A student at a school requests a web page from a server on the internet. The school uses packet switching. The route below shows some of the hardware used b...
Question 1 Report
A student at a school requests a web page from a server on the internet. The school uses packet switching. The route below shows some of the hardware used before the request reaches the internet. The labels A, B and C have been removed. The network has a transmission rate of 6 Mb/s on the connection from the router to the internet.
(a) Complete the labels A, B and C. Use each term once: laptop, router, switch. [3]
(b) State what is meant by latency. [1]
(c) Identify the TCP/IP layer responsible for IP addressing and routing packets between networks. [1]
(d) Explain how packet switching allows a 24 Mb web-page file to be sent across a network. [3]
(e) Give two reasons why communication protocols are needed when devices on a network exchange data. [2]
(f) State the name of the global network that connects many separate networks. [1]
(g) Calculate the minimum transmission time, in seconds, for a 24 Mb file sent at 6 Mb/s. Ignore all delays other than transmission time. [1]
(h) Give one method the student could use to protect data when using public Wi-Fi. [1]
Answer Details
(a) The route is laptop → switch → router → internet [3]. A switch connects devices within the school network; a router connects separate networks.
(b) Latency is the time delay between sending data and receiving it, or before it reaches its destination [1].
(c) IP addressing and routing between networks are functions of the Internet layer [1].
(d) The 24 Mb file is split into smaller packets. Packets are transmitted independently, potentially along available routes. At the destination they are checked and reassembled into the original file; missing or damaged packets can be requested again [3].
(e) Protocols provide agreed communication rules, such as data formats and addressing, so devices can interpret messages consistently [2]. Error checking or rules for ordering and flow are also valid.
(f) The global network is the internet [1].
(g) \[\text{time}=\frac{\text{file size}}{\text{transmission rate}}=\frac{24\text{ Mb}}{6\text{ Mb/s}}=4\text{ s}\] The minimum transmission time is 4 seconds [1].
(h) Use a VPN when using public Wi-Fi [1]. Using HTTPS or avoiding sensitive data are also valid protections.
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