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full Contents for  TS 23.502  Word version:   16.4.0

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1…   4.2.2.2.2   4.2.2.2.3…   4.2.3…   4.2.3.3   4.2.4…   4.2.6   4.2.7…   4.2.9…   4.3…   4.3.2.2…   4.3.2.2.2   4.3.2.2.3…   4.3.3   4.3.4   4.3.5…   4.3.5.2…   4.3.5.4…   4.3.5.6…   4.3.6…   4.4…   4.5…   4.9…   4.9.1.3…   4.9.2…   4.11…   4.11.1.2.2…   4.11.1.3…   4.11.1.4…   4.11.1.5…   4.11.2   4.11.3…   4.12…   4.12.6…   4.12a   4.12b   4.13…   4.13.4…   4.13.6…   4.14…   4.15…   4.15.4…   4.16…   4.16.4…   4.16.8…   4.17…   4.17.9…   4.18…   4.19…   4.23…   4.23.7…   4.23.9…   4.23.11…   4.24   4.25   4.26…   5…   5.2.3…   5.2.5…   5.2.6…   5.2.7…   5.2.8…   5.2.9…   5.2.12…   A…   E…   F…

 

5  Network Function Service proceduresWord-p. 439
5.1  Network Function Service framework procedures
5.1.1  Network Function Service Discovery
The network function (NF) within the core network may expose its capability as service via its service based interfaces, which can be re-used by other NFs. Unless the expected NF information is locally configured on requester NF, e.g. the expected NF is in the same PLMN, the NF service discovery is implemented via the NF discovery.
5.2  Network Function services
5.2.1  General
5.2.2  AMF Services
5.2.2.1  General
The following table shows the AMF Services and AMF Service Operations.
Service Name
Service Operations
Operation Semantic
Known Consumer(s)

Namf_Communication
UEContextTransfer
Request/ Response
Peer AMF
CreateUEContext
Request/ Response
Peer AMF
ReleaseUEContext
Request/ Response
Peer AMF
RegistrationStatusUpdate
Request/ Response
Peer AMF
N1MessageNotify
Subscribe / Notify
SMF, SMSF, PCF, LMF, Peer AMF
N1MessageSubscribe
SMF, SMSF, PCF
N1MessageUnSubscribe
SMF, SMSF, PCF
N1N2MessageTransfer
Request/ Response
SMF, SMSF, PCF, LMF
N1N2TransferFailureNotification
Subscribe / Notify
SMF, SMSF, PCF, LMF
N2InfoSubscribe
Subscribe / Notify
NOTE 1
N2InfoUnSubscribe
NOTE 1
N2InfoNotify
AMF, LMF
EBIAssignment
Request/Response
SMF
AMFStatusChangeSubscribe
Subscribe / Notify
SMF, PCF, NEF, SMSF, UDM
AMFStatusChangeUnSubscribe
Subscribe / Notify
SMF, PCF, NEF, SMSF, UDM
AMFStatusChangeNotify
Subscribe / Notify
SMF, PCF, NEF, SMSF, UDM
NonUeN2MessageTransfer
Request/Response
Peer AMF, CBCF, PWS-IWF, LMF
NonUeN2InfoSubscribe
Subscribe / Notify
CBCF, PWS-IWF
NonUeN2InfoUnSubscribe
CBCF, PWS-IWF
NonUeN2InfoNotify
CBCF, PWS-IWF, LMF
Namf_EventExposure
Subscribe
Subscribe / Notify
NEF, SMF, UDM, NWDAF
Unsubscribe
Subscribe / Notify
NEF, SMF, UDM, NWDAF
Notify
Subscribe / Notify
NEF, SMF, UDM, NWDAF
Namf_MT
EnableUEReachability
Request/Response
SMSF
ProvideDomainSelectionInfo
Request/Response
UDM
Namf_Location
ProvidePositioningInfo
Request/Response
GMLC
EventNotify
Subscribe / Notify
GMLC
ProvideLocationInfo
Request/Response
UDM
CancelLocation
Request/Response
GMLC

NOTE 1:
In this Release of the specification no known consumer is identified to use this service operation.
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5.2.2.2  Namf_Communication serviceWord-p. 440
5.2.2.2.1  General
Service description: This service enables an NF to communicate with the UE through N1 NAS messages or with the AN (both UE and non UE specific). The service operations defined below allow the NF to communicate with the UE and the AN. The following are the key functionalities of this NF service.
  • Provide service operations for transporting N1 messages to the UE;
  • Allow NFs to subscribe and unsubscribe for notifications of specific N1 messages from the UE;
  • Allow NFs to subscribe and unsubscribe for notifications about specific information from AN;
  • Provide service operations for initiating N2 messages towards the AN;
  • Security Context Management; and
  • UE information management and transfer (including its security context);
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5.2.2.2.2  Namf_Communication_UEContextTransfer service operationWord-p. 441
Service operation name:
Namf_Communication_UEContextTransfer
Description:
Provides the UE context to the consumer NF.
Input, Required:
5G-GUTI or SUPI, Access Type, Reason.
Input, Optional:
Integrity protected message from the UE that triggers the context transfer.
Output, Required:
The UE context of the identified UE or only the SUPI and an indication that the Registration Request has been validated. The UE context is detailed in table 5.2.2.2.2-1.
Output, Optional:
Mobile Equipment Identifier (if available), Allowed NSSAI, Mapping Of Allowed NSSAI.
See clause 4.2.2.2.2 for example of usage of this service operation. If the consumer NF sent an integrity protected message from the UE, the AMF uses it to verify whether this request is permitted to retrieve the UE context of the UE. If it is permitted, the AMF provides UE context to the consumer NF in the Namf_Communication_UEContextTransfer response. The following table illustrates the UE Context:
Field
Description

