6 API Definitions

29.5363GPP5G SystemNetwork Slice Admission Control ServicesRelease 18Stage 3TS

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

6.1 Nnsacf_NSAC Service API

6.1.1 Introduction

The Nnsacf_NSAC shall use the Nnsacf_NSAC API.

The API URI of the Nnsacf_NSAC API shall be:

{apiRoot}/<apiName>/<apiVersion>

The request URIs used in HTTP requests from the NF service consumer towards the NF service producer shall have the Resource URI structure defined in clause 4.4.1 of 3GPP TS 29.501 [5], i.e.:

{apiRoot}/<apiName>/<apiVersion>/<apiSpecificResourceUriPart>

with the following components:

– The {apiRoot} shall be set as described in 3GPP TS 29.501 [5].

– The <apiName> shall be "nnsacf-nsac".

– The <apiVersion> shall be "v1".

– The <apiSpecificResourceUriPart> shall be set as described in clause 5.3.

6.1.2 Usage of HTTP

6.1.2.1 General

HTTP/2, IETF RFC 7540 [11], shall be used as specified in clause 5 of 3GPP TS 29.500 [4].

HTTP/2 shall be transported as specified in clause 5.3 of 3GPP TS 29.500 [4].

The OpenAPI [6] specification of HTTP messages and content bodies for the Nnsacf_NSAC API is contained in Annex A.

6.1.2.2 HTTP standard headers

6.1.2.2.1 General

See clause 5.2.2 of 3GPP TS 29.500 [4] for the usage of HTTP standard headers.

6.1.2.2.2 Content type

JSON, IETF RFC 8259 [12], shall be used as content type of the HTTP bodies specified in the present specification as specified in clause 5.4 of 3GPP TS 29.500 [4]. The use of the JSON format shall be signalled by the content type "application/json".

"Problem Details" JSON object shall be used to indicate additional details of the error in a HTTP response body and shall be signalled by the content type "application/problem+json", as defined in IETF RFC 7807 [13].

6.1.2.3 HTTP custom headers

The mandatory HTTP custom header fields specified in clause 5.2.3.2 of 3GPP TS 29.500 [4] shall be supported, and the optional HTTP custom header fields specified in clause 5.2.3.3 of 3GPP TS 29.500 [4] may be supported.

6.1.3 Resources

6.1.3.1 Overview

The figure 6.1.3.1-1 describes the resource URI structure of the Nnsacf-NSAC API.

Figure 6.1.3.1-1: Resource URI structure of the Nnsacf_NSAC API

Table 6.1.3.1-1 provides an overview of the resources and applicable HTTP methods.

Table 6.1.3.1-1: Resources and methods overview

Resource name	Resource URI	HTTP method or custom operation	Description
Slice Collection Subject to NSAC for UEs (Collection)	/slices/ues	POST	Request the NSACF to perform network slice admission control related to the number of UEs registered to a network slice, or a group of network slices.
Slice Collection Subject to NSAC for PDU sessions (Collection)	/slices/pdus	POST	Request the NSACF to perform network slice admission control related to the number of PDU sessions established to a network slice, or a group of network slices.

6.1.3.2 Resource: Slice Collection Subject to NSAC for UEs

6.1.3.2.1 Description

This resource represents the collection of slice subject to NSAC for UEs.

This resource is modelled with the Store resource archetype (see clause C.2 of 3GPP TS 29.501 [5]).

6.1.3.2.2 Resource Definition

Resource URI: {apiRoot}/<apiName>/<apiVersion>/slices/ues

This resource shall support the resource URI variables defined in table 6.1.3.2.2-1.

Table 6.1.3.2.2-1: Resource URI variables for this resource

Name	Data type	Definition
apiRoot	string	See clause 6.1.1
apiVersion	string	See clause 6.1.1

6.1.3.2.3 Resource Standard Methods

6.1.3.2.3.1 POST

This method shall support the URI query parameters specified in table 6.1.3.2.3.1-1.

Table 6.1.3.2.3.1-1: URI query parameters supported by the POST method on this resource

Name	Data type	P	Cardinality	Description	Applicability

This method shall support the request data structures specified in table 6.1.3.2.3.1-2 and the response data structures and response codes specified in table 6.1.3.2.3.1-3.

Table 6.1.3.2.3.1-2: Data structures supported by the POST Request Body on this resource

Data type	P	Cardinality	Description
UeACRequestData	M	1	Request data for NSAC procedure related to the number of UEs per slice.

Table 6.1.3.2.3.1-3: Data structures supported by the POST Response Body on this resource

Data type	P	Cardinality	Response codes	Description
UeACResponseData	M	1	200 OK	Response data for NSAC procedure related to the number of UEs per slice, in the case of not all S-NSSAIs are successful in the NSAC procedure.
n/a			204 No Content	Upon success. Indicates all S-NSSAIs are successful in the NSAC procedure.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set. (NOTE 2)
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection, during a NSAC procedure. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set. (NOTE 2)
ProblemDetails	O	0..1	403 Forbidden	When used to represent the failure of NSAC procedure, the "cause" attribute of the "ProblemDetails" shall be set to one of the following application error codes: – SLICE_NOT_FOUND, if all S-NSSAIs provided in the request are not found from the NSSAI which are subject to NSAC procedure; – ALL_SLICE_FAILED, if the list of S-NSSAIs is fully failed in the NSAC procedure.
NOTE 1: The manadatory HTTP error status code for the POST method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply. NOTE 2: RedirectResponse may be inserted by an SCP, see clause 6.10.9.1 of 3GPP TS 29.500 [4].

Table 6.1.3.2.3.1-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.1.3.2.3.1-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.1.3.2.4 Resource Custom Operations

In this release of this specification, no custom operations associated to this resource is defined.

6.1.3.3 Resource: Slice Collection Subject to NSAC for PDU sessions

6.1.3.3.1 Description

This resource represents the collection of slice subject to NSAC for PDU sessions.

This resource is modelled with the Store resource archetype (see clause C.2 of 3GPP TS 29.501 [5]).

