End-to-end delay

End-to-end delay is the amount of time it takes for information to travel from one place to another. Think of it like the time it takes for a letter to be sent from your house to your friend's house.

First, you write the letter and put it in an envelope. This is like your computer or phone sending a message. Then, you put it in the mailbox and wait for the mail person to pick it up. This is like your message traveling through the internet.

Next, the mail person takes your letter to the post office. This is like your message being sent to a server. At the post office, the letter is sorted and put on a truck or plane to be sent to your friend's city.

In the same way, your message might be sent to different servers and locations before it reaches your friend's device. Each time, it takes a little bit of time for the message to travel, be processed, and sent on to the next location.

Finally, your friend's mail person delivers the letter to their house. This is like your friend's device receiving your message.

All of these steps take time, and they all add up to the end-to-end delay. The delay depends on how far apart you live (how far the message has to travel) and how many servers and locations the message has to go through.