## 6.2 Namf_EventExposure Service API

29.5183GPP5G SystemAccess and Mobility Management ServicesRelease 16Stage 3TS

### 6.2.1 API URI

The Namf_EventExposure shall use the Namf_EventExposure API.

The API URI of the Namf_EventExposure API shall be:

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

The request URI 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 "namf-evts".

– 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, as defined in IETF RFC 7540 [19], 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].

HTTP messages and bodies for the Namf_EventExposure service shall comply with the OpenAPI [23] specification contained in Annex A.

##### 6.2.2.2.1 General

The usage of HTTP standard headers shall be supported as specified in clause 5.2.2 of 3GPP TS 29.500 [4].

##### 6.2.2.2.2 Content type

The following content types shall be supported:

– JSON, as defined in IETF RFC 8259 [8], shall be used as content type of the HTTP bodies specified in the present specification as indicated in clause 5.4 of 3GPP TS 29.500 [4].

– The Problem Details JSON Object (IETF RFC 7807 [36]). The use of the Problem Details JSON object in a HTTP response body shall be signalled by the content type "application/problem+json".

– JSON Patch (IETF RFC 6902 [14]). The use of the JSON Patch format in a HTTP request body shall be signalled by the content type "application/json-patch+json".

##### 6.2.2.3.1 General

In this release of this specification, no custom headers specific to the Namf_EventExposure service are defined. For 3GPP specific HTTP custom headers used across all service based interfaces, see clause 5.2.3 of 3GPP TS 29.500 [4].

### 6.2.3 Resources

#### 6.2.3.1 Overview

Figure 6.2.3.1-1: Resource URI structure of the Namf_EventExposure 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 /subscriptions POST Mapped to the service operation Subscribe, when to create a subscription Individual subscription /{subscriptionId} PATCH Mapped to the service operation Subscribe, when to modify 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 Namf_EventExposure 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}/namf-evts/<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 AmfCreateEventSubscription M 1 Describes of an AMF Event Subscription to be created

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 AmfCreatedEventSubscription M 1 201 Created Represents successful creation of an AMF Event Subscription 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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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: – UE_NOT_SERVED_BY_AMF

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}/namf-evts//subscriptions/{subscriptionId}

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

 Name Data type P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 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 P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 0..1 Identifier of the target NF (service) instance ID towards which the request is redirected

None.

#### 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 Namf_EventExposure 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}/namf-evts/<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 AMF 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(AmfUpdateEventSubscriptionItem) M 1..N Document describes the modification(s) to a AMF Event Subscription array(AmfUpdateEventOptionItem) M 1..1 Document describing the modification to the event subscription options (e.g subscription expiry time).

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 AmfUpdatedEventSubscription M 1 200 OK Represents a successful update on AMF Event Subscription 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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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: – UE_NOT_SERVED_BY_AMF 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

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

 Name Data type P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 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 P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 0..1 Identifier of the target NF (service) instance ID towards which the request is redirected
###### 6.2.3.3.3.2 DELETE

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 DELETE method on this resource

 Name Data type P Cardinality Description n/a

This method shall support the request data structures specified in table 6.2.3.3.3.2-2 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 DELETE Request Body on this resource

 Data type P Cardinality Description n/a

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

 Data type P Cardinality Response codes Description n/a 204 No Content 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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 a request is redirected to the same target resource via a different SCP. In the former case, the URI shall be an alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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.

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

 Name Data type P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 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 P Cardinality Description Location string M 1 An alternative URI of the resource located on an alternative service instance within the same AMF or AMF (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 O 0..1 Identifier of the target NF (service) instance ID towards which the request is redirected

None.

### 6.2.4 Custom Operations without associated resources

There are no custom operations without associated resources supported on Namf_EventExposure Service.

#### 6.2.5.1 General

This clause specifies the notifications provided by the Namf_EventExposure service.

 Notification Callback URI HTTP method or custom operation Description (service operation) AMF Event Notification {eventNotifyUri} POST AMF Event Notification {subsChangeNotifyUri} POST

If a NF service consumer has subscribed to an event(s) supported by Namf_EventExposure service, when AMF aware of a state change of the event, AMF 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].

Call-back URI: {callbackUri}

Call-back URI is provided by NF Service Consumer during creation of the subscription. If the notification is to inform the change of subscription ID and if the "subsChangeNotifyUri" was provided in the AmfEventSubscription, then this callback URI shall be the "subsChangeNotifyUri" provided in the AmfEventSubscription. Otherwise, this callback URI shall be the "eventNotifyUri" provided in the AmfEventSubscription.

