Which of the following is not a layer in OSI Model?

The correct answer is Process Layer. The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven distinct layers. The 'Process Layer' is not one of these standard layers. The OSI model layers are specifically defined to handle different aspects of network communication, from the physical transmission of data to the application-specific interactions.

• Physical Layer is Layer 1 of the OSI model. It deals with the physical connection between devices, including cables, connectors, voltage levels, and the raw transmission of bits.
• Transport Layer is Layer 4 of the OSI model. It is responsible for end-to-end communication between hosts, including segmentation, reassembly, flow control, and error handling for reliable data transfer (e.g., TCP, UDP).
• Network Layer is Layer 3 of the OSI model. It handles logical addressing (IP addresses), routing packets across different networks, and forwarding data between hosts that are not directly connected (e.g., IP).

The actual seven layers of the OSI model are Physical, Data Link, Network, Transport, Session, Presentation, and Application layers. The term 'Process Layer' does not align with this standardized structure.