alphaPlan · Systems learner pack
A packet's journey through a changing network
Reference lesson: How Computers & the Internet Work > The internet > How the internet works
1. Initial model, before definitions
Draw how a three-part message could travel from the sender to the server when there is no direct wire. Label only what you already think is necessary.
2. Prediction
The link from Router A to Router B fails. The server still exists and another route is available. What changes? What stays the same?
3. System map
Build two distinct routes: Sender → Router A → Router B → Destination, and Sender → Router A → Alternate Router → Destination. Move each packet one hop at a time.
Sender · Shkodër
Router A
Router B · Route 1
Alternate Router · Route 2
Destination
Route 1 and Route 2 must remain visibly separate. Removing Route 1 does not remove the destination.
4. Revised model
| Sender | What does it do first? |
|---|---|
| Packet | What must it carry? |
| Router | What does it decide? |
| Destination | What does it do? |
| Failed path | What changes and what does not? |
5. Transfer and teach-back
A library in Korçë uploads a large photograph. One route is congested and one packet is missing. Explain how the model applies, then teach the full journey without looking at the role labels.
Cut-out cards
Cut on dashed borders. This is a simplified learning card, not a real packet header. Text and symbols, not colour, carry meaning.
SENDER Check payload split and address
ROUTER A Read forwarding information; announce next hop
ROUTER B Check assignment; forward on Route 1
ALTERNATE ROUTER Check assignment; forward on Route 2
DESTINATION Record received and missing parts
OBSERVER Record route, delay and what stayed unchanged
FORWARDING / ADDRESS
Destination: learning server
Part 1 of 3
PAYLOAD / CONTENT
LEARN
FORWARDING / ADDRESS
Destination: learning server
Part 2 of 3
PAYLOAD / CONTENT
TOGETHER
FORWARDING / ADDRESS
Destination: learning server
Part 3 of 3
PAYLOAD / CONTENT
TODAY
https://codeforalbania.com/en/learn/how-computers-work/01-networks/how-the-internet-works
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