What is the first step a Cisco device goes through when powered on?

When a Cisco device is powered on, it initiates a sequence of processes starting with the Power-On Self-Test (POST). This step is critical as it ensures that the hardware components of the device, such as the CPU, memory, and interfaces, are functioning correctly before the device attempts to load its operating system. During the POST, the device checks for any hardware malfunctions and verifies that all necessary components are operational. If any issues are detected during this process, the device will typically indicate a failure, preventing it from proceeding further.

Following the successful completion of the POST, the device can then move on to the next stages, such as executing the bootstrap code, loading the operating system image, and ultimately loading the configuration file. It is important for the initial hardware checks, like POST, to be completed successfully to ensure the reliability and stability of the Cisco device's subsequent operations.