A2.3 Data transmissions questions for IB Computer Science

66 questions on Data transmissions, written by Augment in the style of IB exam papers. Six of them are below in full, to answer on paper.

  • IB Computer Science
  • Part of A2 Networks
  • SL and HL

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Written by Augment in the style of IB exams, not past papers. Answer them on paper, then check each one against its markscheme with a free account.

Question 1 · CS-00219Paper 1 · 5 marks

A family home has a laptop, two phones, a smart TV and a games console. They all connect to a home router that uses network address translation (NAT). The internet service provider gives the router one public IP address.

  1. (a)

    Outline how NAT allows all five devices to share the single public IP address.

    2 marks

  2. (b)

    Explain how NAT helps to protect the devices from attackers on the internet.

    3 marks

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Question 2 · CS-00224Paper 1 · 5 marks

A design studio's router uses NAT. Its public IP address is 203.0.113.40. Part of the router's NAT table is shown in Table 1.

Table 1

Private IP address

Private port

Public port

192.168.0.12

51234

40001

192.168.0.15

49820

40002

192.168.0.12

51240

40003

  1. (a)

    A reply packet from a web server arrives at 203.0.113.40, port 40002. State the private IP address and port that the router forwards it to.

    1 mark

  2. (b)

    State how many different devices in the studio appear in Table 1.

    1 mark

  3. (c)

    An attacker sends a packet to 203.0.113.40, port 40007. Explain what the router does with this packet and why this improves the studio's security.

    3 marks

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Question 3 · CS-00287Paper 1 · 4 marks

A start-up sells smart light bulbs. Each bulb connects to the home network and needs an IP address. The company's documentation says the bulbs support both IPv4 and IPv6.

  1. (a)

    State the number of bits in an IPv4 address.

    1 mark

  2. (b)

    State the number of bits in an IPv6 address.

    1 mark

  3. (c)

    Outline one reason why IPv6 was introduced.

    2 marks

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Question 4 · CS-00288Paper 1 · 5 marks

A school's network technician is checking a log that lists the IPv4 addresses of devices that communicated with the school's network yesterday.

Device

IPv4 address

P

192.168.4.20

Q

172.20.1.5

R

172.32.0.9

S

10.250.3.3

T

8.8.4.4

U

192.169.1.1

  1. (a)

    Identify which of the devices P to U have a private IPv4 address.

    3 marks

  2. (b)

    Explain why a computer on the internet cannot send data directly to device P using P's private address.

    2 marks

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Question 5 · CS-00289Paper 1 · 9 marks

A café gives customers free Wi-Fi. Customers' phones are given dynamic IP addresses. The café's card terminal, receipt printer and a small file server have static IP addresses.

  1. (a)

    Distinguish between a static IP address and a dynamic IP address.

    2 marks

  2. (b)

    Explain why the receipt printer is given a static IP address.

    2 marks

  3. (c)

    Describe how a customer's phone is given a dynamic IP address when it joins the café's Wi-Fi.

    3 marks

  4. (d)

    Outline one reason why dynamic addressing suits the customers' phones better than static addressing.

    2 marks

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Question 6 · CS-00290Paper 1 · 8 marks

A family home has a router that performs network address translation (NAT). The internet service provider (ISP) has given the router one public IPv4 address, 203.0.113.25. Part of the router's NAT table is shown.

Private address : port

Public address : port

192.168.1.10 : 50512

203.0.113.25 : 40001

192.168.1.14 : 50512

203.0.113.25 : 40002

192.168.1.22 : 61000

203.0.113.25 : 40003

  1. (a)

    A packet arrives from the internet addressed to 203.0.113.25, port 40002. State the private address and port that the router forwards it to.

    1 mark

  2. (b)

    Explain why the router uses a different public port number for each row, even though two devices used the same private port.

    2 marks

  3. (c)

    Explain how NAT allows all the devices in the home to use the internet with a single public IP address.

    3 marks

  4. (d)

    Outline one security benefit of NAT for the family.

    2 marks

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The notes on A2.3 Data transmissions

More questions in Networks

  1. A2.1Network fundamentals
  2. A2.2Network architecture
  3. A2.3Data transmissionsThis page
  4. A2.4Network security

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