UE has disabled its E-UTRA capability as specified in TS 24.301, the UE may select another RAT, which is not a restricted RAT as specified in clauses 4.2A, of the registered PLMN or a PLMN from the list of equivalent PLMNs that the UE supports;
if another RAT of the registered PLMN or a PLMN from the list of equivalent PLMNs cannot be found, then enter the state 5GMM-REGISTERED.PLMN-SEARCH or 5GMM-DEREGISTERED.PLMN-SEARCH, or the UE does not have a registered PLMN, then enter the state 5GMM-DEREGISTERED.PLMN-SEARCH and perform PLMN selection as specified in TS 23.122. If disabling of the N1 mode capability for 3GPP access was not due to a UE-initiated de-registration procedure for 5GS services over 3GPP access not due to switch-off, the UE may re-enable the N1 capability for this PLMN selection. As an implementation option, if the UE does not have a registered PLMN, instead of performing PLMN selection, the UE may select another RAT of the selected PLMN if the UE has chosen a PLMN and the RAT is supported by the UE; or
if no other allowed PLMN and RAT combinations are available, then the UE may re-enable the N1 mode capability for 3GPP access and indicate to lower layers to remain camped in NG-RAN or satellite NG-RAN of the registered PLMN, and may periodically scan for another PLMN and RAT combination which can provide EPS services or non-EPS services (if the UE supports EPS services or non-EPS services). How this periodic scanning is done, is UE implementation dependent.
When the UE is disabling the N1 mode capability for 3GPP access for an SNPN, it should proceed as follows:
enter the state 5GMM-REGISTERED.PLMN-SEARCH or 5GMM-DEREGISTERED.PLMN-SEARCH and perform SNPN selection as specified in TS 23.122. If disabling of the N1 mode capability for 3GPP access was not due to a UE-initiated de-registration procedure for 5GS services over 3GPP access not due to switch-off, the UE may re-enable the N1 capability for this SNPN selection; or
if no other SNPN is available, then the UE may re-enable the N1 mode capability for 3GPP access and indicate to lower layers to remain camped in NG-RAN of the registered SNPN.
When the UE is disabling the N1 mode capability upon receiving cause value #31 "Redirection to EPC required" as specified in subclauses 5.5.1.2.5, 5.5.1.3.5 and 5.6.1.5, it should proceed as follows:
If the UE is in NB-N1 mode:
if lower layers do not provide an indication that the current E-UTRA cell is connected to EPC or lower layers do not provide an indication that the current E-UTRA cell supports CIoT EPS optimizations that are supported by the UE, search for a suitable NB-IoT cell connected to EPC according to TS 36.304;
if lower layers provide an indication that the current E-UTRA cell is connected to EPC and the current E-UTRA cell supports CIoT EPS optimizations that are supported by the UE, perform a core network selection to select EPC as specified in subclause 4.8.4A.1; or
if lower layers cannot find a suitable NB-IoT cell connected to EPC or there is no suitable NB-IoT cell connected to EPC which supports CIoT EPS optimizations that are supported by the UE, the UE, as an implementation option, may indicate to lower layers to remain camped in E-UTRA cell connected to 5GCN, may then start an implementation-specific timer and enter the state 5GMM-REGISTERED.LIMITED-SERVICE. The UE may re-enable the N1 mode capability for 3GPP access at expiry of the implementation-specific timer, if the timer had been started, and may then proceed with the appropriate 5GMM procedure.
