These are original Marlbridge practice questions, not past exam questions. All scenarios are fictional. Where units matter: 1 byte = 8 bits; “Mbps” means megabits (millions of bits) per second. The rubrics are a suggested Marlbridge rubric, not an official scoring guideline. No calculator is needed.
Question 1 (multiple choice · foundation)
Which best defines a path in a computer network?
- (A) The amount of data a link can carry per second
- (B) A sequence of directly connected devices from a sender to a receiver
- (C) A set of rules that devices follow
- (D) A chunk of data with metadata
Answer and explanation
Answer: (B). A path begins at the sender and ends at the receiver, passing through directly connected devices.
- (A) describes bandwidth.
- (C) describes a protocol.
- (D) describes a packet.
Question 2 (multiple choice · foundation)
Which statement about the Internet and the World Wide Web is correct?
- (A) They are different names for the same thing.
- (B) The Web is a system of linked pages, programs and files that uses the Internet.
- (C) The Internet is a system of linked web pages.
- (D) The Web does not use any protocols.
Answer and explanation
Answer: (B). The Web runs on the Internet and uses HTTP.
- (A) the two are not the same.
- (C) reverses the relationship.
- (D) the Web uses HTTP.
Question 3 (multiple choice · core)
A fictional 30 MB video is sent over a link with a bandwidth of 60 Mbps. Which is the shortest time the transfer could take?
- (A) 0.5 seconds
- (B) 4 seconds
- (C) 5 seconds
- (D) 30 seconds
Answer and explanation
Answer: (B). 30 MB × 8 = 240 megabits. 240 ÷ 60 = 4 seconds.
- (A) is 30 ÷ 60, which forgets the factor of 8.
- (C) uses 10 bits per byte (300 megabits ÷ 60) instead of 8.
- (D) ignores the bandwidth and treats the size in megabytes as seconds.
Question 4 (multiple choice · core)
A message is divided into packets and sent across the Internet. Which statement is true?
- (A) All packets travel the same route and arrive in order.
- (B) Packets may arrive in order, out of order or not at all.
- (C) Packets contain only data, with no information about where they belong.
- (D) A packet can only be sent if every earlier packet has arrived.
Answer and explanation
Answer: (B). Packets are routed independently.
- (A) routes can differ and order is not guaranteed.
- (C) packets include metadata for routing and reassembly.
- (D) packets are sent without waiting for earlier ones to arrive.
Question 5 (multiple choice, select two · core)
Which two features help the Internet add new devices easily?
- (A) Its protocols are open (nonproprietary).
- (B) A single company controls every connection.
- (C) It was designed to be scalable.
- (D) Every message must follow one fixed route.
Answer and explanation
Answer: (A) and (C).
- (B) would make joining dependent on one company.
- (D) fixed routes would make growth and failure handling hard.
Question 6 (multiple choice · core)
A fictional network has devices P, Q, R, S and U joined by exactly these links: P–Q, Q–R, R–U, P–S, S–U. How many different paths are there from P to U that do not visit any device twice?
- (A) 1
- (B) 2
- (C) 3
- (D) 5
Answer and explanation
Answer: (B). P, Q, R, U and P, S, U.
- (A) misses one of the two.
- (C) and (D) count paths that do not exist or repeat devices.
Question 7 (multiple choice · stretch)
A fictional video call is poor because some packets are late. A designer says the call software should use a protocol that sends packets quickly without re-sending late or lost ones. Which reasoning supports this?
- (A) A re-sent packet would arrive too late to be useful in a live conversation, so speed matters more than perfect delivery.
- (B) Late packets must never be re-sent in any application.
- (C) Without re-sending, packets can no longer be identified.
- (D) Lost packets cannot occur on the Internet.
Answer and explanation
Answer: (A). For live audio and video a late packet is often useless, so a protocol such as UDP that skips resending can be a better fit.
- (B) overgeneralises; file downloads need re-sent packets.
- (C) packets still carry metadata.
- (D) packets can be lost.
Question 8 (constructed response · core)
A fictional school network has this layout: a laptop L connects to a switch W. W connects to router A and to router B. A connects to server V. B connects to server V as well.
(a) List the paths from L to V that do not repeat a device. (2 points)
(b) A 15 MB file is sent from V to L. Every link has a bandwidth of 30 Mbps. How many seconds will the transfer take, ignoring other delays? (2 points)
(c) Router A stops working. Explain what happens to the transfer. (1 point)
Answer and explanation
Suggested Marlbridge rubric (5 points).
| Point | Award when the response… |
|---|---|
| 1 | gives path L, W, A, V |
| 2 | gives path L, W, B, V |
| 3 | converts correctly: 15 × 8 = 120 megabits |
| 4 | divides by bandwidth: 120 ÷ 30 = 4 seconds |
| 5 | says routing can use the other path through router B, so the transfer still completes |
Sample response. (a) L, W, A, V and L, W, B, V. (b) 15 MB is 120 megabits; at 30 Mbps it takes 4 seconds. (c) Packets are routed through B instead, so the transfer still works.
Question 9 (constructed response · core)
A web page text is sent as six packets numbered 1 to 6 and they arrive in the order 4, 1, 2, 6, 3. Packet 5 does not arrive.
(a) Explain how the receiver knows packet 5 is missing and can still place the other packets. (2 points)
(b) Describe what happens if the protocol re-requests missing packets, and what happens if it does not. (2 points)
Answer and explanation
Suggested Marlbridge rubric (4 points).
| Point | Award when the response… |
|---|---|
| 1 | says each packet’s metadata includes its number, so the receiver can order them |
| 2 | says the gap in the numbers (no 5) shows a packet is missing |
| 3 | says with a protocol such as TCP the receiver asks for packet 5 again and the page is completed |
| 4 | says without re-requesting (such as UDP), the page has a gap that is not repaired automatically |
Sample response. (a) Packets carry numbers, so the receiver sorts them 1, 2, 3, 4, 6 and sees that 5 is absent. (b) With TCP it asks for packet 5 again and rebuilds the whole page. With UDP the page would be missing that part.
Question 10 (constructed response · stretch)
A student says: “The Internet is the Web, and it is one big computer owned by a single company.” Write a short reply that corrects both claims, using the terms network, protocols and World Wide Web. (4 points)
Answer and explanation
Suggested Marlbridge rubric (4 points).
| Point | Award when the response… |
|---|---|
| 1 | says the Internet is a network of interconnected networks (not one computer) |
| 2 | says it is not owned by a single company; it uses open, standardised protocols |
| 3 | says the World Wide Web is a system of linked pages, programs and files |
| 4 | says the Web uses the Internet (and HTTP), so they are different |
Sample response. The Internet is a network of interconnected networks that uses open protocols that anyone can follow, so no single company owns it. The World Wide Web is only a system of linked pages and files that runs on the Internet using HTTP, so the two are not the same.
How did you do?
Questions 1 to 7 are multiple choice; 8 to 10 are written. If you missed Question 3 or lost marks in Question 8, re-check the factor of 8 between bytes and bits. Re-read “Packets” in the study guide if needed, then use the checklist.