5 Services offered by the TSCTSF

29.5653GPP5G SystemRelease 18Stage 3Time Sensitive Communication and Time Synchronization Function ServicesTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.1 Introduction

Table 5.1-1 summarizes the corresponding APIs defined for this specification.

Table 5.1-1: API Descriptions

Service Name	Clause	Description	OpenAPI Specification File	apiName	Annex
Ntsctsf_TimeSynchronization	6.1	Provides the support to subscribe/unsubscribe to the notification about time synchronization capabilities and to activate and deactivate the time synchronization configuration.	TS29565_Ntsctsf_TimeSynchronization.yaml	ntsctsf-time-sync	A.2
Ntsctsf_QoSandTSCAssistance	6.2	Provides the support to request specific QoS and provide assistance for handling traffic characterized by TSC QoS parameters.	TS29565_Ntsctsf_QoSandTSCAssistance.yaml	ntsctsf-qos-tscai	A.3
Ntsctsf_ASTI	6.3	Provides support for time synchronization service based on 5G access stratum time distribution method.	TS29565_Ntsctsf_ASTI.yaml	ntsctsf-asti	A.4

5.2 Ntsctsf_TimeSynchronization Service

5.2.1 Service Description

5.2.1.1 Overview

This service provides:

– Authorization of NF Service Consumer requests for the subscription to the notification of the capability of time synchronization service.

– Authorization of NF Service Consumer requests to create and update time synchronization configuration, and to activate and deactivate the time synchronization service as described in clause 5.27.1.8 of TS 23.501 [2].

NOTE: The AF can use either the procedure specified in bullet2) for configuring the (g)PTP instance in 5GS or the procedure specified in clause 5.4.2.2 for controlling the 5G access stratum time distribution for a particular UE. The procedures are not intended to be used in conjunction with each other by the AF. However, the (g)PTP instance activation, modification, and deactivation can influence the 5G access stratum time distribution for the UEs that are part of the impacted PTP instance.

5.2.1.2 Network Functions

5.2.1.2.1 TSCTSF

The TSCTSF supports to:

– receive the request to create/update the subscription to the notification of the capability of time synchronization service from the NEF or AF and interact with the related PCF;

– receive the request to delete the subscription to the notification of the capability of time synchronization service from the NEF or AF and remove the information from the related PCF;

– receive the notification of the availability of the user plane node information from the PCF and subscribe the notification of user plane node related events at the PCF;

– determine the capability of time synchronization service based on the capability information received from the DS-TT(s) and NW-TT and notify the NEF or AF of the capability;

– receive the request to create or modify the time synchronization configuration from the NEF or AF, configure and initialize the PTP instance(s) by constructing a PMIC to each DS-TT/UE to activate the time synchronization service in DS-TT and PMIC(s) and UMIC to NW-TT to activate the time synchronization service in NW-TT and provision them to the PCF;

– Notify the NEF or AF of the current state of the time synchronization service configuration;

– receive the request of time synchronization deactivation from the NEF or AF and disable the corresponding PTP instance(s) in the DS-TT(s) and NW-TT.

5.2.1.2.2 NF Service Consumers

The NF service consumer supports to:

– send the request to create/update and delete the subscription to the notification of the capability of time synchronization service to TSCTSF;

– receive the notification of the capability of time synchronization service;

– send the request to create, modify and delete the time synchronization configuration to the TSCTSF;

5.2.2 Service Operations

5.2.2.1 Introduction

Service operations defined for the Ntsctsf_TimeSynchronization service are shown in table 5.2.2.1-1.

Table 5.2.2.1-1: Ntsctsf_TimeSynchronization Service Operations

Service Operation Name	Description	Initiated by
Ntsctsf_TimeSynchronization_CapsSubscribe	Allows the NF service consumer to create or modify a subscription to the notification about the capability of time synchronization service for a list of UEs a group of UEs or any UE using a DNN/S-NSSAI combination.	NF service consumer (e.g. AF, NEF)
Ntsctsf_TimeSynchronization_CapsUnsubscribe	Allows the NF service consumer to delete the subscription to the notification about capability of time synchronization service for a list of UEs, a group of UEs or any UE using a DNN/S-NSSAI combination.	NF service consumer (e.g. AF, NEF)
Ntsctsf_TimeSynchronization_CapsNotify	Allows the TSCTSF to notify the NF service consumer of the capability of time synchronization service.	TSCTSF
Ntsctsf_TimeSynchronization_ConfigCreate	Allows the NF service consumer to create a time synchronization configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_TimeSynchronization_ConfigUpdate	Allows the NF service consumers to update the time synchronization configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_TimeSynchronization_ConfigDelete	Allows the NF service consumer to delete the time synchronization configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_TimeSynchronization_ConfigUpdateNotify	Allows the TSCTSF to notify the NF service consumer of the state of time synchronization configuration.	TSCTSF

NOTE: The NEF and the AF use the Ntsctsf_TimeSynchronization service in the same way.

5.2.2.2 Ntsctsf_TimeSynchronization_CapsSubscribe

5.2.2.2.1 General

This service operation is used by an NF service consumer to subscribe to notification of capability of time synchronization service for a list of UEs, a group of UEs or any UE using a DNN/S-NSSAI combination.

The following procedures using the Ntsctsf_TimeSynchronization_CapsSubscribe service operation are supported:

– creating a new subscription;

– modifying an existing subscription.

5.2.2.2.2 Creating a new subscription

Figure 5.2.2.2.2-1 illustrates the creation of a subscription.

Figure 5.2.2.2.2-1: Creation of a subscription

To subscribe the notification of the capability of time synchronization service, the NF service consumer shall send an HTTP POST message to the TSCTSF to the URI "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions". The HTTP POST message shall include the TimeSyncExposureSubsc data structure as request body. The TimeSyncExposureSubsc data structure shall include:

– the indication of the UEs to which the time synchronization capabilities is requested via:

– identification of a list of individual UEs within a "supis" attribute;

– identification of a list of individual UEs within a "gpsis" attribute;

– indication of any UE within the "anyUeInd" attribute; or

– identification of a group of UE(s) within the "interGroupId" attribute; or

– identification of a group of UE(s) within the "exterGroupId" attribute.

– subscription to event(s) notification as "subscribedEvents" attribute;

– notification URI within the "subsNotifUri" attribute;

– notification correlation Id within the "subsNotifId" attribute;

– DNN with the "dnn" attribute; and

– S-NSSAI with the "snssai" attribute;

and may include:

– the conditions to match for notifying the event within the "eventFilters" attribute;

– notification methods within the "notifMethods" attribute

– maximum number of reports within the "maxReportNbr" attribute;

– expiry time within the "expiry" attribute; and

– report period within the "repPeriod" attribute.

Upon receipt of the HTTP request from the NF service consumer, if the request is authorized, the TSCTSF shall:

– create a new subscription;

– assign a subscription correlation ID;

– select an expiry time that is equal to or less than the expiry time potentially received in the request;

– store the subscription;

– if the "interGroupId" attribute or "exterGroupId" attribute is received from the NF service consumer, interact with the UDM to retrieve the SUPI list that belong to the group using the Nudm_SDM service as defined in 3GPP TS 29.503 [24];

– if the "gpsi" attribute is received from the NF service consumer, interact with the UDM to retrieve the SUPI that corresponds to the GPSI using the Nudm_SDM service as defined in 3GPP TS 29.503 [24];

– use the parameters received from the NF service consumer (i.e. DNN, S-NSSAI and, if available, the list of UEs or UEs that belong to the group of UEs) to determine the matching AF-session(s) and for any such AF-session interact with the PCF by triggering Npcf_PolicyAuthorization_Create/Update request message as defined in 3GPP TS 29.514 [20].

NOTE 1: If the PCF determines an existing PDU Session is potentially impacted by time synchronization service (based on local configuration or SM Policy Association), the PCF invokes Npcf_PolicyAuthorization_Notify service operation to the TSCTSF as defined in clause 4.2.5.16 of 3GPP TS 29.514 [20] to send the received TSC User Plane Node information. At that time, the TSCTSF retrieves from the BSF the PCF binding information (including the UE Identities for the notified PDU session), as specified in 3GPP TS 29.521 [23], and can create the AF-session by sending to the PCF the Npcf_PolicyAuthorization_Create service operation.

– send an HTTP "201 Created" response with TimeSyncExposureSubsc data structure as response body and a Location header field containing the URI of the created individual subscription resource, i.e. "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}".

The TSCTSF shall handle the AF session(s) associated with the "Individual Time Synchronization Exposure Subscription" resource as follows:

– For the association of AF sessions to "Individual Time Synchronization Exposure Subscription" resources:

– Upon PDU Session establishment, i.e. when the TSCTSF receives the Npcf_PolicyAuthorization_Notify service operation for the establishment of a new PDU session, the TSCTSF shall retrieve from the BSF, as specified in 3GPP TS 29.521 [23], the PCF binding information to complete the necessary AF-Session information and triggers the Npcf_PolicyAuthorization_Create request message to the PCF to create an AF-session to subscribe to TSC user plane node related events. The TSCTSF, shall use the parameters of existing "Individual Time Synchronization Exposure Subscription" resources to determine whether they shall be associated to this newly created AF sessionThe TSCTSF associates the new AF session to the "Individual Time Synchronization Exposure Subscription" resources for which these parameters match. The TSCTSF shall read time synchronization capabilities from the DS-TT and NW-TT, if not available in the AF session, from the PCF by triggering Npcf_PolicyAuthorization_Update request message as defined in 3GPP TS 29.514 [20] and determine the (g)PTP capabilities from the DS-TT and the NW-TT as described in clause K.2.1 of 3GPP TS 23.501 [2]. The TSCTSF shall update the time synchronization service capability for this new DS-TT as defined in clause 5.2.2.4.2.

– Upon "Individual Time Synchronization Exposure Subscription" resource creation, the TSCTSF uses the parameters of the created resource to determine which existing AF sessions it matches. The TSCTSF associates the new "Individual Time Synchronization Exposure Subscription" resource to the AF sessionsfor which these parameters match.

– To remove an AF session from the associated ones to the "Individual Time Synchronization Exposure Subscription" resource, when the TSCTSF receives the Npcf_PolicyAuthorization_Notify service operation indicating the termination of an existing PDU session, the TSCTSF triggers the Npcf_PolicyAuthorization_Delete request message to the PCF and determines if the corresponding AF session is associated with the "Individual Time Synchronization Exposure Subscription" resource. If it is so, the TSCTSF shall remove the AF session from the list of AF session(s) associated with the "Individual Time Synchronization Exposure Subscription" resource. The TSCTSF shall update the time synchronization service capability for this removed DS-TT as defined in clause 5.2.2.4.2.

