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OSI Model Deep Dive: Where Protocols Live

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OSI model: 7 layers of abstraction

The OSI model describes networking as seven layers of abstraction, each building on the one below. Data travels down the stack on the sender (each layer adds a header) and up the stack on the receiver (each layer reads and removes its header).

Why learn it? Every network problem can be isolated to a layer: can't reach the server (L3 routing), TCP not connecting (L4 firewall), application errors (L7). Naming the layer narrows troubleshooting dramatically.

Packets in motion — click to inspect:

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