If the UE is in WB-N1 mode:
if lower layers do not provide an indication that the current E-UTRA cell is connected to EPC or lower layers do not provide an indication that the current E-UTRA cell supports CIoT EPS optimizations that are supported by the UE, search for a suitable E-UTRA cell connected to EPC, or for the UE which supports CIoT EPS optimization select a satellite E-UTRA cell connected to EPC via "WB-E-UTRAN(LEO)", "WB-E-UTRAN(MEO)", or "WB-E-UTRAN(GEO)", according to TS 36.304;
if lower layers provide an indication that the current E-UTRA cell is connected to EPC and the current E-UTRA cell supports CIoT EPS optimizations that are supported by the UE, then perform a core network selection to select EPC as specified in subclause 4.8.4A.1; or
if lower layers cannot find a suitable E-UTRA cell connected to EPC, or if the lower layers cannot find a suitable satellite E-UTRA cell via "WB-E-UTRAN(LEO)", "WB-E-UTRAN(MEO)", or "WB-E-UTRAN(GEO)", or there is no suitable E-UTRA cell connected to EPC, or there is no suitable satellite E-UTRA cell connected to EPC via "WB-E-UTRAN(LEO)", "WB-E-UTRAN(MEO)", or "WB-E-UTRAN(GEO)", which supports CIoT EPS optimizations that are supported by the UE, the UE, as an implementation option, may indicate to lower layers to remain camped in E-UTRA cell connected to 5GCN, may then start an implementation-specific timer and enter the state 5GMM-REGISTERED.LIMITED-SERVICE. The UE may re-enable the N1 mode capability for 3GPP access at expiry of the implementation-specific timer, if the timer had been started, and may then proceed with the appropriate 5GMM procedure.
When the UE supporting both N1 mode and S1 mode needs to stay in E-UTRA connected to EPC (e.g. due to the domain selection for UE originating sessions as specified in subclause 4.3.2), in order to prevent unintentional handover or cell reselection from E-UTRA connected to EPC to NG-RAN connected to 5GCN, the UE operating in single-registration mode shall disable the N1 mode capability for 3GPP access and:
shall set the N1mode bit to "N1 mode for 3GPP access not supported" in the UE network capability IE (see TS 24.301) of the ATTACH REQUEST message and the TRACKING AREA UPDATE REQUEST message in EPC; and
the UE NAS layer shall indicate the access stratum layer(s) of disabling of the N1 mode capability for 3GPP access.
If the UE is required to disable the N1 mode capability for 3GPP access and select E-UTRA or another RAT, and the UE is in the 5GMM-CONNECTED mode,
if the UE has a persistent PDU session, then the UE waits until the radio bearer associated with the persistent PDU session has been released;
otherwise the UE shall locally release the established NAS signalling connection;
and enter the 5GMM-IDLE mode before selecting E-UTRA or another RAT.
If the UE is disabling its N1 mode capability for 3GPP access before selecting E-UTRA or another RAT, the UE shall not perform the UE-initiated de-registration procedure of subclause 5.5.2.2.
The UE shall re-enable the N1 mode capability for 3GPP access when the UE performs PLMN selection, SNPN selection or SNPN selection for onboarding services over 3GPP access, unless:
disabling of the N1 mode capability for 3GPP access was due to a UE-initiated de-registration procedure for 5GS services over 3GPP access not due to switch-off; or
the UE has already re-enabled the N1 mode capability for 3GPP access when performing items c) or d) above ; or
If the disabling of N1 mode capability for 3GPP access was due to IMS voice is not available over 3GPP access and the UE's usage setting is "voice centric", the UE shall re-enable the N1 mode capability for 3GPP access when the UE's usage setting is changed from "voice centric" to "data centric", as specified in subclauses 4.3.3.
The UE should memorize the identity of the PLMN or SNPN where N1 mode capability for 3GPP access was disabled and should use that stored information in subsequent PLMN or SNPN selections as specified in TS 23.122.
If the disabling of N1 mode capability for 3GPP access was due to successful completion of an emergency services fallback, the criteria to enable the N1 mode capability again are UE implementation specific.
The UE shall disable the N1 mode capability for 3GPP access if requested by the upper layers (e.g. see clause U.2.2.6.4 of TS 24.229). If the UE disabled the N1 mode capability for 3GPP access based on the request from the upper layers (e.g. see clause U.2.2.6.4 of TS 24.229), the criteria to re-enable the N1 mode capability for 3GPP access after the completion of an emergency service are UE implementation specific.
If the N1 mode capability for 3GPP access was disabled due to the UE initiated de-registration procedure for 3GPP access or for 3GPP access and non-3GPP access and the UE is operating in single-registration mode (see subclause 5.5.2.2.3), upon request of the upper layers to re-register for 5GS services over 3GPP access or the UE needs to come out of unavailability period and resume normal services, the UE shall enable the N1 mode capability for 3GPP access again.