NOTE 2: After the TSCTSF retrieves from the BSF the PCF binding information (including the UE Identities for the notified PDU session), as specified in 3GPP TS 29.521 [23], the TSCTSF can store internally the information required to invoke Npcf_PolicyAuthorization_Create service operation and delay the Npcf_PolicyAuthorization_Create service operation (the creation of the AF session) till the subscription to notification of the capability of time synchronization service is received for the concerned UE. In this case, when the TSCTSF receives the subscription request, the TSCTSF interacts with the PCF by triggering Npcf_PolicyAuthorization_Create message as defined in 3GPP TS 29.514 [20].

NOTE 3: When the TSCTSF receives the Npcf_PolicyAuthorization_Notify service operation indicating the termination of an existing PDU session associated to an AF session that it is not associated with any "Individual Time Synchronization Exposure Subscription" resource, the TSCTSF removes the AF-session and triggers the Npcf_PolicyAuthorization_Delete request message to the PCF.

If the TSCTSF cannot successfully fulfil the received HTTP POST request due to the internal TSCTSF error or due to the error in the HTTP POST request, the TSCTSF shall send the HTTP error response as specified in clause 6.1.7.

5.2.2.2.3 Modifying an existing subscription

Figure 5.2.2.2.3-1 illustrates the modification of a subscription.

Figure 5.2.2.2.3-1: Modification of a subscription

To modify the subscription to the notification of the capability of time synchronization service, the NF service consumer shall send an HTTP PUT message to the TSCTSF to the URI "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}" representing an existing "Individual Time Synchronization Exposure Subscription" resource, as shown in figure 5.2.2.2.3-1, step 1. The HTTP PUT message shall include the TimeSyncExposureSubsc data structure as request body. The TimeSyncExposureSubsc data structure shall include the parameters as defined in clause 5.2.2.2.2.

Upon receipt of the HTTP request from the NF service consumer, if the request is authorized, the TSCTSF shall:

– update the existing "Individual Time Synchronization Exposure Subscription" resource;

– identify the affected AF session(s) based on the parameters received from the NF service consumer and interact with the PCF by triggering Npcf_PolicyAuthorization_Update request message as defined in 3GPP TS 29.514 [20] for the new added UE(s), by triggering Npcf_PolicyAuthorization_Delete request message as defined in 3GPP TS 29.514 [20] for the removed UE(s) or by triggering Npcf_PolicyAuthorization_Update request message as defined in 3GPP TS 29.514 [20] for the existing UE(s) if necessary.

NOTE 2: After the TSCTSF retrieves from the BSF the PCF binding information (including the UE Identities for the notified PDU session), as specified in 3GPP TS 29.521 [23], the TSCTSF can store internally the information required to invoke Npcf_PolicyAuthorization_Create service operation and delay the Npcf_PolicyAuthorization_Create service operation (the creation of the AF-session) till the subscription to notification of the capability of time synchronization service is received for the concerned UE. In this case, when the TSCTSF receives the subscription request, the TSCTSF interacts with the PCF by triggering Npcf_PolicyAuthorization_Create message as defined in in 3GPP TS 29.514 [20].

– update the list of AF sessions that are associated to the "Individual Time Synchronization Exposure Subscription" resource (i.e. add or remove AF sessions as associated to this resource) based on if the parameters of the AF sessions match the updated parameters of the "Individual Time Synchronization Exposure Subscription" resource.

– send a HTTP response including "200 OK" status code with TimeSyncExposureSubsc data structure or "204 No Content" status code, as shown in figure 5.2.2.2.3-1, step 2.

If the HTTP PUT request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP PUT request the cause for the rejection as specified in clause 6.1.7.

If the TSCTSF determines the received HTTP PUT request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.3 Ntsctsf_TimeSynchronization_CapsUnsubscribe service operation

5.2.2.3.1 General

This service operation is used by an NF service consumer to unsubscribe from the notifications.

The following procedure using the Ntsctsf_TimeSynchronization_CapsUnsubscribe service operation is supported:

– unsubscription from capability notifications.

5.2.2.3.2 Unsubscription from capability notifications

Figure 5.2.2.3.2-1 illustrates the unsubscription from event notifications.

Figure 5.2.2.3.2-1: Unsubscription from capability notifications

To unsubscribe from event notifications, the NF service consumer shall send an HTTP DELETE request with: "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}" as Resource URI, where "{subscriptionId}" is the subscription correlation ID of the existing subscription that is to be deleted.

Upon the reception of the HTTP DELETE request, if the received HTTP request is successfully processed and accepted, the TSCTSF shall:

– remove the corresponding subscription;

– identify the affected AF session(s) and, for each AF session, interact with the PCF by triggering Npcf_PolicyAuthorization_Delete request message as defined in 3GPP TS 29.514 [20]; and

– send an HTTP "204 No Content" response.

If the HTTP DELETE request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP DELETE request the cause for the rejection as specified in clause 6.1.7.

If the TSCTSF determines the received HTTP DELETE request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.4 Ntsctsf_TimeSynchronization_CapsNotify service operation

5.2.2.4.1 General

This service operation is used by the TSCTSF to send notifications to NF service consumers upon the detection of the capability of the time synchronization service for a list of UEs.

The following procedure using the Ntsctsf_TimeSynchronization_CapsNotify service operation is supported:

– notification about the capability of time synchronization service.

5.2.2.4.2 Notification about the capability of time synchronization service

Figure 5.2.2.4.2-1 illustrates the notification about the capability of time synchronization service.

Figure 5.2.2.4.2-1: Notification about the capability of time synchronization service

The TSCTSF maintains the association between the AF session(s) and the Individual Time Synchronization Exposure Subscription resource as defined in clause 5.2.2.2.2 and detects the capability of time synchronization service (for a list of UEs, a group of UEs or any UE in a DNN and S-NSSAI), by composing the time synchronization capabilities for the DS-TT/UE(s) connected to the NW-TT based on the capability information received from the DS-TT(s) and NW-TT via the PCF. If the NF service consumer includes an Event Filter with one or more of the requested PTP instance type, requested transport protocol for PTP, or requested PTP Profile, the TSCTSF considers only the DS-TT(s) and NW-TT(s) with these capabilities as part of the time synchronization capability set that is reported to the NF service consumer. If necessary, when the list of AF session(s) associated to the Individual Time Synchronization Exposure Subscription resource changes, e.g. upon PDU Session establishment or termination, the TSCTSF may notify the update of the capability of time synchronization service for the DS-TT/UE(s) connected to the NW-TT(s). In order to send the capability of time synchronization service to the NF service consumer, the TSCTSF shall send an HTTP POST request with "{subsNotifUri}", as previously provided by the NF service consumer within the corresponding subscription, as request URI and TimeSyncExposureSubsNotif data structure as request body that shall include:

– Notification correlation ID provided by the NF service consumer during the subscription within "subsNotifId" attribute; and

– information about the observed event(s) within the "eventNotifs" attribute that shall contain for each observed event an "SubsEventNotification" data structure that shall include:

1. the detected event within the "event" attribute;

2. when the event is "AVAILABILITY_FOR_TIME_SYNC_SERVICE", the capabilities of time synchronization service for one or more user plane nodes with the "timeSyncCapas" attribute. Within each instance of TimeSyncCapability data structure, the TSCTSF shall include the identifier of the applicable NW-TT within the "upNodeId" attribute, the "gmCapables" attribute indicating if the user plane node supports acting as a gPTP and/or PTP grandmaster, the supported 5G clock quality within the "asTimeRes" attribute, if applicable, and the PTP capabilities for each UE within the "ptpCapForUes" attribute, when the UEs are identified with a SUPI, or within "ptpCapForGpsis" attribute, when the UEs are identified with a GPSI.

Upon the reception of an HTTP POST, the NF service consumer shall send an HTTP "204 No Content" response for a successful processing.

If the HTTP POST request from the TSCTSF is not accepted, the NF service consumer shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.1.7.

If the NF service consumer determines the received HTTP POST request needs to be redirected, the NF service consumer shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.5 Ntsctsf_TimeSynchronization_ConfigCreate

5.2.2.5.1 General

This service operation is used by an NF service consumer to create a time synchronization configuration and activate the time synchronization service with the configuration.

The following procedures using the Ntsctsf_TimeSynchronization_ConfigCreate service operation are supported:

– creating a new configuration.

5.2.2.5.2 Creating a new configuration

Figure 5.2.2.5.2-1 illustrates the creation of a configuration.

Figure 5.2.2.5.2-1: Creation of a configuration

To create a configuration, the NF service consumer shall send an HTTP POST message to the TSCTSF to the URI "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}/configurations". The HTTP POST message shall include the TimeSyncExposureConfig data structure as request body, as shown in figure 5.2.2.5.2-1, step 1. The TimeSyncExposureConfig data structure shall include:

– the user plane node Id within the "upNodeId" attribute;

– the requested PTP instance within the "reqPtpIns" attribute;

– the time domian within the "timeDom" attribute;

– the notification URI within the "configNotifUri" attribute;

– the notification correlation Id within the "configNotifId" attribute;

and may include:

– the "gmEnable" attribute set to true if the AF requests 5GS to act as a grandmaster for PTP or gPTP;

– the time synchronization error budget within the "timeSyncErrBdgt" attribute;

– the gandmaster priority with the "gmPrio" attribute; and

– the temporal validity condition within the "tempValidity" attribute.

Upon receipt of the HTTP request from the NF service consumer, if the request is authorized, the TSCTSF shall:

– create a new resource, which represents a new "Individual Time Synchronization Exposure Configuration" instance, addressed by a URI as defined in clause 6.1.3.5 and containing a TSCTSF created resource identifier;

– send an HTTP "201 Created" response with TimeSyncExposureConfig data structure as response body and a Location header field containing the URI of the created Individual Time Synchronization Exposure Configuration resource, i.e. "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subcriptionId}/configuration/{configurationId}", as shown in figure 5.2.2.5.2-1, step 2;

– use the {subscriptionId} within the requested URI and user plane node ID within the "upNodeId" attribute in the request to determine the target UEs and corresponding AF sessions, then use the parameters (e.g. requested PTP instance type, transport protocol, and PTP profile) in the request to determine suitable DS-TT(s) and AF session(s) among all AF session and contact with the each corresponding PCF for the PDU session to configure and initialize the PTP instance in the DS-TT(s) and NW-TT as defined in 3GPP TS 23.502 [3], clause 4.15.9.3.2, step 5-6;

– calculate the Uu time synchronization error budget as specified in clause 5.27.1.9 of 3GPP TS 23.501 [2], subscribe to event notifications of newly registered PCF for the UE for the affected UEs by invoking Nbsf_Management_Subscribe Service Operation as defined in clause 4.2.6 of 3GPP TS 29.521 [23] if not yet done, and send a request to the PCF for the UE for AM policy authorization by invoking Npcf_AMPolicyAuthorization_Create service operation as defined in clause 4.2.2 of 3GPP TS 29.534 [14] providing the appropriate values in the "asTimeDisParam" attribute in order to activate the access stratum time distribution and provide the calculated Uu time synchronization error budget.

