OSI Model

• OSI?

  Open Systems Interconnection.
• ISO?

  International Organization of Standardization.
• What is the OSI model?

  Enables communication between different operating systems.
• What are the layers of the OSI model?


  1. Physical Layer
  2. Datalink Layer
  3. Network Layer
  4. Transport Layer
  5. Session Layer
  6. Presentation Layer
  7. Application Layer
• What does the Physical Layer (1) do?


  Transmits data in bits along the communication channel.
• What does the Datalink Layer (2) do?


  Processes the bits from physical layer and prepares them for the next layer.
• What does the Network Layer (3) do?


  Delivers data to destination logical address (IP).
• What does the Transport Layer (4) do?


  Provides many additional controls for error free transmission of data.
• What does the Session Layer (5) do?


  Provides necessary services for the presentation layer to work.
• What does the Presentation Layer (6) do?


  Displays the data.
• What does the Application Layer (7) do?


  Provides access to structures found in the user-level OSI model.
• OSI model was aimed to design the ideal network communication.