Think it through together · A little story
The robot puts a destination address on a packet. How does a device at a junction know which exit to take?
Lay out the process
- ReadThe destination IP address
- Look it upMatch a reachable network
- ChooseThe next hop or local delivery
- ContinueThe next stop makes its own decision
IP addresses help identify a destination interface, while routing tables provide forwarding directions.
Think of a forwarding table as directions like “to this area, use that exit.” Different routers know about different connections, so each one decides on the next hop.
After reaching the destination network, other mechanisms—such as the local link—are still needed to deliver the data to the right device.
Your turn to try
Does a router have to know every detail about every app at the destination in order to forward a packet?
Have you thought it through? Open for an explanation
Usually not. IP forwarding mainly uses network-layer information; how an application handles the content comes later.
Take away one discovery
IP addresses help identify a destination interface, while routing tables provide forwarding directions.
Try covering the diagram above and explaining each step to someone in your family. If one step is hard to explain, go back and look at that card again.