Cambridge A Level Information Technology (ICT): Communications technology (9626) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover topic 14, Communications technology, of the Cambridge International AS & A Level Information Technology 9626 syllabus for examination in 2025, 2026 and 2027 (version 3), sections 14.1 to 14.10. The topic is A Level only and is assessed in Paper 3 Advanced Theory. Calculators are not allowed in that paper, so every question here is calculator-free.

Learn the content first in the study guide and the revision notes. Course links: hub, checklist, diagnostics. Questions 11 and 12 combine several sections.

Questions

1. Define the terms bandwidth and bit rate. [2]

2. Explain how a switch handles an incoming frame differently from a hub. [3]

3. (calculator-free) A 900 MB design file is uploaded over a link with a bit rate of 60 Mbit/s. Calculate the upload time in seconds. Take 1 MB as 8 Mbit. [3]

4. A school installs a proxy server between its network and the internet. Describe three functions it could perform. [3]

5. A sales manager reads email on a phone, a tablet and an office PC. Explain why IMAP is more suitable than POP3 for her, and name the protocol that sends her emails. [4]

6. For each use, state whether TCP or UDP is more suitable and explain why.

(a) A live video call. [2] (b) Downloading a software update. [2]

7. Data can be sent by packet switching or circuit switching.

(a) Describe the structure of a packet. [3] (b) Explain how circuit switching differs from packet switching. [3]

8. Addressing and routing.

(a) State the number of bits in an IPv4 address and in an IPv6 address. [2] (b) Explain the purpose of ARP. [2] (c) An internet service provider has hundreds of routers. Evaluate the use of dynamic rather than static routing. [3]

9. Wireless technology.

(a) Explain why NFC is used for contactless payment rather than Bluetooth. [2] (b) A café offers Wi-Fi to customers. Describe four ways the owner can secure it. [4]

10. Mobile communication systems.

(a) Describe the structure of a cellular network, including what happens when a user moves. [3] (b) Describe how a television signal is sent to homes by satellite. [3]

11. An engineering firm has 25 office staff. Each needs about 2 Mbit/s for cloud-based software at busy times. The office internet link is 40 Mbit/s. Some staff work from home.

(a) (calculator-free) Show whether the link is enough at busy times. [2] (b) The firm is deciding between moving its files to the cloud and buying a file server for the office. Evaluate the two options. [6] (c) Explain how a VPN lets home workers reach the office network securely. [2]

12. An online retailer is writing a disaster recovery plan. It scores risks from 1 to 5 for likelihood and impact.

Risk	Likelihood	Impact
Server hardware failure	3	4
Flood at the data centre	1	5
Ransomware attack	4	5

(a) (calculator-free) Quantify each risk and state which should be dealt with first. [3] (b) Explain what SQL injection and denial of service are, giving one prevention method for each. [4] (c) Describe a strategy to protect the retailer’s power supply and data. [3]

Answers

1. Bandwidth: the maximum rate at which a link can carry data, in bit/s [1]. Bit rate: the number of bits actually sent (or needed) per second [1]. Examiner insight: “Bandwidth is speed” is too vague; the idea of a maximum capacity is the point that separates it from bit rate.

2. A hub sends the frame out of every port [1]. A switch reads the destination MAC address [1] and, using its table of addresses and ports, sends the frame only to the correct port [1]. Examiner insight: Name the MAC address; “a switch is smarter” earns nothing on its own.

3. 900 × 8 = 7200 Mbit [1]. 7200 ÷ 60 [1] = 120 s [1]. Examiner insight: Show the ×8 step; if the final figure is wrong, visible working is your only route to method credit.

4. Filters requests to block unsuitable sites [1]; caches frequently used pages so they load faster [1]; hides internal IP addresses from the internet [1]. Also accept: logs web use. Examiner insight: Each function must be different; “filters” and “blocks sites” are the same point.

5. IMAP keeps messages on the mail server [1], so all three devices show the same inbox and folders [1]. POP3 normally downloads messages to one device and removes them from the server [1], so other devices would miss them. Emails are sent with SMTP [1]. Examiner insight: Link the protocol to her situation (several devices); a textbook definition alone answers only part of the question.

