Introduction to OSI Layer

OSI Model:-

  • It is a Layered Architecture.
  • It is not a protocol. 

In Layered Architecture, 

Each layer provides services to the upper layer and enjoys services provided by lower layers. Ex. layer 4 provides services to upper layer 5 but enjoys services provided by layer 3.

While sending the data, each layer adds up its own information to the data obtained by one layer above it and sends the complete package to one layer just below it.


Few advantages of layering System:-

  1. Divide and Conquer
  2. Encapsulation
  3. Abstraction. 
  4. Testing.

OSI model is consist of 7 layers:

  1. Physical layer 
  2. Data-link layer
  3. Network layer
  4. Transport layer 
  5. Session layer
  6. Presentation layer
  7. Application layer.

Now we will see Each layer Separately.