SUPI
SUPI (Subscription Permanent Identifier) is the subscriber's permanent identity in 5GS.
Routing Indicator
UE's Routing Indicator that allows together with SUCI/SUPI Home Network Identifier to route network signalling to AUSF and UDM instances capable to serve the subscriber
AUSF Group ID
The AUSF Group ID for the given UE.
UDM Group ID
The UDM Group ID for the UE.
PCF Group ID
The PCF Group ID for the UE.
SUPI-unauthenticated-indicator
This indicates whether the SUPI is unauthenticated.
GPSI
The GPSI(s) of the UE. The presence is dictated by its storage in the UDM.
5G-GUTI
5G Globally Unique Temporary Identifier.
PEI
Mobile Equipment Identity
Internal Group ID-list
List of the subscribed internal group(s) that the UE belongs to.
UE Specific DRX Parameters
UE specific DRX parameters.
UE MM Network Capability
Indicates the UE MM network capabilities.
5GMM Capability
Includes other UE capabilities related to 5GCN or interworking with EPS.
Events Subscription
List of the event subscriptions by other CP NFs. Indicating the events being subscribed as well as any information on how to send the corresponding notifications
LTE-M Indication
Indicates if the UE is a Category M UE. This is based on indication provided by the NG-RAN or by the MME at EPS to 5GS handover.
MO Exception Data Counter
MO Exception Data Counter used for Small Data Rate Control purposes, see clause 5.31.14.3 of TS 23.501.
AMF-Associated Expected UE Behaviour parameters
Indicates per UE the Expected UE Behaviour Parameters and their corresponding validity times as specified in clause 4.15.6.3.

For the AM Policy Association:
AM Policy Information
Information on AM policy provided by PCF. Includes the Policy Control Request Triggers and the Policy Control Request Information. Includes the authorized RFSP and the authorized Service Area Restrictions.
PCF ID
The identifier of the PCF for AM Policy. In roaming, the identifier of V-PCF (NOTE 2).

For the UE Policy Association:
Trigger Information
The Policy Control Request Triggers on UE policy provided by PCF.
PCF ID(s)
The identifier of the PCF for UE Policy. In roaming, the identifiers of both V-PCF and H-PCF (NOTE 1) (NOTE 2).
Subscribed RFSP Index
An index to specific RRM configuration in the NG-RAN that is received from the UDM.
RFSP Index in Use
An index to specific RRM configuration in the NG-RAN that is currently in use.
UE-AMBR in serving network
The UE-AMBR that has been sent to RAN (e.g. based on subscribed UE-AMBR from UDM or UE-AMBR received from PCF)
MICO Mode Indication
Indicates the MICO Mode for the UE.
Extended idle mode DRX Parameters
Negotiated extended idle mode DRX parameters.
Active Time Value for MICO mode
UE specific Active Time value allocated by AMF for MICO mode handling.
Strictly Periodic Registration Timer Indication
An indication that UE shall perform the Periodic Registration Update in a strictly periodic time, see TS 23.501, clause 5.31.7.5.
Voice Support Match Indicator
An indication whether the UE radio capabilities are compatible with the network configuration. The AMF uses it as an input for setting the IMS voice over PS Session Supported Indication over 3GPP access.
Homogenous Support of IMS Voice over PS Sessions
Indicates per UE if "IMS Voice over PS Sessions" is homogeneously supported in all TAs in the serving AMF or homogeneously not supported, or, support is non-homogeneous/unknown, see clause 5.16.3.3 of TS 23.501.
UE Radio Capability for Paging Information
Information used by the NG-RAN to enhance the paging towards the UE (see clause 5.4.4.1 of TS 23.501).
Information On Recommended Cells And RAN nodes For Paging
Information sent by the NG-RAN, and used by the AMF when paging the UE to help determining the NG-RAN nodes to be paged as well as to provide the information on recommended cells to each of these NG-RAN nodes, in order to optimize the probability of successful paging while minimizing the signalling load on the radio path.
UE Radio Capability Information
Information sent by the NG-RAN node and stored in the AMF. The AMF sends this information to the NG-RAN node within the UE context during transition to CM-CONNECTED state, except for NB-IoT when NB-IoT specific UE Radio Access Capability are sent instead.
UE Radio Capability ID
Pointer that uniquely identifies a set of UE Radio Capabilities in UCMF as defined in TS 23.501.
NB-IoT specific UE Radio Access Capability Information
NB-IoT specific UE radio access capabilities.
WUS Assistance Information
Assistance information for determining the WUS group (see TS 23.501).
SMSF Identifier
The Identifier of the SMSF serving the UE in RM REGISTERED state.
SMSF Address
The Address of the SMSF serving the UE in RM-REGISTERED state. (see clause 4.13.3.1).
SMS Subscription
Indicates subscription to any SMS delivery service over NAS irrespective of access type.
SEAF data
Master security information received from AUSF.
Last used EPS PLMN ID
The identifier of the last used EPS PLMN.
Paging Assistance Data for CE capable UE
Paging Assistance Data for Enhanced Coverage level and cell ID provided by the last NG-RAN the UE was connected to.
Enhanced Coverage Restricted Information
Specifies whether CE mode B is restricted for the UE, or both CE mode A and CE mode B are restricted for the UE, or both CE mode A and CE mode B are not restricted for the UE.
Service Gap Time
Used to set the Service Gap timer for Service Gap Control (see TS 23.501, clause 5.31.16).
Running Service Gap expiry time
The time of expiry of a currently running Service Gap Timer (see TS 23.501, clause 5.31.16).
NB-IoT UE Priority
Numerical value used by the NG-RAN to prioritise between UEs accessing via NB-IoT.
List of Small Data Rate Control Statuses
List of Small Data Rate Control Statuses by DNN and S-NSSAI for the released PDU Sessions, see TS 23.501, clause 5.31.14.3.
List of APN Rate Control Statuses
Indicates for each APN, the APN Rate Control Status (see TS 23.401, clause 4.7.7.3) received from an MME when mobility from EPC to 5GC occurs. This information is provided to the MME during 5GC to EPC mobility.

