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IB DP Computer Science — A2 Networks — Network fundamentals | HL | A2.1.5 HL Only
📋 What You Will Learn
- Describe the function of each TCP/IP layer: application, transport, internet, network interface
- Explain why network communication is organised as a layered model at all
- Describe encapsulation and de-encapsulation — how each layer adds and strips its header
- Trace one HTTPS request down the sender's stack, across a router, and up the receiver's stack
- Explain how the layers interact to make transmission reliable even though IP itself is unreliable
📦 Why This Matters Sending a parcel abroad: you write the letter (application), the courier assigns it a tracking number and re-sends it if it goes missing (transport), the postal system routes it country to country by address (internet), and lorries and planes physically move it (network interface). Each layer does its own job and trusts the others to do theirs — that separation is the whole idea of TCP/IP.
Why a Layered Model?
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