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).

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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 and/or the UE 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 and/or a new UE Policy Association). The AMF sends a Namf_Communication_RegistrationStatusUpdate response to the consumer NF.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

The optional AN access information (if available), SUPI, MM Context, Allowed NSSAI and Mapping Of Allowed NSSAI parameters are included if the service operation is invoked towards a peer AMF.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: The consumer NF invokes the Namf_Communication_N1MessageSubscribe service operation (NF ID, N1 message type or N2 information 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/N2 message requested, the AMF creates a binding for the consumer NF to deliver subsequent Namf_Communication_N1MessageNotify or Namf_Communication_N2InfoNotify towards that NF.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: The consumer NF invokes the Namf_Communication_N1MessageUnSubscribe service operation (NF ID, N1 message type or N2 information type to subscribe) on the AMF. The AMF deletes the binding for the consumer NF for the requested N1 message type.

Service operation name: Description: Input, Required: Input, Optional: Namf_Communication_N1N2MessageTransfer supports the transfer of only one N2 message. N2 SM information and N2 NRPPa information are mutually exclusive. Output, Required: Output, Optional: 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 fails to respond to paging, or the UE responds to paging with a Reject Paging Indication, 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. The selected alternative H-SMF ID information may be provided as described in clause 4.3.2.2.2. 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 clauses 4.22.2, 4.22.3, 4.22.6.3 and 4.22.9.4.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Inputs, Required: Input, Optional: Outputs, Required: Outputs, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

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 Report (TAI, Cell ID, N3IWF/TNGF node, UE local IP address and optionally UDP source port number);
• UE moving in or out of a subscribed "Area Of Interest" as described in clauses 5.3.4.4 and 5.6.11 of 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);
• UE Type Allocation code (TAC);
• Frequent mobility re-registration;
• Subscription Correlation ID addition (implicit subscription);
• User State Information in 5GS, as described in clause 5.4.4 of TS 23.632;
• UE access behaviour trends (see clause 4.15.4.2);
• UE location trends (see clause 4.15.4.2); and
• Total number of Mobility Management transactions:
  • The Total number of Mobility Management transactions is used to collect the number of MM transactions of a SUPI or Internal Group ID, for example Dispersion Analytics as specified in TS 23.288. The Total number of transactions is incremented when the NAS signalling transactions from Authentication, Registration, De-Registration, Service Request and UE Configuration Update procedures is completed. Only the periodic reporting mode applies.

In addition to UE access and mobility information event, AMF exposes the "S-NSSAIs per TAI mapping" event providing, per TAI, the related access type and list of supported S-NSSAIs (including indication of S-NSSAIs restricted by AMF). The Event Consumer may use as target of event reporting a list of TAIs, or "any TAI" and may use event filter information including a list of "S-NSSAIs". Whenever there is a change in supported S-NSSAIs (including indication of S-NSSAIs restricted by AMF) for a TAI, the event notification is generated with the updated information. 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.

  The following service operations are defined for the Namf_EventExposure service:

• Namf_EventExposure_Subscribe.
• Namf_EventExposure_UnSubscribe.
• Namf_EventExposure_Notify.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: The NF consumer unsubscribes the event notification by invoking Namf_EventExposure_Unsubscribe (Subscription Correlation ID) to the AMF.

Service operation name: Service operation description: Provides the previously subscribed event information to the NF Consumer which has subscribed to that event before. Input, Required: Input, Optional: Output, Required: Output, Optional: 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. For Subscription Correlation ID changes due to the AMF reallocation, the AMF can send a list of additional subscriptions to UDM in order to trigger an event resynchronization. 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.

Service description:

• 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.
• requesting paging towards a group of UEs as defined in TS 23.247.

Service operation name: Description: Inputs, Required: Inputs, Optional: Outputs, Required: Outputs, Optional: 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Inputs, Required: Inputs, Optional: Outputs, Required: Outputs, Optional: This service operation is used in 5G MBS as specified in TS 23.247.

Service operation name: Description: Inputs, Required: Inputs, Optional: Outputs, Required: Outputs, Optional:

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 local and/or 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 optionally local and/or 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.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: See steps 4 and 10 of clause 6.1.1, steps 5, 14, 18 and 22 of clause 6.1.2, steps 5 and 6 of clause 6.3.1 and step 5 of clause 6.20.3 of TS 23.273, for examples of usage of this service operation.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: See steps 5 and 8 of clause 6.10.1 and step 19 of clause 6.3.1 of TS 23.273 and clause 6.5.4 of TS 23.216 for examples of usage of this service operation.

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional:

Service operation name: Description: Input, Required: Input, Optional: Output, Required: Output, Optional: See steps 4 and 10 of clause 6.3.3 of TS 23.273 for examples of usage of this service operation.