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Computer network

A computer network links devices so they can exchange data, share resources and communicate. This article explains components, types, protocols, history, common uses and key distinctions.

Author: Leandro Alegsa Creation date: November 13, 2022 Last updated: May 19, 2026

simple.wikipedia.org · CC BY 3.0

Overview

A computer network is any arrangement of two or more computing devices that can exchange information and share resources. Networks range from simple peer-to-peer links to vast, global infrastructures. They enable file transfer, remote access, collaboration, centralized services and real-time communications across distances that can be within a single room or span the globe. The term emphasises both the devices (nodes) and the communication pathways between them; for a basic definition see connected devices.

Components and physical elements

At its core a network consists of nodes (computers, servers, printers and sensors) and the media that carry data between them. A node might be any device capable of sending or receiving packets. Essential physical components include network interface cards, cabling or wireless transceivers, and intermediary hardware that manages traffic. Examples of common equipment are:

Network hardware such as cables, fiber and wireless access points
Hubs and switches that connect local devices
Routers and bridges used to join different networks
Servers (for example a web server) and storage systems

Types and topologies

Networks are commonly classified by size and purpose. A Local Area Network (LAN) links devices within a limited area like a single building. Wide Area Networks (WANs) connect LANs across cities or countries. Personal Area Networks (PANs) cover a small personal space, while Metropolitan Area Networks (MANs) span a town or campus. The largest publicly accessible WAN is the global Internet. Topology—the arrangement of nodes and links—may be bus, star, ring, mesh or hybrid, and influences reliability and performance. Wireless technologies provide mobility and flexibility but often trade off throughput or latency compared with wired media; see wireless technologies for more.

Protocols, addressing and software

Networks rely on protocols: agreed rules that govern how data is formatted, addressed, transmitted and interpreted. The Internet uses the TCP/IP suite as its fundamental protocol stack, which organizes communication into layers responsible for linking, routing and application functions. Operating systems and applications implement protocol stacks—examples include Microsoft Windows, Linux and other operating systems. Historically, some platforms used alternative protocols—for instance, Apple introduced Appletalk—but modern networks overwhelmingly adopt TCP/IP. Protocols also define addressing (such as IP addresses and port numbers) that let messages reach the intended destination.

Uses, examples and practical importance

Computer networks enable many everyday and business activities: sharing files and printers between colleagues, hosting websites and online stores (for example a retail shop that displays merchandise), supporting cloud-based applications and real-time services such as video conferencing. Industrial and consumer devices form the Internet of Things, where sensors and controllers exchange small amounts of data for automation and monitoring. Networks also underpin essential infrastructure like email, online banking, telemedicine and logistics systems, and they make large-scale distributed computing and storage possible.

Distinctions, management and security

Important distinctions include intranets versus the public Internet, and segmented versus flat networks. Performance depends on link speed, latency, congestion and the efficiency of routing and switching equipment. Management tasks include addressing, routing, access control and monitoring. Security is a central concern: firewalls, encryption, authentication and intrusion detection protect data in transit and resources on the network. Protocol-level safeguards and best practices help mitigate threats, but network design and ongoing administration are equally important for resilience and privacy.

For further study, introductory resources and technical specifications can expand on specific topics such as routing algorithms, wireless standards, network virtualization and cloud networking; consult general references or specialized guides via links to standards and teaching materials like file exchange examples and protocol documentation at recognized educational sites switch basics, protocol descriptions and vendor documentation.

Topologies

→ Main article: Topology (computer network)

Topology refers to the way in which the various components involved (i.e. mostly computers) in the network are connected by physical or logical paths. In order to integrate several computers in a computer network, good planning is required, which is simplified by the division of the topology. In this way, computer networks are formed in which there are connections and nodes that can be used to reach every other area of the network, if necessary via several intermediate points.

There are a number of basic stereotypes that rarely occur in practice in this clear form. In the star topology, there is a central distribution point that can control everything if necessary and without which nothing works. This topology is actually only used in very small networks, for example home networks or LAN parties. A connection of several star topologies at their concentration points is also called an extended star topology. Tree topology uses a similar approach, but staggered hierarchically. The "top" computer has control over all the others, the power shrinks the lower you sit in the tree. In the ring topology, each computer has a position in a ring and is only connected to its neighbors. As a result, the failure of one computer cripples the computer network. In bus topology, all the participating computers access a medium that is shared and used by all, which can cause collisions on it. The meshed network is a form in which each computer is connected to multiple neighbors and in which redundant paths exist, so that even if one line fails, the network still remains connected through another line. Cell topology plays a special role in wireless networks with their special access characteristics.

In practice, mixed forms of these stereotypes almost always occur, and there are still a number of designations for certain special forms. For example, the spontaneous, self-organized networking of any devices is referred to as a smart network or smart grid.

Organizational coverage (network architecture)

This criterion is often used because it seems less complicated than other properties of networks. In practice, however, this distinction has only limited significance.

Local networks

Body Area Network (BAN)
Wireless Body Area Network (WBAN)
Personal Area Network (PAN)
Wireless Personal Area Network (WPAN) as a term
Local Area Network (LAN)
Wireless LAN (WLAN) as a term

Non-local networks

Metropolitan Area Network (MAN)
Wide Area Network (WAN)
Global Area Network (GAN)
Virtual Private Network (VPN)
Storage Area Network (SAN)

Questions and Answers

Q: What is a computer network?

A: A computer network is a group of two or more computers that are linked together in order to share resources, exchange files, or communicate with other users.

Q: What are nodes in a network?

A: Nodes in a network are devices such as computers, printers, and other devices capable of sending and receiving data from one node to another.

Q: What kind of additional devices may be needed for networks to work correctly?

A: Additional devices such as hubs and switches may be needed for networks to work correctly.

Q: How can different kinds of networks be connected together?

A: Different kinds of networks can be connected together with a router.

Q: Are Local Area Networks (LANs) easier to build than Wide Area Networks (WANs)?

A: Yes, building a LAN is usually easier than connecting different networks by WAN.

Q: Can computers be part of several different networks at the same time?

A: Yes, computers can be part of several different networks at the same time.

Q: What type of communication protocol do most operating systems use?

A: Most operating systems use TCP/IP as their communication protocol.

Author

AlegsaOnline.com - Computer network - Leandro Alegsa

Creation date: November 13, 2022
Last updated: May 19, 2026

URL: https://en.alegsaonline.com/art/22325