###### 6.2.5.2.3.1 POST

This method shall support the request data structures specified in table 6.2.5.2.3.1-1 and the response data structures and response codes specified in table 6.2.5.2.3.1-2.

Table 6.2.5.2.3.1-2: Data structures supported by the POST Request Body

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

Table 6.2.5.2.3.1-3: Data structures supported by the POST Response Body

 Data type P Cardinality Response codes Description n/a 204 No Content RedirectResponse O 0..1 307 Temporary Redirect Temporary redirection. The NF service consumer shall generate a Location header field containing a URI pointing to the endpoint of another NF service consumer to which the notification should be sent. If an SCP redirects the message to another SCP then the location header field shall contain the same URI or a different URI pointing to the endpoint of the NF service consumer to which the notification should be sent. RedirectResponse O 0..1 308 Permanent Redirect Permanent redirection. The NF service consumer shall generate a Location header field containing a URI pointing to the endpoint of another NF service consumer to which the notification should be sent. If an SCP redirects the message to another SCP then the location header field shall contain the same URI or a different URI pointing to the endpoint of the NF service consumer to which the notification should be sent.

Table 6.2.5.2.3.1-4: Headers supported by the 307 Response Code on this resource

 Name Data type P Cardinality Description Location string M 1 A URI pointing to the endpoint of the NF service consumer to which the notification should be sent 3gpp-Sbi-Target-Nf-Id string O 0..1 Identifier of the target NF (service) instance ID towards which the request is redirected

Table 6.2.5.2.3.1-5: Headers supported by the 308 Response Code on this resource

 Name Data type P Cardinality Description Location string M 1 A URI pointing to the endpoint of the NF service consumer to which the notification should be sent 3gpp-Sbi-Target-Nf-Id string O 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 Namf_EventExposure service based interface protocol.

Table 6.2.6.1-1: Namf_EventExposure specific Data Types

 Data type Clause defined Description AmfEventSubscription 6.2.6.2.2 Represents an individual event subscription resource on AMF AmfEvent 6.2.6.2.3 Describes an event to be subscribed AmfEventNotification 6.2.6.2.4 Represents a notification generated by AMF to be delivered AmfEventReport 6.2.6.2.5 Represents a report triggered by a subscribed event type, except the report triggered by UES_IN_AREA_REPORT event type AmfEventMode 6.2.6.2.6 Describes how the reports shall be generated by a subscribed event AmfEventState 6.2.6.2.7 Represents the state of a subscribed event RmInfo 6.2.6.2.8 Represents the registration state of a UE for an access type CmInfo 6.2.6.2.9 Represents the connection management state of a UE for an access type CommunicationFailure 6.2.6.2.11 Describes a communication failure detected by AMF AmfCreateEventSubscription 6.2.6.2.12 Describes of an AMF Event Subscription to be created AmfCreatedEventSubscription 6.2.6.2.13 Represents successful creation of an AMF Event Subscription AmfUpdateEventSubscriptionItem 6.2.6.2.14 Document describes the modification(s) to an AMF Event Subscription AmfUpdatedEventSubscription 6.2.6.2.15 Represents a successful update on an AMF Event Subscription AmfEventArea 6.2.6.2.16 Represents an area to be monitored by an AMF event. LadnInfo 6.2.6.2.17 LADN Information AmfUpdateEventOptionItem 6.2.6.2.18 Document describing the modifications to AMF event subscription options. 5GsUserStateInfo 6.2.6.2.19 Represents the 5GS User state of the UE for an access type TrafficDescriptor 6.2.6.2.20 Represents the Traffic Descriptor UEIdExt 6.2.6.2.21 UE Identity AmfEventSubsSyncInfo 6.2.6.2.22 AMF Event Subscriptions Information for synchronization AmfEventSubscriptionInfo 6.2.6.2.23 Individual AMF Event Subscription Information IdleStatusIndication 6.2.6.2.24 Information about IdleStatusIndication AmfEventType 6.2.6.3.3 Describes the supported event types of Namf_EventExposure Service AmfEventTrigger 6.2.6.3.4 Describes how AMF should generate the report for the event LocationFilter 6.2.6.3.5 Describes the supported filters of LOCATION_REPORT event type UeReachability 6.2.6.3.7 Describes the reachability of the UE RmState 6.2.6.3.9 Describes the registration management state of a UE CmState 6.2.6.3.10 Describes the connection management state of a UE 5GsUserState 6.2.6.3.11 Describes the 5GS User State of a UE LossOfConnectivityReason 6.2.6.3.12 Describes the reason for loss of connectivity ReachabilityFilter 6.2.6.3.13 Event filter for REACHABILITY_REPORT event type.

