Key Concepts

Review core concepts you need to learn to master this subject

OSI Model

The OSI Model is a conceptual, implementation-neutral model that describes networking in seven separate layers, where each layer covers a set of functions and tasks.

This model helps us communicate while we do network troubleshooting and architecture.

Network Basics
Lesson 1 of 1
  1. 1
    What happens when we access Codecademy? How are we able to access the content provided by this course? The answer to this question is simple. Networking! However, the actual processes behind networ…
  2. 2
    When we talk about a network, that could be anything connecting two or more devices. It’s important we understand the different types of networks. Networks are broken into different subsets based…
  3. 3
    The OSI (Open Systems Interconnection) Model was created in the mid-1980s and is a conceptual model that breaks networking into seven separate layers. Each layer refers to a set of functions that…
  4. 4
    ### Layer 1 – Physical The Physical, and lowest layer of the model, is responsible for the ways wires are configured, the way signals are transferred over those wires, and the radio frequencies…
  5. 5
    In layers 3 and 4, we begin to see how data is routed between different networks and how transportation protocols function within these layers! ### Layer 3 – Network The Network layer describe…
  6. 6
    ### Layer 5 – Session When two computers or devices have started an exchange of information, we call that a session. The Session layer in OSI is responsible for opening, closing, and maintain…
  7. 7
    The OSI Model isn’t the only model that describes networking. The OSI Model is essential for understanding the granular details of networking, but it is neutral to implementations. You will hear m…
  8. 8
    Now that we have a conceptual model of everything it takes for data to travel in a network, let’s talk about some of the most common network protocols we use everyday. What are network protocols? …
  9. 9
    The protocols in the last exercise are all involved in everyday Internet activity. Below are some other Application-layer protocols that are more commonly used by IT professionals. — ### SSH _S…
  10. 10
    Networks, and the technology behind networking, help us connect to the world around us. Through following multiple protocols, we’re able to use physical technologies to exchange a massive amount of…

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