What Is a Computer Network?

Computer networking, and digital technology in general, can be pretty intimidating for many people. But when you break computer networking down to its foundation, it's not so difficult to understand. In this article, learn the basics of computer networking, its key benefits, and some different types of computer networks.

What is a computer network?

A computer network is a system that connects multiple devices, allowing them to communicate with each other. Networked devices can include personal computers, phones, printers, servers, and even refrigerators; essentially, it includes any device that shares a network connection.

With computer networks, communication allows for the sharing of resources among devices. Before networking existed, we could only perform one-to-one communication between devices. This meant that in the office, every single computer needed its own printer in order to print documents. Computer network infrastructure, however, allows all the network computers to connect and print from one central printer.

Now, almost everything we do relies on computer networking. Whether you're shopping online, streaming Netflix, or sending emails, computer networking is a necessary part of the process.

Components of computer networks

Computer networks range in size; the largest computer network in the world is the Internet, while the smallest and most basic is the personal area network (PAN). Big or small, networks are comprised of devices, links, communication protocols, and defense systems. To understand how computer networks function, consider a home wireless local area network (LAN) as an example.

Various devices, including computers, phones, gaming devices, and printers, make up home networks. However, other devices are necessary for a network to function - namely routers and switches.

Routers and switches connect devices to one another across a network. The difference between the two is that routers store data and deliver it in the form of data packets, while switches route the data from input ports to a certain output port. Routers connect networks to each other and connect those networks to a modem, providing Internet access. Switches connect the devices within a network.

Most home networks use routers with built-in switches which allow you to transmit data and communicate with devices on the network. They also serve as a gateway that opens up communication channels with devices on different networks. These networks use links as the transmission medium through which data flows. Most links now are wireless, as most home networks are wireless, though links can also be wired.

Computer networks and IP addresses

Even with all of the necessary equipment and technology, in order for devices to communicate, they need to know the location - or "address" - of other devices. Thanks to network address translation, all these devices can operate under a single public IP address, which users can view on WhatIsMyIP.

Users can also change their IP address using VPNs, proxies, and other methods. Modern networks typically use the TCP/IP model to communicate where each device is, given its IP address.

Some, however, use the OSI (Open Systems Interconnect) model. These systems allow network computers or devices to transfer data and work in conjunction with one another, using protocols like FTP (File Transfer Protocol) to function properly.

How to defend a computer network

Finally, any strong computer network needs a defense system. Without defense systems in place, networks are vulnerable to attacks from malicious actors.  Common network defense systems include:

• Firewalls, which block or allow data packets based on preset security rules set by an administrator
• Proxy servers, secure software systems that act as a gateway between a device and the rest of the Internet
• Single sign-on (SSO), a service that lets users use one sign-on for several different applications
• Virtual private networks (VPNs), which use advanced encryption protocols and secure tunneling techniques to encapsulate all online data transfers

The protection methods you or your system administrators choose to employ is up to you; just keep in mind that networked computers can potentially spread malware or viruses to one another. Protecting the network protects everyone and every device on it.

Computer network topologies

Computer networks have a variety of network topologies. A network topology is the structural arrangement of the network. Each dictates how the components are connected to one another, which means that the network topology you use is crucial to achieving peak function on your network. The most common network topologies are:

• Point to point topology
• Star topology
• Ring topology
• Tree topology
• Full mesh topology
• Hybrid topology

Point to point network topology

In a point to point network, the network has two nodes: the sender and the receiver. This type of topology is the simplest when it comes to communication, as it only involves the two nodes and a basic transfer of data across a dedicated connection.

Star network topology

A star network connects multiple devices, or nodes, to a single central node. This hub can either be active or passive, but the devices are most often connected to the central node through RJ45 connectors or coaxial cables. This topology relies on the performance of the central hub for the performance of the entire network.

Ring network topology

A ring network connects devices with two neighboring devices in a network, essentially creating a circular ring shape. This network topology requires many repeaters, and it requires more than one node in order for all devices to properly function. This topology, too, uses RJ45 cables or coaxial cables to connect.

Tree network topology

The tree topology is a variation of the star network topology, as it relies on multiple star networks as its base. Like a tree with a trunk and branches, this topology creates a top-to-bottom data flow from a central hub to secondary hubs. Those secondary hubs or nodes then transmit data to more systems. Computer network admins can easily add more devices to an existing network with this topology.

Full mesh network topology

In a full mesh network topology structure, each devices connects to another via a channel on the network. It allows for fast communication between devices, as there are dedicated channels or links between each device.

Hybrid network topology

A hybrid network is a sort of free-for-all; it's a combination of all types of network topologies. The nodes can take any form on the network, making this topology extremely flexible and open to the addition of new devices. However, because of the amount of cabling and network architecture involved, these networks require a higher cost and greater planning than other, more basic topologies.

Types of computer networks

Computer networks vary depending on the size, design, organization, and transmission medium. As network size increases, so does the complexity of the network architecture; sometimes, networks even need to be subnetted in order to adequately accommodate their size. This article covers just the basics of computer networking.

From smallest to largest, here are the different types of networks:

Personal area network (PANs)

One person uses this network in a small space, such as a personal office. These types of networks connect personal devices such as laptops, speakers, tablets, and phones - typically using wireless technology such as Bluetooth or WiFi. Personal area networks are like LANs, just more individualized.

Local area networks (LANs)

A local area network connects devices in a small geographic area like a home, school, or office building. LANs usually connect these devices via switches or a router using the TCP/IP communication protocol. LAN connections can be either wired or wireless, although wired connections are usually much faster.

Because LANs are small and the number of devices is limited, they are typically more high speed than other computer network types. Within a LAN, routers serve as the gateway for devices to connect to external networks.

Campus area networks (CANs) and metropolitan area networks (MANs)

Both CANs and MANs are large networks made up of many interconnected LANs. Universities, organizations, and governments use CANs to connect different buildings or regional offices to each other. Metropolitan area networks cover larger geographic areas like cities or localities. They may also serve as Internet service providers (ISPs) for geographic regions.

Wide area networks (WANs)

Wide area networks cover large geographical areas such as cities, regions, and even countries. They are the largest type of network; like CANs and MANs, they connect smaller LANs into one network. The Internet itself is considered a WAN.

Frequently asked questions

What are computer networks?

Computer networks are systems that connect computers and other devices in order for them to share resources and transmit data.

What are four types of computer networks?

The four primary types of computer networking, or computer networks, are personal area networks (PANs), local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs).

What is an example of a computer network?

A local area network in your office building or place of work is an example of a computer network. Though each person has their own device, all the devices are interconnected through a central router or modem.