Table 6.2.6.1-2 specifies data types re-used by the Namf_EventExposure 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 Namf_EventExposure service based interface.

Table 6.2.6.1-2: Namf_EventExposure re-used Data Types

 Data type Reference Comments Supi 3GPP TS 29.571 [6] GroupId 3GPP TS 29.571 [6] DurationSec 3GPP TS 29.571 [6] Gpsi 3GPP TS 29.571 [6] Uri 3GPP TS 29.571 [6] Pei 3GPP TS 29.571 [6] UserLocation 3GPP TS 29.571 [6] TaI 3GPP TS 29.571 [6] TimeZone 3GPP TS 29.571 [6] AccessType 3GPP TS 29.571 [6] Ecgi 3GPP TS 29.571 [6] EUTRA Cell Identifier Ncgi 3GPP TS 29.571 [6] NR Cell Identifier NfInstanceId 3GPP TS 29.571 [6] ProblemDetails 3GPP TS 29.571 [6] Problem Details SupportedFeatures 3GPP TS 29.571 [6] Supported Features DateTime 3GPP TS 29.571 [6] NgApCause 3GPP TS 29.571 [6] PresenceInfo 3GPP TS 29.571 [6] Presence Reporting Area Information PresenceState 3GPP TS 29.571 [6] Describes the presence state of the UE to a specified area of interest Dnn 3GPP TS 29.571 [6] Snssai 3GPP TS 29.571 [6] DddTrafficDescriptor 3GPP TS 29.571 [6] Downlink Data Delivery Traffic Descriptor SamplingRatio 3GPP TS 29.571 [6] Sampling Ratio. RedirectResponse 3GPP TS 29.571 [6] Response body of the redirect response message. ReferenceId 3GPP TS 29.503 [35] NsiId 3GPP TS 29.531 [18] NSI ID NFType 3GPP TS 29.510 [29] NF type

#### 6.2.6.2 Structured data types

##### 6.2.6.2.1 Introduction

Structured data types used in Namf_EventExposure service are specified in this clause.