For each access type level context within the UE access and mobility context:
Access Type
Indicates the access type for this context.
RM State
Registration management state.
Registration Area
Current Registration Area (a set of tracking areas in TAI List).
TAI of last Registration
TAI of the TA in which the last Registration Request was initiated.
User Location Information
Information on user location.
Mobility Restrictions
Mobility Restrictions restrict mobility handling or service access of a UE. It consists of RAT restriction, Forbidden area, Service area restrictions and Core Network type restriction. It may also contain an Allowed CAG list and, optionally an indication whether the UE is only allowed to access 5GS via CAG cells.
Security Information for CP
As defined in TS 33.501.
Security Information for UP
As defined in TS 33.501.
Allowed NSSAI
Allowed NSSAI consisting of one or more S-NSSAIs for serving PLMN in the present Registration Area.
Mapping Of Allowed NSSAI
Mapping Of Allowed NSSAI is the mapping of each S-NSSAI of the Allowed NSSAI to the S-NSSAIs of the Subscribed S-NSSAIs.
S-NSSAIs subject to Network Slice-Specific Authentication and Authorization
Subscribed S-NSSAIs Subject to NSSAA as to allow the AMF to initiate the NSSAA procedure for a certain S-NSSAI which was previously authorized.
Also including the status, i.e. result, of the NSSAA.
Inclusion of NSSAI in RRC Connection Establishment Allowed by HPLMN
[Only for 3GPP access] it defines whether the UDM has indicated that the UE is allowed to include NSSAI in the RRC connection Establishment in clear text.
Access Stratum Connection Establishment NSSAI Inclusion Mode
Defines what NSSAI, if any, to include in the Access Stratum connection establishment as specified in TS 23.501, clause 5.15.9.
CM state for UE connected via N3IWF/TNGF
Identifies the UE CM state (CM-IDLE, CM-CONNECTED) for UE connected via N3IWF/TNGF
N2 address information for N3IWF/TNGF
Identifies the N3IWF/TNGF to which UE is connected. Exists only if CM state for UE connected via N3IWF/TNGF is CM-CONNECTED.
AMF UE NGAP ID
Identifies the UE association over the NG interface within the AMF as defined in TS 38.413. This parameter exists only if CM state for the respective Access Type is CM-CONNECTED.
RAN UE NGAP ID
Identifies the UE association over the NG interface within the NG-RAN node as defined in TS 38.413. This parameter exists only if CM state for the respective Access Type is CM-CONNECTED.
Network Slice Instance(s)
The Network Slice Instances selected by 5GC for this UE.
URRP-AMF information
UE Reachability Request Parameter contains a list of URRP-AMF flags and associated authorised NF IDs. Each URRP-AMF flag indicates whether direct UE reachability notification has been authorised by the HPLMN towards the associated NF ID or not.
SoR Update Indicator for Initial Registration
An indication whether the UDM requests the AMF to retrieve SoR information when the UE performs NAS Registration Type "Initial Registration".
SoR Update Indicator for Emergency Registration
An indication whether the UDM requests the AMF to retrieve SoR information when the UE performs NAS Registration Type "Emergency Registration".
Charging Characteristics
The Charging Characteristics as defined in Annex A, clause A.1 of TS 32.256.

For each PDU Session level context:
S-NSSAI(s)
The S-NSSAI(s) associated to the PDU Session.
DNN
The associated DNN for the PDU Session.
Network Slice Instance id
The network Slice Instance information for the PDU Session
PDU Session ID
The identifier of the PDU Session.
SMF Information
The associated SMF identifier and SMF address for the PDU Session.
Access Type
The current access type for this PDU Session.
EBI-ARP list
The allocated EBI and associated ARP pairs for this PDU session.
5GSM Core Network Capability
The UEs 5GSM Core Network Capability as defined in TS 23.501, clause 5.4.4b.
SMF derived CN assisted RAN parameters tuning
These are PDU Session specific parameters received from the SMF and used by the AMF to derive the Core Network assisted RAN parameters tuning.

NOTE 1:
The AMF transfers the PCF ID to the SMF during PDU Session Establishment. The SMF may select the PCF identified by the PCF ID as described in TS 23.501, clause 6.3.7.1. In HR roaming case, the AMF transfers the identifier of H-PCF as described in clause 4.3.2.2.2. In LBO roaming case, the AMF transfers the identifier of V-PCF as described in clause 4.3.2.2.1.
NOTE 2:
The PCF ID in AM Policy Association information and the PCF ID in UE Policy Association Information should be the same in non-roaming case. The V-PCF ID in AM Policy Association information and the V-PCF ID in UE Policy Association Information should be the same in roaming case.

