Multiplexing
Multiplexing is the process by which multiple applications on the same host communicate with different hosts at the same time. Multiplexing gaurentees each application only gets the messages related to communications they have made. This is done by the use of ports - an additional address system on top of IP addresses.
There are two types of multiplexing, connection orientated multiplexing and connection-less multiplexing. Connection here refers to an agreed way to and stop a communication.