##### 6.2.6.2.2 Type: AmfEventSubscription

Table 6.2.6.2.2-1: Definition of type AmfEventSubscription

##### 6.2.6.2.3 Type: AmfEvent

Table 6.2.6.2.3-1: Definition of type AmfEvent

 Attribute name Data type P Cardinality Description type AmfEventType M 1 Describes the AMF event type to be reported immediateFlag boolean O 0..1 Indicates if an immediate event report in the subscription response is requested. The report contains the current value / status of the event stored at the time of the subscription in the AMF (NOTE 1). If the flag is not present then immediate reporting shall not be done. areaList array(AmfEventArea) O 1..N Identifies the area to be applied. More than one instance of AmfEventArea IE shall be used only when the AmfEventArea is provided during event subscription for Presence Reporting Area subscription. locationFilterList array(LocationFilter) O 1..N Describes the filters to be applied for LOCATION_REPORT event type. If this attribute is not present in the request, it indicates the change of the TA used by the UE should be reported. refId ReferenceId O 0..1 Indicates the Reference Id associated with the event. (NOTE 3) trafficDescriptorList array(TrafficDescriptor) O 1..N Indicates the filters to be applied for AVAILABILITY_AFTER_DDN_FAILURE event type. reportUeReachable boolean C 0..1 This IE shall be present and set to value "true" by the source AMF to request the target AMF to notify the subscriber when UE becomes reachable, during inter-AMF mobility procedures. When present, this IE shall be set as following: – true: target AMF shall notify the subscriber when UE becomes reachable – false (default): target AMF shall not notify the subscriber when UE becomes reachable, until next reporting trigger is detected, i.e. DDN failure detected (for AVAILABILITY_AFTER_DDN_FAILURE event) or UE becomes unreachable for downlink traffic (for "UE Reachable for DL Traffic" of REACHABILITY_REPORT event) This IE only applies to following Event Types: – AVAILABILITY_AFTER_DDN_FAILURE – REACHABILITY_REPORT (for "UE Reachable for DL Traffic") reachabilityFilter ReachabilityFilter O 0..1 When present, this IE shall indicate the filter to be applied for the REACHABILITY_REPORT event type. If the subscription of REACHABILITY_REPORT is for "UE Reachability Status Change", the AMF shall report current reachability state and subsequent updated reachability state of the UE, when AMF becomes aware of a UE reachability state change between REACHABLE, UNREACHABLE and REGULATORY_ONLY. If the subscription of REACHABILITY_REPORT is for "UE Reachable for DL Traffic", the AMF shall report the "REACHABLE" state, when the UE transitions to CM-CONNECTED mode or when the UE will become reachable for paging, as specified in table 4.15.3.1-1, clauses 4.2.5 and 4.3.3 of 3GPP TS 23.502 [3]. If this IE is absent, the subscription of REACHABILITY_REPORT is for "UE Reachability Status Change". maxReports integer O 0..1 This IE may be present if the trigger is set to "CONTINUOUS". When present, this IE describes the maximum number of reports that can be generated by the subscribed event. If the AMF event subscription is for a group of UEs, this parameter shall be applied to each individual member UE of the group. If the event subscription is transferred from source AMF to a target AMF, this IE shall contain: – the remaining number of reports for the event subscription, in the case of individual UE event subscription; or – the remaining number of reports for the event subscription for this specific UE, in the case of a group event subscription. If the group subscription has not expired and all reports have been sent already for this event, the remaining number of reports shall be set to "0". (NOTE 2) maxResponseTime DurationSec C 0..1 This IE shall be present, when the UDM subscribes to "REACHABILITY_REPORT" event for "UE Reachable for DL Traffic" on behalf of the AF and the AF sets the Maximum Response Time in the Monitoring Configuration. When present, this IE shall indicate the Maximum Response Time configured by the AF. idleStatusInd boolean O 0..1 Idle Status Indication request. May be present if type is REACHABILITY_REPORT or AVAILABILITY_AFTER_DDN_FAILURE true: Idle status indication is requested false (default): Idle status indication is not requested NOTE 1: The current value of the location is the last known location if the immediate report filter request to provide the 3GPP location information down to the Cell-ID or the TAI. An NF Service Consumer willing to only receive the current location shall not set the immediateFlag to true when subscribing to a location event report. NOTE 2: When creating an AMF event subscription with multiple events, the same maximum number of reports shall apply to each event. Accordingly, maxReports in this attribute should not be present when creating an AMF event subscription; if it is present, it shall contain the same value for all events and maxReports in the AmfEventMode shall have precedence over the maxReports in this attribute. maxReports in this attribute and maxReports in the AmfEventMode have different semantics when transferring the event subscription from a source AMF to a target AMF. NOTE 3: Each Monitoring Configuration subscribed via UDM Event Exposure service uses a Reference Id as the key. This IE shall carry the Reference Id when UDM subscribes to the AMF event for the corresponding Monitoring Configuration.

Table 6.2.6.2.4-1: Definition of type AmfEventNotification

 Attribute name Data type P Cardinality Description Applicability notifyCorrelationId string C 0..1 This IE shall be included if the notification is not for informing creation of a new subscription Id. This IE shall also be included if the notification is for informing the creation of a new subscription Id and the corresponding event subscription did not contain subsChangeNotifyCorrelationId attribute (see clause 6.2.6.2.2). When present, this IE shall 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. subsChangeNotifyCorrelationId string C 0..1 This IE shall be included if the notification is for informing the creation of a new subscription Id at the AMF and the corresponding event subscription contains the subsChangeNotifyCorrelationId attribute (see clause 6.2.6.2.2). When present, this IE shall be set to the value of the subsChangeNotifyCorrelationId provided during subscription (see clause 6.2.6.2.2). reportList array(AmfEventReport) C 1..N This IE shall be present if a event is reported. When present, this IE represents the event reports to be delivered. eventSubsSyncInfo AmfEventSubsSyncInfo C 0..1 This IE may be present for AMF to initiate event subscription synchronization with UDM during UE mobility procedures. When present, this IE shall contain the information for event subscription synchronization, including all active event subscriptions specificially targeting the UE. ESSYNC
##### 6.2.6.2.5 Type: AmfEventReport

Table 6.2.6.2.5-1: Definition of type AmfEventReport

##### 6.2.6.2.12 Type: AmfCreateEventSubscription

Table 6.2.6.2.12-1: Definition of type AmfCreateEventSubscription

 Attribute name Data type P Cardinality Description subscription AmfEventSubscription M 1 Represents the AMF Event Subscription resource to be created. supportedFeatures SupportedFeatures C 0..1 This IE shall be present if at least one optional feature defined in clause 6.2.8 is supported. oldGuami Guami C 0..1 This IE shall be present during an AMF planned removal procedure when the NF Service Consumer initiates a request towards the target AMF, for a UE associated to an AMF that is unavailable (see clause 5.21.2.2 of 3GPP TS 23.501 [2]).
##### 6.2.6.2.13 Type: AmfCreatedEventSubscription

