8.7 Discover service APIs

23.2223GPPCommon API Framework for 3GPP Northbound APIsRelease 18TS

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

8.7.1 General

The following procedure in this subclause corresponds to the architectural requirements on discover service APIs.

8.7.2 Information flows

8.7.2.1 Service API discover request

Table 8.7.2.1-1 describes the information flow service API discover request from the API invoker to the CAPIF core function.

Table 8.7.2.1-1: Service API discover request

Information element	Status	Description
API invoker identity information	M	Identity information of the API invoker discovering service APIs
Query information	M	Criteria for discovering matching service APIs (e.g. service API type, Serving Area Information (optional), preferred AEF location (optional), required API provider name (optional), interfaces, protocols) (see NOTE)
NOTE: It should be possible to discover all the service APIs.

8.7.2.2 Service API discover response

Table 8.7.2.2-1 describes the information flow service API discover response from the CAPIF core function to the API invoker.

Table 8.7.2.2-1: Service API discover response

Information element	Status	Description
Result	M	Indicates the success or failure of the discovery of the service API information
Service API information (see NOTE 2)	O (see NOTE 1)	List of service APIs corresponding to the request, including API description such as service API name, service API type, Serving Area Information (optional), interface details (e.g. IP address, port number, URI), protocols, version, data format
CAPIF core function identity information	O (see NOTE 1)	Indicates the CAPIF core function serving the service API category provided in the query criteria
NOTE 1: The service API information or the CAPIF core function identity information or both shall be present if the Result information element indicates that the service API discover operation is successful. Otherwise both shall not be present. NOTE 2: If topology hiding is enabled for the service API, the interface details shall be the interface details of AEF acting as service communication entry point for the service API.

8.7.3 Procedure

Figure 8.7.3-1 illustrates the procedure for discover service APIs.

The service API discovery mechanism is supported by the CAPIF core function.

Pre-conditions:

1. The API invoker is onboarded and has received an API invoker identity.

2. The CAPIF core function is configured with a discovery policy information (e.g. to restrict discovery to category of APIs) for API invoker(s).

Figure 8.7.3-1: Discover service APIs

1. The API invoker sends a service API discover request to the CAPIF core function. It includes the API invoker identity, and may include query information.

2. Upon receiving the service API discover request, the CAPIF core function verifies the identity of the API invoker (via authentication). The CAPIF core function retrieves the stored service API(s) information from the CAPIF core function (API registry) as per the query information in the service API discover request. Further, the CAPIF core function applies the discovery policy and performs filtering of service APIs information retrieved from the CAPIF core function.

3. The CAPIF core function sends a service API discover response to the API invoker with the list of service API information for which the API invoker has the required authorization.