The client-server paradigm is extensively applied on the Internet.
Networks heavily employ the client-server concept where one program running on a computer acts as a server that provides services to programs running on other computers and acting as clients requesting services from the server. For instance, suppose that you have a LAN with only one printer attached to one of the interconnected computers. That computer must have a printer server running. That server controls the printer operation so as to be able to provide printing services to the other LAN computers. Meanwhile, the other computers must have printer clients running. Those clients are capable of contacting the printer server through the communication medium so as to request printing services.
