# OSI Layers ![OSI Model by Layers](/files/yHKn6aYE72BMQYMautev) {% embed url="" %} ### **Physical Layer (Layer 1)** Deals with the physical connection between devices, including the transmission and reception of raw bit streams over physical media such as cables or wireless. ### **Data Link Layer (Layer 2)** Responsible for creating a reliable link between two directly connected nodes, addressing errors in the physical layer and ensuring a consistent flow of data. ### **Network Layer (Layer 3)** Manages the routing of data packets between devices on different networks. It addresses logical addressing and determines the best path for data to reach its destination. ### **Transport Layer (Layer 4)** Ensures reliable data transfer between devices across a network. It handles end-to-end communication, error recovery, and flow control. ### **Session Layer (Layer 5)** Establishes, maintains, and terminates connections between applications. It manages sessions, allowing for data exchange and synchronization between applications on different devices. ### **Presentation Layer (Layer 6)** Handles data translation, encryption, and compression, ensuring that the data sent from the application layer of one system can be properly read by the application layer of another. ### **Application Layer (Layer 7)** Provides network services directly to end-users or applications. It enables communication between software applications, including functions like file transfers, email, and remote login. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://ejpt-certification.certs-study.com/networking/osi-layers.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.