The internet
Computers & Computational Thinking
Work at your pace. Take a break between stages; there is no countdown.
You need: paper, a pencil and this lab. A helper is welcome for reading and discussion.Connect to what you know
A saved picture can travel to another computer. Let’s follow a request and its response.
Understand it, step by step
- 1
Your device is the client. When you open a page, it asks a server for information. A server is another computer running a service, not the internet itself.
- 2
Routers pass data towards a destination using addresses. Information travels in small packets. Different packets may take different routes; our model shows only one simple route.
- 3
A reply must travel back before your browser can display it. A disconnected link can stop the journey. Wi-Fi connects you to a local network; it does not guarantee that the server is reachable.
Ask for cat.png: device sends request → router forwards → server reads the file → server sends response → router forwards back → device displays the picture. The screen cannot show the new file at the request stage.
Pause and predict
Where would the journey stop if the router’s outgoing link failed?