If the temporal validity condition is provided and if the start-time is in the future, the TSCTSF shall maintain the time synchronization configuration and then proceed as described above when the start-time is reached; otherwise, if the start-time is in the past, the TSCTSF shall proceed as described above immediately. When the stop-time is reached for active time synchronization service configuration, the TSCTSF shall proceed as Ntsctsf_TimeSynchronization_ConfigDelete was received as described in clause 5.2.2.7.2 without interacting with the AF.

The TSCTSF shall associate the affected AF session to the "Individual Time Synchronization Exposure Configuration". When receiving the Npcf_PolicyAuthorization_Notify service operation indicating the termination of an existing PDU session and the corresponding AF session is associated with the "Individual Time Synchronization Exposure Configuration" resource, the TSCTSF shall remove the AF session from the list of AF sessions associated with the "Individual Time Synchronization Exposure Configuration" resource and invoke Npcf_AMPolicyAuthorization_Delete service operation as defined in clause 4.2.4 of 3GPP TS 29.534 [14] to remove the access stratum time distribution parameters for the UE if they were provided.

If the HTTP POST request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.1.7.

If the TSCTSF determines the received HTTP POST request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.6 Ntsctsf_TimeSynchronization_ConfigUpdate

5.2.2.6.1 General

This service operation is used by an NF service consumer to update a time synchronization configuration.

The following procedures using the Ntsctsf_TimeSynchronization_ConfigUpdate service operation are supported:

– Updating an existing configuration.

5.2.2.6.2 Updating an existing configuration

Figure 5.2.2.6.2-1 illustrates the updating of an existing configuration.

Figure 5.2.2.6.2-1: Update of a configuration

To update a configuration, the NF service consumer shall send an HTTP PUT request to the resource "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}/configurations/{configurationId}" representing an existing "Individual Time Synchronization Exposure Configuration" resource, as shown in figure 5.2.2.6.2-1, step 1, to modify the configuration.

The TimeSyncExposureConfig data structure provided in the request body shall include:

– the user plane node Id within the "upNodeId" attribute;

NOTE 1: The user plane node Id cannot be changed during the modification.

– the requested PTP instance within the "reqPtpIns" attribute;

– the time domain within the "timeDom" attribute;

NOTE 2: The user plane node Id, the requested PTP instance and the time domain cannot be changed during the modification.

– the notification URI within the "configNotifUri" attribute;

– the notification correlation Id within the "configNotifId" attribute;

NOTE 2: If the notification URI or notification correlation Id is not changed the previously value is included.

and may include:

– the "gmEnable" attribute set to true if the AF requests 5GS to act as a grandmaster for PTP or gPTP;

– the time synchronization error budget within the "timeSyncErrBdgt" attribute;

– the gandmaster priority with the "gmPrio" attribute; and

– the temporal validity condition within the "tempValidity" attribute.

Upon receipt of the corresponding HTTP PUT message, if the request is authorized, theTSCTSF shall:

– update the existing "Individual Time Synchronization Exposure Configuration" resource;

– send a HTTP response including "200 OK" status code with TimeSyncExposureConfig data structure or "204 No Content" status code, as shown in figure 5.2.2.6.2-1, step 2;

– use the {subscriptionId} within the requested URI and user plane node ID within the "upNodeId" attribute in the request to determine the target UEs and corresponding AF-sessions, then use the updated parameters (e.g. requested PTP instance type, transport protocol, and PTP profile) in the request to determine suitable DS-TT(s) and AF session(s) among all AF session and contact with the each correspondingPCF for the PDU session to configure and initialize the PTP instance in the DS-TT(s) and NW-TT as defined in 3GPP TS 23.502 [3], clause 4.15.9.3.3, step 5-6. The TSCTSF associates the new affected AF session(s) with the "Individual Time Synchronization Exposure Configuration" resource.

– If the time synchronization error budget is provided, updated, or removed, calculate the Uu time synchronization error budget as specified in clause 5.27.1.9 of 3GPP TS 23.501 [2]and send a request to the PCF for the UE for AM policy authorization by invoking Npcf_AMPolicyAuthorization_Update service operation as defined in clause 4.2.3 of 3GPP TS 29.534 [14] in order to update the Uu time synchronization error budget.

If the temporal validity condition was provided but it is removed during the update of time synchronization configuration, the TSCTSF shall perform the time synchronization configuration as described above without considering the temporal validity condition.

If the temporal validity condition was not provided and the temporal validity condition is provided during the update of configuration, the TSCTSF shall perform as follows:

– if the start-time is in the future, the TSCTSF shall maintain the time synchronization configuration and then proceeds as described above when the start-time is reached; otherwise, if the start-time is in the past, the TSCTSF shall proceed as described above immediately;

– When the stop-time is reached for active time synchronization service configuration, the TSCTSF shall proceed as Ntsctsf_TimeSynchronization_ConfigDelete was received as described in clause 5.2.2.7.2 without interacting with the AF.

If the temporal validity condition was provided and the temporal validity condition is updated during the update of configuration, the TSCTSF shall perform as follows:

– if the previously provided time configuration is being applied but the new start-time is in the future, the TSCTSF shall proceed as Ntsctsf_TimeSynchronization_ConfigDelete was received as described in clause 5.2.2.7.2 without interacting with the AF firstly and then proceeds as described above when the new start-time is reached; otherwise if the time synchronization configuration has been created but the new start-time is in the past, the TSCTSF keep the existing configuration;

– when the new stop-time is reached for active time synchronization service configuration, the TSCTSF shall proceed as Ntsctsf_TimeSynchronization_ConfigDelete was received as described in clause 5.2.2.7.2 without interacting with the AF;

– if the previously provided time configuration is not being applied because the previously provided start-time is in the future, the TSCTSF shall perform as the case that the temporal validity condition was not provided previously.

If the HTTP PUT request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP PUT request the cause for the rejection as specified in clause 6.1.7.

If the TSCTSF determines the received HTTP PUT request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.7 Ntsctsf_TimeSynchronization_ConfigDelete

5.2.2.7.1 General

This service operation is used by an NF service consumer to delete a time synchronization configuration.

The following procedures using the Ntsctsf_TimeSynchronization_ConfigDelete service operation are supported:

– Deleting an existing configuration.

5.2.2.7.2 Deleting an existing configuration

Figure 5.2.2.7.2-1 illustrates the deleting of an existing configuration.

Figure 5.2.2.7.2-1: Deletion of a configuration

To delete a configuration, the NF service consumer shall send an HTTP DELETE request to the resource "{apiRoot}/ntsctsf-time-sync/<apiVersion>/subscriptions/{subscriptionId}/configurations/{configurationId}" representing an existing "Individual Time Synchronization Exposure Configuration" resource, as shown in figure 5.2.2.7.2-1, step 1, to delete the configuration.

Upon the reception of an HTTP DELETE request and if the HTTP DELETE request is accepted by the TSCTSF, the TSCTSF shall:

– remove the corresponding configuration and respond with "204 No Content" as shown in figure 5.2.2.7.2-1, step 2;

– use the {configurationId} within the requested URI to identify the time synchronization service configuration and the corresponding AF sessions, and then interact with:

– the PCF(s) for the PDU Session to disable the corresponding PTP instance(s) in the DS-TT(s) and NW-TT as defined in 3GPP TS 23.502 [3], clause 4.15.9.3.4, step 5-6.

– the PCF(s) for the UE to remove the time synchronization error budget by invoking the Npcf_AMPolicyAuthorization_Delete service operation as defined in clause 4.2.4 of 3GPP TS 29.534 [14].

If the HTTP DELETE request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP DELETE request the cause for the rejection as specified in clause 6.1.7.

If the TSCTSF determines the received HTTP DELETE request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.2.2.8 Ntsctsf_TimeSynchronization_ConfigUpdateNotify

5.2.2.8.1 General

This service operation is used by an TSCTSF to notify the NF Service Consumer of the current state of the time synchronization configuration.

The following procedures using the Ntsctsf_TimeSynchronization_ConfigUpdateNotify service operation are supported:

– notification about the current state of the time synchronization configuration.

5.2.2.8.2 Notifying the current state of an existing configuration

Figure 5.2.2.8.2-1 illustrates the notification about the current state of the time synchronization configuration.

Figure 5.2.2.8.2-1: Notification about the current state of the time synchronization configuration

When the TSCTSF receives the notification of the change in the PTP instance for each DS-TT and/or NW-TT from the PCF as defined in clause 4.2.5.13 of 3GPP TS 29.514 [20], the TSCTSF shall determine the current state of the time synchronization configuration and sends an HTTP POST request with "{configNotifUri}", as previously provided by the NF service consumer within the corresponding configuration, as URI and the TimeSyncExposureConfigNotif data structure as request body, as shown in figure 5.2.2.8.2-1, step 1.

The TimeSyncExposureConfigNotif data structure as request body that shall include:

– Notification correlation ID provided by the NF service consumer during the configuration within the "configNotifId" attribute;

– current states of the time synchronization configuration for the DS-TT port(s) and/or NW-TT port within the "stateOfConfig" attribute.

If the HTTP POST request from the TSCTSF is not accepted, the NF service consumer shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.1.7.

5.3 Ntsctsf_TSCQoSandAssistance Service

5.3.1 Service Description

5.3.1.1 Overview

This service provides:

– Authorization of NF Service Consumer requests for the resource reservation for TSC.

– NF Service Consumer request to reserve or update resources for handling traffic characterized by TSC QoS parameters as described in clause 6.1.3.22 of TS 23.503 [19].

5.3.1.2 Network Functions

5.3.1.2.1 TSCTSF

The TSCTSF supports to:

– receive the request to reserve or update a specific QoS or a specific QoS with additional Alternative QoS for an AF session;

– receive the request to delete the AF session with requested QoS or the AF session with requested QoS including Alternative Service Requirements

– receive the request to subscribe or unsubscribe to the event(s) about the AF session with requested QoS or the AF session with requested QoS including Alternative Service Requirements;

– determine the requested PDB and construct the TSC Assistance Container; and

– Notify the NF service consumer of the event(s).

5.3.1.2.2 NF Service Consumers.

The NF service consumer supports to:

– send the request to reserve or update a specific QoS or a specific QoS with additional Alternative QoS for an AF session;

– send the request to delete the AF session with requested QoS or the AF session with requested QoS including Alternative Service Requirements

– send the request to subscribe or unsubscribe to the event(s); and

– receive the notification of the event(s).

5.3.2 Service Operations

5.3.2.1 Introduction

Service operations defined for the Ntsctsf_QoSandTSCAssistance service are shown in table 6.3.2.1-1.