6. (a) UDP [1]: no acknowledgements or resending, so less delay; a lost packet matters less than lag in a live call [1]. (b) TCP [1]: every packet must arrive and be in order, and TCP acknowledges and resends lost data [1]. Examiner insight: The choice alone is not enough; the reason must refer to the use (delay for calls, completeness for files).

7. (a) Header containing source and destination addresses [1] and a sequence number [1]; payload containing the data, with a trailer holding an error check [1]. (b) Circuit switching reserves a dedicated channel [1] for the whole session [1], whereas in packet switching packets share links and may take different routes [1]. Examiner insight: In (b) write both sides of the comparison; describing only circuit switching leaves the “differs” half unanswered.

8. (a) IPv4: 32 bits [1]. IPv6: 128 bits [1]. (b) ARP finds the MAC address [1] that matches a known IP address on the local network, so the frame can be delivered [1]. (c) Dynamic routing updates routing tables automatically, so it adapts when a link fails [1]; static routing would need hundreds of tables kept by hand [1]; but dynamic routing uses bandwidth and processing to share route information, though for a large network the benefits outweigh this [1]. Examiner insight: “Evaluate” needs a drawback and a conclusion, not only advantages.

9. (a) NFC works only when devices are almost touching [1], so it is harder to intercept and a payment cannot be made accidentally from across a room [1]. (b) Use WPA2 or WPA3, not WEP [1]; set a strong passphrase and change it regularly [1]; change the router’s default admin password [1]; keep firmware updated [1]. Also accept: a separate guest network for customers. Examiner insight: “Use a password” is too general; say which password and why.

10. (a) The area is divided into cells, each served by a base station [1]; neighbouring cells use different frequencies so they can be reused elsewhere [1]; as a user moves, the connection is handed over to the next cell’s base station [1]. (b) The signal is encoded and sent from a ground station on the uplink [1]; the satellite’s transponder amplifies it and changes its frequency [1]; it is sent back on the downlink and received by home dishes [1]. Examiner insight: Keep the steps in order; uplink and downlink must both appear.

11. (a) 25 × 2 = 50 Mbit/s needed [1], which is more than 40 Mbit/s, so the link is not enough at busy times [1]. (b) Cloud: no hardware to buy and storage grows on demand [1]; files are reachable from home [1]; but it depends on the internet link, already overloaded [1]. File server: fast local access not limited by the link [1]; but it costs more to buy and maintain and is a single point of failure [1]. Conclusion: a file server, or a cloud move only with a faster link [1]. (c) The VPN creates an encrypted tunnel over the internet [1], so home workers’ traffic cannot be read and they connect as if on the office LAN [1]. Examiner insight: In (b), use the figure from (a); a conclusion tied to the scenario is what turns a list into an evaluation.

12. (a) Server failure 3 × 4 = 12; flood 1 × 5 = 5 [1]; ransomware 4 × 5 = 20 [1]. Ransomware first [1]. (b) SQL injection: database code typed into a web form to read or change data [1]; prevent by checking and rejecting unsafe input [1]. DoS: flooding the server with requests so customers cannot reach it [1]; prevent with a firewall that blocks suspicious traffic [1]. (c) A UPS and surge protection keep servers running and undamaged during power problems [1]; regular back-ups [1] stored off site or in the cloud, with the restore process tested [1]. Examiner insight: In (c) “make back-ups” alone is thin; frequency, location and testing are separate points.

Where marks are usually lost

• Writing “faster” with no reason when comparing TCP and UDP.
• Forgetting to multiply megabytes by 8.
• Naming a server without saying what it does in the scenario.
• Describing only one side of a “differs” or “compare” question.
• Listing advantages in an “evaluate” question with no drawback or conclusion.
• Giving the same security measure twice in different words.
• Confusing MAC addresses (local delivery) with IP addresses (routing).
• Leaving out the uplink or downlink in a satellite description.

Next steps

• Revision notes
• Study guide
• 9626 course hub
• Printable checklist
• All free 10-minute diagnostics
• Book a free trial class

Official syllabus

Cambridge International AS & A Level Information Technology 9626, syllabus for examination in 2025, 2026 and 2027 (version 3), Cambridge University Press & Assessment: topic 14, Communications technology, sections 14.1 to 14.10.