When two computers exchange data over the internet, it travels in small units called packets. Each packet includes:
- Payload: the data you want to send
- Headers: metadata with source and destination IP addresses
Packets move from the source host to the destination host through intermediary devices (routers). Each hop forwards the packet closer to its destination. The network can route packets along different paths; unreliable hops may drop packets. The internet’s design tolerates these failures by allowing multiple routes, though some packets may still be lost.