Server processes publish connection-port objects that are visible to all processes. When a client wants services from a subsystem,
it opens a handle to the server’s connection-port object and sends a connection request to that port.
The server then creates a channel and returns a handle to the client. The channel consists of a pair of private communication ports: one for client—server messages,
the other for server—client messages. Additionally,communication channels support a callback mechanism that allows the client and server to accept requests when they would normally be expecting a reply.