Table 5.3.2.1-1: Ntsctsf_TimeSynchronization Service Operations

Service Operation Name	Description	Initiated by
Ntsctsf_QoSandTSCAssistance_Create	Allows the NF service consumer to request the network to provide a specific QoS or a specific QoS with additional Alternative QoS for an AF session.	NF service consumer (e.g. AF, NEF)
Ntsctsf_QoSandTSCAssistance_Update	Allows the NF service consumer to request the network to update the QoS or the QoS with additional Alternative QoS for an AF session	NF service consumer (e.g. AF, NEF)
Ntsctsf_QoSandTSCAssistance_Delete	Allows the NF service consumer to request the network to delete the AF session with requested QoS or the AF session with requested QoS including Alternative Service Requirements.	NF service consumer (e.g. AF, NEF)
Ntsctsf_QoSandTSCAssistance_Notify	Allows the TSCTSF to report the QoS Flow level event(s) to the NF service consumer.	TSCTSF
Ntsctsf_QoSandTSCAssistance_Subscribe	Allows the NF service consumer to subscribe to the event(s).	NF service consumer (e.g. AF, NEF)
Ntsctsf_QoSandTSCAssistance_Unsubscribe	Allows the NF service consumer to unsubscribe to the event(s).	NF service consumer (e.g. AF, NEF)

NOTE: The NEF and the AF use the Ntsctsf_QoSandTSCAssistance service in the same way.

5.3.2.2 Ntsctsf_QoSandTSCAssistance_Create

5.3.2.2.1 General

This service operation is used by an NF service consumer to request the network to provide a specific QoS for an AF session.

The following procedures using the Ntsctsf_QoSandTSCAssistance_Create service operation are supported:

– Initial provisioning of TSC related service information.

– Subscriptions to Service Data Flow QoS notification control.

– Subscription to Service Data Flow Deactivation

– Subscription to resources allocation outcome

– Subscriptions to Service Data Flow QoS Monitoring Information.

– Initial provisioning of sponsored connectivity information.

5.3.2.2.2 Initial provisioning of TSC related service information

This procedure is used to set up a TSC AF application session context for the service as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.2.2-1 illustrates the initial provisioning of TSC related service information.

Figure 5.3.2.2.2-1: Initial provisioning of TSC related service information

When a new TSC AF application session context needs to be established, the NF service consumer shall invoke the Ntsctsf_QoSandTSCAssistance_Create service operation by sending the HTTP POST request to the resource URI representing the "TSC Application Sessions" collection resource of the TSCTSF, as shown in figure 5.3.2.2.2-1, step 1.

The NF service consumer shall include the "TscAppSessionContextData" data type in the payload body of the HTTP POST request in order to request the creation of the "Individual TSC Application Session Context" resource. The "Individual TSC Application Session Context" resource and the "Events Subscription" sub-resource are created as described below.

The NF service consumer shall include in the "TscAppSessionContextData" data structure:

– the AF identifier within the "afId" attribute;

– either the IP address (IPv4 or IPv6) of the PDU session within the "ueIpAddr" attribute for IP type PDU session or the MAC address of the DS-TT port within the "ueMac" attribute for Ethernet type PDU sessions;

– either the Application Id within the "appId" attribute or the flow information within:

a. for IP flows, the "flowInfo" attribute; or

b. for Ethernet flows, either the "ethFlowInfo" attribute or, if the Ethernet_UL/DL_Flows feature is supported, the "enEthFlowInfo" attribute;

– the QoS reference within the "qosReference" attribute or the individual QoS parameter set (i.e. requested GBR, requested MBR, requested maximum burst size, requested priority if received and requested 5GS delay if received) within the "tscQosReq" attribute;

– the input information to construct the TSC Assistance Container within the "tscaiInputUl" attribute and/or "tscaiInputDl" attribute of the "tscQosReq" attribute; and

– the URI where the TSCTSF can request to the NF service consumer to delete the "Individual TSC Application Session Context" resource within the "notifUri" attribute;

and may include:

– the DNN within the "dnn" attribute;

– the S-NSSAI within the "snssai" attribute;

– the domain identity in the "ipDomain" attribute;

– an ordered list of alternative QoS references within the "altQosReferences" attribute if the QoS reference is provided or an ordered list of requested alternative QoS parameters set(s) within the "altQosReqs" attribute if the individual QoS parameter set is provided; and

– the request of the notification of certain user plane events within the "evSubsc" attribute. Within the EventsSubscReqData data structure, the NF service consumer shall include:

a) the URI where the TSCTSF sends the event notification to the NF service consumer within the "notifUri" attribute;

b) a Notification Correlation Identifier for the requested notifications within the "notifCorreId" attribute;

c) the subscribed events within the "events" attribute;

d) the usage threshold within the "usgThres" attribute if the "USAGE_REPORT" event is subscribed; and

e) QoS monitoring information within the "qosMon" attribute if the "QOS_MONITORING" event is subscribed.

Upon the reception of this HTTP POST request, the TSCTSF shall:

– construct the TSC Assistance Container based on information provided by the NF service consumer;

– if the Requested 5GS delay including the requested 5GS delay within the individual QoS parameter set or within the requested alternative QoS parameters set(s) is received from NF service consumer, calculate a Requested PDB by subtracting the UE-DS-TT residence time either provided by the PCF or pre-configured at TSCTSF from the Requested 5GS delay;

– if the time domain information is not received with the Burst Arrival Time or Periodicity within the "tscQosReq" attribute from the NF service consumer, the TSCTSF may indicate Time Domain = "5GS" within the "tscaiTimeDom" attribute within the "tscQosReq" attribute to indicate that the NF service consumer does not provide the time domain information;

NOTE 1: The Time Domain value corresponding to "5GS" is locally configured in the SMF and in the TSCTSF, and indicates that the AF does not provide a Time Domain and the provided TSCAI input information will be used without adjustments.

– interact with the PCF for the received UE address:

a) if the TSCTSF has an AF-session with the PCF for the received UE address, the TSCTSF shall interact with the PCF by triggering a Npcf_PolicyAuthorization_Update request to provision the related parameters to the PCF as defined in 3GPP TS 29.514 [20]; or

b) if the TSCTSF does not have an AF-Session with the PCF for the received UE address, the TSCTSF shall discover the PCF for the PDU session as specified in 3GPP TS 29.521 [23], and shall interact with the PCF by triggering a Npcf_PolicyAuthorization_Create to provision the related parameters to the PCF as defined in 3GPP TS 29.514 [20]; and

NOTE 2: If the PCF determines an existing PDU Session is related with TSC traffic (based on local configuration or SM Policy Association), the PCF invokes Npcf_PolicyAuthorization_Notify service operation to the TSCTSF as defined in clause 4.2.5.16 of 3GPP TS 29.514 [20] to send the received TSC User Plane Node information. At that time, the TSCTSF retrieves from the BSF the PCF binding information, as specified in 3GPP TS 29.521 [23], and can create the AF-session by sending to the PCF the Npcf_PolicyAuthorization_Create service operation, if TSC related information, as e.g. QoS requirements, and/or subscription to PMIC(s)/UMIC updates need to be provided to the PCF.

NOTE 3: After the TSCTSF retrieves from the BSF the PCF binding information (including the UE Identities for the notified PDU session), as specified in 3GPP TS 29.521 [23], the TSCTSF can store internally the received information and delay the Npcf_PolicyAuthorization_Create service operation (the creation of the AF-session). In this case, when the TSCTSF receives the QoS request, the TSCTSF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Create request to provision the related parameters to the PCF as defined in 3GPP TS 29.514 [20].

– if receiving a successful response from the PCF, the TSCSTF shall create an "Individual TSC Application Session Context" resource and send to the NF service consumer a "201 Created" response to the HTTP POST request, as shown in figure 5.3.2.2.2-1, step 2. If the "evSubsc" attribute is received, the "Events Subscription" sub-resource shall be created within the "Individual TSC Application Session Context" resource. The TSCTSF shall include in the "201 Created" response:

a) a Location header field; and

b) a "TscAppSessionContextData" data type in the payload body.

The Location header field shall contain the URI of the created "Individual TSC Application Session Context" i.e. "{apiRoot}/ntsctsf-qos-tscai/v1/tsc-app-sessions/{appSessionId}".

When "Events Subscription" sub-resource is created in this procedure, the NF service consumer shall build the sub-resource URI by adding the path segment "/events-subscription" at the end of the URI path received in the Location header field.

5.3.2.2.3 Subscriptions to Service Data Flow QoS notification control

The NF service consumer shall use the "EventsSubscReqData" data type as described in clause 5.3.2.2.2 and shall include in the HTTP POST request message an event within the "evSubsc" attribute with the "event" attribute set to "QOS_GUARANTEED" and an event within the "evSubsc" attribute with the "event" attribute set to "QOS_NOT_GUARANTEED".

The PCF shall reply to the NF service consumer as described in clause 5.3.2.2.2.

As result of this action, the TSCTSF shall set the appropriate subscription to QoS notification control as described in in 3GPP TS 29.514 [20].

5.3.2.2.4 Subscription to Service Data Flow Deactivation

The NF service consumer shall use the "EventsSubscReqData" data type as described in clause 5.3.2.2.2 and shall include in the HTTP POST request message an event entry within the "evSubsc" attribute with the "event" attribute set to "FAILED_RESOURCES_ALLOCATION".

The PCF shall reply to the NF service consumer as described in clause 5.3.2.2.2.

As result of this action, the PCF shall set the appropriate subscription to service data flow deactivation as described in in 3GPP TS 29.514 [20].

5.3.2.2.5 Subscription to resources allocation outcome

The NF service consumer shall use the "EventsSubscReqData" data type as described in clause 5.3.2.2.2 and shall include in the HTTP POST request message:

– if the NF service consumer requests the TSCTSF to provide a notification when the resources associated to the service information have been allocated, an event entry within the "events" attribute with the "event" attribute set to "SUCCESSFUL_RESOURCES_ALLOCATION"; and/or

– if the NF service consumer requests the TSCTSF to provide a notification when the resources associated to the service information cannot be allocated, an event entry within the "events" attribute with the "event" attribute set to "FAILED_RESOURCES_ALLOCATION".

The TSCTSF shall reply to the NF service consumer as described in clause 5.3.2.2.2.

As result of this action, the TSCTSF shall set the appropriate subscription to notification of resources allocation outcome as described in in 3GPP TS 29.514 [20].

5.3.2.2.6 Subscriptions to Service Data Flow QoS Monitoring Information

The NF service consumer shall use the "EventsSubscReqData" data type as described in clause 5.3.2.2.2 and shall include in the HTTP POST request message an event within the "evSubsc" attribute with the "event" attribute set to "QOS_MONITORING" and include the QoS monitoring information with the "qosMon" attribute. Within the QosMonitoringInformation data structure, the AF shall include:

– one or more requested QoS Monitoring Parameter(s) within the "reqQosMonParams"; and

– one or more report frequency within the "repFreqs" attribute; and

– when the "repFreqs" attribute includes the value "PERIODIC", the reporting period within the "repPeriod" attribute; and

– when the "repFreqs" attribute includes the value "EVENT_TRIGGERED", the AF shall include:

– the delay threshold for downlink with the "repThreshDl" attribute;

– the delay threshold for uplink with the "repThreshUl" attribute; and/or

– the delay threshold for round trip with the "repThreshRp" attribute; and

– the minimum waiting time between subsequent reports within the "waitTime" attribute.

