An application delivery controller is like a robot friend that helps our computer and phone talk to other computers and phones when we want to use the internet.
Imagine you want to play a game or watch a video on your computer. You type in the website address and press enter. But there are many other people trying to do the same thing on the internet at the same time. This can make the game or video slow or even stop working.
That's where the application delivery controller robot friend comes in. It helps to balance the load of people trying to use the internet, by sending each of us to different servers that can handle the workload better. For instance, one server might be faster for people who want to watch videos, and another server might be faster for those who want to play games.
This way, the application delivery controller robot friend helps to make sure everyone using the internet gets a fair share of the resources, and everything runs quickly and smoothly.