How Data Travels Across a Network
Packets, hops, and the invisible roads of the internet.
Key takeaways
- Data travels in discrete packets, not streams.
- Each packet carries source/destination IP and traverses multiple routers (hops).
- The OSI model provides a layered framework for understanding where things go wrong.
- TTL prevents packets from circulating forever in routing loops.
Every time you open a web page, your browser breaks the request into packets — small chunks of data each labeled with a source address, a destination address, and metadata about how to reassemble them at the other end.
Those packets don't travel a single dedicated wire. They hop through a series of routers, each one making a local decision: "Based on my routing table, the next hop toward that destination is over here." The packet might pass through 12 routers between your laptop and a cloud server in another country.
Knowledge check
A packet with TTL=1 arrives at a router. What happens?