6.1.3.3.2 Resource Definition

Resource URI: {apiRoot}/<apiName>/<apiVersion>/slices/pdus

This resource shall support the resource URI variables defined in table 6.1.3.3.2-1.

Table 6.1.3.3.2-1: Resource URI variables for this resource

Name	Data type	Definition
apiRoot	string	See clause 6.1.1
apiVersion	string	See clause 6.1.1

6.1.3.3.3 Resource Standard Methods

6.1.3.3.3.1 POST

This method shall support the URI query parameters specified in table 6.1.3.3.3.1-1.

Table 6.1.3.3.3.1-1: URI query parameters supported by the POST method on this resource

Name	Data type	P	Cardinality	Description	Applicability

This method shall support the request data structures specified in table 6.1.3.3.3.1-2 and the response data structures and response codes specified in table 6.1.3.3.3.1-3.

Table 6.1.3.3.3.1-2: Data structures supported by the POST Request Body on this resource

Data type	P	Cardinality	Description
PduACRequestData	M	1	Request data for NSAC procedure related to the number of PDU sessions per slice.

Table 6.1.3.3.3.1-3: Data structures supported by the POST Response Body on this resource

Data type	P	Cardinality	Response codes	Description
PduACResponseData	M	1	200 OK	Response data for NSAC procedure related to the number of PDU sessions per slice, in the case of not all S-NSSAIs are successful in the NSAC procedure.
n/a			204 No Content	Upon success. Indicates all S-NSSAIs are successful in the NSAC procedure.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set. (NOTE 2)
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set. (NOTE 2)
ProblemDetails	O	0..1	403 Forbidden	When used to represent the failure of NSAC procedure, the "cause" attribute of the "ProblemDetails" shall be set to one of the following application error codes: – SLICE_NOT_FOUND, if all S-NSSAIs provided in the request are not found from the NSSAI which are subject to NSAC procedure; – ALL_SLICE_FAILED, if the list of S-NSSAIs is fully failed in the NSAC procedure.
NOTE 1: The manadatory HTTP error status code for the POST method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply. NOTE 2: RedirectResponses may be inserted by an SCP, see clause 6.10.9.1 of 3GPP TS 29.500 [4].

Table 6.1.3.3.3.1-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.1.3.3.3.1-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.1.3.3.4 Resource Custom Operations

In this release of this specification, no custom operations associated to this resource is defined.

6.1.4 Custom Operations without associated resources

In this release of this specification, no custom operations without associated resources are defined.

6.1.5 Notifications

6.1.5.1 General

Notifications shall comply to clause 6.2 of 3GPP TS 29.500 [4] and clause 4.6.2.3 of 3GPP TS 29.501 [5].

Table 6.1.5.1-1: Notifications overview

Notification

Callback URI

HTTP method or custom operation

Description

(service operation)

EAC Mode Notification

{EACNotificationUri}

POST

Notify the NF Service Customer (e.g. AMF) of the activation/deactivation of EAC mode.

6.1.5.2 EAC Mode Notification

6.1.5.2.1 Description

The EAC Mode Notification is used by the NSACF to inform the NF Service Consumer (e.g. AMF) of the activation/deactivation of EAC mode.

6.1.5.2.2 Target URI

The Callback URI "{EACNotificationUri}" shall be used with the callback URI variables defined in table 6.1.5.2.2-1.

Table 6.1.5.2.2-1: Callback URI variables

Name	Definition
eacNotificationUri	Notification URI for receiving EAC mode notification.

6.1.5.2.3 Standard Methods

6.1.5.2.3.1 POST

This method shall support the request data structures specified in table 6.1.5.2.3.1-1 and the response data structures and response codes specified in table 6.1.5.2.3.1-1.

Table 6.1.5.2.3.1-1: Data structures supported by the POST Request Body

Data type	P	Cardinality	Description
EACNotification	M	1	EAC mode notification

Table 6.1.5.2.3.1-2: Data structures supported by the POST Response Body

Data type	P	Cardinality	Response codes	Description

NOTE: The mandatory HTTP error status codes for the POST method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

6.1.6 Data Model

6.1.6.1 General

This clause specifies the application data model supported by the API.

Table 6.1.6.1-1 specifies the data types defined for the Nnsacf_NSAC service based interface protocol.

Table 6.1.6.1-1: Nnsacf_NSAC specific Data Types

Data type	Clause defined	Description	Applicability
UeACRequestData	6.1.6.2.2	Input data for NSAC procedure related to the number of UEs per slice.
UeACResponseData	6.1.6.2.3	Response data of NSAC procedure for controlling the number of UEs.
EACNotification	6.1.6.2.4	EAC mode notification
AcuOperationItem	6.1.6.2.5	An operation item for NSAC procedure, indicating an S-NSSAI subject to NSAC and the associated operation.
AcuFailureItem	6.1.6.2.6	A failure item which indicates the failed S-NSSAI and the failure reason.
PduACRequestData	6.1.6.2.7	Input data for NSAC procedure related to the number of PDUs per slice.
PduACResponseData	6.1.6.2.8	Response data of NSAC procedure for controlling the number of PDU sessions.
EACMode	6.1.6.3.3	EAC mode
AcuFlag	6.1.6.3.4	Update Flag for NSAC procedure
AcuFailureReason	6.1.6.3.5	Indicates the failure reason for an S-NSSAI in the NSAC procedure
UeACRequestInfo	6.1.6.2.9	One item of a UE and associated NSAC action.
PduACRequestInfo	6.1.6.2.10	One item of a PDU session and associated NSAC action.

Table 6.1.6.1-2 specifies data types re-used by the Nnsacf_NSAC service based interface protocol from other specifications, including a reference to their respective specifications and when needed, a short description of their use within the Nnsacf_NSAC service based interface.

