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 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 to send MSGin5G Messages towards Legacy 3GPP UE or Non-3GPP UE.
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).