Define network

What Is a Computer Network?

A computer network is two or more computing devices connected together so that they can communicate and share resources. The connection can be made using physical cables (wired) or via radio signals (wireless). Once connected, devices on a network can share files, hardware (such as printers), and internet access, and can communicate with each other.

Networks exist at every scale: from two laptops connected in a home, to thousands of devices across a school campus, to the global infrastructure of the internet. In every case, the defining feature is that the devices can exchange data with each other.

Switch Laptop Desktop PC Printer Server shared resource

Four devices connected to a central switch form a network. All devices can communicate and share resources such as the printer.

Advantages and Disadvantages of Computer Networks

Advantages of Computer Networks

  • Sharing resources: hardware such as printers, scanners, and storage devices can be shared across many devices, reducing the cost of purchasing separate hardware for each user. For example, a school can connect all computers to one printer rather than buying one per room.
  • Sharing files and data: files can be stored centrally on a server and accessed by any authorised user on the network. This avoids multiple versions of documents being created on different machines and simplifies collaboration.
  • Shared internet access: a single internet connection can be shared across all devices on a network, reducing cost compared to each device having its own connection.
  • Communication: users on a network can communicate via email, instant messaging, or video calls without using external services. In a business, this allows rapid internal communication.
  • Centralised management and security: network administrators can manage all devices from one location - installing software, applying updates, and enforcing security policies across the entire network at once.
  • Centralised backup: data stored on a central server can be backed up once, protecting all users' work simultaneously.

Disadvantages of Computer Networks

  • Security risks: connecting devices together creates pathways that can be exploited by malicious users. A virus or malware infection can spread rapidly across a network. Unauthorised users may attempt to gain access to shared resources or data.
  • Cost of setup: installing network infrastructure - cabling, switches, routers, wireless access points, and servers - requires significant upfront investment. Larger networks require more equipment and specialist staff to manage.
  • Single point of failure: if a central component (such as a server or switch) fails, it may affect all devices on the network simultaneously. A standalone computer is only affected by its own hardware failures.
  • Dependency on the network: if the network goes down, users may lose access to shared files, shared software, and internet access all at once, potentially halting work entirely.
  • Increased management overhead: a network requires ongoing maintenance, monitoring, and administration. Larger networks require dedicated IT staff, adding to operational costs.

 Key Takeaways

  • A computer network is two or more devices connected together to communicate and share resources.
  • Key advantages: sharing hardware and files, shared internet access, internal communication, centralised management and backup.
  • Key disadvantages: security risks (malware spread, unauthorised access), setup cost, single points of failure, dependency on network availability.
  • Networks trade the convenience of resource sharing and centralised management against the risks of security vulnerabilities and infrastructure dependency.