As an implementation option, the UE may start a timer for enabling the N1 mode capability for 3GPP access when the UE disables the N1 mode capability for 3GPP access. The UE should memorize the identity of the PLMNs or SNPNs where N1 mode capability for 3GPP access was disabled. On expiry of this timer:
if the UE is in Iu mode or A/Gb mode and is in idle mode as specified in TS 24.008, the UE should enable the N1 mode capability for 3GPP access;
if the UE is in Iu mode and a PS signalling connection exists, but no RR connection exists, the UE may abort the PS signalling connection before enabling the N1 mode capability for 3GPP access; or
if the UE is in S1 mode and is in EMM-IDLE mode as specified in TS 24.301, the UE should enable the N1 mode capability for 3GPP access; and
if the UE is in Iu mode or A/Gb mode and an RR connection exists, the UE should delay enabling the N1 mode capability for 3GPP access until the RR connection is released. If the UE is in S1 mode and is in EMM-CONNECTED mode as specified in TS 24.301, the UE should delay enabling the N1 mode capability for 3GPP access until the NAS signalling connection in S1 mode is released.
When the UE enables the N1 mode capability for 3GPP access, the UE shall remove the PLMN or SNPN from the memorized identity of the PLMNs or SNPNs where N1 mode capability for 3GPP access was disabled.
The UE may disable the N1 mode capability for currently camped PLMN or SNPN over 3GPP access (see TS 23.122) if no network slice is available for the camped PLMN or SNPN (see subclauses 5.5.1.2.5 and 5.5.1.3.5). If the disabling of N1 mode capability for 3GPP access was due to no network slices available, the UE should memorize the identity of the PLMN or SNPN where N1 mode is disabled due to no available network slices or the list of SNPNs where N1 mode is disabled due to no available network slices, respectively. As an implementation option, the UE may start a timer TNSU for enabling the N1 mode capability that was disabled due to no available network slices for the 3GPP access. The value of timer TNSU is UE implementation specific. The UE should remove the memorized identity of the PLMNs or SNPNs where N1 mode is disabled due to no available network slice upon:
the expiry of the timer TNSU; or
receiving REGISTRATION ACCEPT message containing the Network slicing indication IE with the Network slicing subscription change indication set to "Network slicing subscription changed".
If the UE receives ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST message provided with S-NSSAI and the PLMN ID in the Protocol configuration options IE or Extended protocol configuration options IE (see subclause 6.5.1.3 of TS 24.301), the UE may remove the PLMN ID from the memorized identity of the PLMNs where N1 mode is disabled due to no available network slices.
If the UE attempts to establish an emergency PDU session in a PLMN or SNPN where N1 mode capability was disabled due to the UE's registration attempt counter have reached 5, the UE may enable N1 mode capability for that PLMN memorized by the UE.
If the UE supports access to an SNPN providing access for localized services in SNPN and access for localized services in SNPN is enabled, then:
the UE may re-enable the N1 mode capability for 3GPP access if disabled for that SNPN when:
the validity information of the SNPN contained in the "credentials holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN" changes from not met to met; or
the validity information of a GIN broadcasted by an SNPN contained in the "credentials holder controlled prioritized list of preferred GINs for access for localized services in SNPN" changes from not met to met; and
the UE need not re-enable N1 mode capability for 3GPP access for that SNPN if the N1 mode capability for 3GPP access for that SNPN was disabled due to 5GMM cause value #27 (N1 mode not allowed).
When the UE disables the N1 mode capability for non-3GPP access, the UE NAS layer shall not initiate any 5GS NAS procedures towards the network over non-3GPP access.
When the UE supporting both N1 mode and S1 mode needs to stay in non-3GPP access connected to EPC (e.g. due to the domain selection for UE originating sessions as specified in subclause 4.3.2), in order to prevent unintentional selection of a non-3GPP access network connected to 5GCN, the UE operating in single-registration mode shall not transfer any PDN connection to a non-3GPP access network connected to the 5GCN.