Table 6.1.6.1-2: Nnsacf_NSAC re-used Data Types

Data type	Reference	Comments	Applicability
ProblemDetails	3GPP TS 29.571 [16]	Problem Details
RedirectResponse	3GPP TS 29.571 [16]	Redirect Response
Supi	3GPP TS 29.571 [16]	Subscription Permanent Identifier
Snssai	3GPP TS 29.571 [16]	Single NSSAI
NfInstanceId	3GPP TS 29.571 [16]	NF Instance ID
Uri	3GPP TS 29.571 [16]	Resource or callback URI
AccessType	3GPP TS 29.571 [16]	Access Type
NFType	3GPP TS 29.510 [17]	NF Type
Fqdn	3GPP TS 29.571 [16]	FQDN
PduSessionId	3GPP TS 29.571 [16]	PDU Session Identifier
PlmnId	3GPP TS 29.571 [16]	PLMN ID

6.1.6.2 Structured data types

6.1.6.2.1 Introduction

This clause defines the structures to be used in resource representations.

6.1.6.2.2 Type: UeACRequestData

Table 6.1.6.2.2-1: Definition of type UeACRequestData

Attribute name	Data type	P	Cardinality	Description	Applicability
ueACRequestInfo	array(UeACRequestInfo)	M	1..N	List of UEs and their associated NSAC action details
nfId	NfInstanceId	M	1	Indicates the NF Instance ID. When present, it shall carry one of the following values: – the AMF Instance ID, if the request is from an AMF; the SMF Instance ID, if the request is from a combined SMF+PGW-C in EPS interworking case.
nfType	NFType	O	0..1	Indicates the NF type of the requester NF. When present, it shall carry one of the following values: NFType=AMF, if the request is from an AMF; NFType=SMF, if the request is from a combined SMF+PGW-C in EPS interworking case.
eacNotificationUri	Uri	O	0..1	Indicates the EAC notification callback URI. If the EAC notification callback URI is present, the AMF Instance ID shall also be present.
NOTE: If the NF consumer is combined SMF+PGW-C, the combined SMF+PGW-C determines the Access Type based on the RAT type parameter in the PMIP or GTP message received from the ePDG; or alternatively it can internally determine the Access Type based on the source node (e.g. SGW) sending the request for the PDN Connection establishment.

6.1.6.2.3 Type: UeACResponseData

Table 6.1.6.2.3-1: Definition of type UeACResponseData

Attribute name	Data type	P	Cardinality	Description	Applicability
acuFailureList	map(array(AcuFailureItem))	C	1..N(1..M)	Indicates a list of S-NSSAI which is failed in the NSAC procedure, and the reasons for each S-NSSAI. Key of the map is the SUPI of the UE.

6.1.6.2.4 Type: EACNotification

Table 6.1.6.2.4-1: Definition of type EACNotification

Attribute name	Data type	P	Cardinality	Description	Applicability
eacModeList	map(EACMode)	O	1..N	a map of EAC Mode where the S-NSSAI serves as the key.

6.1.6.2.5 Type: AcuOperationItem

Table 6.1.6.2.5-1: Definition of type AcuOperationItem

Attribute name	Data type	P	Cardinality	Description	Applicability
updateFlag	AcuFlag	M	1	Indicates the operation (i.e. increase or decrease) to the impacted S-NSSAI.
snssai	Snssai	M	1	Indicates the S-NSSAI for the increase or decrease operation. It shall contain S-NSSAI in serving PLMN or the mapped S-NSSAI in home PLMN.
plmnId	PlmnId	C	0..1	Indicates the PLMN ID associated to the S-NSSAI for increase or decrease operation. It shall be present in the NSAC procedure for the HR or LBO roaming case, or if the NSACF serves multiple PLMNs.

6.1.6.2.6 Type: AcuFailureItem

Table 6.1.6.2.6-1: Definition of type AcuFailureItem

Attribute name	Data type	P	Cardinality	Description	Applicability
snssai	Snssai	M	1	Indicates the S-NSSAI which is failed in the NSAC procedure. It shall contain S-NSSAI in serving PLMN or the mapped S-NSSAI in home PLMN.
reason	AcuFailureReason	M	1	Indicates the reason of an S-NSSAI which is failed in the NSAC procedure.
pduSessionId	PduSessionId	C	0..1	The PDU session Identifier, shall be present when response is for pduAC.
plmnId	PlmnId	C	0..1	Indicates the PLMN ID associated to the S-NSSAI which is failed in the NSAC procedure. It shall be present in the NSAC procedure for the HR or LBO roaming case, or if the NSACF serves multiple PLMN.

6.1.6.2.7 Type: PduACRequestData

Table 6.1.6.2.7-1: Definition of type PduACRequestData

Attribute name	Data type	P	Cardinality	Description	Applicability
pduACRequestInfo	array(PduACRequestInfo)	M	1..N	List of UEs and their associated NSAC action details
nfId	NfInstanceId	O	0..1	Indicates the SMF Instance ID.
pgwFqdn	Fqdn	O	0..1	Indicates the PGW-C FQDN, if the request is from a combined SMF+PGW-C, in EPS interworking case.

6.1.6.2.8 Type: PduACResponseData

Table 6.1.6.2.8-1: Definition of type PduACResponseData

Attribute name	Data type	P	Cardinality	Description	Applicability
acuFailureList	map(array(AcuFailureItem))	C	1..2	Indicates a list of S-NSSAIs which are failed in the NSAC procedure, and the reasons for each S-NSSAI. Key of the map is the SUPI of the UE.

6.1.6.2.9 Type: UeACRequestInfo

Table 6.1.6.2.x-1: Definition of type UeACRequestInfo

Attribute name	Data type	P	Cardinality	Description	Applicability
Supi	Supi	M	1	Supi
anType	AccessType	M	1	Indicates the access type over which the UE registers to the network or deregisters from the network. (NOTE)
acuOperationList	array(AcuOperationItem)	M	1..N	A list of S-NSSAI to which the UE is to be registered or from which the UE is to be de-registered.
additionalAnType	AccessType	O	0..1	Indicates the additional access type, when the UE deregisters from the network, if the UE previously registered to the network over 3GPP access and Non-3GPP access

6.1.6.2.10 Type: PduACRequestInfo

Table 6.1.6.2.7-1: Definition of type PduACRequestData

Attribute name	Data type	P	Cardinality	Description	Applicability
supi	Supi	M	1	Supi
anType	AccessType	M	1	Indicates the access type over which the PDU session is to be established or released.
pduSessionId	PduSessionId	M	1	The PDU session Identifier
acuOperationList	array(AcuOperationItem)	M	1..2	A list of S-NSSAI to which the PDU session is to be established or from which the PDU session is to be released.
additionalAnType	AccessType	O	0..1	Indicates the additional access type, for a Multiple-Access PDU session, if the PDU session is to be established over both 3GPP access and Non-3GPP access, or if the PDU session is to be released from both 3GPP access and Non-3GPP access.

