What is link-state?

Link-state is like knowing where everyone is on a playground so you can choose the fastest path to your favorite slide.

Imagine you and your friends are playing tag on a big playground. Each of you knows how fast you run, but you don’t know where everyone else is. If you want to catch someone or avoid being caught, you need to know the whole map, who’s near the swings, who’s hiding behind the trees, and who’s sprinting toward the slide.

That’s what link-state means in a network: every device (like a router) knows the whole map of how fast data can travel between all the other devices. It's like having a bird’s-eye view of the playground, you can see where everyone is and plan your moves better.

In a network, each router sends out messages saying: “Hey, I’m here, and this is how long it takes to reach my neighbors.” All the routers collect these messages and build a map of the whole network. Then they can pick the best path for data, just like you picking the quickest way to your slide based on where everyone else is.