The host process refers to the process which receives the remote call and runs the executor. It is also used as a remote process.
The client process refers to the process where the remote call originates from.
The user’s code implements the actual methods or features that will be running in the host process. Only its headers need to be exposed to both the client and the host.
The source code that is written for the client process, where it would make a remote call.
The host refers to the socket that listens on the port, and the client refers to the socket that connects to the host.