6.1.6.3 Simple data types and enumerations

6.1.6.3.1 Introduction

This clause defines simple data types and enumerations that can be referenced from data structures defined in the previous clauses.

6.1.6.3.2 Simple data types

The simple data types defined in table 6.1.6.3.2-1 shall be supported.

Table 6.1.6.3.2-1: Simple data types

Type Name	Type Definition	Description	Applicability

6.1.6.3.3 Enumeration: EACMode

The enumeration EACMode represents the mode of Early Admission Control. It shall comply with the provisions defined in table 6.1.6.3.3-1.

Table 6.1.6.3.3-1: Enumeration EACMode

Enumeration value	Description	Applicability
"ACTIVE"	EAC mode is enabled.
"DEACTIVE"	EAC mode is disabled.

6.1.6.3.4 Enumeration: AcuFlag

The enumeration AcuFlag indicates the operation (i.e. increase or decrease) applied to a list of S-NSSAI during the NSAC procedure. It shall comply with the provisions defined in table 6.1.6.3.4-1.

Table 6.1.6.3.4-1: Enumeration AcuFlag

Enumeration value	Description	Applicability
"INCREASE"	Indicates the impacted list of S-NSSAI is to be added to the NSACF for a UE (or a PDU session).
"DECREASE"	Indicates the impacted list of S-NSSAI is to be removed from the NSACF for a UE (or a PDU session).
"UPDATE"	Indicates for the impacted S-NSSAIs the access type of a PDU session is to be replaced.

6.1.6.3.5 Enumeration: AcuFailureReason

The enumerationAcuFailureReason indicates the operation result of the NSAC procedure for an individual S-NSSAI. It shall comply with the provisions defined in table 6.1.6.3.5-1.

Table 6.1.6.3.5-1: Enumeration AcuFailureReason

Enumeration value	Description	Applicability
"SLICE_NOT_FOUND"	Indicates that an S-NSSAI is not found by the NSACF from the list of S-NSSAIs which are subject to NSAC procedure.
"EXCEED_MAX_UE_NUM"	Indicates for an S-NSSAI the number of UEs has exceeded the configured maximum number of UEs, if network slice admission control is not specific to one access type.
"EXCEED_MAX_UE_NUM_3GPP"	Indicates for an S-NSSAI the number of UEs has exceeded the configured maximum number of UEs, if network slice admission control is required for 3GPP access. (NOTE)
"EXCEED_MAX_UE_NUM_N3GPP"	Indicates for an S-NSSAI the number of UEs has exceeded the configured maximum number of UEs, if network slice admission control is required for Non-3GPP access. (NOTE)
"EXCEED_MAX_PDU_NUM"	Indicates for an S-NSSAI the number of PDU sessions has exceeded the configured maximum number of PDU sessions if network slice admission control is not specific to one access type.
"EXCEED_MAX_PDU_NUM_3GPP"	Indicates for an S-NSSAI the number of PDU sessions has exceeded the configured maximum number of PDU sessions, if network slice admission control is required for 3GPP access.
"EXCEED_MAX_PDU_NUM_N3GPP"	Indicates for an S-NSSAI the number of PDU sessions has exceeded the configured maximum number of PDU sessions, if network slice admission control is required for Non-3GPP access.
NOTE: If this value is returned in the NSAC response message, how the NF service consumer (e.g. AMF) utilizes the access information carried in the AcuFailureReason value is implementation specific.

6.1.6.4 Data types describing alternative data types or combinations of data types

In this release, no alternative data types or combinations of data types are defined in this specification.

6.1.6.5 Binary data

In this release, no binary data types are defined in this specification.

6.1.7 Error Handling

6.1.7.1 General

For the Nnsacf_NSAC API, HTTP error responses shall be supported as specified in clause 4.8 of 3GPP TS 29.501 [5]. Protocol errors and application errors specified in table 5.2.7.2-1 of 3GPP TS 29.500 [4] shall be supported for an HTTP method if the corresponding HTTP status codes are specified as mandatory for that HTTP method in table 5.2.7.1-1 of 3GPP TS 29.500 [4].

In addition, the requirements in the following clauses are applicable for the Nnsacf_NSAC API.

6.1.7.2 Protocol Errors

No specific procedures for the Nnsacf_NSAC service are specified.

6.1.7.3 Application Errors

The application errors defined for the Nnsacf_NSAC service are listed in Table 6.1.7.3-1.

Table 6.1.7.3-1: Application errors

Application Error	HTTP status code	Description
SLICE_NOT_FOUND	403 Forbidden	All S-NSSAIs provided in the request are not found by the NSACF from the list of S-NSSAIs which are subjected to NSAC procedure.
ALL_SLICE_FAILED	403 Forbidden	All S-NSSAIs are failed in the NSAC procedure, e.g. due to exceed the configured maximum number of UEs.

6.1.8 Feature negotiation

The optional features in table 6.1.8-1 are defined for the Nnsacf_NSAC API. They shall be negotiated using the extensibility mechanism defined in clause 6.6 of 3GPP TS 29.500 [4].

Table 6.1.8-1: Supported Features

Feature number	Feature Name	Description

6.1.9 Security

As indicated in 3GPP TS 33.501 [8] and 3GPP TS 29.500 [4], the access to the Nnsacf_NSAC API may be authorized by means of the OAuth2 protocol (see IETF RFC 6749 [9]), based on local configuration, using the "Client Credentials" authorization grant, where the NRF (see 3GPP TS 29.510 [10]) plays the role of the authorization server.