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5.2.2.2.3  Namf_Communication_RegistrationStatusUpdate service operationWord-p. 445
Service operation name:
Namf_Communication_RegistrationStatusUpdate
Description:
This service operation is used by the consumer NF to inform the AMF that a prior UE context transfer has resulted in the UE successfully registering with it. The UE context is marked inactive in the AMF.
Input, Required:
5G-GUTI, Status.
Input, Optional:
PDU Session ID(s) (indicates the PDU Session(s) to be released), PCF ID (indicates that the PCF ID that handles the AM Policy association has changed).
Output, Required:
None.
Output, Optional:
None.
See clause 4.2.2.2.2 step 10 for example usage of this service operation. When the AMF receives this request, it marks the UE context information as inactive since the UE context has been successfully transferred to the peer NF and the UE has successfully registered there. The AMF receives information about whether the AM Policy Association Information in the UE context will be used or not (i.e. new AMF may select a different PCF and then create a new AM Policy Association). The AMF sends a Namf_Communication_RegistrationStatusUpdate response to the consumer NF.
NOTE 2:
Whether notification Ack need a separate message or be realized in the transport layer will be determined in TS 29.518.
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5.2.2.2.4  Namf_Communication_N1MessageNotify service operation
Service operation name:
Namf_Communication_N1MessageNotify
Description:
AMF notifies the N1 message received from the UE to a destination CN NF.
Input, Required:
AMF ID (GUAMI), N1 Message(s)
Input, Optional:
local time zone, UE's current location, AN type AN N2 terminating point, Allowed NSSAI, Mapping Of Allowed NSSAI, SUPI, MM Context, LMF identification.
Output, Required:
None.
Output, Optional:
None.
The destination NF type to be notified is determined based on one of the following:
  • The N1 message type is always known to be consumed by one particular NF type; or
  • An NF had explicitly subscribed for the particular N1 message type to be notified towards it.
NOTE:
Whether notification Ack need a separate message or be realized in the transport layer will be determined in TS 29.518.
The optional AN N2 terminating point, SUPI, MM Context, Allowed NSSAI and Mapping Of Allowed NSSAI parameters are included if the service operation is invoked towards a peer AMF.
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5.2.2.2.5  Namf_Communication_N1MessageSubscribe service operationWord-p. 446
Service operation name:
Namf_Communication_N1MessageSubscribe.
Description:
An NF can subscribe with the AMF to get notified of a particular N1 message type from the UE.
Input, Required:
CN NF ID, N1 Message Type
Input, Optional:
SUPI.
Output, Required:
None.
Output, Optional:
None.
The consumer NF invokes the Namf_Communication_N1MessageSubscribe service operation (NF ID, N1 message type to subscribe) on the AMF. The consumer NF shall provide a SUPI for UE associated N1 message subscriptions. If the consumer NF is allowed to subscribe for the type of N1 message requested, the AMF creates a binding for the consumer NF to deliver subsequent Namf_Communication_N1MessageNotify towards that NF.
NOTE:
Whether Subscription Ack need a separate message or be realized in the transport layer will be determined in TS 29.518.
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5.2.2.2.6  Namf_Communication_N1MessageUnSubscribe service operation
Service operation name:
Namf_Communication_N1MessageUnSubscribe.
Description:
An NF can unsubscribe with the AMF to stop notifying a particular N1 message type from the UE.
Input, Required:
CN NF ID, N1 Message Type
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
The consumer NF invokes the Namf_Communication_N1MessageUnSubscribe service operation (NF ID, N1 message type to subscribe) on the AMF. The AMF deletes the binding for the consumer NF for the requested N1 message type.
NOTE:
Whether UnSubscribe Ack need a separate message or be realized in the transport layer will be determined in TS 29.518.
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5.2.2.2.7  Namf_Communication_N1N2MessageTransfer service operation
Service operation name:
Namf_Communication_N1N2MessageTransfer.
Description:
CN NF request to transfer downlink N1 and/or N2 message to the UE and/or AN through the AMF.
Input, Required:
CN NF ID, Message type (N1 or N2 or both), Message Container (s) where at least one of the message containers (N1 or N2) is required.
Input, Optional:
last message indication, Session ID, Paging Policy Indicator, ARP, Area of validity for the N2 SM information, 5QI, N1N2TransferFailure Notification Target Address, type of N2 SM information, type of N2 NRPPa information, Extended Buffering Support. MA PDU session Accepted indication, target access type (3GPP access or non-3GPP access).
Namf_Communication_N1N2MessageTransfer supports the transfer of only one N2 message. N2 SM information and N2 NRPPa information are mutually exclusive.
Output, Required:
Result indication.
Output, Optional:
Redirection information, Estimated Maximum wait time.
If the UE is in CM-IDLE state, the AMF initiates the network triggered service request procedure as specified in clause 4.2.3.3 and responds to the consumer NF with a result indication, "attempting to reach UE". Otherwise, the AMF responds to the consumer NF, with a Namf_Communication_N1N2MessageTransfer response, providing a result indication of whether the AMF was able to successfully transfer the N1 and/or the N2 message towards the UE and/or the AN. A result indication of "N1/N2 transfer success" does not mean that N1 message is successfully received by the UE. It only means that the AMF is able to successfully send the N1 or N2 message towards the AN.
The "Area of validity for the N2 SM information", if included is used by the AMF to determine whether the N2 SM information provided by the consumer NF can be used towards the AN based on the current location of the UE. If the location of the UE is outside the "Area of validity for the N2 SM information" indicated, the AMF shall not send the N2 SM information to the AN.
