Networking allows sharing data and resources among various computers. A computer network is mainly classified into three types: Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN). LAN connects nodes over a short distance. MAN connects nodes over an area larger than a LAN but smaller than a WAN. WAN connects nodes over large geographical areas.
Network topology defines the way to group computers to form a network. In bus topology, the nodes are connected to a single backbone cable by a transceiver. In ring topology, each node is connected to the other to form a circular ring. In star topology, each node is connected to a central switch or hub. The tree topology integrates multiple star topologies onto a bus. In mesh topology, each computer is connected to every other computer.
Communication media are the cables used to connect various devices. The communication media is classified into two types: guided media and unguided media. In guided media, the computers are connected with each other through cables. The guided media is used for short distance data transmission. The cables used for guided communication are twisted pair cable, coaxial cable and fiber optic cable. In unguided media, the computers are connected with each other through waves. It is used for long distance data transmission. Examples of unguided communication are micro wave, radio and satellite. Network devices are the components used to connect various computers and other electronic devices together to share the information. Network devices include modem, hub, switch, repeater, router, and gateway. Network security provides freedom from risk. Some commonly used network security measures are authorisation, authentication, firewall and intrusion detection.