Layers of the OSI Model and Their Functions

During a Network Engineer L1 interview, you may be asked about the OSI model. The OSI model is a conceptual framework used to understand how different networking protocols work together in a network. It is divided into seven layers, each serving a specific function:

1. Physical Layer: Deals with the physical connection between devices. It transmits raw data bits over a physical medium.
2. Data Link Layer: Handles error detection and correction. It also defines how devices access the network and control data flow.
3. Network Layer: Responsible for routing and forwarding data packets between different networks. It determines the best path for data to travel.
4. Transport Layer: Ensures data transfer between devices is reliable and error-free. It segments and reassembles data into packets.
5. Session Layer: Establishes, manages, and terminates communication sessions between devices.
6. Presentation Layer: Translates, encrypts, and compresses data for efficient transmission between devices.
7. Application Layer: Interacts directly with software applications. It enables user interfaces and network services.

Understanding the functions of each OSI layer is crucial for network engineers to troubleshoot network issues effectively and deploy network solutions efficiently.