The PCF shall reply to the NF service consumer as described in clause 5.3.2.2.2.

As result of this action, the TSCTSF shall set the appropriate subscription to service data flow QoS monitoring information as described in in 3GPP TS 29.514 [20].

5.3.2.2.7 Initial provisioning of sponsored connectivity information

The NF service consumer may include in the HTTP POST request message described in clause 5.3.2.2.2 an application service provider identity and a sponsor identity within the "aspId" attribute and "sponId" attribute. Additionally, the NF service consumer may provide an indication to the TSCTSF of sponsored data connectivity not enabled by including the "sponStatus" attribute set to "SPONSOR_DISABLED".

To support the usage monitoring of sponsored data connectivity, the NF service consumer may subscribe with the TSCTSF to the notification of usage threshold reached. The NF service consumer may also include the "evSubsc" attribute with:

– the usage thresholds to apply in the "usgThres" attribute; and

– an entry of the "events" attribute set to "USAGE_REPORT".

The PCF shall reply to the NF service consumer as described in clause 5.3.2.2.2.

As result of this action, the TSCTSF shall provision the sponsored data connectivity information to the PCF as described in in 3GPP TS 29.514 [20].

5.3.2.3 Ntsctsf_QoSandTSCAssistance_Update

5.3.2.3.1 General

This service operation is used by an NF service consumer to request the network to update the QoS and/or additional Alternative QoS for an AF session.

The following procedures using the Ntsctsf_QoSandTSCAssistance_Update service operation are supported:

– Modification of TSC related service information.

– Modification of Subscription to Service Data Flow QoS notification control.

– Modification of Subscription to Service Data Flow Deactivation.

– Modification of subscription to resources allocation outcome.

– Modification of Subscription to Service Data Flow QoS Monitoring Information.

– Modification of sponsored connectivity information.

5.3.2.3.2 Modification of TSC related service information

This procedure is used to modify an existing TSC application session context as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.3.2-1 illustrates the modification of TSC related service information using HTTP PATCH method.

Figure 5.3.2.3.2-1: Modification of TSC related service information using HTTP PATCH

The NF service consumer may modify the TSC application session context information at any time and invoke the Ntsctsf_QoSandTSCAssistance_Update service operation by sending the HTTP PATCH request message to the resource URI representing the "Individual TSC Application Session Context" resource, as shown in figure 5.3.2.3.2-1, step 1, with the modifications to apply.

The JSON body within the PATCH request shall include the "TscAppSessionContextUpdateData" data type and shall be encoded according to "JSON Merge Patch", as defined in IETF RFC 7396 [22].

The NF service consumer may include in the "TscAppSessionContextUpdateData" data structure:

– the updated flow information within the "flowInfo" attribute for IP flows or, either the "ethFlowInfo" or, if the Ethernet_UL/DL_Flows feature is supported, the "enEthFlowInfo" attribute for Ethernet flows;

– the updated application Id within the "appId" attribute;

– the updated QoS reference within the "qosReference" attribute or the updated individual QoS parameter set within the "tscQosReq" attribute;

– the updated input information to construct the TSC Assistance Container within the "tscaiInputUl" attribute and/or "tscaiInputDl" attribute of the "tscQosReq" attribute;

– the updated URI where the TSCTSF can request to the NF service consumer to delete the "Individual TSC Application Session Context" resource within the "notifUri".

– the updated ordered list of alternative QoS references within the "altQosReferences" attribute or updated ordered list of requested alternative QoS parameters set(s) within the "altQosReqs" attribute; and

– the updated event subscription information within the "evSubsc" attribute. Within the EventsSubscReqDataRm data structure, the NF service consumer shall include:

– the new complete list of subscribed events within the "events" attribute;

– when the NF service consumer requests to update the additional information related to an event (e.g. the NF service consumer needs to provide new thresholds to the TSCTSF in the "usgThres" attribute related to the "USAGE_REPORT" event), the additional information within the corresponding attribute(s).

NOTE 1: Note that when the NF service consumer requests to remove an event, this event is not included in the "events" attribute.

NOTE 2: When an event is included in the "events" attribute and its related additional information is set to null, the PCF considers the subscription to this event is active, but the related procedures stop applying.

NOTE 3: When an event is removed from the "events" attribute but its related information is not set to null, the PCF considers the subscription to this event is terminated, the related additional information is removed, and the related procedures stop applying.

The NF service consumer shall remove existing event subscription information by setting to null the "evSubsc" attribute included in "TscAppSessionContextUpdateData".

NOTE 4: The "notifUri" attribute within the EventsSubscReqData data structure can be modified to request that subsequent notifications are sent to a new NF service consumer.

Upon the reception of this HTTP PATCH request, the TSCTSF shall

– if the updated Requested 5GS delay including the requested 5GS delay within the individual QoS parameter set or within the requested alternative QoS parameters set(s) is received from NF service consumer, re-calculate a Requested PDB by subtracting the UE-DS-TT residence time provided by the PCF or pre-configured in the TSCTSF from the Requested 5GS delay;

– update the TSC Assistance Container based on updated information provided by the NF service consumer;

NOTE 5: The Time Domain value corresponding to "5GS" is locally configured in the SMF and in the TSCTSF, and indicates that the AF does not provide a Time Domain and the provided TSCAI input information will be used without adjustments.

– interact with the PCF by triggering a Npcf_PolicyAuthorization_Update request to provision the related parameters to the PCF as defined in 3GPP TS 29.514 [20];

– if receiving a successful response from the PCF, the TSCSTF shall update the "Individual TSC Application Session Context" resource and send a "200 OK" or "204 No Content" response to the HTTP POST request to the NF service consumer, as shown in figure 5.3.2.3.2-1, step 2.

If the TSCTSF cannot successfully fulfil the received HTTP PATCH request due to the internal TSCTSF error or due to the error in the HTTP PATCH request, the TSCTSF shall send the HTTP error response as specified in clause 6.2.7.

If the TSCTSF determines the received HTTP PATCH request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.3.2.3.3 Modification of Subscription to Service Data Flow QoS notification control

The NF service consumer shall use the HTTP PATCH method to update the "Events Subscription" sub-resource together with the modifications to the "Individual TSC Application Sessions" resource.

The NF service consumer shall include in the HTTP PATCH request message described in clause 5.3.2.3.2, the updated event subscription information within the "evSubsc" attribute. Within the EventsSubscReqDataRm data type, the NF service consumer shall include the "events" attribute with the "QOS_GUARANTEED" and "QOS_NOT_GUARANTEED" values to indicate the subscription to QoS notification control or include the "events" but without the "QOS_GUARANTEED" and "QOS_NOT_GUARANTEED" values to indicate the termination of the subscription to QoS notification control.

As result of this action, the TSCTSF shall set the appropriate subscription to QoS notification control as described in 3GPP TS 29.514 [20].

The PCF shall reply to the NF service consumer as described in clause 5.3.2.3.2.

5.3.2.3.4 Modification of Subscription to Service Data Flow Deactivation

The NF service consumer shall use the HTTP PATCH method to update the "Events Subscription" sub-resource together with the modifications to the "Individual TSC Application Sessions" resource.

The NF service consumer shall include in the HTTP PATCH request message described in clause 5.3.2.3.2, the updated event subscription information within the "evSubsc" attribute. Within the EventsSubscReqDataRm data type, the NF service consumer shall include the "events" attribute with the "FAILED_RESOURCES_ALLOCATION" values to the subscription to service data flow deactivation or include the "events" but without "FAILED_RESOURCES_ALLOCATION" value to indicate the termination of the subscription to Service Data Flow Deactivation.

As result of this action, the TSCTSF shall set the appropriate subscription to QoS notification control as described in 3GPP TS 29.514 [20].

The PCF shall reply to the NF service consumer as described in clause 5.3.2.3.2.

5.3.2.3.5 Modification of subscription to resources allocation outcome

The NF service consumer shall use the HTTP PATCH method to modify the "Events Subscription" sub-resource together with the modifications to the "Individual TSC Application Sessions" resource.

The NF service consumer shall include in the HTTP PATCH request message described in clause 5.3.2.3.2, the updated event subscription information within the "evSubsc" attribute. Within the EventsSubscReqDataRm data type, the NF service consumer shall include the "events" attribute with the "SUCCESSFUL_RESOURCES_ALLOCATION" value for the successful resource allocation and/or "FAILED_RESOURCES_ALLOCATION" value for the unsuccessful resource allocation to the subscription to resources allocation outcome or include the "events" but without "SUCCESSFUL_RESOURCES_ALLOCATION" and/or "FAILED_RESOURCES_ALLOCATION" value to indicate the termination of the subscription to resources allocation outcome.

As result of this action, the TSCTSF shall set the appropriate subscription to resources allocation outcome as described in 3GPP TS 29.514 [20].

The TSCTSF shall reply to the NF service consumer as described in clause 5.3.2.3.2.

5.3.2.3.6 Modification of Subscription to Service Data Flow QoS Monitoring Information

The NF service consumer shall use the HTTP PATCH method to update the "Events Subscription" sub-resource together with the modifications to the "Individual TSC Application Sessions" resource.

– to create a subscription to QoS monitoring information:

a) include the "events" attribute with the "QOS_MONITORING" value; and

b) include the updated QoS monitoring information within the "qosMon" attribute as defined in clause 5.3.2.2.6;

– to remove a subscription to QoS monitoring information:

a) include the "events" attribute without "QOS_MONITORING".

As result of this action, the TSCTSF shall set the appropriate subscription to Service Data Flow QoS Monitoring Information as described in 3GPP TS 29.514 [20].

The PCF shall reply to the NF service consumer as described in clause 5.3.2.3.2.

5.3.2.3.3 Modification of sponsored connectivity information

The NF service consumer shall use the HTTP PATCH method to modify the sponsored connectivity information.

The NF service consumer shall include in the HTTP PATCH request message described in clause 5.3.2.3.2, an application service provider identity and a sponsor identity within the "aspId" attribute and "sponId" attribute, and optionally an indication of whether to enable or disable sponsored data connectivity within the "sponStatus" attribute set to the applicable value to provide sponsored connectivity information or to update existing sponsored connectivity information.

If the NF service consumer requests to enable sponsored data connectivity the NF service consumer shall change the "sponStatus" attribute value to "SPONSOR_ENABLED".