Table 6.2.6.2.13-1: Definition of type AmfCreatedEventSubscription

 Attribute name Data type P Cardinality Description subscription AmfEventSubscription M 1 Represents the newly created AMF Event Subscription resource. subscriptionId Uri M 1 Represents the URI of the newly created AMF Event Subscription resource. This shall contain an absolute URI set to the Resource URI specified in clause 6.2.3.3.2. (NOTE 2) reportList array(AmfEventReport) O 1..N Represents the immediate event reports (i.e. the current value / status of the events subscribed), if available (NOTE 1). supportedFeatures SupportedFeatures C 0..1 This IE shall be present if at least one optional feature defined in clause 6.2.8 is supported. NOTE 1: If the subscription is on behalf of another NF and the NF service consumer has not indicated supporting of IERSR feature (see 6.2.8), then the reports attribute shall be absent. NOTE 2: 3GPP TS 23.502 [3] specifies this attribute as "Subscription Correlation ID".
##### 6.2.6.2.14 Type: AmfUpdateEventSubscriptionItem

Table 6.2.6.2.14-1: Definition of type AmfUpdateEventSubscriptionItem

 Attribute name Data type P Cardinality Description op string M 1 This IE indicates the patch operation as defined in IETF RFC 6902 [14] to be performed on resource. This IE shall support the following values: Enum: "add" Enum: "replace" Enum: "remove" path string M 1 This IE contains a JSON pointer value (as defined in IETF RFC 6901 [40]) that references a location of a resource on which the patch operation shall be performed. This IE shall contain the JSON pointer to a valid index of the "/eventList" array in the AMF Event Subscription, formatted with following pattern: ‘\/eventList\/[0-]$|\/eventList\/[1-9][0-9]*$’ Example: "/eventList/0" stands for the first member of the array; "/eventList/10" stands for the 11th member of the array; "/eventList/-" stands for a new (non-existent) member after the last existing array element. Only allowed with "add" operation. value AmfEvent C 0..1 This IE indicates a new AMF event to be added or updated value of an existing AMF event to be modified. It shall be present if the patch operation is "add" or "replace"
##### 6.2.6.2.15 Type: AmfUpdatedEventSubscription

Table 6.2.6.2.15-1: Definition of type AmfUpdatedEventSubscription

 Attribute name Data type P Cardinality Description subscription AmfEventSubscription M 1 Represents the updated AMF Event Subscription resource. reportList array(AmfEventReport) O 1..N Represents the immediate event reports (i.e. the current value / status of the events subscribed), if available (NOTE). NOTE: For newly added AMF event subscription(s) with the immediateFlag attribute set to true, immediate event report(s) of the corresponding AMF event subscription shall be provided if available.
##### 6.2.6.2.16 Type: AmfEventArea

Table 6.2.6.2.16-1: Definition of type AmfEventArea

 Attribute name Data type P Cardinality Description Applicability presenceInfo PresenceInfo C 0..1 This IE shall be present if the Area of Interest subscribed is not a LADN service area (e.g Presence Reporting Area or a list of TAIs / cell Ids) . (See NOTE1, NOTE 2) ladnInfo LadnInfo C 0..1 This IE shall be present if the Area of Interest subscribed is a LADN service area. sNssai Snssai O 0..1 When present, it shall contain the associated S-NSSAI of the area. ENA nsiId NsiId O 0..1 When present, this IE shall contain the associated NSI ID of the S-NSSAI. ENA NOTE 1: When the AmfEventArea is provided during event subscription, then for UE specific presence reporting area subscription, the praId along with what constitutes that UE specific presence reporting area (i.e. set of Tai and/or set of ecgi and/or set of ncgi and/or set of globalRanNodeId) shall be provided. NOTE 2: If the subscription is for a Set of Core Network Predefined Presence Reporting Areas and both the AMF and the NF service consumer support the "APRA" feature, the PRA Identifier for the Set shall be carried in the "praId" IE and the individual PRA identifier shall be carried in the "additionalPraId" IE; if the subscription is for a Set of Core Network Predefined Presence Reporting Areas and the AMF or NF service consumer does not support the "APRA" feature, the individual PRA identifier shall be carried in the "praId" IE and the "additionalPraId" IE shall not be present.

