Computer networks: what are they, and how do they support the internet?

Computers and the internet that connects them are among the most important advancements in human technology, but how do they actually work? The answer lies in computer networks.

Computer networking is what links different computing devices and allows them to communicate with one another. These network devices can include web servers, routers, modems, and the computers themselves, and are commonly referred to as nodes. 

The internet, meanwhile, is essentially a network of networks. Imagine a bank of computers connected to a router in one network, and another computer connected to a modem on another network. The internet is what connects these two separate networks together.

What is the purpose of computer networks?

It was just a few short decades ago that computer technology and tasks were largely unconnected from one another, and manual human intervention would be required to facilitate collaboration. For example, a computer and its word processing software could be used to create a document, but the document would then need to be saved to a physical disk that was inserted into the computer, ejected, manually shared, and then inserted into another person’s computer before it could be opened for editing by another person on another device.

Enter computer networking, which enables seamless, instant file and data sharing with any number of other people. Whether sending quick email messages, a massive spreadsheet, multimedia such as images and videos, e-commerce data, or working in collaborative systems where information can be stored and shared, it’s now difficult to picture a world without computer networking technologies.

Other uses for computer networks include:

• Sharing resources, such as internet connections, printers, and servers, among large groups of computer users.
• Creating central backups of important information, ensuring that data can be retrieved from anywhere – even if it’s accidentally deleted from a device within the network.
• Managing information technology (IT) teams across organisations. For example, computer networks allow IT teams to centrally maintain software, manage security, and distribute appropriate upgrades and computer power as needed.

How do networks work?

Computer networks link nodes through a mix of protocols, rules, and algorithms that explain how the nodes should send and receive electronic data through the links. 

The links themselves are guided by transmission media such as physical ethernet cables, high-speed fibre-optic cables, and wireless WiFi.

Other important components within a computer network are routers, which facilitate communication between different networks, and switches, which connect devices within a network.

Network architecture

There are two different network architecture designs:

1. Client-server architecture, in which resources and services are managed by a central server or group of servers, and resources aren’t shared between clients. This architecture design is also known as a tiered model owing to its multiple levels.
2. Peer-to-peer architecture, or P2P, in which all of the computers connected on the network are peers, with equal powers and privileges. Each device on the network can act as client or server, resources – such as memory, processing power, storage, and bandwidth – can be shared, and there is no central server. 

Network topologies

A network’s topology is the physical or logical structure of its nodes and links. There are several configuration topology options, including:

• Bus, in which all of the nodes within a network are linked to only one other node directly, and data transmission occurs in one direction.
• Ring, in which each node is connected to two other nodes, creating a ring format, and data flows bi-directionally. 
• Star, in which all nodes within a network are connected to a common central computer hub. This network topology is considered a reliable, well-performing option because data doesn’t have to go through each node.
• Mesh, which has both full mesh and partial mesh options. In full mesh topologies, all nodes are connected to one another and can exchange data back and forth. In partial mesh networks, some nodes are connected to all others, while other nodes are only connected to one or two different nodes within the network.
• Tree, in which two or more star networks are connected.
• Point-to-point, in which network connectivity is limited to two endpoints.

What are the different types of networks?

Local area networks (LANs)

Local area networks are networks that are typically limited in size and dictated by geographical area. For example, a LAN is likely to be used by a small company to connect all of its computers and devices within a single office or building. 

Wide area networks (WANs)

A wide area network is essentially an interconnected group of local area networks. WANs can span cities and even countries to transmit and share data long-distance.

Cloud networks

Cloud networks are cloud-based WANs and increasingly popular with businesses and large organisations.

Virtual private networks (VPNs)

VPNs are a type of network that create secure, private connections within public networks. 

Metropolitan area networks (MANs)

Large than a LAN but smaller than a WAN, MANs connect devices within a metropolitan area.

Private networks

An example of a private network are employee intranets and similar communication networks used by businesses and other organisations.

How does the internet work?

The internet as we know it now is effectively a global network, connecting computer systems and networks around the world. While it’s worth noting that any interconnected networks may be referred to as an internet, or internetworking, the global internet used by billions of people today is defined by its unified global addressing system, packet switching, and the routing methods of the internet (IP) protocol.

To connect to the internet, an individual simply needs a device with internet access capabilities, and some form of service from an internet service provider (ISP). The ISP will connect the device to a network that has been set up to communicate within the world wide web through a variety of common protocols, such as:

• The internet protocol suite, TCP/IP.
• The domain name system (DNS) protocol, which converts domain names used in web browsers into an internet protocol (IP) address.
• The hypertext transfer protocol secure (HTTPS), which requests from an IP address the HTML content for web pages so that they can be displayed for the user.
• The user datagram protocol (UDP), which is a communication protocol used for quick communication and data transmission on the internet. It’s commonly used for time-sensitive uses, such as video playback.

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Develop comprehensive knowledge and skills across specialised and applied areas of computer science with the MSc Computer Science at the University of Wolverhampton. This flexible Master’s degree has been developed for ambitious individuals who may not have a background in computer science, and is delivered 100% online.

One of the key modules on this course focuses on networks and the internet, so you will examine the protocols, architecture, and devices that construct computer networks and how they are used to enable the internet to function. You will study operating systems and services, TCP/IP IPV6 network infrastructure, LANs and WANs, WiFi, Bluetooth and mobile security, ACLs, firewalls and IPS systems, and the architecture of the internet. After studying this module, you will be able to demonstrate a deep understanding of the underpinning principles, practice and applications of networking, and be able to use tools to simulate and evaluate different network designs.