If the disabling of N1 mode capability for non-3GPP access was due to IMS voice is not available over non-3GPP access in 5GS and the UE's usage setting is "voice centric", the UE shall re-enable the N1 mode capability for non-3GPP access when the UE's usage setting is changed from "voice centric" to "data centric" as specified in subclauses 4.3.3.
The UE shall re-enable the N1 mode capability for non-3GPP access when a new PLMN or SNPN is selected over non-3GPP access.
The UE may disable the N1 mode capability for the currently camped PLMN or SNPN over non-3GPP access if no network slice is available for the camped PLMN or SNPN.
As an implementation option, the UE may start a timer for re-enabling the N1 mode capability for non-3GPP access, after the N1 mode capability for non-3GPP access was disabled. On the expiry of this timer, the UE should re-enable the N1 mode capability for non-3GPP access.
Disable of the satellite NG-RAN capability shall only be performed when the UE is in 5GMM-IDLE mode.
When disabling the satellite NG-RAN capability, the UE:
shall memorize the identity of the PLMN where the satellite NG-RAN capability was disabled; and
shall use that stored information in subsequent PLMN selections as specified in TS 23.122.
As an implementation option, the UE may start a timer for enabling satellite NG-RAN capability and on expiry of this timer UE shall remove the PLMN from the memorized identity of the PLMNs where the satellite NG-RAN capability was disabled.
In order to interwork with ePDG connected to EPC, the UE shall operate as specified in either subclause 4.8.2.3 or subclause 4.8.3. Which subclause the UE follows is chosen by the UE irrespective of the interworking without N26 interface indicator.
The UE shall not attempt to transfer PDU sessions with PDU session type "Ethernet" or "Unstructured" to an ePDG connected to EPC.
The UE shall not attempt to transfer PDU sessions with the selected SSC mode set to "SSC mode 2" or "SSC mode 3" to an ePDG connected to EPC.
The 5GS in a PLMN supports updating UE parameters via NAS signalling. The feature enables the HPLMN to securely and dynamically re-configure the UE configuration parameters stored on the USIM and the ME.
In this release of the specification, updates of the following USIM configuration parameters are supported:
routing indicator.
In this release of specification, updates of the following ME configuration parameters are supported:
default configured NSSAI.
disaster roaming information.
The 5GS in an SNPN supports updating UE parameters via NAS signalling. The feature enables the SNPN to securely and dynamically re-configure the UE configuration parameter stored on the USIM if the UE used the USIM for registration to the SNPN.
In this release of the specification, updates of the following USIM configuration parameters are supported:
routing indicator.
In this release of specification, updates of the following ME configuration parameters are supported:
routing indicator.
default configured NSSAI.
The update of UE configuration parameters is initiated by the network using the network-initiated downlink NAS transport procedure as described in subclause 5.4.5.3. The ME acknowledgement of successful reception of the updated UE configuration parameter information is sent back to the network using the UE-initiated uplink NAS transport procedure as described in subclause 5.4.5.2.
The ATSSS feature is an optional feature that may be supported by the UE and the 5GCN.
The ATSSS feature enables a multi-access PDU connectivity service, which can exchange PDUs between the UE and a data network by simultaneously using one 3GPP access network and one non-3GPP access network. The multi-access PDU connectivity service is realized by establishing a multi-access PDU session, i.e. a PDU session that can have user-plane resources on two access networks.
The UE can request an MA PDU session when the UE is registered via both 3GPP and non-3GPP accesses, or when the UE is registered via one access only. The MA PDU session management is performed based on the PDU session management procedures.
The detailed description of the procedures for ATSSS between the UE and the network across one 3GPP access network and one non-3GPP access network are specified in TS 24.193.
A 5G-RG, a W-AGF acting on behalf of an FN-RG or a W-AGF acting on behalf of an N5GC device can use wireline access network to access the 5GCN by using NAS signalling procedures as described in TS 23.501, TS 23.502 and TS 23.316.
Wireline access is a type of non-3GPP access.