If OAuth2 is used, an NF Service Consumer, prior to consuming services offered by the Nnsacf_NSAC API, shall obtain a "token" from the authorization server, by invoking the Access Token Request service, as described in 3GPP TS 29.510 [10], clause 5.4.2.2.

NOTE: When multiple NRFs are deployed in a network, the NRF used as authorization server is the same NRF that the NF Service Consumer used for discovering the Nnsacf_NSAC service.

The Nnsacf_NSAC API defines a single scope nnsacf-nsac" for the entire service, and it does not define any additional scopes at resource or operation level.

6.2 Nnsacf_SliceEventExposure Service API

6.2.1 Introduction

The Nnsacf_SliceEventExposure shall use the Nnsacf_SliceEventExposure API.

The API URI of the Nnsacf_SliceEventExposure API shall be:

{apiRoot}/<apiName>/<apiVersion>

The request URIs used in HTTP requests from the NF service consumer towards the NF service producer shall have the Resource URI structure defined in clause 4.4.1 of 3GPP TS 29.501 [5], i.e.:

{apiRoot}/<apiName>/<apiVersion>/<apiSpecificResourceUriPart>

with the following components:

– The {apiRoot} shall be set as described in 3GPP TS 29.501 [5].

– The <apiName> shall be "nnsacf-slice-ee".

– The <apiVersion> shall be "v1".

– The <apiSpecificResourceUriPart> shall be set as described in clause 6.2.3.

6.2.2 Usage of HTTP

6.2.2.1 General

HTTP/2, IETF RFC 7540 [11], shall be used as specified in clause 5 of 3GPP TS 29.500 [4].

HTTP/2 shall be transported as specified in clause 5.3 of 3GPP TS 29.500 [4].

The OpenAPI [6] specification of HTTP messages and content bodies for the Nnsacf_SliceEventExposure API is contained in Annex A.

6.2.2.2 HTTP standard headers

6.2.2.2.1 General

See clause 5.2.2 of 3GPP TS 29.500 [4] for the usage of HTTP standard headers.

6.2.2.2.2 Content type

6.2.2.3 HTTP custom headers

6.2.3 Resources

6.2.3.1 Overview

The figure 6.2.3.1-1 describes the resource URI structure of the Nnsacf_SliceEventExposure API.

Figure 6.2.3.1-1: Resource URI structure of the Nnsacf_SliceEventExposure API

Table 6.2.3.1-1 provides an overview of the resources and applicable HTTP methods.

Table 6.2.3.1-1: Resources and methods overview

Resource name	Resource URI	HTTP method or custom operation	Description
Subscriptions Collection (Collection)	/subscriptions	POST	Mapped to the service operation Subscribe, when to create a subscription
Individual subscription	/subscriptions/{subscriptionId}	PATCH	Mapped to the service operation Subscribe, when to modify the subscription partially
		PUT	Mapped to the service operation Subscribe, when to modify the subscription completely
		DELETE	Mapped to the service operation Unsubscribe

6.2.3.2 Resource: Subscriptions collection

6.2.3.2.1 Description

This resource represents a collection of subscriptions created by NF service consumers of Nnsacf_SliceEventExposure service.

This resource is modelled as the Collection resource archetype (see clause C.2 of 3GPP TS 29.501 [5]).

6.2.3.2.2 Resource Definition

Resource URI: {apiRoot}/nnsacf-slice-ee/<apiVersion>/subscriptions

This resource shall support the resource URI variables defined in table 6.2.3.2.2-1.

Table 6.2.3.2.2-1: Resource URI variables for this resource

Name	Data type	Definition
apiRoot	string	See clause 6.2.1
apiVersion	string	See clause 6.2.1.

6.2.3.2.3 Resource Standard Methods

6.2.3.2.3.1 POST

This method shall support the URI query parameters specified in table 6.2.3.2.3.1-1.

Table 6.2.3.2.3.1-1: URI query parameters supported by the POST method on this resource

Name	Data type	P	Cardinality	Description
n/a

This method shall support the request data structures specified in table 6.2.3.2.3.1-2 and the response data structures and response codes specified in table 6.2.3.2.3.1-3.

Table 6.2.3.2.3.1-2: Data structures supported by the POST Request Body on this resource

Data type	P	Cardinality	Description
SACEventSubscription	M	1	Represents the subscription to the events for slice admission control

Table 6.2.3.2.3.1-3: Data structures supported by the POST Response Body on this resource

Data type	P	Cardinality	Response codes	Description
CreatedSACEventSubscription	M	1	201 Created	Represents successful creation of the events subscription for slice admission control
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
ProblemDetails	O	0..1	403 Forbidden	Indicates the creation of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SLICE_NOT_FOUND
NOTE: The manadatory HTTP error status code for the POST method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

Table 6.2.3.2.3.1-4: Headers supported by the 201 Response Code on this resource

Name	Data type	P	Cardinality	Description
Location	string	M	1	Contains the URI of the newly created resource, according to the structure: {apiRoot}/nnsacf-slice-ee/<apiVersion>/subscriptions/{subscriptionId}

Table 6.2.3.2.3.1-5: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.3.2.3.1-6: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.2.3.2.4 Resource Custom Operations

In this release of this specification, no custom operations associated to this resource is defined.

6.2.3.3 Resource: Individual subscription

6.2.3.3.1 Description

This resource represents an individual of subscription created by NF service consumers of Nnsacf_SliceEventExposure service.

This resource is modelled as the Document resource archetype (see clause C.1 of 3GPP TS 29.501 [5]).

6.2.3.3.2 Resource Definition

Resource URI: {apiRoot}/nnsacf-slice-ee/<apiVersion>/subscriptions/{subscriptionId}

This resource shall support the resource URI variables defined in table 6.2.3.3.2-1.

Table 6.2.3.3.2-1: Resource URI variables for this resource

Name	Data type	Definition
apiRoot	string	See clause 6.2.1
apiVersion	string	See clause 6.2.1.
subscriptionId	string	String identifies an individual subscription to the NSACF event exposure service

6.2.3.3.3 Resource Standard Methods

6.2.3.3.3.1 PATCH

This method shall support the URI query parameters specified in table 6.2.3.3.3.1-1.