If the consumer NF knows that a specific downlink N1 message is the last message to be transferred in this transaction, the consumer NF shall include the last message indication in the Namf_Communication_N1N2MessageTransfer service operation so that the AMF knows that the no more downlink N1 message need to be transferred for this transaction.
The CN NF is implicitly subscribed to be notified of N1N2TransferFailure by providing the N1N2TransferFailure Notification Target Address. When AMF detects that the UE failes to response to paging or the AMF determines the UE is temporarily unreachable e.g. due to extended idle mode DRX or MICO mode, the AMF invokes the Namf_Communication_N1N2TransferFailureNotification to provide the failure notification to the location addressed by N1N2TransferFailure Notification Target Address.
The "Extended Buffering applies" indication, if included, is used by the AMF to include "Estimated Maximum Wait time" in Namf_Communication_N1N2 TransferFailureNotification if invoked due to the UE being unreachable.
If the result of the service operation fails, the AMF shall set the corresponding cause value in the result indication which can be used by the NF consumer for further action. If the related UE is not served by AMF and the AMF knows which AMF is serving the UE, the AMF provides redirection information which can be used by the consumer NF to resend UE related message to the AMF that serves the UE.
If the consumer NF is a SMF and he request includes N2 SM information, the SMF indicates the type of N2 SM information. If the consumer NF is a LMF and the request includes N2 NRPPa information, the LMF indicates the type of N2 NRPPa information.
NOTE:
The actual N2 SM information or N2 NRPPa information is not interpreted by the AMF.
The Small Data Rate Control Status is included if a PDU Session is being released and the UPF or NEF provided Small Data Rate Control Status when the PDU Session was released for the AMF to store.
For the usage of MA PDU session Accepted indication and target access type (3GPP access or non-3GPP access) see clause 4.22.2.1.
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5.2.2.2.7A  Namf_Communication_N1N2TransferFailureNotification service operationWord-p. 447
Service operation name:
Namf_Communication_N1N2TransferFailureNotification.
Description:
The AMF uses this notification to inform the NF service consumer that initiated an earlier Namf_Communication_N1N2MessageTransfer, that the AMF failed to deliver the N1 message to the UE as the UE failed to respond to paging.
Input, Required:
Cause, N1N2MessageTransfer Notification Target Address.
Input, Optional:
Estimated Maximum wait time.
Output, Required:
None.
Output, Optional:
None.
5.2.2.2.8  Namf_Communication_N2InfoSubscribe service operationWord-p. 448
Service operation name:
Namf_Communication_N2InfoSubscribe.
Description:
An NF invokes this service operation to subscribe for the delivery of information contained in a specific N2 message type.
Input, Required:
CN NF ID, N2 information type to be subscribed.
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
5.2.2.2.9  Namf_Communication_N2InfoUnsubscribe service operation
Service operation name:
Namf_Communication_N2InfoUnSubscribe.
Description:
An NF can invoke this service operation to unsubscribe for the delivery of information contained in a specific N2 message type.
Input, Required:
CN NF ID, N2 information type to unsubscribe.
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
The consumer NF invokes the Namf_Communication_N2InfoUnSubscribe service operation (CN NF ID, N2 information type to unsubscribe) on the AMF. The AMF deletes the binding for the consumer NF to for the requested information to unsubscribe.
5.2.2.2.10  Namf_Communication_N2InfoNotify service operation
Service operation name:
Namf_Communication_N2InfoNotify.
Description:
The AMF uses this service operation to notify a particular N2 message information towards the NFs that have subscribed (implicitly or explicitly) for the specific information. This service operation is also used to redirect the N2 message to the AMF that are serving the UE.
Input, Required:
AMF ID (GUAMI), N2 information.
Input, Optional:
Indication of the I-SMF change/removal.
Output, Required:
None.
Output, Optional:
None.
5.2.2.2.11  Namf_Communication_CreateUEContext service operation
Service operation name:
Namf_Communication_CreateUEContext
Description:
This service operation is used by a source AMF to create the UE context in a target AMF during handover procedures.
Input, Required:
5G-GUTI, UE context of the identified UE. As decribed in Table 5.2.2.2.2-1, the UE context may include the SUPI, DRX parameters, AM policy information, UE Radio Capability ID, PCF ID, UE network capability, used N1 security context information, event subscriptions by other consumer NF, and the list of SM PDU Session IDs along with the SMF handling the PDU Session, N2 information including source to target RAN transparent container, Endpoint information of S-AMF to receive N2 information notification about handover complete.
Input, Optional:
allocated EBI information, PCF ID, MS Classmark 2, STN-SR, C MSISDN, and the Supported Codec IE.
Output, Required:
Cause, N2 information including Target to Source transparent container, N2 SM information (PDU Sessions failed to be setup list, and the N3 DL forwarding information), handle for the UE context created, PCF ID.
Output, Optional:
None.
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5.2.2.2.12  Namf_Communication_ReleaseUEContext service operationWord-p. 449
Service operation name:
Namf_Communication_ReleaseUEContext
Description:
This service operation is used by a source AMF to release the UE context in a target AMF during handover cancel procedures.
Input, Required:
Handle of the UE context.
Input, Optional:
None.
Output, Required:
Cause.
Output, Optional:
None.
5.2.2.2.13  Namf_Communication_EBIAssignment service operation
Service operation name:
Namf_Communication_EBIAssignment.
Description:
The consumer NF uses this service operation to request a bunch of EPS Bearer IDs for a PDU Session, and optionally indicate to the AMF the list of EBI(s) to be released.
Inputs, Required:
SUPI, PDU Session ID, ARP list.
Input, Optional:
Released EBI list.
Outputs, Required:
None.
Outputs, Optional:
a list of <ARP, EBI> pair, <ARP, Cause> pair.
