Computer network is a collection of computers that are interconnected to share information and processing resources. Networks enable data to be transferred rapidly from one computer to another. Network users can share information or even work together on the same document.
Networks come in several types. Local area networks (LAN’s) connect computers in a single location, such as an office. LAN’s frequently employ client-server computing. A central computer called the server holds common files and performs difficult tasks. Computers connected to the server are called clients. Users at client computers can retrieve files from the server or move files from computer to computer through the LAN. Besides sharing information, LAN users share resources, such as printers. Cables typically connect the computers and other devices to the LAN. Wireless networks often use a technology called Wi-Fi. Wi-Fi and similar technologies enable communication between computing devices by means of radio waves sent through the air.
Wide area networks (WAN’s) can spread across states, across countries, or even around the world. The computers and devices attached to the WAN communicate via telephone lines or high-speed private communications lines. Many LAN’s are connected to WAN’s and are able to use their resources. Secure links known as firewalls prevent users of a WAN from gaining unauthorized access to resources on a LAN.
The world’s largest network is the Internet. The Internet connects computers and computer networks around the world.
In addition to enabling computers to communicate, networks enable users to work together. On some networks, for example, people in widely separated offices can all work on a document at the same time. As one user makes changes to the document, others connected to the network can see the changes. Such network operations require special software (computer programs).
See also Distributed computing .
