Have you ever played a game with your friends where you pass a message from one person to another? Imagine that you and your friends are computers in a big circle, and you want to pass messages between all of you.
But how do you know who to pass the message to next, and what do you do if someone in the middle can't understand it?
This is where Systems Network Architecture (SNA) comes in. It's like having rules for passing messages between computers in a big circle.
SNA makes sure that every computer (or person) knows:
1. Who they are supposed to pass the message to and in what order.
2. How to create a message that other computers (or people) can understand.
3. What to do if someone in the middle can't understand the message.
So even though you might not see them, there are rules and processes that help computers communicate with each other, just like rules and processes help you and your friends pass messages in a game.