Which approach is used to identify issues by examining each layer of the OSI model starting from Layer 1?

Identifying issues in a network by examining each layer of the OSI model starting from Layer 1 typically utilizes a bottom-to-top approach. This method begins with the physical layer, which is the foundation of network communication, and allows for a systematic troubleshooting process. By addressing potential problems at the lowest level first, technicians can ensure that the fundamental hardware components and their connectivity are functioning correctly before moving up through the layers.

Using the bottom-to-top approach, any problems encountered at Layer 1—such as issues with cabling, connectors, or physical devices—can be resolved. Once the foundational elements are verified, the technician can then examine Layer 2 for link-layer issues and continue upward through the OSI layers, up to Layer 7, where the application protocols reside. This methodical process helps in accurately pinpointing where within the stack issues may originate, ensuring that each layer is operational before advancing to the next.

While other approaches, like layered analysis, may involve reviewing each layer, the specific terminology of bottom-to-top directly reflects the starting point at Layer 1 and the progression that follows, making it the most fitting choice for the question posed.