What is a computer network

A computer network forms when multiple computers or devices connect together, allowing them to communicate and share information.

Types of computer networks

Networks are classified based on their size and geographical coverage. The two main types are local area networks (LANs) and wide area networks (WANs), each suited to different needs.

Local area network (LAN)

A local area network (LAN) connects devices over a small geographical area, typically within a single site or building.

Key features of a LAN:

• Coverage area - Restricted to a limited space, such as a home, school, office, or university.
• Ownership - All hardware belongs to the individual or organisation using the network.
• Connection types - Can be wired (using cables) or wireless (using technologies like Wi-Fi).
• Common uses - Connecting devices like computers, tablets, printers, and smart TVs for sharing resources.

For example, a home LAN might link a PC, a laptop, and a printer, allowing family members to print documents from any device.

Wide area network (WAN)

A wide area network (WAN) spans larger distances by linking multiple LANs across different locations.

Key features of a WAN:

• Coverage area - Connects networks over wide regions, such as cities or countries.
• Setup and cost - Organisations often rent infrastructure like communication lines rather than buying it, due to high setup costs compared to LANs.
• Common examples - Businesses use WANs to connect offices in different cities; the internet itself is a massive WAN that links global networks.

WANs enable long-distance data sharing but require more complex and expensive arrangements than LANs.

Benefits and drawbacks of computer networks

Connecting devices in a network offers several advantages for efficiency and collaboration, but it also introduces potential issues that need careful management.

Benefits of networks

• Resource sharing - Hardware like printers can be accessed by multiple users, reducing the need for duplicates.
• Centralised management - Software can be installed or updated across all devices simultaneously, saving time compared to individual updates.
• Efficient communication - Networks enable fast, low-cost interactions, such as sending emails or sharing files.
• Flexible access - User accounts can be stored in a central location, allowing login from any connected device.

Drawbacks of networks

• High initial costs - Setting up requires purchasing hardware like cables, switches, or access points.
• Dependency on key components - If a central server fails, the entire network may stop functioning.
• Security risks - Viruses and other malware can spread quickly between connected devices.
• Management challenges - Large networks can be complex to maintain, often needing specialist IT support.

Networks improve connectivity and productivity, but organisations must weigh these against the risks and costs involved.

Hardware required for networks

Building a network requires specific hardware to enable connections and data transmission. The choice of hardware depends on whether the network is wired or wireless.

Essential network hardware

• Network interface card (NIC) - A component inside a device that enables it to join a network; available for both wired and wireless connections.
• Switch - Connects multiple devices within a LAN, directing data to the correct destination.
• Router - Transfers data between different networks, commonly used to link a LAN to the internet.
• Wireless access point (WAP) - Allows devices to connect wirelessly to a network, similar to a switch but using radio waves instead of cables.

Many home devices combine a router, switch, and WAP into a single unit for convenience.

Wired and wireless networks

Networks can use physical cables for connections (wired) or radio waves for transmission (wireless). Each type has distinct characteristics affecting setup, performance, and suitability.

Wired networks

Wired networks rely on cables to link devices, providing reliable and fast data transfer.

Key aspects of wired networks:

• Cable types - Common options include Ethernet cables for standard connections and fibre optic cables for high-speed, long-distance transmission.
• Factors influencing cable choice:
  • Cost - Ethernet is cheaper for short distances, while fibre optic is more expensive but offers better performance.
  • Transmission distance - Fibre optic cables can carry data over longer ranges without signal loss.
  • Speed - Fibre optic provides faster data rates, making it ideal for high-demand environments.

Wireless networks

Wireless networks transmit data using radio waves, eliminating the need for physical cables.

Key aspects of wireless networks:

• Setup requirements - Need a wireless access point (WAP) to enable devices to connect without wires.
• Convenience features - Devices can automatically detect and join the network, allowing mobility within the coverage area.

Advantages and disadvantages of wireless networks

While wireless networks offer freedom from cables, they come with trade-offs compared to wired options.

Advantages of wireless networks

• Convenience - Devices connect automatically without physical setup, enabling easy access from anywhere in range.
• Mobility - Users can move around freely within the network coverage area while staying connected.
• Easy installation - No need to run cables through walls or across rooms, reducing setup time and cost.
• Scalability - Adding new devices is simple without requiring additional physical connections.

Disadvantages of wireless networks

• Security risks - Wireless signals can be intercepted more easily than wired connections, making networks vulnerable to unauthorised access.
• Interference - Other wireless devices or physical obstacles can disrupt signal quality and reduce performance.
• Range limitations - Signal strength decreases with distance from the access point, potentially creating dead zones.
• Speed variations - Connection speeds may be slower and less consistent than wired networks, especially with multiple users.