If the NF service consumer requests to disable sponsored data connectivity the NF service consumer shall provide an indication to disable sponsored data connectivity to the TSCTSF by setting the "sponStatus" attribute to "SPONSOR_DISABLED".

To support the usage monitoring of sponsored data connectivity, the NF service consumer may also include in the HTTP PATCH a new or modified "evSubsc" attribute with:

– the usage thresholds to apply in the "usgThres" attribute; and

– an entry of the "events" attribute set to "USAGE_REPORT".

The PCF shall reply to the NF service consumer as described in clause 5.3.2.3.2.

As result of this action, the TSCTSF shall provision the updated sponsored data connectivity information to the PCF as described in in 3GPP TS 29.514 [20].

5.3.2.4 Ntsctsf_QoSandTSCAssistance_Delete

5.3.2.4.1 General

This service operation is used by an NF service consumer to request the network to delete the AF session with requested QoS or the AF session with requested QoS including Alternative Service Requirements.

The following procedures using the Ntsctsf_QoSandTSCAssistance_Delete service operation are supported:

– TSC AF application session context termination.

– Reporting usage for sponsored data connectivity

5.3.2.4.2 TSC AF application session context termination

This procedure is used to terminate an AF application session context for the service as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.4.2-1 illustrates the application session context termination.

Figure 5.3.2.4.2-1: Application session context termination

When a TSC AF session is terminated, and if the TSC AF application session context was created as described in clause 5.3.2.2, the NF service consumer shall invoke the Ntsctsf_QoSandTSCAssistance_Delete service operation to the TSCTSF using an HTTP POST request, as shown in figure 5.3.2.4.2-1, step 1.

The NF service consumer shall set the request URI to "{apiRoot}/ntsctsf-qos-tscai/v1/tsc-app-sessions/{appSessionId}/delete".

The NF service consumer may include in the body of the HTTP POST the "EventsSubscReqData" data type with the "evSubsc" attribute indicating the corresponding list of events to subscribe to.

When the TSCTSF receives the HTTP POST request from the NF service consumer, indicating the termination of the TSC AF application session context information, the TSCTSF shall acknowledge that request by sending an HTTP response message with the corresponding status code.

If the HTTP POST request from the NF service consumer is accepted, the TSCTSF shall send to the NF service consumer:

a) if event information is reported, TSCTSF shall defer sending the response to the NF service consumer and shall immediately interact with the PCF to terminate the AF session with the event report, as specified in 3GPP TS 29.514 [20]. After receiving the event information from the PCF, the TSCTSF shall send a "200 OK" response to HTTP POST request, as shown in figure 5.3.2.4.2-1, step 2a, including in the "EventsNotification" to report to the NF service consumer;

b) otherwise, the TSCTSF shall send to the NF service consumer a "204 No Content".

If the TSCTSF determines the received HTTP POST request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.3.2.4.3 Reporting usage for sponsored data connectivity

When The NF service consumer indicated to enable sponsored data connectivity and the NF service consumer provided usage thresholds for such sponsor to the TSCTSF, the TSCTSF shall report accumulated usage to the NF service consumer using the response of the Ntsctsf_QoSandTSCAssistance_Delete service operation.

This procedure is initiated when:

– the "Individual TSC Application Session" is deleted by the NF service consumer; or

– the TSCTSF requests the deletion of the "Individual TSC Application Session" to the NF service consumer, as described in clause 5.2.2.5.3, due to PDU session termination, the termination of all the service data flows of the Individual TSC Application Session.

To report the accumulated usage, the TSCTSF shall immediately configure the PCF to retrieve the accumulated usage as specified in 3GPP TS 29.514 [20]. When the TSCTSF receives the usage information from the PCF, the TSCTSF shall notify the NF service consumer by including the "EventsNotification" data type in the response of the HTTP POST request as described in clause 5.3.2.4.2.

The TSCTSF shall within an instance of "events" attribute include:

– "USAGE_REPORT" within the "event" attribute;

– accumulated usage within the "usgRep" attribute.

5.3.2.5 Ntsctsf_QoSandTSCAssistance_Notify

5.3.2.5.1 General

The Ntsctsf_QoSandTSCAssistance_Notify service operation enables notification to NF service consumers that the previously subscribed event for the existing TSC application session context occurred or that the TSC application session context is no longer valid.

The following procedures using the Ntsctsf_QoSandTSCAssistance_Notify service operation are supported:

– Notification about TSC application session context event.

– Notification about TSC application session context termination.

– Notification about Service Data Flow QoS notification control.

– Notification about Service Data Flow Deactivation

– Notification about resources allocation outcome.

– Notification about Service Data Flow QoS Monitoring control.

– Reporting usage for sponsored data connectivity.

5.3.2.5.2 Notification about TSC application session context event

This procedure is invoked by the TSCTSF to notify the NF service consumer when a certain, previously subscribed, application session context event occurs, as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.5.2-1 illustrates the notification about TSC application session context event.

Figure 5.3.2.5.2-1: Notification about application session context event

When the TSCTSF determines that the event for the existing TSC AF application session context, to which the NF service consumer has subscribed to, occurred e.g. upon reception of an event notification for a PDU session from the PCF as described in 3GPP TS 29.514 [20], the TSCTSF shall invoke the Ntsctsf_QoSandTSCAssistance_Notify service operation by sending the HTTP POST request (as shown in figure 5.3.2.5.2-1, step 1) to the NF service consumer using the notification URI received in the subscription creation (or modification), as specified in clause 5.3.2.2.2, 5.3.2.3.2, and 5.3.2.6, and appending the "notify" segment path at the end of the URI. The TSCTSF shall provide in the body of the HTTP POST request the "EventsNotification" data type including:

– the notification correlation Id within the "notifCorreId"; and

– the list of the reported events in the "events" attribute.

The NF service consumer notification of other specific events using the Ntsctsf_QoSandTSCAssistance_Notify request is described in the related clauses.

Upon the reception of the HTTP POST request from the TSCTSF indicating that the PDU session and/or service related event occurred, the NF service consumer shall acknowledge that request by sending an HTTP response message with the corresponding status code.

If the HTTP POST request from the TSCTSF is accepted, the NF service consumer shall acknowledge the receipt of the event notification with a "204 No Content" response to HTTP POST request, as shown in figure 5.3.2.5.2-1, step 2.

If the HTTP POST request from the TSCTSF is not accepted, the NF service consumer shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.2.7.

5.2.2.5.3 Notification about TSC application session context termination

This procedure is invoked by the TSCTSF to notify the NF service consumer that the TSC application session context is no longer valid, as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.2.2.5.3-1 illustrates the notification about application session context termination.

Figure 5.2.2.5.3-1: Notification about TSC application session context termination

When the TSCTSF determines that the TSC application session context is no longer valid, the TSCTSF shall invoke the Ntsctsf_QoSandTSCAssistance_Notify service operation by sending the HTTP POST request (as shown in figure 5.2.2.5.3-1, step 1) using the notification URI received in the "Individual TSC Application Session Context" context creation, as specified in clause 5.3.2.2, and appending the "terminate" segment path at the end of the URI, to trigger the NF service consumer to request the TSC application session context termination (see clause 5.3.2.4.2). The TSCTSF shall provide in the body of the HTTP POST request the "TerminationInfo" data type including:

– the Individual TSC Application Session Context resource identifier related to the termination notification in the "resUri" attribute; and

– the TSC application session context termination cause in the "termCause" attribute.

Upon the reception of the HTTP POST request from the TSCTSF requesting the TSC application session context termination, the NF service consumer shall acknowledge that request by sending an HTTP response message with the corresponding status code.

If the HTTP POST request from the TSCTSF is accepted, the NF service consumer shall acknowledge the receipt of the TSC application session context termination request with a "204 No Content" response to HTTP POST request (as shown in figure 5.2.2.5.3-1, step 2) and shall invoke the Ntsctsf_QoSandTSCAssistance_Delete service operation to the TSCTSF as described in clause 5.3.2.4.

If the HTTP POST request from the TSCTSF is not accepted, the NF service consumer shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.2.7.

5.3.2.5.4 Notification about Service Data Flow QoS notification control

When the TSCTSF receives the notification about Service Data Flow QoS notification control from the PCF as described in 3GPP TS 29.514 [20], the TSCTSF shall inform the NF service consumer accordingly if the NF service consumer has previously subscribed as described in clauses 5.3.2.2.3 and 5.3.2.3.3.

The PCF shall notify the NF service consumer by including the "EventsNotification" data type in the body of the HTTP POST request as described in clause 5.3.2.5.2.

The TSCTSF shall within an instance of "events" attribute include:

– "QOS_GUARANTEED" or "QOS_NOT_GUARANTEED" within the "event" attribute;

– the identification of the affected service flows (if not all the flows are affected) encoded in the "flowIds" attribute if applicable; and

– the reference to the Alternative Service Requirement corresponding alternative QoS parameter set if received from the PCF within the "appliedQosRef" attribute. When the "appliedQosRef" attribute is omitted and the "event" attribute is NOT_GUARANTEED, it indicates that the lowest priority alternative QoS profile could not be fulfilled.

5.3.2.5.5 Notification about Service Data Flow Deactivation

When the TSCTSF receives the notification about service data flow deactivation from the PCF as described in 3GPP TS 29.514 [20], the TSCTSF shall inform the NF service consumer accordingly if the NF service consumer has previously subscribed as described in clauses 5.3.2.2.4 and 5.3.2.3.4.

The PCF shall notify the NF service consumer by including the "EventsNotification" data type in the body of the HTTP POST request as described in clause 5.3.2.5.2.

The TSCTSF shall within an instance of "events" attribute include:

– "FAILED_RESOURCES_ALLOCATION" within the "event" attribute;

– the identification of the affected service flows (if not all the flows are affected) encoded in the "flowIds" attribute if applicable.

5.3.2.5.6 Notification about resources allocation outcome

When the TSCTSF receives the notification about resources allocation outcome from the PCF as described in 3GPP TS 29.514 [20], the TSCTSF shall inform the NF service consumer accordingly if the NF service consumer has previously subscribed as described in clauses 5.3.2.2.5 and 5.3.2.3.5.

The TSCTSF shall notify the NF service consumer by including the "EventsNotification" data type in the body of the HTTP POST request as described in clause 5.3.2.5.2.

The TSCTSF shall within an instance of "events" attribute include:

– "SUCCESSFUL_RESOURCES_ALLOCATION" within the "event" attribute if the "SUCCESSFUL_RESOURCES_ALLOCATION" event is received from the PCF or "FAILED_RESOURCES_ALLOCATION" within the "event" attribute if the "FAILED_RESOURCES_ALLOCATION" event is received from the PCF;

– the identification of the affected service flows (if not all the flows are affected) encoded in the "flowIds" attribute if applicable.

– the reference to the Alternative Service Requirement corresponding alternative QoS parameter set if received from the PCF within the "appliedQosRef" attribute.