A 5G-RG simultaneously connected to the same 5GCN of a PLMN over a 3GPP access and a wireline access is connected to a single AMF.
5G-RG maintains the N1 NAS signalling connection with the AMF over the wireline access network after all the PDU sessions for the 5G-RG over that access have been released or handed over to 3GPP access.
The 5G-RG connected to 5GCN via NG-RAN is specified in TS 23.316.
When accessing the 5GCN over 3GPP access, in addition to requirements specified for the 5G-RG in the present document, the 5G-RG shall also perform requirements specified in the present document for a UE accessing 5GCN over 3GPP access. When accessing the 5GCN over wireline access, in addition to requirements specified for the 5G-RG in the present document, the 5G-RG shall also perform requirements specified in the present document for a UE accessing 5GCN over non-3GPP access. If a requirement specified for the 5G-RG in the present document contradicts a requirement specified for the UE in the present document, the 5G-RG shall perform the requirement specified in the present document for the 5G-RG.
For the scenario of FN-RG, which does not support N1 mode, the W-AGF acting on behalf of the FN-RG exchanges NAS signalling messages with an AMF.
For the scenario of N5GC device, which does not support N1 mode, the W-AGF acting on behalf of the N5GC device exchanges NAS signalling messages with an AMF.
For the scenario of AUN3 device, which does not support N1 mode, the 5G-RG acting on behalf of the AUN3 device exchanges NAS signalling messages with an AMF. If the 5G-RG is not registered and connected to the 5GCN over wireline access, the 5G-RG acting on behalf of an AUN3 device shall not initiate the initial registration procedure on behalf of the AUN3 device.
When the 5G-RG acting on behalf of an AUN3 device initiates the initial registration procedure on behalf of the AUN3 device, the 5G-RG shall not include the requested NSSAI in the REGISTRATION REQUEST message.
For the scenario of NAUN3 device, which does not support N1 mode, the 5G-RG acting on behalf of a connectivity group consisting of one or more NAUN3 devices exchanges NAS signalling messages with an AMF.
In addition to requirements specified for the W-AGF acting on behalf of the FN-RG (or on behalf of the N5GC device) in the present document, the W-AGF acting on behalf of the FN-RG (or on behalf of the N5GC device) shall also perform requirements specified in the present document for a UE accessing 5GCN over non-3GPP access. If a requirement specified for the W-AGF acting on behalf of the FN-RG (or on behalf of the N5GC device) in the present document contradicts a requirement specified for the UE in the present document, the W-AGF acting on behalf of the FN-RG (or on behalf of the N5GC device) shall perform requirement specified in the present document for the W-AGF acting on behalf of the FN-RG (or on behalf of the N5GC device).
The PDU session authentication and authorization procedure is not supported in a PDU session established by the W-AGF acting on behalf of the FN-RG or on behalf of the N5GC device.
The W-AGF acting on behalf of the N5GC device requests the establishment of a PDU Session on behalf of the N5GC device upon registration. Only one PDU session per N5GC device is supported.
The 5G-RG acting on behalf of an AUN3 device requests the establishment of a PDU Session on behalf of the AUN3 device upon registration. Only one PDU session per AUN3 is supported.
The 5G-RG acting on behalf of a connectivity group consisting of one or more NAUN3 devices requests the establishment of a PDU Session on behalf of the connectivity group. Only one PDU session per the connectivity group is supported, where all the NAUN3 devices in the connectivity group share the same PDU session.
A 5G-RG or an FN-RG provide a non-3GPP access network to UEs. A UE connected to a non-3GPP access network provided by the 5G-RG or the FN-RG can access to the 5GCN via the N3IWF or via the TNGF as described in TS 23.316.
The 5G-RG or the W-AGF acting on behalf of the FN-RG shall indicate "ANDSP not supported by the UE" in the UE policy classmark IE during the UE-initiated UE state indication procedure as specified in clause D.2.2.
The 5G-RG or the W-AGF acting on behalf of the FN-RG shall indicate "Reporting URSP rule enforcement not supported by the UE" in the UE policy classmark IE during the UE-initiated UE state indication procedure as specified in subclause D.2.2.