The consumer NF invokes the Namf_Communication_EBIAssignment service operation when it determines that one or more EPS Bearer IDs are required for EPS QoS mapping for a PDU Session. The ARP list indicates the number of the requested EBIs, and the corresponding ARP. The AMF uses the ARP list (including ARP priority level, the pre-emption capability and the pre-emption vulnerability) and the S-NSSAI to prioritize the EBI request, AMF can revoke the EBI from an ongoing lower priority PDU Session, if the maximum number of EBIs have been reached and a session with a higher priority requests an EBI. The AMF responds the consumer NF with a cause which indicates whether the assignment is successful or not. If the assignment is successful, the AMF provides a list of <ARP, EBI> pair to the consumer NF.
If the consumer NF determines that some EBIs are not needed, the consumer NF indicates the EBI(s) that can be released in the Released EBI list.
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5.2.2.2.14  Namf_Communication_AMFStatusChangeSubscribe service operation
Service operation name:
Namf_Communication_AMFStatusChangeSubscribe
Description:
This service operation is used by an NF to subscribe for AMF Status Change notification.
Input, Required:
GUAMI(s).
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
See clause 5.21.2.2 of TS 23.501 for the example usage of this service operation. The GUAMI(s) is used to identify the AMF.
5.2.2.2.15  Namf_Communication_AMFStatusChangeUnSubscribe service operationWord-p. 450
Service operation name:
Namf_Communication_AMFStatusChangeUnSubscribe
Description:
This service operation is used by an NF to unsubscribe for AMF Status Change notification.
Input, Required:
GUAMI(s).
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
See clause 5.21.2.2 of TS 23.501 for the example usage of this service operation. The GUAMI(s) is used to identify the AMF.
5.2.2.2.16  Namf_Communication_AMFStatusChangeNotify service operation
Service operation name:
Namf_Communication_AMFStatusChangeNotify
Description:
Report AMF Status change (e.g. AMF unavailable) notification to subscribed NFs.
Input, Required:
GUAMI(s).
Input, Optional:
Target AMF(s) Name associated with the indicated GUAMI.
Output, Required:
None.
Output, Optional:
None.
See clause 5.21.2.2 of TS 23.501 for the example usage of this service operation. The GUAMI(s) is used to identify the AMF. For network deployment without UDSF case, the target AMF Name which is to serve the user of the indicated GUAMI is also included.
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5.2.2.2.17  Namf_Communication_NonUeN2MessageTransfer service operation [R16]
Service operation name:
Namf_Communication_NonUeN2MessageTransfer
Description:
NF Service Consumer requests to transfer a non-UE specific message to NG-RAN node(s) via N2.
Input, Required:
N2 Message Container.
Input, Optional:
TAI List, RAT Selector (ng-eNB or gNB), Global RAN Node List.
Output, Required:
N2 Information Transfer Result.
Output, Optional:
PWS Result Data.
PWS Result Data is included when parts of a PWS received message have not been comprehended or were missing, or if the message contained logical errors. It may contain the Unknown Tracking Area List which may be present in the associated PWS response message.
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5.2.2.2.18  Namf_Communication_NonUeN2InfoSubscribe service operation [R16]
Service operation name:
Namf_Communication_NonUeN2InfoSubscribe
Description:
The NF Service Consumer invokes this service operation to subscribe to the delivery of non-UE specific information from the NG-RAN node sent via N2 to the AMF.
Input, Required:
NF Service Consumer ID, N2 information type to be subscribed.
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
5.2.2.2.19  Namf_Communication_NonUeN2InfoUnSubscribe service operation [R16]Word-p. 451
Service operation name:
Namf_Communication_NonUeN2InfoUnSubscribe
Description:
The NF Service Consumer invokes this service operation to unsubscribe to stop notifying non-UE specific N2 information.
Input, Required:
Subscription Correlation Id.
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
5.2.2.2.20  Namf_Communication_NonUeN2InfoNotify service operation [R16]
Service operation name:
Namf_Communication_NonUeN2InfoNotify
Description:
The AMF uses this service operation to notify a particular event towards the NF Service Consumer that has subscribed for the specific information. The AMF receives messages for such events from NG-RAN via N2.
Input, Required:
N2 information.
Input, Optional:
None.
Output, Required:
None.
Output, Optional:
None.
5.2.2.3  Namf_EventExposure service
5.2.2.3.1  General
Service description: This service enables an NF to subscribe and get notified about an Event ID.
Following UE access and mobility information event are considered (Event ID is defined in clause 4.15.1 and Table 4.15.3.1-1):
  • Location changes (TAI, Cell ID, N3IWF/TNGF node, UE local IP address and optionally UDP source port number, Area Of Interest);
  • UE moving in or out of a subscribed "Area Of Interest" as described in clauses 5.3.4.4 and 5.6.11 in TS 23.501;
  • Number of UEs served by the AMF and located in "Area Of Interest";
  • Time zone changes (UE Time zone);
  • Access Type changes (3GPP access or non-3GPP access);
  • Registration state changes (Registered or Deregistered);
  • Connectivity state changes (IDLE or CONNECTED);
  • UE loss of communication;
  • UE reachability status;
  • UE indication of switching off SMS over NAS service;
  • Subscription Correlation ID change (implicit subscription);
  • Type Allocation code (TAC);
  • Frequent mobility re-registration;
  • Subscription Correlation ID addition (implicit subscription); and
  • User State Information in 5GS.
Event Filters are used to specify the conditions to match for notifying the event (i.e. "List of Parameter values to match"). If there are no conditions to match for a specific Event ID, then the Event Filter is not provided. The following table provides some examples on how the conditions to match for event reporting can be specified for various Event IDs for AMF exposure.
NOTE:
The conditions to match can be set based on AMF-associated expected UE Behaviour parameter(s) to only notify the event when the UE's behaviour deviates from its expected UE behaviour as described in TS 23.288.
Event ID
Event Filter (List of Parameter Values to Match)

