Security must be applied across all layers of a system, from the physical infrastructure to the application interface. In this episode, we explore the layered nature of system architecture—starting with the OSI model’s seven layers, then expanding into how security is applied at the hardware, system, and application levels. You’ll learn how to align controls with each layer’s function, recognize common threats at each level, and understand how layered defenses provide coverage across the stack. This foundational knowledge helps you design and evaluate more secure system architectures.