Content for  TS 23.558  Word version:  19.3.0

The illustration of layered application architecture with the generic SEAL and Application Enabler server functions available in the cloud is shown in Figure A.4.1-1.

The examples of application specific client are V2X application specific client, FF application specific client, UAS application specific client or other vertical application specific client residing on the UE. Similarly, the application specific server could be e.g. V2X application specific server, FF application specific server, UAS application specific server or other vertical application specific server. The UE may consist of an application enabler client. The examples of application enabler client include V2X application enabler client, FF application enabler client, UAS application enabler client or other vertical application enabler client residing on the UE. Similarly, the application enabler server could be V2X application enabler server, FF application enabler Server, UAS application enabler server or other vertical application enabler server. The illustration of layered application architecture with generic SEAL and Application Enabler server functions available in the edge is shown in Figure A.4.1-2.

While the server functions of an application specific server can be made available only as an EAS, it is also possible that certain application specific server functions are available both at the edge and in the cloud. Similarly, the server functions of an application enabler server can be made available only as an EAS, it is also possible that certain application enabler server functions are available both at the edge and in the cloud. When the server functions of an application are both available at the edge and the cloud, there may be a need for interaction between the two corresponding application servers, which is out of scope of this specification.

There are several options to support SEAL service APIs to be exposed to the EAS. The EES can act as the CAPIF core function, and the SEAL servers acting the AEF and publish the SEAL service API to the EES. Further, the SEAL service APIs is discovered by the EASs acting as the API invoker during the service API discover procedure as specified in TS 23.222. The EES can act as the API topology hiding entry and re-expose SEAL service APIs as specified in TS 23.434 to EAS via EDGE-3 which utilizes the CAPIF-2/2e reference point as specified in TS 23.222.

There are several options to support vertical application enabler server (e.g., V2X application enabler server) APIs to be exposed to the EAS. The EES can act as the CAPIF core function, and the vertical application enabler server acting the AEF and publish the vertical application enabler server APIs to the EES. Further, the vertical application enabler server APIs is discovered by the EASs acting as the API invoker during the service API discover procedure as specified in TS 23.222. The EES can act as the API topology hiding entry and re-exposes vertical application enabler server APIs, e.g., VAE server APIs as specified in TS 23.286 to EAS via EDGE-3 which utilizes the CAPIF-2/2e reference point as specified in TS 23.222.