7.1.1 OSI Model (7 Layers)

The OSI Model (which stands for Open Systems Interconnection) is a way to understand how different parts of a network work together. It breaks down the process of sending and receiving data into 7 different layers, starting from what you see on your screen all the way down to the physical wires. Each layer has a specific job, and they work together to make sure information gets where it needs to go.

Imagine sending a letter:

Application Layer: You write the letter (your message, like a video game sending player data).
Presentation Layer: You make sure the letter is in a language the receiver understands (like converting data formats).
Session Layer: You decide to start a conversation with someone and keep it open while you're talking.
Transport Layer: You decide if you want to make sure the letter arrives perfectly (like registered mail for important data) or if it's okay if a bit gets lost (like streaming video).
Network Layer: You decide the best route for the letter to take across different cities (like figuring out the path for data across the Internet).
Data Link Layer: You put the letter in an envelope, write the street address, and make sure it's ready for the local mail delivery.
Physical Layer: You put the letter in the mailbox for the mail carrier to pick up and deliver (this is the actual wires, cables, or Wi-Fi signals).

It's a very detailed model, mostly used for understanding and designing complex networks.

Bibliography:

What is the OSI Model? (2024, May 15). Cloudflare Learning Center. https://www.cloudflare.com/learning/ddos/glossary/open-systems-interconnection-model-osi/
OSI Model. (n.d.). Imperva.com. https://www.imperva.com/learn/application-security/osi-model/