The router
The router sends the request onward and brings the reply back to the right device.
One more sentence, for a grown-up
Several devices can share one router. The router keeps track of which reply belongs to which device. Roughly, as of 2026, a home router is still one small box.
About the size of a thick book. The model is not to scale.
Real: What it looks like.
- Packets
- The reply
Keys: arrows rotate · + / − zoom · 0 reset · 1–4 views · S signal · T tour · L labels · Space spin. The model is stylised. The network on this page is made up.
Every labeled part
- 1
Inside the house
Phones and computers connect on this side.
- 2
Outside the house
The request leaves toward the rest of the internet on this side.
- 3
Who is who
The router remembers which device asked, so the reply comes back to that one.
- 4
The reply
The answer comes back through the same box.
- Packets
- The reply
Try it
A reply comes back. Pick which device it belongs to.
The reply goes to the phone. The other device does not get this one.