Computer networking is the practice of interfacing two or more computing devices with each other for the purpose of sharing data. Computer networks are built with a combination of hardware and software.
Information in this article focuses on wireless networking and computer networks, which are related to, but different than, social networking.
Computer Network Classification and Area Networks
Computer networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically span a single home, school, or small office building, whereas wide area networks (WANs), reach across cities, states, or even across the world. The internet is the world's largest public WAN.
Computer networks also differ in their design approach. The two basic forms of network design are called client-server and peer-to-peer. Client-server networks feature centralized server computers that store email, web pages, files, and applications accessed by client computers and other client devices. On a peer-to-peer network, conversely, all devices tend to support the same functions. Client-server networks are common in business and peer-to-peer networks are common in homes.
A network topology defines the network layout or structure from the point of view of data flow. In bus networks, for example, all computers share and communicate across one common conduit, whereas in a star network, data flows through one centralized device. Common types of network topologies include bus, star, ring, and mesh.
Communication languages used by computer devices are called network protocols. Another way to classify computer networks is by the set of protocols they support. Networks often implement multiple protocols and each network supports specific applications. Popular protocols include TCP/IP — the one commonly found on the internet and in home networks.
Computer Network Hardware and Software
Special purpose communication devices including network routers, access points, and network cables physically glue a network together. Network operating systems and other software applications generate network traffic and enable users to do useful things.1:22
What Is a Router and How Does it Work?
Home Computer Networking
While other types of networks are built and maintained by engineers, home networks belong to homeowners who often have little or no technical background. Various manufacturers produce broadband router hardware designed to simplify home network setup. A home router enables devices in different rooms to efficiently share a broadband internet connection, helps household members share files and printers within the network, and improves overall network security.
Home networks have increased in capability with each generation of new technology. Years ago, people commonly set up a home network to connect a few PCs, share documents, and perhaps share a printer. Now it's common for households to network game consoles, digital video recorders, and smartphones for streaming sound and video. Home automation systems have also existed for many years, but these have grown in popularity recently with practical systems that control lights, digital thermostats, and appliances.
Business Computer Networks
Small and home office (SOHO) environments use technology that is similar to home networks. Businesses often have additional communication, data storage, and security requirements that require expanding networks in different ways, particularly as the business gets larger.
Whereas a home network generally functions as one LAN, a business network tends to contain multiple LANs. Companies with buildings in multiple locations utilize wide-area networking to connect these branch offices together. Though also available and used by some households, voice over IP communication, network storage, and backup technologies are prevalent in businesses. Larger companies also maintain internal web sites, called intranets, to help with employee business communication.
Networking and the Internet
The popularity of computer networks sharply increased with the creation of the World Wide Web (WWW) in the 1990s. Public web sites, peer-to-peer (P2P) file sharing systems, and various other services run on internet servers across the world.
Wired vs. Wireless Computer Networking
Many of the same protocols such as TCP/IP work in both wired and wireless networks. Networks with Ethernet cables predominated in businesses, schools, and homes for several decades. Wi-Fi has emerged as the preferred option for building new computer networks, in part to support smartphones and the other wireless gadgets that have triggered the rise of mobile networking.