5.3.2.5.7 Notification about Service Data Flow QoS Monitoring control

When the TSCTSF receives the notification about Service Data Flow QoS Monitoring control from the PCF as described in 3GPP TS 29.514 [20], the TSCTSF shall inform the NF service consumer accordingly if the NF service consumer has previously subscribed as described in clauses 5.3.2.2.6 and 5.3.2.3.6.

The PCF shall notify the NF service consumer by including the "EventsNotification" data type in the body of the HTTP POST request as described in clause 5.3.2.5.2.

The TSCTSF shall within an instance of "events" attribute include:

– "QOS_MONITORING" within the "event" attribute;

– the identification of the affected service flows (if not all the flows are affected) encoded in the "flowIds" attribute if applicable; and

– the "qosMonReports" array with:

a) one or two uplink packet delays within the "ulDelays" attribute;

c) one or two downlink packet delays within the "dlDelays" attribute; and/or

d) one or two round trip packet delays within the "rtDelays" attribute.

5.3.2.5.8 Reporting usage for sponsored data connectivity

When the NF service consumer enabled sponsored data connectivity and the NF service consumer provided usage thresholds for such sponsor to the TSCTSF, the TSCTSF shall report accumulated usage to the NF service consumer using the Npcf_PolicyAuthorization_Notify service operation when:

– the TSCTSF detects that the usage threshold provided by the NF service consumer has been reached; or

– the NF service consumer disables the sponsored data connectivity.

The TSCTSF shall notify the NF service consumer of the accumulated usage by including the "EventsNotification" data type in the body of the HTTP POST request as described in clause 5.3.2.5.2.

The TSCTSF shall within an instance of "events" attribute include:

– "USAGE_REPORT" within the "event" attribute;

– accumulated usage within the "usgRep" attribute.

When the NF service consumer receives the HTTP POST request, it shall acknowledge the request by sending a "204 No Content" response to the TSCTSF. The NF service consumer may terminate the Individual Application Session Context sending an HTTP POST as described in clause 5.3.2.4.2 or update the Individual Application Session Context information by providing a new usage threshold sending an HTTP PATCH request to the TSCTSF as described in clause 5.3.2.3.2 or an HTTP PUT request to the TSCTSF as described in clause 5.3.2.6.2.

5.3.2.6 Ntsctsf_QoSandTSCAssistance_Subscribe

5.3.2.6.1 General

The Ntsctsf_QoSandTSCAssistance_Subscribe service operation enables NF service consumers handling of subscription to events for the existing TSC application session context. Subscription to events shall be created:

– within the application session context establishment procedure by invoking the Ntsctsf_QoSandTSCAssistance_Subscribe service operation, as described in clause 5.3.2.2; or

– within the TSC application session context modification procedure by invoking the Ntsctsf_QoSandTSCAssistance_Subscribe service operation, as described in clause 5.3.2.3; or

– by invoking the Ntsctsf_QoSandTSCAssistance_Subscribe service operation for the existing TSC application session context, as described in clause 5.3.2.6.2.

The following procedures using the Ntsctsf_QoSandTSCAssistance_Subscribe service operation is supported:

– Handling of subscription to events for the existing TSC application session context.

– Subscription to Service Data Flow QoS Monitoring Information.

– Subscription to Usage Monitoring of Sponsored Data Connectivity.

5.3.2.6.2 Handling of subscription to events for the existing TSC application session context

This procedure is used to create a subscription to events for the existing TSC AF application session context bound to the corresponding PDU session or to modify an existing subscription, as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.6.2-1 illustrates the creation of events subscription information using HTTP PUT method.

Figure 5.3.2.6.2-1: Creation of events subscription information using HTTP PUT

Figure 5.3.2.6.2-2 illustrates the modification of events subscription information using HTTP PUT method.

Figure 5.3.2.6.2-2: Modification of events subscription information using HTTP PUT

When the NF service consumer decides to create a subscription to one or more events for the existing TSC application session context or to modify an existing subscription previously created by itself at the TSCTSF, the NF service consumer shall invoke the Ntsctsf_QoSandTSCAssistance_Subscribe service operation by sending the HTTP PUT request to the resource URI representing the "Events Subscription" sub-resource in the TSCTSF, as shown in figure 5.3.2.6.2-1, step 1 and figure 5.3.2.6.2-2, step 1. The NF service consumer shall provide in the "EventsSubscReqData" data type of the body of the HTTP PUT request:

– the "events" attribute with the list of events to be subscribed;

– the "notifUri" attribute that includes the Notification URI to indicate to the TSCTSF where to send the notification of the subscribed events;

– the notification correlation Id within the "notifCorreId" attribute; and

– the specific event information related to the subscribed event, e.g. QoS monitoring information within the "qosMon" attribute if the "QOS_MONITORING" event is subscribed.

NOTE: The "notifUri" attribute within the EventsSubscReqData data structure can be modified to request that subsequent notifications are sent to a new NF service consumer.

Upon the reception of the HTTP PUT request from the NF service consumer, the TSCTSF shall decide whether the received HTTP PUT request is accepted.

If the TSCTSF accepted the HTTP PUT request to create a subscription to events, the TSCTSF shall create the "Events Subscription" sub-resource and shall send the HTTP response message to the NF service consumer as shown in figure 5.3.2.6.2-1, step 2. The TSCTSF shall include in the "201 Created" response:

– a Location header field that shall contain the URI of the created "Events Subscription" sub-resource i.e. "{apiRoot}/ntsctsf-qos-tscai/v1/tsc-app-sessions/{appSessionId}/events-subscription"; and

– a response body with the "EventsSubscReqData" data type representing the created "Events Subscription" sub-resource.

If the TSCTSF accepted the HTTP PUT request to modify the events subscription, the TSCTSF shall modify the "Events Subscription" sub-resource and shall send to the NF service consumer:

– the HTTP "204 No Content" response (as shown in figure 5.3.2.6.2-2, step 2a); or

– the HTTP "200 OK" response (as shown in figure 5.3.2.6.2-2, step 2b) including in the "EventsSubscReqData" data type the updated representation of the "Events Subscription" sub-resource.

If the HTTP POST request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP POST request the cause for the rejection as specified in clause 6.2.7.

If the TSCTSF determines the received HTTP POST request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.3.2.6.3 Subscription to Service Data Flow QoS Monitoring Information

This procedure is used by NF service consumer to subscribe and/or modify the subscription for notification about service data flow QoS monitoring information.

The NF service consumer shall include in the HTTP PUT request message the "EventsSubscReqData" data type, which shall contain:

– to create a subscription to QoS monitoring information:

– the "events" attribute with an entry containing the value "QOS_MONITORING" to create a subscription to notification about service data flow QoS monitoring information;

– include the updated QoS monitoring information within the "qosMon" attribute as defined in clause 5.3.2.2.6

– to remove a subscription to QoS monitoring information:

– the "events" attribute containing an array that omits the values "QOS_MONITORING".

The NF service consumer shall include other events related information as described in clause 5.3.2.6.1.

As result of this action, the TSCTSF shall set the appropriate subscription to service data flow QoS monitoring information as described in in 3GPP TS 29.514 [20].

The TSCTSF shall reply to the NF service consumer as described in clause 5.3.2.6.1.

5.3.2.6.4 Subscription to Usage Monitoring of Sponsored Data Connectivity

This procedure is used by NF service consumer to subscribe and/or modify the subscription for notification about usage monitoring of sponsored data connectivity.

The NF service consumer shall include in the HTTP PUT request message the "EventsSubscReqData" data type, which shall contain:

– to create a subscription to usage monitoring of sponsored data connectivity:

– the "events" attribute with an entry containing the value "USAGE_REPORT" to create a subscription to notification about usage monitoring of sponsored data connectivity;

– include the usage thresholds to apply in the "usgThres" attribute.

– to remove a subscription to usage monitoring of sponsored data connectivity:

– the "events" attribute containing an array that omits the values "USAGE_REPORT".

The NF service consumer shall include other events related information as described in clause 5.3.2.6.1.

As result of this action, the TSCTSF shall set the appropriate subscription to usage monitoring of sponsored data connectivity as described in in 3GPP TS 29.514 [20].

The TSCTSF shall reply to the NF service consumer as described in clause 5.3.2.6.1.

5.3.2.7 Ntsctsf_QoSandTSCAssistance_Unsubscribe

5.3.2.7.1 General

The Ntsctsf_QoSandTSCAssistance_Unsubscribe service operation enables NF service consumers to remove subscription to all subscribed events for the existing TSC application session context. Subscription to events shall be removed:

– by invoking the Ntsctsf_QoSandTSCAssistance_Unsubscribe service operation for the existing application session context, as described in clause 5.3.2.7.2; or

– within the application session context modification procedure by invoking the Ntsctsf_QoSandTSCAssistance_Update service operation, as described in clause 5.3.2.3; or

– within the TSC application session context termination procedure by invoking the Ntsctsf_QoSandTSCAssistance_Delete service operation, as described in clause 5.3.2.4.

The following procedure using the Ntsctsf_QoSandTSCAssistance_Unsubscribe service operation is supported:

– Unsubscription to events.

5.3.2.7.2 Unsubscription to events

This procedure is used to unsubscribe to all subscribed events for the existing TSC AF application session context, as defined in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and 3GPP TS 23.503 [19].

Figure 5.3.2.7.2-1 illustrates the unsubscription to events using the HTTP DELETE method.

Figure 5.3.2.7.2-1: Removal of events subscription information using HTTP DELETE

When the NF service consumer decides to unsubscribe to all subscribed events for the existing TSC application session context, the NF service consumer shall invoke the Ntsctsf_QoSandTSCAssistance_Unsubscribe service operation by sending the HTTP DELETE request message to the resource URI representing the "Events Subscription" sub-resource in the TSCTSF, as shown in figure 5.3.2.7.2-1, step 1.

Upon the reception of the HTTP DELETE request message from the NF service consumer, the TSCTSF shall decide whether the received HTTP request message is accepted.

If the HTTP DELETE request message from the NF service consumer is accepted, the TSCTSF shall delete "Events Subscription" sub-resource and shall send to the NF service consumer a HTTP "204 No Content" response message. The TSCTSF may delete the existing subscription to event notifications for the related PDU session from the PCF as described in 3GPP TS 29.514 [20].

If the HTTP DELETE request from the NF service consumer is not accepted, the TSCTSF shall indicate in the response to HTTP DELETE request the cause for the rejection as specified in clause 6.2.7.

If the TSCTSF determines the received HTTP DELETE request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.4 Ntsctsf_ASTI Service

5.4.1 Service Description

5.4.1.1 Overview

This service provides authorization of NF Service Consumer requests for the activation, update, and deactivation of the 5G access stratum time distribution.

