Congestion window

Imagine going to a store where they have a really cool toy that everyone wants to buy. However, the store only allows a certain number of people in at a time to prevent overcrowding. This is similar to how the internet works. When you try to send data, like a picture or a message, it can only go so fast and handle so much at a time.

Congestion window is like a limit on how much data can be sent and how fast it can be sent before things get too crowded. Just like the store limits the number of people who can come in at once, congestion window limits the amount of data that can be sent through the internet connection at one time. This is important because if too much data is sent too quickly, it can cause problems like slow internet or even a crash.

Think of it like a faucet in your bathroom. If you turn it on too far, water starts to splash out everywhere and make a mess. But if you only let a little bit of water through at a time, it's much easier to control and won't cause a mess. The same goes for congestion window - by limiting the amount of data that can go through at once, it helps keep things running smoothly and avoids a big mess.