Table 6.2.6.2.17-1: Definition of type LadnInfo

 Attribute name Data type P Cardinality Description ladn string M 1 Represents the Local Access Data Network DNN. The AMF shall identify the list of tracking areas corresponding to the LADN DNN based on local configuration. presence PresenceState C 0..1 This IE shall be included when the UE presence in area of interest is reported. When present, this IE contains the status of UE presence within the Area of Interest (IN / OUT / UNKNOWN).
##### 6.2.6.2.18 Type: AmfUpdateEventOptionItem

Table 6.2.6.2.18-1: Definition of type AmfUpdateEventOptionItem

 Attribute name Data type P Cardinality Description op string M 1 This IE indicates the patch operation as defined in IETF RFC 6902 [14] to be performed on resource. This IE shall support the following values: Enum: "replace" path string M 1 This IE contains a JSON pointer value (as defined in IETF RFC 6901 [40]) that references a location of a resource on which the patch operation shall be performed. This IE shall contain the JSON pointer to "/options/expiry" attribute of the event subscription resource. Pattern: "\/options\/expiry\$" value DateTime M 1 This IE indicates the updated expiry timer value as suggested by the NF service consumer.
##### 6.2.6.2.19 Type: 5GsUserStateInfo

Table 6.2.6.2.19-1: Definition of type 5GsUserStateInfo

 Attribute name Data type P Cardinality Description 5gsUserState 5GsUserState M 1 Describes the 5GS user state of the UE accessType AccessType M 1 Describes the access type of the UE that applies to the 5GS user state reported.
##### 6.2.6.2.20 Type: TrafficDescriptor

Table 6.2.6.2.20-1: Definition of type TrafficDescriptor

 Attribute name Data type P Cardinality Description dnn Dnn C 0..1 This IE shall be present if it is available. When present, it shall indicate the Data Network Name. sNssai Snssai C 0..1 This IE shall be present if it is available. When present, it shall indicate the associated S-NSSAI for the PDU Session. dddTrafficDescriptorList array(DddTrafficDescriptor) C 1..N This IE shall be present if it is available. When present, it shall indicate the Traffic Descriptor related to the traffic.
##### 6.2.6.2.21 Type: UEIdExt

Table 6.2.6.2.21-1: Definition of type UEIdExt

 Attribute name Data type P Cardinality Description supi Supi C 0..1 This IE shall be present if available. When present, this IE identifies the SUPI of the UE associated with the report. gpsi Gpsi C 0..1 This IE shall be present if available. When present, this IE identifies the GPSI of the UE associated with the report.
##### 6.2.6.2.22 Type: AmfEventSubsSyncInfo

Table 6.2.6.2.22-1: Definition of type AmfEventSubsSyncInfo

 Attribute name Data type P Cardinality Description Applicability subscriptionList array(AmfEventSubscriptionInfo) M 1..N This IE shall contain all active subscriptions in the AMF for the target UE.
##### 6.2.6.2.23 Type: AmfEventSubscriptionInfo

Table 6.2.6.2.23-1: Definition of type AmfEventSubscriptionInfo

 Attribute name Data type P Cardinality Description Applicability subId Uri M 1 This IE shall contain the URI of the subscription resource of events with Reference Id. notifyCorrelationId string M 1 This IE shall contain the notification correlation ID of the subscription. refIdList array(ReferenceId) M 1..N This IE shall contain the Reference Ids of the events in the subscription, one Reference Id per event. oldSubId Uri C 0..1 This IE shall be present if new event subscription Id is created in the new AMF, i.e. the event subscription has been retrieved from an old AMF in UE context during EPS to 5GS mobility. When present, this IE shall include the URI of the subscription resouce on the source AMF.
##### 6.2.6.2.28 Type: IdleStatusIndication

Table 6.2.6.2.28-1: Definition of type IdleStatusIndication

 Attribute name Data type P Cardinality Description Applicability timeStamp DateTime O 0..1 Point in time when the UE returned to Idle activeTime DurationSec O 0..1 Active Time granted to the UE. subsregTimer DurationSec O 0..1 Subscribed periodic registration time. edrxCycleLength integer O 0..1 Contains the eDRX cycle length in milliseconds. suggestedNumOfDlPackets integer O 0..1 Suggested number of downlink packets to be buffered