Area of Interest
<Parameter Type = TAI, Value = TA1>
<Parameter Type = PRA ID, Value = PRA ID value>
Area of Interest
<Parameter Type = TAI, Value = TA1>
<Parameter Type = S-NSSAI, Value = S-NSSAI1>
<Parameter Type = NSI ID, Value = NSI ID1>
Access Type
<Parameter Type=AN Type, Value=3GPP Access">
Location
<Parameter Type=TAI, Value=wildcard> (to report any TAI change)
Location
<Parameter Type=TAI Value=abnormal> (to report only when the TAI deviates from expected values based on Expected UE Moving Trajectory).

The following service operations are defined for the Namf_EventExposure service:
  • Namf_EventExposure_Subscribe.
  • Namf_EventExposure_UnSubscribe.
  • Namf_EventExposure_Notify.
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5.2.2.3.2  Namf_EventExposure_Subscribe service operationWord-p. 452
Service operation name:
Namf_EventExposure_Subscribe.
Description:
The consumer NF uses this service operation to subscribe to or modify event reporting for one UE, a group of UE(s) or any UE.
Input, Required:
NF ID, Target of Event Reporting: UE(s) ID (SUPI or Internal Group Identifier or indication that any UE is targeted), ((set of) Event ID(s) defined in clause 5.2.2.3.1, Notification Target Address (+ Notification Correlation ID))s, Event Reporting Information defined in Table 4.15.1-1.
Input, Optional:
(Event Filter (s) associated with each Event ID; Event Filter (s) are defined in clause 5.2.2.3.1, Subscription Correlation ID (in the case of modification of the event subscription), Expiry time.
Output, Required:
When the subscription is accepted: Subscription Correlation ID (required for management of this subscription), Expiry time (required if the subscription can be expired based on the operator's policy).
Output, Optional:
First corresponding event report is included, if available (see clause 4.15.1).
The NF consumer subscribes to the event notification by invoking Namf_EventExposure to the AMF. The AMF allocates an Subscription Correlation ID for the subscription and responds to the consumer NF with the Subscription Correlation ID. UE ID identifies the UE, SUPI and/or GPSI. Event ID (see clause 4.15.1) identifies the events that the NF consumer is interested in. The Subscription Correlation ID is unique within the AMF Set.
The ((set of) Event ID(s), Notification Target Address (+ Notification Correlation ID)) helps the Event Receiving NF to co-relate a notification against a corresponding event subscription for the indicated Event ID.
In the case that the NF consumer subscribes to the AMF on behalf of other NF, the NF consumer include the Notification Target Address(+Notification Correlation ID) of other NF for the Event ID which is to be notified to other NF directly, and the Notification Target Address(+Notification Correlation ID) of itself for the Subscription Correlation ID change event. Each Notification Target Address(+ Notification Correlation ID) is associated with the related (set of) Event ID(s).When the Subscription Correlation ID change due to the AMF reallocation, the notification is sent to NF consumer which triggers this subscription.
Event filter may include "AN type(s)" as part of the list of parameter values to match, and it indicates to subscribe the event per Access Type.
Event receiving NF ID identifies the NF that shall receive the event reporting.
When the consumer NF needs to modify an existing subscription previously created by itself in the AMF, it invokes Namf_EventExposure_Subscribe service operation which contains the Subscription Correlation ID and the new Event Filters with Event ID to the AMF.
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5.2.2.3.3  Namf_EventExposure_UnSubscribe service operationWord-p. 453
Service operation name:
Namf_EventExposure_UnSubscribe.
Description:
The NF consumer uses this service operation to unsubscribe for a specific event for one UE, group of UE(s), any UE.
Input, Required:
Subscription Correlation ID.
Input, Optional:
None.
Output, Required:
Operation execution result indication.
Output, Optional:
None.
The NF consumer unsubscribes the event notification by invoking Namf_EventExposure_Unsubscribe (Subscription Correlation ID) to the AMF.
5.2.2.3.4  Namf_EventExposure_Notify service operation
Service operation name:
Namf_EventExposure_Notify.
Service operation description: Provides the previously subscribed event information to the NF Consumer which has subscribed to that event before.
Input, Required:
AMF ID (GUAMI), Notification Correlation Information, Event ID, corresponding UE(s) (SUPI(s) and if available GPSI(s)), time stamp.
Input, Optional:
Event specific parameter list.
Output, Required:
None.
Output, Optional:
None.
When the AMF detects a UE access and mobility event corresponding to a Subscription, it invokes Namf_EventExposure_Notify service operation to the NF consumer(s) which has subscribed to the UE mobility event before. The event is notified towards the consumers for which the Event filters (which may include "AN type(s)") match. The Notification Target Address (+ Notification Correlation ID) indicates to the Event Receiving NF the specific event notification subscription. The event specific parameter indicates the type of mobility event and related information, e.g. Registration Area Update/new Registration Area.
The optional event specific parameter list provides the values that matched for generating the event notification. The parameter values to match are specified during the event subscription (see clause 5.2.2.3.2). For example if the event type reported is "AN change", the event specific parameter list contains the value of the new AN.
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5.2.2.4  Namf_MT serviceWord-p. 454
5.2.2.4.1  General
Service description: It provides a NF the service to request information related to capabilities that make sure UE is reachable to send MT signalling or data to a target UE. The following are the key functionalities of this NF service
