The CINET layer performs a multiplexing and demultiplexing function between an application program and the several transports that are active. When a socket is initially created with the socket() call, it is generally available to all the transports. Once the socket becomes associated with a single transport, all subsequent calls go to that one transport; the other transports have no knowledge of the socket at all. Server sockets typically remain associated with all the transports while client sockets often become associated with just one.