The MSGin5G Server and Application Server may support CAPIF. When CAPIF is supported:
The MSGin5G Server shall support the CAPIF API provider domain functions (i.e. CAPIF-2/2e, CAPIF-3/3e, CAPIF-4/4e and CAPIF-5/5e as specified in TS 23.222) as shown in Figure 5.5.1-1;
The Application Server shall act as API invoker and support the API invoker functions (i.e. CAPIF-1/1e and CAPIF-2/2e as specified in TS 23.222) as shown in Figure 5.5.1-1.
The Service based architecture for MSGin5G Service is represented using functional entities and reference points between the functional entities as specified in clause 5.
The M5S function is a service based function exhibited by MSGin5G Server.
The M5C function is the MSGin5G Client.
The AC is the Application Client.
The L3G function is a service based function exhibited by Legacy 3GPP Message Gateway.
The N3G function is a service based function exhibited by Non-3GPP Message Gateway.
The BMG function is a service based function exhibited by the Broadcast Message Gateway.
The M5S manages the distribution of the messages it has received from MSGin5G UE, from Application Server, or from N3G (on behalf of Non-3GPP UE) or from L3G (on behalf of Legacy 3GPP UE).
The M5S invokes services provided by L3G/N3G/BMG to send MSGin5G messages towards Legacy 3GPP UE, Non-3GPP UE, or the broadcast delivery mechanism.
The AS/L3G/N3G invokes services provided by M5S to send MSGin5G messages to M5S on behalf of Legacy 3GPP UE or Non-3GPP UE.
The M5S invokes services provided by SEAL Group management function to do MSGin5G Group management.
The M5S/L3G/N3G invokes services provided by SEAL Configuration management function to do service configuration (including UE service ID provisioning).