A system is any accumulation of autonomous PCs that speak with each other over a common system medium. In simple terms, a computer network is a collection of two or more computers linked together for the purpose of sharing information and resources. At the point when these PCs are participated in a system, individuals can share records and peripherals, for example, modems, printers, reinforcement drives, or CD-ROM drives. Each computer on the network is called a node and hence, a network is a series of points or nodes interconnected by communication paths (transmission media). A system can be as little and straightforward as two PCs that offer a printer or as mind boggling as the world’s biggest system, the Internet. When networks at multiple locations are connected using services available from phone companies, people can send e-mail, share links to the global Internet, or conduct video conferences in real time with other remote users. As companies rely on applications like electronic mail and database management for core business operations, computer networking becomes increasingly more important.