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The TCP/IP model
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Sending a message across the internet is split into four layers. Each layer does one job and passes the data on.
Four layers
Down then up
On the sending computer, data passes down the layers: each layer adds its own information.
On the receiving computer, data passes up the layers and each layer removes and uses its information.
Routers in between only need the lower layers.
On the receiving computer, data passes up the layers and each layer removes and uses its information.
Routers in between only need the lower layers.
Why use layers?
Each layer is self-contained, so one layer can be changed without affecting the others (for example, swapping Ethernet for Wi-Fi).
Different manufacturers can build hardware or software for one layer that works with the rest.
It breaks a complicated problem into manageable parts.
Different manufacturers can build hardware or software for one layer that works with the rest.
It breaks a complicated problem into manageable parts.
A web page is requested from a laptop on Wi-Fi. Name a protocol used at each layer.
- Application: HTTPS
- Transport: TCP
- Internet: IP
- Link: Wi-Fi
Answer: HTTPS, TCP, IP, Wi-Fi
TCP/IP has four layers: application, transport, internet and link. Data goes down the layers when sent and up when received. Layers let each part be developed and changed separately.
The interactive lesson includes the diagrams for this topic.
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