Which OSI layer is identified as Layer 5 in the model?

• A. Application Layer
• B. Network Layer
• C. Session Layer
• D. Presentation Layer

Answer: (C)

Layer 5 in the OSI model is the Session Layer. This layer is responsible for establishing, maintaining, and terminating communication sessions between applications. It also manages dialog control—deciding which party can send data at a given time—and can provide synchronization points (checkpoints) within a data stream to recover from interruptions.

For context, the layers above and below: Layer 4 is the Transport Layer, which handles end-to-end data delivery and reliability; Layer 6 is the Presentation Layer, which deals with data format, encryption, and compression; Layer 7 is the Application Layer, which provides network services directly to software applications. The Network Layer, Layer 3, handles routing and addressing.