The Non-3GPP QoS Assistance Information (N3QAI) is introduced to enable a 5G-RG to perform the QoS differentiation for the UE behind the 5G-RG, the AUN3 device behind the 5G-RG or the NAUN3 device behind the 5G-RG. The network may provide the N3QAI associated with the QoS flow during the PDU session establishment procedure as defined in subclause 6.4.1 or during the PDU session modification procedure as defined in subclause 6.4.2.
If the AMF receives an indication from the W-AGF that there is no 5G-RG connected to the same wireline for an AUN3 device as specified in TS 23.316, the AMF shall locally de-register the AUN3 device.
If the UE is not SNPN enabled, the UE is always considered to be not operating in SNPN access operation mode. If the UE is SNPN enabled, the UE can operate in SNPN access operation mode. Details of activation and deactivation of SNPN access operation mode at the SNPN-enabled UE are up to UE implementation.
The functions and procedures of NAS described in the present document are applicable to an SNPN and an SNPN-enabled UE unless indicated otherwise. The key differences brought by the SNPN to the NAS layer are as follows:
a.
instead of the PLMN selection process, the SNPN selection process is performed by a UE operating in SNPN access operation mode (see TS 23.122 and TS 24.502 for further details on the SNPN selection);
b.
a "permanently forbidden SNPNs" list and a "temporarily forbidden SNPNs" list are managed per access type independently (i.e. 3GPP access or non-3GPP access) and, if the UE supports access to an SNPN using credentials from a credentials holder, equivalent SNPNs or both, per entry of the "list of subscriber data" or, if the UE supports access to an SNPN using credentials from a credentials holder, per the PLMN subscription, by a UE operating in SNPN access operation mode instead of forbidden PLMN lists. If the UE supports onboarding services in SNPN, an additional "permanently forbidden SNPNs for onboarding services in SNPN" list and an additional "temporarily forbidden SNPNs for onboarding services in SNPN" list are managed. If the UE supports access to an SNPN providing access for localized services in SNPN, an additional "permanently forbidden SNPNs for access for localized services in SNPN" list and an additional "temporarily forbidden SNPNs for access for localized services in SNPN" list per entry of the "list of subscriber data" and per the PLMN subscription are managed for 3GPP access only. These lists shall be maintained across activation and deactivation of SNPN access operation mode;
c.
inter-system change to and from S1 mode is not supported;
d.
void;
e.
CAG is not supported in SNPN access operation mode;
f.
with respect to the 5GMM cause values:
5GMM cause values #74 "Temporarily not authorized for this SNPN" and #75 "Permanently not authorized for this SNPN" are supported whereas these 5GMM cause values cannot be used in a PLMN; and
5GMM cause values #11 "PLMN not allowed", #31 "Redirection to EPC required", #73 "Serving network not authorized", and #76 "Not authorized for this CAG or authorized for CAG cells only" are not supported whereas these 5GMM cause values can be used in a PLMN;
g.
a list of "5GS forbidden tracking areas for roaming" and a list of "5GS forbidden tracking areas for regional provision of service" are managed per SNPN and, if the UE supports access to an SNPN using credentials from a credentials holder, equivalent SNPNs or both, entry of the "list of subscriber data" or, if the UE supports access to an SNPN using credentials from a credentials holder,PLMN subscription (see TS 23.122);
h.
when accessing SNPN services via a PLMN using 3GPP access, access to 5GCN of the SNPN is performed using 5GMM procedures for non-3GPP access, 5GMM parameters for non-3GPP access, the UE is performing access to SNPN over non-3GPP access and the UE is not operating in SNPN access operation mode over 3GPP access. When accessing PLMN services via a SNPN using 3GPP access, access to 5GCN of the PLMN is performed using 5GMM procedures for non-3GPP access, 5GMM parameters for non-3GPP access, the UE is not performing access to SNPN over non-3GPP access, and the UE is operating in SNPN access operation mode over 3GPP access. From the UE's NAS perspective, accessing PLMN services via an SNPN and accessing SNPN services via a PLMN are treated as untrusted non-3GPP access. If the UE is accessing the PLMN using non-3GPP access, the access to 5GCN of the SNPN via PLMN is not specified in this release of the specification.
