What you will learn
- Name the OSI layers
- Map TCP/IP to OSI
- Place common protocols by layer
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The basics, in plain English
When two computers talk, a lot has to happen: a cable carries electricity, that becomes data, that data finds the right machine, and finally an app reads it. To keep this manageable, people split the whole journey into stacked “layers”, where each layer only worries about its own job.
- Layer
- One step in the journey of data. Each layer does one job and hands off to the next, like an assembly line.
- OSI model
- A teaching map that splits networking into 7 layers, from physical cables up to the app.
- TCP/IP model
- The simpler, real-world version used by the internet, with 4 layers instead of 7.
- Protocol
- An agreed set of rules for how two computers format and exchange messages.
- Why layers help
- When something breaks, you can ask “which layer failed?” instead of guessing about everything at once.
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Layered thinking
OSI has seven layers; TCP/IP collapses them to four. The value is mental: when something breaks, you ask which layer.
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