Table 6.2.3.3.3.1-1: URI query parameters supported by the PATCH method on this resource

Name	Data type	P	Cardinality	Description
n/a

This method shall support the request data structures specified in table 6.2.3.3.3.1-2 and the response data structures and response codes specified in table 6.2.3.3.3.1-3.

Table 6.2.3.3.3.1-2: Data structures supported by the PATCH Request Body on this resource

Data type	P	Cardinality	Description
array(PatchItem)	M	1..N	It contains the list of changes to be made to the subscription, according to the JSON PATCH format specified in IETF RFC 6902 [14].

Table 6.2.3.3.3.1-3: Data structures supported by the PATCH Response Body on this resource

Data type	P	Cardinality	Response codes	Description
CreatedSACEventSubscription	M	1	200 OK	Represents successful update of the events subscription for slice admission control
n/a			204 No Content	Represents a successful update of the events subscription for slice admission control, and no information needs to be returned to the NF service consumer.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
ProblemDetails	O	0..1	403 Forbidden	Indicates the modification of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SLICE_NOT_FOUND
ProblemDetails	O	0..1	404 Not Found	Indicates the modification of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SUBSCRIPTION_NOT_FOUND
NOTE: The manadatory HTTP error status code for the PATCH method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

Table 6.2.3.3.3.1-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.3.3.3.1-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.2.3.3.3.2 PUT

This method shall support the URI query parameters specified in table 6.2.3.3.3.2-1.

Table 6.2.3.3.3.2-1: URI query parameters supported by the PUT method on this resource

Name	Data type	P	Cardinality	Description
n/a

This method shall support the request data structures specified in table 6.2.3.3.3.2-2 and the response data structures and response codes specified in table 6.2.3.3.3.2-3.

Table 6.2.3.3.3.2-2: Data structures supported by the PUT Request Body on this resource

Data type	P	Cardinality	Description
SACEventSubscription	M	1	Represents the events subscription for slice admission control to be completely replaced.

Table 6.2.3.3.3.2-3: Data structures supported by the PUT Response Body on this resource

Data type	P	Cardinality	Response codes	Description
CreatedSACEventSubscription	M	1	200 OK	Represents successful update of the events subscription for slice admission control.
n/a			204 No Content	Represents the events subscription modification provided by the NF Service Consumer is accepted entirely.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
ProblemDetails	O	0..1	403 Forbidden	Indicates the creation of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SLICE_NOT_FOUND
ProblemDetails	O	0..1	404 Not Found	Indicates the modification of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SUBSCRIPTION_NOT_FOUND
NOTE: The manadatory HTTP error status code for the PUT method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

Table 6.2.3.3.3.2-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.3.3.3.2-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

An alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.2.3.3.3.3 DELETE

This method shall support the URI query parameters specified in table 6.2.3.3.3.3-1.

Table 6.2.3.3.3.3-1: URI query parameters supported by the DELETE method on this resource

Name	Data type	P	Cardinality	Description
n/a

This method shall support the request data structures specified in table 6.2.3.3.3.3-2 and the response data structures and response codes specified in table 6.2.3.3.3.3-3.

Table 6.2.3.3.3.3-2: Data structures supported by the DELETE Request Body on this resource

Data type	P	Cardinality	Description
n/a

Table 6.2.3.3.3.3-3: Data structures supported by the DELETE Response Body on this resource

Data type	P	Cardinality	Response codes	Description
n/a			204 No Content	Upon success, an empty response body shall be returned.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same NSACF or NSACF (service) set.
ProblemDetails	O	0..1	404 Not Found	Indicates the modification of subscription has failed due to application error. The "cause" attribute may be used to indicate one of the following application errors: – SUBSCRIPTION_NOT_FOUND.
NOTE: The manadatory HTTP error status code for the DELETE method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

Table 6.2.3.3.3.3-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

A URI pointing to the endpoint of another NF service consumer to which the notification should be sent.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.3.3.3.3-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

A URI pointing to the endpoint of another NF service consumer to which the notification should be sent.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.2.3.3.4 Resource Custom Operations

In this release of this specification, no custom operations associated to this resource is defined.

6.2.4 Custom Operations without associated resources

In this release of this specification, no custom operations without associated resources are defined.

6.2.5 Notifications

6.2.5.1 General

This clause specifies the notifications provided by the Nnsacf_SliceEventExposure service.

Table 6.2.5.1-1: Notifications overview

Notification

Callback URI

HTTP method or custom operation

Description

(service operation)

NSACF Event Notification

{eventNotifyUri}

POST

6.2.5.2 NSACF Event Notification

If a NF service consumer has subscribed to an event(s) supported by Nnsacf_SliceEventExposure service, when NSACF aware of a state change of the event, NSACF shall create a notification including the event state report, and shall deliver the notification to the call-back URI, following Subscribe/Notify mechanism defined in 3GPP TS 29.501 [5].

6.2.5.2.1 Notification Definition

Call-back URI: {callbackUri}

Call-back URI is "eventNotifyUri" provided by NF Service Consumer during creation of the subscription.

6.2.5.2.2 Notification Standard Methods

6.2.5.2.2.1 POST

This method shall support the request data structures specified in table 6.2.5.2.2.1-1 and the response data structures and response codes specified in table 6.2.5.2.2.1-2.

Table 6.2.5.2.2.1-2: Data structures supported by the POST Request Body

Data type	P	Cardinality	Description
SACEventReport	M	1	Represents the notification to be delivered

Table 6.2.5.2.2.1-3: Data structures supported by the POST Response Body

Data type	P	Cardinality	Response codes	Description
n/a			204 No Content	Upon success, an empty response body shall be returned.
RedirectResponse	O	0..1	307 Temporary Redirect	Temporary redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an URI pointing to the endpoint of another NF service consumer to which the notification should be sent.
RedirectResponse	O	0..1	308 Permanent Redirect	Permanent redirection. The response shall include a Location header field containing a different URI, or the same URI if this is a redirection triggered by an SCP to the same target resource via another SCP. In the former case, the URI shall be an URI pointing to the endpoint of another NF service consumer to which the notification should be sent.
NOTE: The manadatory HTTP error status code for the POST method listed in Table 5.2.7.1-1 of 3GPP TS 29.500 [4] also apply.

