Starting with the layer closest to the user what is the correct order of layers of the OSI model?

• A. Physical, Data Link, Network, Transport, Session, Presentation, Application
• B. Presentation, Data Link, Network, Transport, Session, Physical, Application
• C. Application, Presentation, Session, Transport, Network, Data Link, Physical
• D. Application, Physical, Session, Transport, Network, Data Link, Presentation

Answer: (C)

Starting from the layer closest to the user, the correct order from top to bottom is: Application, Presentation, Session, Transport, Network, Data Link, Physical. This arrangement reflects how software interacts with data and how that data is ultimately transmitted over a physical medium. Each layer has a distinct role: the Application layer provides interfaces for software applications; Presentation handles data formatting and encoding; Session manages dialogue and control between endpoints; Transport ensures reliable end-to-end delivery and flow control; Network handles routing and logical addressing; Data Link packages data for node-to-node transfer and frames; Physical transmits the raw bits over the physical medium. The other options mix or reverse these layers, starting from the wrong end or jumbling the sequence, which breaks the established dependencies and responsibilities of the OSI model.