Open Systems Interconnection (OSI)

Open Systems Interconnection (OSI) is a model that defines a networking framework to implement protocols in seven layers:

  1. Physical
  2. Data Link
  3. Network
  4. Transport
  5. Session
  6. Presentation
  7. Application

This model was designed by ISO (International Organization for Standardization) as a design template for building network systems. The lower layers deal with electrical signals, chunks of binary data, and routing of these data across networks. Higher levels cover network requests and responses, representation of data, and network protocols as seen from a user’s point of view.