Table 6.2.5.2.2.1-4: Headers supported by the 307 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

A URI pointing to the endpoint of another NF service consumer to which the notification should be sent.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.5.2.2.1-5: Headers supported by the 308 Response Code on this resource

Name

Data type

Cardinality

Description

Location

string

A URI pointing to the endpoint of another NF service consumer to which the notification should be sent.

Or the same URI, if a request is redirected to the same target resource via a different SCP.

3gpp-Sbi-Target-Nf-Id

string

0..1

Identifier of the target NF (service) instance ID towards which the request is redirected

6.2.6 Data Model

6.2.6.1 General

This clause specifies the application data model supported by the API.

Table 6.2.6.1-1 specifies the data types defined for the Nnsacf_SliceEventExposure service based interface protocol.

Table 6.2.6.1-1: Nnsacf_SliceEventExposure specific Data Types

Data type	Clause defined	Description	Applicability
SACEventSubscription	6.2.6.2.2	Request data to create the event subscription
CreatedSACEventSubscription	6.2.6.2.3	Response data on created event subscription
SACEventReport	6.2.6.2.4	Event notification
SACEvent	6.2.6.2.5	Describes an event to be subscribed
SACEventReportItem	6.2.6.2.6	Represents a report triggered by a subscribed event type
SACEventState	6.2.6.2.7	Represents the state of a subscribed event
SACEventType	6.2.6.3.3	Describes the supported event types
SACEventTrigger	6.2.6.3.4	Describes how NSACF should generate the report for the event

Table 6.2.6.1-2 specifies data types re-used by the Nnsacf_SliceEventExposure service based interface protocol from other specifications, including a reference to their respective specifications and when needed, a short description of their use within the Nnsacf_SliceEventExposure service based interface.

Table 6.2.6.1-2: Nnsacf_SliceEventExposure re-used Data Types

Data type	Reference	Comments	Applicability
PatchItem	3GPP TS 29.571 [16]
Uri	3GPP TS 29.571 [16]	Callback URI
NfInstanceId	3GPP TS 29.571 [16]	NF Instance Id
DurationSec	3GPP TS 29.571 [16]	Time value in seconds
SACInfo	3GPP TS 29.571 [16]	SAC Information
DateTime	3GPP TS 29.571 [16]	UTC time
SupportedFeatures	3GPP TS 29.571 [16]	Supported Features
Snssai	3GPP TS 29.571 [16]	S-NSSAI
SACEventStatus	3GPP TS 29.571 [16]	SAC Event Status

6.2.6.2 Structured data types

6.2.6.2.1 Introduction

This clause defines the structures to be used in resource representations.

6.2.6.2.2 Type: SACEventSubscription

Table 6.2.6.2.2-1: Definition of type SACEventSubscription

Attribute name	Data type	P	Cardinality	Description	Applicability
event	SACEvent	M	1	Describes the event to be subscribed in subscription request.
eventNotifyUri	Uri	M	1	Identifies the recipient of notifications sent by NSACF for this subscription.
nfId	NfInstanceId	M	1	Indicates the instance identity of the network function creating the subscription.
notifyCorrelationId	string	C	0..1	This IE shall be present if available. If present, this IE identifies the notification correlation ID. The NSACF shall include this ID in the notifications. The value of this IE shall be unique per subscription for a given NF service consumer.
maxReports	integer	C	0..1	This IE shall be present if available. If present, this IE contains the maximum number of reports that can be generated by each subscribed event in the subscription.
expiry	DateTime	C	0..1	This IE shall be included in an event subscription response, if, based on operator policy and taking into account the expiry time included in the request, the NSACF needs to include an expiry time. This IE may be included in an event subscription request. When present, this IE shall represent the time after which the subscribed event(s) shall stop generating report and the subscription becomes invalid. This IE shall be absent in the response for one time and immediate reporting (see clause 5.3.2.2.4).
supportedFeatures	SupportedFeatures	C	0..1	This IE shall be present if at least one optional feature defined in clause 6.3.8 is supported.

6.2.6.2.3 Type: CreatedSACEventSubscription

Table 6.2.6.2.3-1: Definition of type CreatedSACEventSubscription

Attribute name	Data type	P	Cardinality	Description	Applicability
subscription	SACEventSubscription	M	1	Represents the newly created SAC Event Subscription resource.
subscriptionId	string	M	1	Represents the subscription Id of the newly created SAC Event Subscription resource.
report	SACEventReportItem	C	0..1	This IE shall be present if available and if the immediateFlag attribute is set to "true" in subscription request. When present, this IE represents the immediate event report (i.e. the current value of the event subscribed).
supportedFeatures	SupportedFeatures	C	0..1	This IE shall be present if at least one optional feature defined in clause 6.3.8 is supported.

6.2.6.2.4 Type: SACEventReport

Table 6.2.6.2.4-1: Definition of type SACEventReport

Attribute name

Data type

Cardinality

Description

Applicability

report

SACEventReportItem

This IE represents the event report to be delivered.

notifyCorrelationId

string

0..1

This IE shall be present if available.

If present, this IE indicate the notification correlation Id provided by the NF service consumer during event subscription. This parameter can be useful if the NF service consumer uses a common call-back URI for multiple subscriptions.

6.2.6.2.5 Type: SACEvent

Table 6.2.6.2.5-1: Definition of type SACEvent

Attribute name	Data type	P	Cardinality	Description	Applicability
eventType	SACEventType	M	1	Describes the event type to be reported.
eventTrigger	SACEventTrigger	C	0..1	Describes how the reports are triggered. (See NOTE 1)
eventFilter	array(Snssai)	M	1..N	This IE shall indicate the S-NSSAI list to be applied.
notificationPeriod	DurationSec	C	0..1	This IE shall be present if the eventTrigger is set to "PERIODIC". When present, this IE contains the time period for the event reports.
notifThreshold	SACInfo	C	0..1	This IE shall be present if the eventTrigger is set to "THRESHOLD". When present, this IE Indicates the monitoring threshold value, upon which event notification(s) are triggered.
immediateFlag	boolean	O	0..1	This attribute shall be set to "true" to indicate an immediate event report in the subscription response is requested. The report contains the current value of the event stored at the time of the subscription in the NSACF. (See NOTE)
NOTE 1: The eventTrigger shall not be present if the maxReports attribute in the SACEventSubscription is set to 1. Otherwise, the eventTrigger shall be present. NOTE 2: If the immediateFlag flag is absent or set to "false", then the immediate reporting shall not be done.

