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? Networking! Your device uses a network connection and goes through a series of defined 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 developed in the 1970s and 1980s, and it is a conceptual model that breaks networking into seven separate layers. Each layer refers to a set of fu…
  4. 4
    ### Layer 1 – Physical The Physical, and lowest layer of the model, covers how unstructured data, like bits, is transmitted. Some concrete examples of this are the ways wires are configured, th…
  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. You will hear more often about the TCP/IP model, which is a 4-layered model that makes direct reference to current Internet implemen…
  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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