Networks & the Internet (Cambridge (CIE) A Level Computer Science): Exam Questions

A video doorbell is attached to the front door of a house. The doorbell uses a motion sensor to detect when a visitor walks in front of the door. When the motion sensor is activated:

• The digital camera in the doorbell starts recording a video.

• A message is transmitted to a smartphone so that the person who lives in the house can watch the video.

The doorbell also has a button that can be pressed. When the button is pressed, a message is transmitted to a smartphone to play the doorbell sound.

The videos are stored on the doorbell’s internal secondary storage device and overwritten when the secondary storage device is full.

The video doorbell allows both real-time and on-demand bit streaming.

(i) State what is meant by bit streaming.

(1)

(ii) Give two differences between real-time and on-demand bit streaming.

(2)

A bank allows customers to access their accounts using an application that they can download onto a device such as a smartphone.

The system that allows customers to access their accounts using the application is a client-server model.

Describe the roles of the different devices in this model.

A business is creating a local area network (LAN) in its office.

The business is deciding which topology to use.

Tick (✓) one or more boxes in each row to identify the topology, or topologies, each statement describes.

(5)

The LAN will connect to the internet through a router. The router has a public IPv6 address.

(i) State why the router has a public IP address.

(1)

(ii) One difference between an IPv4 and IPv6 address is that the numbers in an IPv4 address are separated by full stops and in an IPv6 address they are separated by colons.

Identify two other differences between an IPv4 and IPv6 address.

(2)

An assessment board scans exam papers and stores the digitised papers on a server. Exam markers download the digitised papers to mark. The exam markers then upload the mark for each paper.

The exam markers use software that operates as a thin-client to mark the exam papers.

Complete the table by identifying two characteristics of a thin-client.

Describe how each characteristic will be used in this software.

Data transmitted on the internet passes through multiple different systems.

(i) Describe the role of routers in the transmission of data through the internet.

(2)

(ii) Describe the role of the PSTN (Public Switched Telephone Network) in the transmission of data through the internet.

(2)

A multimedia design company has an office with a LAN (local area network). The LAN can have up to 20 devices connected with cables and other devices connected using wireless access.

The company has private cloud storage for its employees to store their work.

(i) Define the term private cloud.

(1)

(ii) Describe the benefits to the company of using private cloud storage instead of public cloud storage.

(3)

Part of the internal structure of the wired LAN is a star topology.

Explain how packets are transmitted between two devices in a star topology.

A different part of the network uses the Ethernet protocol.

(i) A collision is detected.

Describe how the collision is managed using Carrier Sense Multiple Access/Collision Detection (CSMA/CD).

(2)

(ii) Identify two drawbacks of using CSMA/CD.

(2)

The devices in the office have static private IP addresses.

State what is meant by a static private IP address.

Explain the meaning of the phrase:

BitTorrent protocol provides peer-to-peer file sharing.

A school has a Local Area Network (LAN).

The LAN connects to the internet using a router.

Describe the function of a router in a network.

Complete the following table by writing the purpose of each of these other hardware devices used to support the LAN.

The students can save their school files on a public cloud.

Identify two drawbacks of the students storing their files on the public cloud.

A new classroom is being set up with 20 computers and a switch.

Explain one advantage of implementing a star topology instead of a bus topology in the new classroom.

A Local Area Network (LAN) contains four devices:

• a router

• two laptop computers

• a server.

The server has the IP address 192.168.3.2

Explain why this is not an IPv6 address.

(i) The LAN is set up as a star topology.

Draw a diagram of the topology of the LAN.

(2)

(ii) Explain how data is transmitted between the two laptops in the LAN.

(2)

(iii) Subnetting can be used to separate a network into logical segments.

Describe two other reasons why subnetting is used in a network.

(4)

State three tasks performed by devices to deal with collisions when using the Carrier Sense Multiple Access /Collision Detection (CSMA/CD) protocol in a network.

The following incomplete table contains types of IP addresses and their descriptions.

Complete the table by writing the missing types of IP addresses and the missing descriptions.

A company sells online Computer Science courses to students in different countries. The courses are stored on a public cloud.

(i) Explain why the company uses a public cloud to store these courses.

(2)

(ii) Describe two disadvantages of storing data on a public cloud compared to storing data on a server in a Local Area Network (LAN).

(4)