#### 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
##### 6.2.6.3.3 Enumeration: AmfEventType

Table 6.2.6.3.3-1: Enumeration AmfEventType

##### 6.2.6.3.4 Enumeration: AmfEventTrigger

Table 6.2.6.3.4-1: Enumeration AmfEventTrigger

 Enumeration value Description "ONE_TIME" Defines that AMF should generate report for the event only once. After reporting, the subscription to this event will be terminated. "CONTINUOUS" Defines that AMF should continuously 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 "PERIODIC" Defines that AMF 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.
##### 6.2.6.3.5 Enumeration: LocationFilter

Table 6.2.6.3.5-1: Enumeration LocationFilter

 Enumeration value Description "TAI" Indicates any change of the TA used by the UE should be reported "CELL_ID" Indicates any change of the Cell used by the UE should be reported "N3IWF" Indicates any change of the N3IWF node used by the UE should be reported "UE_IP" Indicates any change of the UE local IP address should be reported "UDP_PORT" Indicates any change of local UDP port used by the UE reported "TNAP_ID" Indicates any change of the TNAP ID used by the UE should be reported "GLI" Indicates any change of the Global Line Id used by the UE should be reported "TWAP_ID" Indicates any change of the TWAP ID used by the UE should be reported
##### 6.2.6.3.7 Enumeration: UeReachability

Table 6.2.6.3.7-1: Enumeration UeReachability

 Enumeration value Description "UNREACHABLE" Indicates the UE is not reachable, e.g. when the Mobile Reachable Timer in AMF expires. "REACHABLE" Indicates the UE is reachable for services and downlink traffic. "REGULATORY_ONLY" Indicates the UE is reachable only for Regulatory Prioritized Service as the UE is in Not Allowed Areas.
##### 6.2.6.3.9 Enumeration: RmState

Table 6.2.6.3.9-1: Enumeration RmState

 Enumeration value Description "REGISTERED" Indicates the UE in RM-REGISTERED state "DEREGISTERED" Indicates the UE in RM-DEREGISTERED state
##### 6.2.6.3.10 Enumeration: CmState

Table 6.2.6.3.10-1: Enumeration CmState

 Enumeration value Description "IDLE" Indicates the UE is in CM-IDLE state "CONNECTED" Indicates the UE is in CM-CONNECTED state
##### 6.2.6.3.11 Enumeration: 5GsUserState

Table 6.2.6.3.11-1: Enumeration 5GsUserState

 Enumeration value Description "DEREGISTERED" Indicates the UE in RM-DEREGISTERED state "CONNECTED_NOT_REACHABLE_FOR_PAGING" Indicates the UE is in the RM-REGISTERED state in 5GS and the UE is not reachable for paging. "CONNECTED_REACHABLE_FOR_PAGING" Indicates the UE is in the RM-REGISTERED state in 5GS and the UE is reachable for paging. "NOT_PROVIDED_FROM_AMF" Indicates that the 5GS User State cannot be retrieved from the AMF (NOTE) NOTE: This value is not sent by AMF (it may be sent by UDM to HSS).
##### 6.2.6.3.12 Enumeration: LossOfConnectivityReason

Table 6.2.6.3.12-1: Enumeration LossOfConnectivityReason

 Enumeration value Description "DEREGISTERED" Indicates the UE is deregistered. "MAX_DETECTION_TIME_EXPIRED" Indicates the mobile reachable timer is expired. "PURGED" Indicates the UE is purged.
##### 6.2.6.3.13 Enumeration: ReachabilityFilter

Table 6.2.6.3.13-1: Enumeration ReachabilityFilter

 Enumeration value Description "UE_REACHABILITY_STATUS_CHANGE" Indicates subscription for "UE Reachability Status Change". "UE_REACHABLE_DL_TRAFFIC" Indicates subscription for "UE Reachable for DL Traffic".

None.

### 6.2.7 Error Handling

#### 6.2.7.1 General

HTTP error handling shall be supported as specified in clause 5.2.4 of 3GPP TS 29.500 [4].

#### 6.2.7.2 Protocol Errors

Protocol Error Handling shall be supported as specified in clause 5.2.7 of 3GPP TS 29.500 [4].

#### 6.2.7.3 Application Errors

The common application errors defined in the Table 5.2.7.2-1 in 3GPP TS 29.500 [4] may also be used for the Namf_EventExposure service, and the following application errors listed in Table 6.2.7.3-1 are specific for the Namf_EventExposure service.

Table 6.2.7.3-1: Application errors

 Application Error HTTP status code Description UE_NOT_SERVED_BY_AMF 403 Forbidden Indicates the creation or the modification of a subscription has failed due to an application error when the UE is not served by the AMF. SUBSCRIPTION_NOT_FOUND 404 Not Found Indicates the modification of subscription has failed due to an application error when the subscription is not found in the AMF.

