OSI, the Networking Seven Layer Cake

Welcome to the OSI model, a seven-layered cake of networking taste that helps data get from point A to point B. Each layer has its job and adds its sweet taste to the Network cake stack.

1. Layer1: The Physical Layer

   
   

   The first layer is like the cake stand, It’s the actual space where everything happens. In networking, this layer handles the physical connections, like cables, switches, and wireless signals. It’s the foundation, the real-world stuff that you can actually touch.

   NOTE: No physical layer, no data transmission.

2. Layer 2: The Data Link Layer

   
   

   The Data Link Layer ensures that each cake layer is aligned perfectly, In networking, this is where MAC addresses live, helping to direct traffic and make sure data doesn’t get lost on its way in. The Data Link Layer keeps things orderly, making sure data enters and exits smoothly.

3. Layer 3: The Network Layer

   
   

   This filling is what connects all the layers. Enter the Network Layer, which is basically the GPS for your data. It figures out the best route to take, using IP addresses to make sure data goes exactly where it’s supposed to. The Network Layer is your data’s guide, getting data from point A to point B efficiently.

4. Layer 4: The Transport Layer

   
   

   The Transport Layer is your security, ensuring that data is delivered safely and reliably. If something goes wrong and you agreed in advance on fixing it (TCP), it steps in to fix the problem, retransmitting lost data or reorganising it if it gets jumbled.

5. Layer 5: The Session Layer

   The Session Layer is like the decorations on your cake, the Session Layer making sure communication between devices is smooth and uninterrupted. This layer sets up and maintains connections (sessions) between devices, making sure everything stays coordinated and in sync.

6. Layer 6: The Presentation Layer

   
   

   Just like frosting makes the cake look appetising, the Presentation Layer formats and translates data into something that’s visually appealing and understandable for us humans.

7. Layer 7: The Application Layer

   
   

   The cherries, sprinkles, or whatever toppings you love most. This layer is where users interact directly, enjoying the final product. In networking terms, this is where applications like web browsers and email clients live, giving you the tools to interact with the network.

Below is a table that breaks down each layer of the OSI model, listing the associated devices, protocols, and technologies.

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Note: The image is copied from here: https://x.com/gabsmashh/status/1263112005692555265