About Networks and communication in A Level Computer Science
Networks and communication is one of the 10 main topics in our A Level Computer Science (Cambridge (CAIE) 9618) question bank, and about 4% of its real questions come from it. Tayyari Karo has 50 real questions on this topic from 2021 to 2026, from Paper 1, Paper 3. By difficulty: 35 medium, 12 easy, 3 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
Try 8 real questions
These are real past-paper questions. Think of your answer first, then open the explanation.
May/June 2026 · Paper 1 · Networks and communication
A networked computer game competition takes place in a school; the game is hosted on a server on the school LAN and each competitor logs on using their own computer. (a) The game runs as a thin-client. Give two characteristics of a thin-client system. [2]
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1 mark each to max 2: data is not stored on the client computer // all data is stored on the server; the client is reliant on access to the server; the client is heavily reliant on the network connection; the client requires few local resources (memory/processing power/storage); the client performs minimal functions/processes.
A thin client does little processing itself and relies on the server.
May/June 2026 · Paper 1 · Networks and communication
The school's network uses subnetting. Give three benefits of using subnetting in a network. [3]
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1 mark each to max 3 (any sensible benefit): splits a larger network into smaller/more manageable parts; increased efficiency ('just faster' is not enough); reduced congestion/fewer collisions; improved security; easier to isolate faults; easier to scale a network with subnets.
Subnetting divides a network into smaller segments, reducing congestion and improving security.
October/November 2025 · Paper 1 · Networks and communication
Explain how the web browser uses the URL to access the web page.
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Browser checks cache, parses URL, queries DNS server for IP address, creates connection, sends request, renders and displays result, stores IP in cache.
Four bullet points describing the process.
May/June 2024 · Paper 1 · Networks and communication
(a) A business is creating a LAN. Tick (✓) one or more boxes to identify the topology each statement describes.
• All devices connect to one central device
• All devices connect to a central cable
• Multiple paths for packets to travel
• Robust against damage because if any line fails, rest of network retains full functionality
• Most likely to lose data through collisions
Bus | Star | Mesh
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All devices connect to one central device → Star ✓
All devices connect to a central cable → Bus ✓
Multiple paths for packets to travel → Mesh ✓
Robust against damage → Star ✓ and Mesh ✓
Most likely to lose data through collisions → Bus ✓
5 marks: 1 for each correct row.
October/November 2024 · Paper 3 · Networks and communication
4 Describe how the layers of the TCP/IP protocol stack interact with each other.
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• Each layer can only accept input from the next higher layer or the next lower layer
• There is an interface between the adjacent layers which is the only interaction between layers
• Data is added to the headers as the frames/packets pass through the layers
• The interactions are carried out by installed software
• User interaction takes place at the highest/Application layer
• Direct access to hardware takes place at the lowest/Link layer
4 marks: 1 for each mark point to max 4.
October/November 2023 · Paper 1 · Networks and communication
(d) Explain one advantage of implementing a star topology instead of a bus topology in the new classroom.
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• Star topology is more resilient to faults because there is no single cable and leads to less disruption to teaching
• Higher performance as fewer collisions because each device is only connected to the switch
• Easier to add new nodes because each device connects directly to the switch
• Easier to fault find compared to bus topology
2 marks: 1 for advantage and 1 for valid corresponding expansion.
May/June 2021 · Paper 1 · Networks and communication
(b) Describe two drawbacks to Melinda and her friends of using a peer-to-peer network.
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Drawback 1: Reduced security / no central management of security — each computer is only as secure as the weakest computer on the network, and each computer is at risk from viruses from other computers.
Drawback 2: No central management of backup — if data from one computer is not backed up it is lost to all of them. (Also acceptable: no central management of files/software, individual computers may respond slower, all computers need to be switched on to share files.)
4 marks: 1 per bullet point to max 2 per drawback.
October/November 2021 · Paper 1 · Networks and communication
(a) State whether the network will be a LAN or a WAN. Justify your choice.
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LAN.
• Small geographical area
• No leasing external infrastructure/transmission media
• Does not use internet to transmit within the building
3 marks: 1 for LAN, 1 for small area, 1 for justification.
