A.2 Networks
Reason about network communication
Explain layered protocols, addressing, routing, and secure communication.
Examples use Python. The current IB course also permits Java.
Separate the jobs of network services
A protocol defines rules shared by communicating systems. Addressing identifies a destination, routing selects a path, and transport mechanisms handle delivery behavior. DNS looks up names; it does not deliver the requested web page itself.
Layering separates responsibilities so one implementation can change without replacing the entire network. Encapsulation attaches information needed by a lower layer; the receiver interprets and removes that information at the corresponding stage.
Evaluate a network design
For a school network, compare throughput, latency, coverage, reliability, and cost against the users' needs. Bandwidth is capacity; latency is delay. A high-capacity connection may still have enough delay to disrupt a live conversation.
Encryption protects message content, authentication helps establish identity, and authorization limits access. Redundancy improves resilience, but introduces cost and management work. Justify the design in the scenario rather than listing advantages without context.
Check yourself
Can high bandwidth guarantee a low-delay video call?Show answer
No. Bandwidth and latency are different characteristics, and congestion or distant routing may still introduce delay.
References used to build these lessons
We used these official documents as references when building this course's lessons. They are the sources for the syllabus structure and course requirements.
International Baccalaureate · First assessment 2027
This PDF is the public IB subject brief. The complete subject guide and assessment requirements are available through your school or the IB Programme Resource Centre.