A2.2 Network architecture: notes and practice
A2.2 covers how networks are laid out and organised: topologies, client-server and peer-to-peer models, segmentation with subnets and VLANs, and reading CIDR notation. At HL it adds the jobs of servers such as DNS and DHCP.
Paper 1Mixed3 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.
- Describe common network topologies including star, mesh and hybrid
- Compare topologies on cost, resilience, performance and ease of expansion, and pick one for a scenario
- State the function of DNS, DHCP, file, mail, proxy and web serversHL
- Describe how a DNS lookup resolves a domain name to an IP addressHL
- Describe how a client obtains an IP address from a DHCP serverHL
- Compare the client-server and peer-to-peer models
- Choose between client-server and peer-to-peer for a scenario and justify it
- Explain why networks are segmented and what segmentation achieves for performance and security
- Describe subnetting and VLANs as segmentation techniques
- Interpret CIDR notation to identify a network range
Practice questions
Original questions written for the 2027 course, marked as you go. Easiest first.
- DNS lookup step by stepWritten · Stretch
- Star or mesh network for four buildingsWritten · Stretch
- CIDR subnet addresses for a schoolWritten · Stretch
Exam tips for A2.2
- When picking a topology, weigh cost against resilience for the situation described.
- Practise working out how many addresses a CIDR block like /24 or /26 gives.
- At HL, describe a DNS lookup as an ordered chain of requests, from the local cache outwards.
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.