Emergency services are not supported in an SNPN when a UE accesses SNPN services via a PLMN;
i.
when registered to an SNPN, the UE shall use only the UE policies provided by the registered SNPN;
j1.
inclusion of a TAI of an SNPN other than the registered SNPN, into the LADN service area is not supported. The AMF of an SNPN shall only include one or more TAIs of the registered SNPN into the LADN service area;
j2.
inclusion of a TAI of an SNPN other than the registered SNPN, into the allowed area or the non-allowed area, of the 3GPP access service area restrictions is not supported. The AMF of an SNPN shall include only one or more TAIs of the registered SNPN into the allowed area or the non-allowed area, of the 3GPP access service area restrictions;
k.
void;
l.
void;
m.
UE mobility between SNPNs in 5GMM-CONNECTED mode is supported when the SNPNs are equivalent SNPNs for the selected entry of the "list of subscriber data" or the selected PLMN subscription. UE mobility between SNPNs in 5GMM-IDLE mode is supported when the UE supports access to an SNPN using credentials from a credentials holder or when the SNPNs are equivalent SNPNs or both for the selected entry of the "list of subscriber data" or the selected PLMN subscription. UE mobility between an SNPN and a PLMN is not supported;
n.
CIoT 5GS optimizations are not supported;
o.
void;
p.
when registering or registered to an SNPN, the UE shall handle the 5GS mobile identity as described in subclause 5.5.1.2.2;
q.
when registering or registered to an SNPN, the UE shall only consider:
a last visited registered TAI visited in the same SNPN as an available last visited registered TAI; or
a last visited registered TAI visited using the same entry of the "list of subscriber data" or the same PLMN subscription as an available last visited registered TAI, if the UE supports access to an SNPN using credentials from a credentials holder, equivalent SNPNs or both;
r.
emergency service fallback is not supported;
s.
when registering or registered for onboarding services in SNPN, the UE shall not provide the requested NSSAI to the network;
s1.
when performing initial registration for onboarding services in SNPN, the UE shall set the 5GS registration type value to "SNPN onboarding registration";
t.
when registering or registered for onboarding services in SNPN, the AMF shall not provide the configured NSSAI, the allowed NSSAI or the rejected NSSAI to the UE, shall use the S-NSSAI included in the AMF onboarding configuration data for onboarding services in SNPN and shall not perform NSSAA procedure for S-NSSAI used for onboarding services in SNPN;
u.
the UE can access an SNPN indicating that onboarding is allowed using default UE credentials for primary authentication in order for the UE to be configured with one or more entries of the "list of subscriber data";
x.
eCall over IMS is not supported in SNPN access operation mode and the UE ignores any USIM configuration for eCall only mode;
y.
when registering or registered for onboarding services in SNPN, the AMF shall store in the 5GMM context of the UE an indication that the UE is registered for onboarding services in SNPN;
z.
a UE with multiple valid entries of "list of subscriber data", or one or more valid USIMs and one or more valid entries of "list of subscriber data", capable of initiating and maintaining simultaneous separate registration states over 3GPP access with PLMN(s) or SNPN(s), using identities and credentials associated with those entries of "list of subscriber data", or USIMs and entries of "list of subscriber data", and supporting one or more of the N1 NAS signalling connection release, the paging indication for voice services, the reject paging request, the paging restriction and the paging timing collision control may use procedures defined for MUSIM UE, even if the UE does not include multiple valid USIMs;
za.
when the UE is registering or registered for onboarding services in SNPN, the network slice admission control is not performed;
zb.
when the UE is registered for onboarding services in SNPN (as specified in subclause 3.1), the UE determines that the number dialled is an emergency number, and emergency services are not supported in the SNPN, the UE shall perform a local de-registration and utilize the procedures specified in TS 23.167 and TS 24.229 to select a domain for the emergency session attempt;
A PNI-NPN is made available by means of e.g. dedicated DNNs or by one or more S-NSSAIs allocated for it. A CAG can be optionally used in order to prevent UEs not allowed to access a PNI-NPN from accessing the PNI-NPN. The key enablers for the CAG in the NAS layer are as follows:
provisioning of a "CAG information list" as specified in TS 23.122, from network to UE via the generic UE configuration update procedure, the registration procedure, the service request procedure, and the network-initiated de-registration procedure.