6.2.6.2.6 Type: SACEventReportItem

Table 6.2.6.2.6-1: Definition of type SACEventReportItem

Attribute name	Data type	P	Cardinality	Description	Applicability
eventType	SACEventType	M	1	Describes the type of the event which triggers the report
eventState	SACEventState	M	1	Describes the state of the event which triggered the report.
timeStamp	DateTime	M	1	This IE shall contain the time at which the event is generated.
eventFilter	Snssai	M	1	This IE shall indicate the S-NSSAI to be applied.
sliceStautsInfo	SACEventStatus	C	0..1	If the "eventType" attribute is set to "NUM_OF_REGD_UES" or "NUM_OF_ESTD_PDU_SESSIONS", this parameter shall be included to indicate the current network slice status information for the concerned network slice. (NOTE)
NOTE: For periodic reporting, both of the values expressed in percentage and in numerical shall be included.

6.2.6.2.7 Type: SACEventState

Table 6.2.6.2.7-1: Definition of type SACEventState

Attribute name	Data type	P	Cardinality	Description	Applicability
active	boolean	M	1	Represents the active state of the subscribe event. "TRUE" value indicates the event will continue generating reports; "FALSE" value indicates the event will not generate further report.
remainReports	integer	O	0..1	Represents the number of remain reports to be generated by the subscribed event.
remainDuration	DurationSec	O	0..1	Represents how long the subscribed event will continue generating reports.

6.2.6.3 Simple data types and enumerations

6.2.6.3.1 Introduction

This clause defines simple data types and enumerations that can be referenced from data structures defined in the previous clauses.

6.2.6.3.2 Simple data types

The simple data types defined in table 6.2.6.3.2-1 shall be supported.

Table 6.2.6.3.2-1: Simple data types

Type Name	Type Definition	Description	Applicability

6.2.6.3.3 Enumeration: SACEventType

Table 6.2.6.3.3-1: Enumeration SACEventType

Enumeration value	Description	Applicability
"NUM_OF_REGD_UES"	A NF subscribes to this event to receive the current number of registered UEs for a network slice.
"NUM_OF_ESTD_PDU_SESSIONS"	A NF subscribes to this event to receive the current number of established PDU Sessions for a network slice.

6.2.6.3.4 Enumeration: SACEventTrigger

Table 6.2.6.3.4-1: Enumeration SACEventTrigger

Enumeration value

Description

Applicability

"THRESHOLD"

Defines that the NSACF should generate reports for the event when the defined threshold value is reached, until the subscription to this event ends:

– due to end of report duration or

– up to the maximum number of reports or

– the event being unsubscribed explicitly.

"PERIODIC"

Defines that the NSACF should periodically generate reports for the event, until the subscription to this event ends:

– due to end of report duration or

– up to the maximum number of reports or

– the event being unsubscribed explicitly.

6.2.6.4 Data types describing alternative data types or combinations of data types

In this release, no alternative data types or combinations of data types are defined in this specification.

6.2.6.5 Binary data

In this release, no binary data types are defined in this specification.

6.2.7 Error Handling

6.2.7.1 General

For the Nnsacf_SliceEventExposure API, HTTP error responses shall be supported as specified in clause 4.8 of 3GPP TS 29.501 [5]. Protocol errors and application errors specified in table 5.2.7.2-1 of 3GPP TS 29.500 [4] shall be supported for an HTTP method if the corresponding HTTP status codes are specified as mandatory for that HTTP method in table 5.2.7.1-1 of 3GPP TS 29.500 [4].

In addition, the requirements in the following clauses are applicable for the Nnsacf_SliceEventExposure API.

6.2.7.2 Protocol Errors

No specific procedures for the Nnsacf_SliceEventExposure service are specified.

6.2.7.3 Application Errors

The application errors defined for the Nnsacf_SliceEventExposure service are listed in Table 6.2.7.3-1.

Table 6.2.7.3-1: Application errors

Application Error	HTTP status code	Description
SLICE_NOT_FOUND	403 Forbidden	The given S-NSSAI is not found by the NSACF in the list of S-NSSAIs which are subjected to NSAC procedure.

6.2.8 Feature negotiation

The optional features in table 6.3.8-1 are defined for the Nnsacf_SliceEventExposure API. They shall be negotiated using the extensibility mechanism defined in clause 6.6 of 3GPP TS 29.500 [4].

Table 6.2.8-1: Supported Features

Feature number	Feature Name	Description

6.2.9 Security

As indicated in 3GPP TS 33.501 [8] and 3GPP TS 29.500 [4], the access to the Nnsacf_SliceEventExposure API may be authorized by means of the OAuth2 protocol (see IETF RFC 6749 [9]), based on local configuration, using the "Client Credentials" authorization grant, where the NRF (see 3GPP TS 29.510 [10]) plays the role of the authorization server.

If OAuth2 is used, an NF Service Consumer, prior to consuming services offered by the Nnsacf_SliceEventExposure API, shall obtain a "token" from the authorization server, by invoking the Access Token Request service, as described in 3GPP TS 29.510 [10], clause 5.4.2.2.

NOTE: When multiple NRFs are deployed in a network, the NRF used as authorization server is the same NRF that the NF Service Consumer used for discovering the Nnsacf_SliceEventExposure service.

The Nnsacf_SliceEventExposure API defines a single scope "nnsacf-slice-ee" for the entire service, and it does not define any additional scopes at resource or operation level.

Annex A (normative):
OpenAPI specification