What is the correct order of the OSI layers starting from Layer 7 down to Layer 1?

The correct order of the OSI layers from Layer 7 down to Layer 1 is indeed Application, Presentation, Session, Transport, Network, Data Link, Physical. This reflects the standard model defined by the International Organization for Standardization (ISO), which categorizes network protocols and services into these distinct layers for better interoperability and understanding.

Starting from the topmost layer, Layer 7 (Application), it encompasses protocols that support application-level functions like HTTP, FTP, and others that interact directly with user applications. The Presentation layer, which is Layer 6, deals with data translation, encryption, and compression, ensuring that the data is presented in a readable format for the Application layer. Layer 5, the Session layer, manages sessions and controls the dialogues between computers.

Moving down, Layer 4 is the Transport layer, which is responsible for end-to-end communication and error correction. Layer 3, the Network layer, handles routing and forwarding of data packets. Layer 2, the Data Link layer, focuses on node-to-node data transfer and error detection in the physical layer. Finally, Layer 1, the Physical layer, refers to the physical connection between devices, which includes cables, switches, and the electrical signals used to transmit data.