NOTE: The AF can use either the procedure specified in bullet 1) and 2) of clause 5.2.1.1 for configuring the (g)PTP instance in 5GS or the procedure specified in Ntsctsf_ASTI service for controlling the 5G access stratum time distribution for a particular UE. The procedures are not intended to be used in conjunction.

5.4.1.2 Network Functions

5.4.1.2.1 TSCTSF

The TSCTSF supports to:

– receive the request to activate or update the 5G access stratum time distribution configuration from the NEF or AF and provide it for the target UE(s) to the PCF;

– receive the request to delete the 5G access stratum time distribution configuration from the NEF or AF and provide it for the target UE(s) to the PCF;

– receive the request to query the status of the access stratum time distribution from the NEF or AF and respond to the NEF or AF with the status of the access stratum time distribution.

5.4.1.2.2 NF Service Consumers

The NF service consumer supports to:

– send the request to create, modify and delete the 5G access stratum time distribution configuration to the TSCTSF; and

– query the status of the access stratum time distribution configuration.

5.4.2 Service Operations

5.4.2.1 Introduction

Service operations defined for the Ntsctsf_ASTI service are shown in table 5.4.2.1-1.

Table 5.4.2.1-1: Ntsctsf_ASTI Service Operations

Service Operation Name	Description	Initiated by
Ntsctsf_ASTI_Create	Allows the NF service consumer to create a 5G access stratum time distribution configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_ASTI_Update	Allows the NF service consumer to update a 5G access stratum time distribution configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_ASTI_Delete	Allows the NF service consumer to delete a 5G access stratum time distribution configuration.	NF service consumer (e.g. AF, NEF)
Ntsctsf_ASTI_Get	Allows the NF service consumer to query the status of the 5G access stratum time distribution configuration.	NF service consumer (e.g. AF, NEF)

NOTE: The NEF and the AF use the Ntsctsf_ASTI service in the same way.

5.4.2.2 Ntsctsf_ASTI_Create

5.4.2.2.1 General

This service operation is used by an NF service consumer to create a 5G access stratum time distribution configuration.

The following procedures using the Ntsctsf_ASTI_Create service operation are supported:

– creating a new configuration..

5.4.2.2.2 Creating a new configuration

Figure 5.4.2.2.2-1 illustrates the creation of a configuration.

Figure 5.4.2.2.2-1: Creation of a configuration

To create a configuration, the NF service consumer shall send an HTTP POST message to the TSCTSF to the URI "{apiRoot}/ntsctsf-asti/<apiVersion>/configurations". The HTTP POST message shall include the AccessTimeDistributionData data structure as request body, as shown in figure 5.4.2.2.2-1, step 1. The AccessTimeDistributionData data structure shall include:

– one of the indication of the UEs to which the 5G access stratum time distribution configuration is requested via:

– identification of a list of individual UEs within the "supis" attribute; or

– identification of a group of UE(s) within the "interGrpId" attribute;

– identification of a list of individual UEs within the "gpsis" attribute;

– identification of a group of UE(s) within the "exterGrpId" attribute; and

– 5G access stratum time distribution parameters within the "asTimeDisParam" attribute;

Within the "asTimeDisParam" attribute inside the AccessTimeDistributionData data structure, the NF service consumer:

– shall include the "asTimeDisEnabled" attribute set to true if the access stratum time distribution via Uu reference point should be activated (otherwise, if the access stratum time distribution via Uu reference point should be inactive, the "asTimeDisEnabled" attribute may either be omitted or included and set to "false");

– may include the time synchronization error budget within the "timeSyncErrBdgt" attribute;

– may include the temporal validity condition within the "tempValidity" attribute.

Upon receipt of the HTTP request from the NF service consumer, if the request is authorized, the TSCTSF shall:

– if the 5G access stratum time distribution configuration applies to an internal group of UEs indicated in the "interGrpId" attribute or to an external group of UEs indicated in the "exterGrpId" attribute, interact with the UDM to retrieve the list of individual UEs that belong to the group using the Nudm_SDM service as defined in 3GPP TS 29.503 [24];

– if the 5G access stratum time distribution configuration applies to a list of individual UEs within the "gpsis" attribute, interact with the UDM to retrieve the SUPI(s) that corresponds to each of the GPSI(s) using the Nudm_SDM service as defined in 3GPP TS 29.503 [24];

– subscribe to event notifications of newly registered PCF for the UE by invoking Nbsf_Management_Subscribe Service Operation as defined in 3GPP TS 29.521 [23], if not yet subscribed;

– If the access stratum time distribution via Uu reference point is being activated (i.e. the "asTimeDisEnabled" attribute within the "asTimeDisParam" attribute was received and set to true), calculate the Uu time synchronization error budget as specified in clause 5.27.1.9 of 3GPP TS 23.501 [2];

– interact with the PCF for a UE to provide the configuration information for each target UE using the Npcf_AMPolicyAuthorization_Create service operation as defined in 3GPP TS 29.534 [14];

– create a new resource, which represents a new "Individual ASTI Configuration" instance, addressed by a URI as defined in clause 6.1.3.7 and containing a TSCTSF created resource identifier; and

– send an HTTP "201 Created" response with AccessTimeDistributionData data structure as response body and a Location header field containing the URI of the created Individual ASTI Configuration resource, i.e. "{apiRoot}/ntsctsf-asti/<apiVersion>/configurations/{configId}", as shown in figure 5.4.2.2.2-1, step 2.

5.4.2.3 Ntsctsf_ASTI_Update

5.4.2.3.1 General

This service operation is used by an NF service consumer to update a 5G access stratum time distribution configuration.

The following procedures using the Ntsctsf_ASTI_Update service operation are supported:

– Updating an existing configuration.

5.4.2.3.2 Updating an existing configuration

Figure 5.4.2.3.2-1 illustrates the updating of an existing configuration.

Figure 5.4.2.3.2-1: Update of a configuration

To update a configuration, the NF service consumer shall send an HTTP PUT request to the resource "{apiRoot}/ntsctsf-asti/<apiVersion>/configurations/{configId}" representing an existing "Individual ASTI Configuration" resource, as shown in figure 5.4.2.3.2-1, step 1, to modify the configuration.

The AccessTimeDistributionData data structure provided in the request body shall include an updated representation of the "Individual ASTI Configuration" resource with the updated 5G access stratum time distribution configuration information as defined in clause 5.4.2.2.2.

Upon receipt of the corresponding HTTP PUT message, if the request is authorized, theTSCTSF shall:

– if the access stratum time distribution via Uu reference point is being activated (i.e. the "asTimeDisEnabled" attribute within the "asTimeDisParam" attribute was received and set to true) or a time synchronization error budget for an active access stratum time distribution is provided or updated by the AF, calculate the Uu time synchronization error budget as specified in clause 5.27.1.9 of 3GPP TS 23.501 [2];

– interact with the PCF for a UE to provide the updated configuration information using the Npcf_AMPolicyAuthorization_Update service operation as defined in 3GPP TS 29.534 [14]; and

– update the existing "Individual ASTI Configuration" resource. Then the TSCTSF shall send a HTTP response including "200 OK" status code with AccessTimeDistributionData data structure or "204 No Content" status code, as shown in figure 5.4.2.3.2-1, step 2.

If the TSCTSF cannot successfully fulfil the received HTTP PUT request due to the internal TSCTSF error or due to the error in the HTTP PUT request, the TSCTSF shall send the HTTP error response as specified in clause 6.3.7.

If the TSCTSF determines the received HTTP PUT request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.4.2.4 Ntsctsf_ASTI_Delete

5.4.2.4.1 General

This service operation is used by an NF service consumer to delete a 5G access stratum time distribution configuration.

The following procedures using the Ntsctsf_ASTI_Delete service operation are supported:

– Delete an existing configuration.

5.4.2.4.2 Delete an existing configuration

Figure 5.4.2.4.2-1 illustrates the deleting of an existing configuration.

Figure 5.4.2.4.2-1: Deletion of a configuration

To delete a configuration, the NF service consumer shall send an HTTP DELETE request to the resource "{apiRoot}/ntsctsf-asti/<apiVersion>/configurations/{configId}" representing an existing "Individual ASTI Configuration" resource, as shown in figure 5.4.2.4.2-1, step 1, to delete the configuration.

Upon the reception of an HTTP DELETE request from the NF service consumer, if the HTTP DELETE request is authorized, the TSCTSF shall:

– interact with the PCF for a UE to remove the configuration information in the PCF by using the Npcf_AMPolicyAuthorization_Delete service operation as defined in 3GPP TS 29.534 [14].

– remove the corresponding configuration and respond with "204 No Content" as shown in figure 5.4.2.4.2-1, step 2.

If the TSCTSF cannot successfully fulfil the received HTTP DELETE request due to the internal TSCTSF error or due to the error in the HTTP DELETE request, the TSCTSF shall send the HTTP error response as specified in clause 6.3.7.

If the TSCTSF determines the received HTTP DELETE request needs to be redirected, the TSCTSF shall send an HTTP redirect response as specified in clause 6.10.9 of 3GPP TS 29.500 [4].

5.4.2.5 Ntsctsf_ASTI_Get

5.4.2.5.1 General

This service operation is used by an NF service consumer to retrieve ths status of the access stratum time distribution for a list of UEs.

The following procedures using the Ntsctsf_ASTI_Get service operation are supported:

– Retrieve the status of access stratum time distribution.

5.4.2.5.2 Retrieve the status of access stratum time distribution

Figure 5.4.2.5.2-1 illustrates the retrieval of the status of access stratum time distribution.

Figure 5.4.2.5.2-1: Retrieval of the status of access stratum time distribution

To retrieve the status of access stratum time distribution, the NF service consumer shall send an HTTP POST request to the resource "{apiRoot}/ntsctsf-asti/<apiVersion>/configurations/retrieve". The HTTP POST message shall include the StatusRequestData data structure as request body, as shown in figure 5.4.2.5.2-1, step 1. The StatusRequestData data structure shall include:

– identification of a list of individual UEs within the "supis" attribute;

Upon the reception of an HTTP POST request and if the HTTP POST request is accepted by the TSCTSF, the TSCTSF determines the status of the access stratum time distribution is active for a UE if there is a 5G access stratum time distribution configuration applicable to the UE, i.e., it applies according to the temporal validity, if present, and the access time distribution via Uu reference point is activated; otherwise, the status of the access stratum time distribution is inactive for the UE.

The TSCTSF shall send an HTTP "200 OK" response with the StatusResponseData data structure as response body, as shown in figure 5.4.2.5.2-1, step 2 to notify of the status.

Within the StatusResponseData data structure, TSCTSF may include:

– a list of UE identifier(s) whose status of the access stratum time distribution is inactive within the "inactiveUes" attribute;

– the "activeUes" attribute containing one or more the ActiveUe instances which includes the UE identifier whose status of the access stratum time distribution is active within the "supi" attribute and the requested time synchronization error budget, if available, within the "timeSyncErrBdgt" attribute.