OSI model simple explanation.

OSI model simple explanation.

OSI stands for Open System Interconnection.

This method is used to define the method of communication between two devices. OSI model has multiple layers each stacked on one another.

Let's understand the layers one by one.

These are the seven layers of the OSI model.

  1. Physical layer

  2. Data link layer

  3. Network layer

  4. Transport layer

  5. Session layer

  6. Presentation layer

  7. Application layer

The first four layers ( Application layer, Presentation layer, Session layer, and Transport layer ) are the layers that interact with the software and the bottom three layers ( Network layer, Data Link layer, and Physical layer ) are the layers that interact with the hardware.

Now let's understand the use of each layer.

LayerFunctionExample
7Application LayerThis is the only layer that interacts with the user.SMTP
6Presentation LayerThis layer is also called as Translation layer. This layer is responsible for encrypting/decrypting data.JPG, GIF, HTTPS
5Session LayerThis layer establishes a connection between two devices/hosts. The period till which this connection is present is called a session.PPTP
4Transport LayerResponsible for end-to-end communication between two devices, it breaks the data into smaller pieces called segments.TCP, UDP
3Network LayerData transfer between networks. If further breaks the segments into small packets and re-assembles them on the sender device.Routes
2Data Link LayerSomewhat similar to the data link layer, but in this the data is transferred between the same network.Switches
1Physical LayerInvolves the data transfer over to physical layersNICS, Cables

So this is the OSI layer explanation in a very simple manner. Do follow me on my socials.

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