中文（繁體）
中文（简体）
English
S6 ICT: Networking and Data Transmission – Practice Paper 3 (Challenge, 10 Questions)
S6 ICT: Networking and Data Transmission – Practice Paper 3 (Challenge, 10 Questions)
Paper three moves to planning: slash 22 and slash 20 budgets, usable bandwidth after utilisation, packet counts under the MTU, aggregation limits and fibre delay.
Quick answer A slash 22 holds 1 024 addresses and 1 022 hosts; a slash 16 cut into slash 20 gives sixteen blocks of 4 096; 500 Mbps at 65 percent moves 2 GB in 49.2 seconds; a 1 500 byte MTU leaves 1 460 for data and 685 packets carry 1 000 000 bytes.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | about 22 minutes |
| Difficulty mix | Foundation 1 · Intermediate 3 · Challenge 4 · Error redo 2 |
| Chapter | Chapter: S6 ICT | Networking and Data Transmission: Bandwidth, Subnets and Latency |
| Level | Challenge |
02 Questions (10 items)
- FoundationHow many addresses does a slash 22 network hold, and how many hosts are usable?
- IntermediateA slash 16 network at 172.16.0.0 is cut into slash 20 subnets. How many subnets and how many addresses each?
- IntermediateA 500 Mbps link runs at 65 percent utilisation. How long does a 2 GB file take, with 1 GB as 1 000 MB?
- IntermediateWith a 1 500 byte MTU and 20 byte IP and TCP headers, how many packets carry 1 000 000 bytes of data?
- ChallengeThree 100 Mbps links are bundled by link aggregation. What is the total, and can one TCP connection use it all?
- ChallengeLight travels at about 200 million metres per second in a 20 km fibre. What are the one way and round trip delays?
- ChallengeA slash 20 network of 4 096 addresses serves six departments of 500 computers, each on a slash 23. What is left?
- ChallengeA 1 Gbps link is saturated for six hours a day and averages 100 Mbps for the other eighteen. What is the daily volume in TB?
- Error redoError retry: a student read 1 Gbps as 1 GB every second. How long does a 24 GB backup really take?
- Error redoError retry: a student said a slash 26 mask of 255.255.255.192 allows 192 hosts. What is the correct host count?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 1 024 addresses and 1 022 hosts | Ten host bits give 1 024 addresses, and removing the two reserved ones leaves 1 022. |
| 2 | Sixteen subnets of 4 096 addresses each | Borrowing four bits from sixteen to twenty gives sixteen subnets, and twelve host bits leave 4 096 addresses. |
| 3 | About 49.2 seconds | Usable bandwidth is 325 Mbps and 2 GB is 16 000 Mb, which divides to 49.23 seconds. |
| 4 | 685 packets | Each packet carries 1 460 bytes, and 1 000 000 over 1 460 rounds up to 685. |
| 5 | 300 Mbps in total, but a single connection stays at 100 Mbps | Aggregation spreads flows across links, so one TCP stream still rides a single link and caps at 100 Mbps. |
| 6 | 0.1 ms one way and 0.2 ms round trip | 20 000 metres over 200 million metres per second is 0.0001 seconds or 0.1 ms, and the round trip doubles it. |
| 7 | 1 024 addresses remain | Six slash 23 blocks of 512 addresses take 3 072, and 4 096 minus 3 072 leaves 1 024. |
| 8 | About 3.51 TB | Six hours at 1 000 Mbps gives 21 600 000 Mb and eighteen hours at 100 Mbps adds 6 480 000 Mb, totalling 28 080 000 Mb or 3.51 TB. |
| 9 | 125 MB/s, so about 192 seconds | One gigabit per second is 125 MB per second, and 24 000 MB over 125 gives 192 seconds. |
| 10 | 62 hosts | 192 is only a byte value of the mask, and the 64 address block leaves 62 hosts after the reserved ones. |
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.
Find a tutor freeTutor 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.