The OSI and TCP/IP models provide a layered approach to understanding how data is transmitted, received, and managed across networks. In this episode, we refresh your understanding of these models and their significance in network security. We explore the function of each layer—from physical cabling to application-level protocols—and explain how attacks and defenses map to specific layers. You’ll also learn how these models aid in troubleshooting, forensic analysis, and control implementation. Mastery of these foundational models helps CISSPs design and secure resilient networked systems.