The "CAG information list" provisioned by the network, if available, is stored in the non-volatile memory in the ME as specified in Annex C. The "CAG information list" stored in the ME is kept when the UE enters 5GMM-DEREGISTERED state. Annex C specifies condition under which the "CAG information list" stored in the ME is deleted. Additionally, when a USIM is inserted, if:
no "CAG information list" is stored in the non-volatile memory of the ME; or
the SUPI from the USIM does not match the SUPI stored together with the "CAG information list" in the non-volatile memory of the ME;
and the UE has a "CAG information list" stored in the USIM (see TS 31.102), the UE shall store the "CAG information list" from the USIM into the ME, as specified in Annex C. The "Allowed CAG list" included in the entry for the HPLMN or EHPLMN in "CAG information list" stored in the USIM can contain a range of CAG-IDs.
The UE supporting CAG may perform the initial registration for emergency services via a non-CAG cell in a PLMN for which the UE has an "indication that the UE is only allowed to access 5GS via CAG cells" or via a CAG cell for which none of CAG-ID(s) is authorized based on the "Allowed CAG list" (see TS 23.122) for the selected PLMN. If a UE supporting CAG having an emergency PDU session is camping on:
a CAG cell and none of the CAG-ID(s) of the CAG cell is authorized based on the "Allowed CAG list" for the current PLMN in the UE's subscription; or
a non-CAG cell in a PLMN for which the UE's subscription contains an "indication that the UE is only allowed to access 5GS via CAG cells";
the AMF shall behave as specified in subclause 5.4.4.2, 5.5.1.3.4 or 5.6.1.4.1.
If a UE supporting enhanced CAG information is in a CAG cell with a CAG-ID which:
was authorized based on the "Allowed CAG list" associated with the current PLMN in the "CAG information list" stored in the ME; and
becomes not authorized based on the "Allowed CAG list" (e.g., time validity information no longer matches UE's current time); and
none of the CAG-ID(s) supported by the current CAG cell is currently authorized based on the "Allowed CAG list" of the entry for the current PLMN in the stored "CAG information list", and:
the entry for the current PLMN in the "CAG information list" does not include an "indication that the UE is only allowed to access 5GS via CAG cells", then the UE shall abort ongoing UE initialted 5GMM procedures, if any, locally release the NAS signalling connection, if any, enter the state 5GMM-REGISTERED.LIMITED-SERVICE and shall search for a suitable cell according to TS 38.304 or TS 36.304 with the stored "CAG information list"; or
the entry for the current PLMN in the stored "CAG information list" includes an "indication that the UE is only allowed to access 5GS via CAG cells" and:
one or more CAG-ID(s) are authorized based on the "Allowed CAG list" of the entry for the current PLMN in the stored "CAG information list", the UE shall abort ongoing UE initialted 5GMM procedures, if any, locally release the NAS signalling connection, if any, enter the state 5GMM-REGISTERED.LIMITED-SERVICE and shall search for a suitable cell according to TS 38.304 or TS 36.304 with the stored "CAG information list"; or
no CAG-ID is authorized based on the "Allowed CAG list" of the entry for the current PLMN in the stored "CAG information list" and:
the UE does not have an emergency PDU session, then the UE shall abort ongoing UE initialted 5GMM procedures, if any, locally release the NAS signalling connection, if any, enter the state 5GMM-REGISTERED.PLMN-SEARCH and shall apply the PLMN selection process defined in TS 23.122 with the stored "CAG information list"; or
the UE has an emergency PDU session, then the UE shall perform a local release of all PDU sessions associated with 3GPP access except for the emergency PDU session and enter the state 5GMM-REGISTERED.LIMITED-SERVICE.