What is a network, and what makes one perform well or badly?
Types of network (LAN and WAN), the factors that affect network performance, and the difference between client-server and peer-to-peer networks.
An OCR J277 1.3.1 answer on LANs and WANs, the factors that affect network performance (bandwidth, number of users, transmission media, interference), and the difference between client-server and peer-to-peer networks.
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What this dot point is asking
OCR wants you to define a LAN and a WAN with examples, explain the factors that affect how well a network performs, and distinguish client-server from peer-to-peer networks. The performance factors must come with a mechanism (why the factor changes speed), and the client-server versus peer-to-peer comparison needs clear contrasts.
LANs and WANs
Factors affecting network performance
Client-server and peer-to-peer networks
Putting it together
The geographical scale tells you LAN or WAN: one site is a LAN, spread across distances is a WAN. The management model tells you client-server or peer-to-peer: central servers and control for organisations, equal peers and simplicity for small home setups. Performance depends mainly on bandwidth and how many users share it, then on the media and interference. A strong exam answer always links a chosen design back to the size of the network and what it must do.
Try this
Q1. State one difference between a LAN and a WAN. [1 mark]
- Cue. A LAN covers a small area (one site); a WAN covers a large area (between cities or countries).
Q2. State two factors that affect network performance. [2 marks]
- Cue. Any two of: bandwidth, number of users sharing it, transmission media (fibre/copper/wireless), interference or distance.
Q3. State one advantage of a client-server network over a peer-to-peer network. [1 mark]
- Cue. Centralised management, security and backups (or shared resources controlled in one place).
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20214 marksState the difference between a LAN and a WAN, and give one example of each.Show worked answer →
A LAN (local area network) connects devices over a small geographical area, such as a single building or site (for example a school or office network), and the organisation usually owns all the hardware and cabling. A WAN (wide area network) connects devices over a large geographical area, such as between cities or countries (for example the internet, or a bank linking branches), and uses infrastructure that is often hired from telecommunications companies.
Examples (one mark each): LAN - a home or school network; WAN - the internet.
Markers reward "small/single site" versus "large/geographically dispersed" and a correct example for each. Saying a LAN is "a small number of computers" without the geographical point is weaker.
OCR 20224 marksExplain two factors that can affect the performance of a network.Show worked answer →
Award up to two marks per factor (named plus explained), to a maximum of four.
Bandwidth: the maximum amount of data that can be transmitted in a given time. Higher bandwidth lets more data through per second, so the network is faster; bandwidth shared between many users means each gets less.
Number of users / amount of traffic: more devices using the network at once share the available bandwidth, so each transfer slows down, especially at busy times.
Other acceptable factors: the transmission media (fibre is faster and less prone to interference than copper, which is faster than wireless), wireless interference and distance from the access point, and the use of error-prone connections that need data resending.
Markers reward two distinct named factors, each with a clear explanation of how it changes performance.
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Sources & how we know this
- OCR GCSE (9-1) Computer Science (J277) specification — OCR (2020)