Episode 13: OSI Layer 1 and Layer 2 — Physical and Data Link Layers

This episode examines the first two layers of the OSI model: the Physical Layer and the Data Link Layer. The Physical Layer is introduced as the foundation, responsible for transmitting raw bits across cables, fiber, or wireless signals. The Data Link Layer builds on this by handling framing, addressing with MAC addresses, and ensuring reliable delivery between directly connected devices. These layers define how data actually moves from one endpoint to another, making them central to both exam questions and practical troubleshooting.

Real-world examples are provided, such as identifying faulty cabling, mismatched duplex settings, or addressing conflicts at the MAC layer. The episode also explains how protocols like Ethernet operate at Layer 2 and how devices such as switches make forwarding decisions. These insights help you recognize the types of problems associated with the lower layers of the model and how to approach them systematically. By mastering Layer 1 and Layer 2, you strengthen your ability to diagnose physical and link-related issues in both exam scenarios and professional practice. Produced by BareMetalCyber.com, where you’ll find more cyber audio courses, books, and information to strengthen your certification path.