IP
Problem
Ethernet works locally.
But your laptop needs to communicate with a server thousands of kilometres away across many different networks.
A local MAC address isn't enough.
We need an address that says:
Where in the interconnected network is the destination?
Solution — IP
Devices receive logical IP addresses.
Packets carry:
Source: 192.168.1.20
Destination: 142.250.184.78
Routers use the destination IP to move the packet across networks toward its destination.
Core idea: IP provides addressing and packet delivery across interconnected networks.