UE to (R)AN:
AN message (
Registration Request (
last visited TAI
[Mapping Of Requested NSSAI
Default Configured NSSAI Indication,
UE Radio Capability Update,
UE MM Core Network Capability,
PDU Session status,
List Of PDU Sessions To Be Activated,
Follow on request,
Requested DRX parameters,
[LADN DNN(s) or Indicator Of Requesting LADN Information]
UE Policy Container (
the list of PSIs,
indication of UE support for ANDSP and the operating system identifier
In the case of NG-RAN, the AN parameters include e.g. 5G-S-TMSI or GUAMI
, the Selected PLMN ID and Requested NSSAI, the AN parameters also include Establishment cause.
The Establishment cause provides the reason for requesting the establishment of an RRC connection.
The Registration type indicates if the UE wants to perform an Initial Registration (i.e. the UE is in RM-DEREGISTERED state),
a Mobility Registration Update (i.e. the UE is in RM-REGISTERED state and initiates a Registration procedure due to mobility or due to the UE needs to update its capabilities or protocol parameters,
or to request a change of the set of network slices it is allowed to use),
a Periodic Registration Update (i.e. the UE is in RM-REGISTERED state and initiates a Registration procedure due to the Periodic Registration Update timer expiry, see clause 18.104.22.168.1
or an Emergency Registration (i.e. the UE is in limited service state).
When the UE is performing an Initial Registration the UE shall indicate its UE identity in the Registration Request message as follows, listed in decreasing order of preference:
If the UE was previously registered in EPS and has a valid EPS GUTI, the UE provides 5G-GUTI as explained in step 2 of clause 22.214.171.124.3 step 2a.
a native 5G-GUTI assigned by the which the UE is attempting to register, if available;
a native 5G-GUTI assigned by an equivalent PLMN to the PLMN to which the UE is attempting to register, if available;
a native 5G-GUTI assigned by any other PLMN, if available.
NOTE 1: This can also be a 5G-GUTIs assigned via another access type.
Otherwise, the UE shall include its SUCI in the Registration Request as defined in TS 33.501 .
If the UE has a NAS security context, as defined in TS 24.501  the UE includes in the Security parameters an indication that the NAS message is integrity protected and partially ciphered to indicate to the AMF how to process the enclosed parameters.
If the UE has no NAS security context, the Registration Request message shall only contain the cleartext IEs as defined in TS 24.501 .
When the UE is performing an Initial Registration (i.e., the UE is in RM-DEREGISTERED state) with a native 5G‑GUTI
then the UE shall indicate the related GUAMI
information in the AN parameters.
When the UE is performing an Initial Registration with its SUCI
, the UE shall not indicate any GUAMI
information in the AN parameters.
For an Emergency Registration, the SUCI shall be included if the UE does not have a valid 5G-GUTI available; the PEI shall be included when the UE has no SUPI and no valid 5G-GUTI.
In other cases, the 5G-GUTI is included and it indicates the last serving AMF.
The UE may provide the UE's usage setting based on its configuration as defined in TS 23.501  clause 126.96.36.199
In case of Initial Registration or Mobility Registration Update, the UE includes the Mapping Of Requested NSSAI
(if available), which is the mapping of each S‑NSSAI
of the Requested NSSAI
to the S‑NSSAI
s of the Configured NSSAI
for the HPLMN, to ensure that the network is able to verify whether the S‑NSSAI
(s) in the Requested NSSAI
are permitted based on the Subscribed S‑NSSAI
The UE includes the Default Configured NSSAI Indication if the UE is using a Default Configured NSSAI, as defined in TS 23.501 .
In the case of Mobility Registration Update, the UE includes in the List Of PDU Sessions To Be Activated the PDU Sessions for which there are pending uplink data.
When the UE includes the List Of PDU Sessions To Be Activated, the UE shall indicate PDU Sessions only associated with the access the Registration Request is related to.
As defined in TS 24.501
 the UE shall include always-on PDU Sessions which are accepted by the
network in the List Of PDU Sessions To Be Activated even if there are no pending uplink data for those PDU Sessions.
NOTE 2: A PDU Session corresponding to a LADN is not included in the List Of PDU Sessions To Be Activated when the UE is outside the area of availability of the LADN
The UE MM Core Network Capability is provided by the UE and handled by AMF as defined in TS 23.501  clause 5.4.4a
The UE includes in the UE MM Core Network Capability an indication if it supports Request Type flag "handover" for PDN connectivity request during the attach procedure as defined in 188.8.131.52.1 of TS 23.501
The UE may provide either the LADN DNN(s) or an Indication Of Requesting LADN Information as described in TS 23.501  clause 5.6.5.
If available, the last visited TAI
shall be included in order to help the AMF produce Registration Area for the UE.
The Security parameters are used for Authentication and integrity protection, see TS 33.501 .
Requested NSSAI indicates the Network Slice Selection Assistance Information (as defined in clause 5.15 of TS 23.501 ).
The PDU Session status indicates the previously established PDU Sessions in the UE.
When the UE is connected to the two AMFs belonging to different PLMN via 3GPP access and non-3GPP access then the PDU Session status indicates the established PDU Session of the current PLMN in the UE.
The Follow-on request is included when the UE has pending uplink signalling and the UE doesn't include List Of PDU Sessions To Be Activated, or the Registration type indicates the UE wants to perform an Emergency Registration.
In Initial Registration and Mobility Registration Update, UE provides the UE Requested DRX parameters, as defined in clause 5.4.5 of TS 23.501
The UE provides UE Radio Capability Update indication as described in TS 23.501
The UE access selection and PDU session selection identifies the list of UE access selection and PDU session selection policy information stored in the UE, defined in clause 6.6 of TS 23.503
They are used by the PCF to determine if the UE has to be updated with new PSIs or if some of the stored ones are no longer applicable and have to be removed.