What's network

A network is defined as a group of two or more computer systems linked together. There are many types of computer
networks , including the following:
local-area networks (LANs) : The computers are geographically close together (that is, in the same building).
wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves.
campus-area networks (CANs) : The computers are within a limited geographic area, such as a campus or military base.
metropolitan-area networks MANs) : A data network designed for a town or city.
home-area networks (HANs) : A network contained within a user's home that connects a person's digital devices.
Network Characteristics
In addition to these types, the following characteristics are also used to categorize different types of networks:
topology : The geometric arrangement of a computer system. Common topologies include a bus, star , and ring. See the Network topology diagrams in the Quick Reference section of Webopedia.
protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called
Ethernet . Another popular LAN protocol for PCs is the IBM token-ring network .
architecture : Networks can be broadly classified as using either a
peer-to-peer or client/server architecture .
Computers on a network are sometimes called nodes . Computers and devices that allocate resources for a network are called servers.