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S6 ICT: Data Communications and Networking (Paper 4 (error clinic))
S6 ICT: Data Communications and Networking (Paper 4 (error clinic))
Paper 4 (error clinic): ten questions on data communications and networking with worked numbers, answers and one line notes.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S6 ICT: Data Communications and Networking |
| Level | S6 |
02 Questions (10 items)
- FoundationWhat does a subnet mask do?
- FoundationIn what unit is data sent across a network?
- FoundationCan a private IP address be routed directly on the internet?
- IntermediateWhat is the difference between a MAC address and an IP address?
- IntermediateCompared with a wireless link, which connection is usually more stable?
- IntermediateCan a switch replace a router for sending data to another network?
- ChallengeA 12 MB file is sent at 24 Mbps. How many seconds does it take?
- ChallengeHow many usable host addresses does a /30 subnet mask give?
- ChallengeA 60 GB file is sent at 80 Mbps. How many minutes does it take? (1 GB = 1024 MB, one decimal place)
- Error redoError clinic: a Wi-Fi network with a password is always secure. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | It separates the network part of an IP address from the host part | Bits set to one in the mask mark the network, and zero bits mark the host. |
| 2 | Packets | A file is cut into packets, each carrying its own source and destination address. |
| 3 | No | Internet routers do not forward private addresses, so NAT must translate them first. |
| 4 | A MAC address is fixed on the network card, while an IP address changes with the network | MAC addresses forward frames inside one network, and IP addresses find paths across networks. |
| 5 | A wired connection | Wireless links suffer from distance, walls and interference, so the speed varies more. |
| 6 | No, routing between networks needs a router | A switch only forwards by MAC address inside one network and cannot choose paths between networks. |
| 7 | 4 seconds | 12 multiplied by 8 gives 96 megabits, which divided by 24 gives 4 seconds. |
| 8 | 2 addresses | Host bits are 32 minus 30, which is 2, and two to the power two minus two gives 2. |
| 9 | About 102.4 minutes | 60 times 1024 times 8 gives 491520 megabits, which divided by 80 gives 6144 seconds, that is 102.4 minutes. |
| 10 | The encryption type, password strength and whether it has leaked all matter | WEP or weak passwords can be cracked, and public networks also carry man in the middle risks. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Decide first whether a network question is conceptual or numerical. For concepts, separate the device layers: hub, switch and router. For calculations, multiply megabytes by eight to get megabits, then divide by the bandwidth to get seconds. For subnet masks, usable hosts equal two to the power of the host bits, minus two.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
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