  • paging UE if UE is in IDLE state and respond other NF after the UE enters CM-CONNECTED state.
  • response to the requester NF if UE is in CONNECTED state.
  • providing the terminating domain selection information for IMS voice to the consumer NF.
5.2.2.4.2  Namf_MT_EnableUEReachability service operation
Service operation name:
Namf_MT_EnableUEReachability.
Description:
The consumer NF uses this service operation to request enabling UE reachability.
Inputs, Required:
NF ID, UE ID.
Inputs, Optional:
Extended Buffering Support.
Outputs, Required:
Result indication.
Outputs, Optional:
Redirection information, Estimated Maximum wait time.
See clause 4.13.3.6 and clause 4.24.2 for details on the usage of this service operation.
The consumer NF does not need to know UE state. The AMF accepts the request and respond the consumer NF immediately if UE is in CM-CONNECTED state. If the UE is in CM-IDLE state, the AMF may page the UE and respond to the consumer NF after the UE enters CM-CONNECTED state.
If the result of the service operation fails, the AMF shall set the corresponding cause value in the result indication which can be used by the NF consumer for further action. If the related UE is not served by the AMF and the AMF knows which AMF is serving the UE, the AMF provides redirection information which can be used by the NF consumer to resend UE related message to the AMF that serves the UE.
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5.2.2.4.3  Namf_MT_ProvideDomainSelectionInfo
Service operation name:
Namf_MT_ProvideDomainSelectionInfo.
Description:
Provides the UE information for terminating domain selection of IMS voice to the consumer NF.
Input, Required:
SUPI.
Input, Optional:
None.
Output, Required:
Success/Failure indication.
Output, Optional:
Indication of supporting IMS voice over PS Session or not, Time stamp of the last radio contact with the UE, Current RAT type.
5.2.2.5  Namf_Location service
5.2.2.5.1  General
Service description: This service enables an NF to request location information for a target UE. The following are the key functionalities of this NF service.
  • Allow NFs to request the current or last known geodetic and optionally civic location of a target UE.
  • Allow NFs to be notified of event information related to emergency sessions or deferred UE location.
  • Allow NFs to request Network Provided Location Information (NPLI) and/or local time zone corresponding to the location of a target UE.
  • Allow NFs to request a deferred geodetic and and optionally civic location of a target UE for Periodic, Triggered and UE Available Location Events.
  • Allow NFs to cancel an ongoing session for periodic or triggered location of a target UE.
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5.2.2.5.2  Namf_Location_ProvidePositioningInfo service operationWord-p. 455
Service operation name:
Namf_Location_ProvidePositioningInfo
Description:
Provides UE positioning information to the consumer NF.
Input, Required:
UE Identification (SUPI or PEI), Client Type.
Input, Optional:
Location QoS, Supported GAD shapes, UE Privacy Requirements, External Client Identification, Deferred location type, Deferred location parameters, Notification Target address, Notification Correlation ID.
Output, Required:
Success/Failure indication
Output, Optional:
Geodetic Location, Civic Location, Position Methods Used, Failure Cause.
See steps 4 and 10 of clause 6.1.1, steps 5, 14, 18 and 22 of clause 6.1.2 and steps 5 and 6 of clause 6.3.1 of TS 23.273, for examples of usage of this service operation.
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5.2.2.5.3  Namf_Location_EventNotify service operation
Service operation name:
Namf_Location_EventNotify
Description:
Provides UE location related event information related to emergency sessions or deferred location to the consumer NF.
Input, Required:
Type of location related event (e.g. emergency session initiation, deferred location for the UE available event, activation of location for periodic or triggered location, mobility of a target UE to a new AMF or MME for a deferred location), UE Identification (SUPI or PEI).
Input, Optional:
GPSI, Geodetic Location, Civic Location, Position methods used, Notification Target address, Notification Correlation ID, address of a new AMF or MME.
Output, Required:
None.
Output, Optional:
None.
See steps 5 and 8 of clause 6.10.1 and step 19 of clause 6.3.1 of TS 23.273 for examples of usage of this service operation.
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5.2.2.5.4  Namf_Location_ProvideLocationInfo service operation
Service operation name:
Namf_Location_ProvideLocationInfo
Description:
Provides Network Provided Location Information (NPLI) of a target UE to the consumer NF.
Input, Required:
UE Identification (SUPI).
Input, Optional:
5GS Location Information Request, Current Location Request, RAT type Requested, Local Time Zone Request.
Output, Required:
Success/Failure indication.
Output, Optional:
5GS Location Information (Cell Identity, Tracking Area Identity, Geographical/Geodetic Information, Current Location Retrieved, Age of Location Information, Current RAT Type), Local Time Zone, Failure Cause. In the case of non-3GPP access: a UE local IP address (used to reach the N3IWF/TNGF) and optionally UDP or TCP source port number (if NAT is detected).
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5.2.2.5.5  Namf_Location_CancelLocation service operation [R16]Word-p. 456
Service operation name:
Namf_Location_CancelLocation
Description:
Cancels an ongoing deferred location of a target UE to the consumer NF.
Input, Required:
UE Identification (SUPI), Notification Target address, Notification Correlation ID.
Input, Optional:
None.
Output, Required:
Success/Failure indication.
Output, Optional:
None.
See steps 4 and 10 of clause 6.3.3 of TS 23.273 for examples of usage of this service operation.

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