Why are computers connected in a network, and what is the difference between a LAN and a WAN?
Understand why computers are connected in a network and understand the different types of networks (LAN, WAN).
A focused answer to Edexcel GCSE Computer Science 4.1.1 and 4.1.2, covering why computers are connected in a network and the difference between a local area network (LAN) and a wide area network (WAN).
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What this dot point is asking
Edexcel wants you to explain why computers are connected in a network (the benefits) and to distinguish the two main types of network by size: the local area network (LAN) and the wide area network (WAN).
Why computers are networked
The exam wants benefits explained, not just listed. Sharing one printer and one internet connection across many machines saves money compared with equipping each computer separately. Sharing files centrally lets people collaborate on the same documents and ensures everyone uses the current version. Central backup and management means data is protected and software is updated from one place rather than on every machine. These are why almost all organisations network their computers.
There are some trade-offs to be aware of: networks need management, and they introduce security risks (malware can spread, and data can be intercepted) and a single point of failure if a central server or connection goes down. But for most organisations the benefits clearly outweigh these.
Local area networks (LANs)
A school or office network is a typical LAN: the computers, switches, cabling and wireless access points are all on one site and owned by the organisation. Because everything is local and owned, a LAN can offer fast data transfer and the organisation has full control over it. LANs can be wired (Ethernet cabling) or wireless (Wi-Fi), or a mix of both.
Wide area networks (WANs)
A company with offices in different cities connects them with a WAN, often joining several LANs together. The internet is the largest WAN, connecting networks across the whole world. Because a WAN relies on long-distance, often leased infrastructure, it is usually slower and more expensive per unit of data than a LAN, and the organisation does not control all of the equipment it uses.
LAN versus WAN: the key contrasts
The discriminators Edexcel rewards are geographical size (small site versus large area such as between cities or countries) and ownership of the infrastructure (the organisation owns a LAN's equipment, but leases a WAN's long-distance infrastructure from third parties). A consequence is that LANs are typically faster and cheaper per unit of data and fully under the owner's control, while WANs cover far greater distances using shared, leased links.
Try this
Q1. State one benefit of connecting computers in a network. [1 mark]
- Cue. Any one of: share hardware (such as a printer); share an internet connection; share files and data; communicate; central backup and management.
Q2. State one difference between a LAN and a WAN. [1 mark]
- Cue. A LAN covers a small area (one site, owned equipment); a WAN covers a large area (such as between cities, using leased third-party infrastructure).
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20224 marksA small office connects its computers in a network. Explain two benefits the office gains from networking its computers rather than using them as standalone machines.Show worked answer →
Give two developed benefits that fit an office.
First, the computers can share hardware such as a single printer and share an internet connection, which saves the cost of buying a printer and connection for every machine.
Second, staff can share files and data centrally and communicate (for example by email or messaging), so they can work on the same documents and collaborate, and files can be backed up centrally rather than on each machine separately.
Markers reward two developed benefits relevant to the office: sharing hardware and the internet connection (cost saving), sharing files and data, central backup, and communication or collaboration. Each point must be explained, not just listed.
Edexcel 20213 marksState what the abbreviations LAN and WAN stand for, and give one difference between a LAN and a WAN.Show worked answer →
LAN stands for local area network and WAN stands for wide area network.
One difference: a LAN covers a small geographical area, such as a single building or site, and the organisation usually owns all the cabling and equipment, whereas a WAN covers a large geographical area, such as between cities or countries, and uses infrastructure (often leased) from third parties (for example telecommunications providers).
Markers reward both expansions and one valid difference, the clearest being geographical size (small site versus large area) and ownership of the infrastructure.
Related dot points
- Understand how the internet is structured, including IP addressing and routers.
A focused answer to Edexcel GCSE Computer Science 4.1.3, covering how the internet is structured as a global network of networks, the role of IP addresses in identifying devices, and how routers direct data.
- Understand how the characteristics of wired and wireless connectivity impact on performance (speed, range, latency, bandwidth), that network speeds are measured in bits per second, and construct expressions involving file size, transmission rate and time.
A focused answer to Edexcel GCSE Computer Science 4.1.4 and 4.1.5, covering how wired and wireless connectivity affect speed, range, latency and bandwidth, network speed units, and calculating file size, transmission rate and time.
- Understand the role of and need for network protocols (Ethernet, Wi-Fi, TCP/IP, HTTP, HTTPS, FTP) and email protocols (POP3, SMTP, IMAP).
A focused answer to Edexcel GCSE Computer Science 4.1.6, covering the role of and need for network protocols and what each of Ethernet, Wi-Fi, TCP/IP, HTTP, HTTPS, FTP, POP3, SMTP and IMAP is for.
- Understand how the four-layer (application, transport, internet, link) TCP/IP model handles data transmission over a network, and understand the characteristics of network topologies (bus, star, mesh).
A focused answer to Edexcel GCSE Computer Science 4.1.7 and 4.1.8, covering how the four-layer TCP/IP model (application, transport, internet, link) handles data transmission, and the characteristics of bus, star and mesh network topologies.
- Understand the importance of network security, ways of identifying network vulnerabilities (penetration testing, ethical hacking) and methods of protecting networks (access control, physical security, firewalls).
A focused answer to Edexcel GCSE Computer Science 4.2.1, covering the importance of network security, identifying vulnerabilities by penetration testing and ethical hacking, and protecting networks with access control, physical security and firewalls.
Sources & how we know this
- Pearson Edexcel GCSE (9-1) Computer Science (1CP2) specification — Pearson (2020)