### 6.2.8 Feature Negotiation

The feature negotiation mechanism specified in clause 6.6 of 3GPP TS 29.500 [4] shall be used to negotiate the optional features applicable between the AMF and the NF Service Consumer, for the Namf_EventExposure service, if any.

The NF Service Consumer shall indicate the optional features it supports for the Namf_EventExposure service, if any, by including the supportedFeatures attribute in payload of the HTTP Request Message for subscription resource creation.

The AMF shall determine the supported features for the service operations as specified in clause 6.6 of 3GPP TS 29.500 [4] and shall indicate the supported features by including the supportedFeatures attribute in payload of the HTTP response for subscription resource creation.

The syntax of the supportedFeatures attribute is defined in clause 5.2.2 of 3GPP TS 29.571 [6].

The following features are defined for the Namf_EventExposure service:

Table 6.2.8-1: Features of supportedFeatures attribute used by Namf_EventExposure service

 Feature Number Feature M/O Description 1 ENA O Enablers for Network Automation for 5G An AMF and an NF that support this feature shall support the procedures specified in 3GPP TS 23.288 [38]. 2 APRA O Additional Presence Reporting Area An AMF that supports this feature shall support subscription of "PRESENCE_IN_AOI_REPORT" event with a Set of Core Network Predefined Presence Reporting Areas and generating event report including both PRA Set ID and additional PRA ID referring to an individual PRA in the Set. An NF service consumer that supports this feature shall support receiving "PRESENCE_IN_AOI_REPORT" event with additional PRA ID referring to an individual PRA in the Set. 3 ESSYNC O Event Subscription Synchronization An AMF and UDM that supports this feature shall support the event subscription synchronization procedure, as specified in clause 5.3.2.4.2. 4 ES3XX M Extended Support of HTTP 307/308 redirection An NF Service Consumer (e.g. NEF) that supports this feature shall support handling of HTTP 307/308 redirection for any service operation of the Namf_EventExposure service. An NF Service Consumer that does not support this feature does only support HTTP redirection as specified for 3GPP Release  15. 5 IERSR O Immediate Event Report in Subscription Creation Response for Subscriptions on behalf of another NF An NF consumer (e.g. UDM) supporting this feature shall be able to handle the immediate event reports in the Subscription Creation Response for subscriptions on behalf of another NF, as specified in clause 5.3.2.2.2. Feature number: The order number of the feature within the supportedFeatures attribute (starting with 1). Feature: A short name that can be used to refer to the bit and to the feature. M/O: Defines if the implementation of the feature is mandatory ("M") or optional ("O"). Description: A clear textual description of the feature.

### 6.2.9 Security

As indicated in 3GPP TS 33.501 [27], the access to the Namf_EventExposure API may be authorized by means of the OAuth2 protocol (see IETF RFC 6749 [28]), using the "Client Credentials" authorization grant, where the NRF (see 3GPP TS 29.510 [29]) plays the role of the authorization server.

If Oauth2 authorization is used, an NF Service Consumer, prior to consuming services offered by the Namf_EventExposure API, shall obtain a "token" from the authorization server, by invoking the Access Token Request service, as described in 3GPP TS 29.510 [29], 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 Namf_EventExposure service.

The Namf_EventExposure API defines scopes for OAuth2 authorization as specified in 3GPP TS 33.501 [27]; it defines a single scope consisting on the name of the service (i.e., "namf-evts"), and it does not define any additional scopes at resource or operation level.

### 6.2.10 HTTP redirection

An HTTP request may be redirected to a different AMF service instance, within the same AMF or a different AMF of an AMF set, e.g. when an AMF service instance is part of an AMF (service) set or when using indirect communications (see 3GPP TS 29.500 [4]). See the ES3XX feature in clause 6.2.8.

An SCP that reselects a different AMF producer instance will return the NF Instance ID of the new AMF producer instance in the 3gpp-Sbi-Producer-Id header, as specified in clause 6.10.3.4 of 3GPP TS 29.500 [4].

If an AMF within an AMF set redirects a service request to a different AMF of the set using an 307 Temporary Redirect or 308 Permanent Redirect status code, the identity of the new AMF towards which the service request is redirected shall be indicated in the 3gpp-Sbi-Target-Nf-Id header of the 307 Temporary Redirect or 308 Permanent Redirect response as specified in clause 6.10.9.1 of 3GPP TS 29.500 [4].