A computer network is a group of computers and other hardware devices that are linked together through communication media to further communication and resource sharing among a wide range of users and computer. Computer networks are commonly identified based on their characteristics. A computer network is a kind of telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.

Network computer devices that originate, route and terminate the data are called network nodes. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices are said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other.

Computer networks support applications such as access to the World Wide Web, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications. Computer networks differ in the physical media used to transmit their signals, the communications protocols to organize network traffic, the network’s size, topology and organizational intent.

There are many types of networks, including:
• Local Area Networks (LAN)
• Personal Area Networks (PAN)
• Home Area Networks (HAN)
• Wide Area Networks (WAN)
• Campus Networks
• Metropolitan Area Networks (MAN)
• Enterprise Private Networks
• Internetworks
• Backbone Networks (BBN)
• Global Area Networks (GAN)
• The Internet