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A2.3 Data transmissions: notes and practice

A2.3 covers how data actually moves: IP and MAC addresses, IPv4 and IPv6, NAT, cables and wireless, and packet switching. At HL it adds static and dynamic routing.

Paper 1Mixed2 practice questions

What you need to know

Our summary of the topic in our own words, not the IB guide. Points marked HL are for Higher Level only.

  • Explain what an IP address is and how it differs from a MAC address
  • Compare IPv4 and IPv6 and explain why IPv6 exists
  • Distinguish public from private addresses and static from dynamic assignment
  • Explain what network address translation does and why it is needed
  • Compare transmission media including twisted pair, fibre optic and wireless on speed, range, cost and interference
  • Choose a transmission medium for a described deployment and justify it
  • Explain packet switching and what a packet contains
  • Describe how switches and routers move packets, and why packets can arrive out of order
  • Compare static and dynamic routingHL
  • Trace how data moves across a local area network under a given routing setupHL

Practice questions

Original questions written for the 2027 course, marked as you go. Easiest first.

Exam tips for A2.3

  • Keep IP and MAC addresses straight: IP is logical and can change, MAC belongs to the network card.
  • When choosing a medium, compare speed, range, cost and interference for the place described.
  • Explain why packets can arrive out of order and what puts them back together.

Updated 24 October 2026. Topic codes are used as labels. Everything on this page is written by ExamSpine and is not endorsed by the IB.