B.1 CAPIF relationship with 3GPP EPS network exposure
23.2223GPPCommon API Framework for 3GPP Northbound APIsRelease 18TS
B.1.1 General
The table B.1.1-1 shows the relationship between CAPIF and EPS network exposure aspects. The details of SCEF and its role in exposing network capabilities of EPS to 3rd party applications are specified in 3GPP TS 23.682 [2]
Table B.1.1-1: CAPIF relationship with 3GPP EPS network exposure
|
Aspects |
CAPIF |
EPS network exposure |
|
Entity providing the APIs to external or 3rd party applications |
AEF |
SCEF |
|
Entity providing framework related services to the applications (discovery, authentication, authorization, etc) |
CAPIF core function |
SCEF |
|
Entity representing the external or 3rd party applications |
API invoker |
SCS/AS |
|
Entity providing framework related services to support the APIs operation and management (publish, policy enforcements, charging) |
CAPIF core function |
SCEF |
|
Interface/Reference point for exposing network capabilities as APIs |
CAPIF-2 and CAPIF-2e (Do not include the service specific aspects) |
T8 |
|
Interface/Reference point for exposing framework services as APIs to the applications |
CAPIF-1 and CAPIF-1e |
Not specified. (May be via T8) |
|
Interface/Reference point for framework services to support the APIs operation and management |
CAPIF-3, CAPIF-4 and CAPIF-5 |
Internal to SCEF |
B.1.2 Deployment models
B.1.2.1 General
Based on the relationship captured in table B.1.1-1, the following deployment models for CAPIF are possible to enable EPS network exposure.
NOTE: The deployment models captured in subclause 7 are possible for the SCEF deployment compliant with CAPIF. Not all deployment models are illustrated in this subclause.
B.1.2.2 SCEF implements the CAPIF architecture
Figure B.1.2.2-1 illustrates the deployment model where SCEF implements the CAPIF architecture.
Figure B.1.2.2-1: SCEF implements the CAPIF architecture
The SCEF can implement the functionalities of the CAPIF core function, the API exposing function, the API publishing function and the API management function.
According to the CAPIF architecture, CAPIF-2 and CAPIF-2e consist of framework aspects and service specific aspects. The service specific aspects are out of scope of CAPIF. T8 can implement the service specific aspects of CAPIF-2 and CAPIF-2e, and can provide the service APIs exposed by SCEF (AEF) to the SCS/AS (API invoker).
The SCEF can additionally provide CAPIF-1 and CAPIF-1e (CAPIF APIs) to the SCS/AS (API invokers).
B.1.2.3 SCEF implements the service specific aspect compliant with the CAPIF architecture
Figure B.1.2.3-1 illustrates the deployment model where SCEF implements the service specific aspect compliant with the CAPIF architecture.
Figure B.1.2.3-1: SCEF implements the service specific aspect compliant with the CAPIF architecture
3GPP EPS can deploy the CAPIF core function along with the SCEF.
The SCEF can implement the functionalities of the API provider domain functions.
According to the CAPIF architecture, CAPIF-2 and CAPIF-2e consist of framework aspects and service specific aspects. The service specific aspects are out of scope of CAPIF. T8 can implement the service specific aspects of CAPIF-2 and CAPIF-2e, and can provide the service APIs exposed by SCEF (AEF) to the SCS/AS (API invoker).
The SCEF can implement the CAPIF-3 reference point/interface to the CAPIF core function.
B.1.2.4 Distributed deployment of the SCEF compliant with the CAPIF architecture
Figure B.1.2.4-1 illustrates the distributed deployment model where the SCEF implements the service specific aspect compliant with the CAPIF architecture.
Figure B.1.2.4-1: Distributed deployment of SCEF compliant with the CAPIF architecture
The 3GPP EPS can deploy the CAPIF core function, the SCEF-2 (API exposing function as a gateway) along with the SCEF-1 as illustrated in subclause 7.3.
The SCEF can implement the functionalities of API provider domain functions.
According to the CAPIF architecture, CAPIF-2 or CAPIF-2e consists of framework aspects and service specific aspects. The service specific aspects are out of scope of the CAPIF. T8 can implement the service specific aspects of CAPIF-2 or CAPIF-2e and can provide the service APIs exposed by the SCEF-2 (AEF as a gateway) to the SCS/AS (API invoker).
The SCEF-2 can implement the CAPIF-3 reference point to the CAPIF core function and the SCEF-1 can implement the CAPIF-4 and CAPIF-5 reference points to the CAPIF core function.
Editor’s Note: The illustration of this deployment model requires further study.