Few subfields of computer science and computer technology have undergone such drastic development in recent years as the techniques of computer and system networking. These are distributed systems of autonomous computers that communicate with each other in a network. All computers of a network can be reached under their address and can participate in the communication.
The classical tasks of computer networks are characterized in the most different compound functionalities: Computer network, data network, availability network, functional network, performance network, load network and communication network. The computers participating in a network operate with their own operating systems and communicate with each other via networks.
Computer networks are usually classified according to distance, ranging from a few centimeters in the case of the Very Local Area Network( VLAN) to building and campus networks( LAN), city networks ( MAN), wide area networks (WAN) and global networks( GAN).