Cisco Certified Network Associate (CCNA) Practice Exam

The booting sequence of a Cisco router consists of several key processes that help ensure the device starts up correctly. After the Power-On Self Test (POST) verifies that hardware components are functioning properly, the next critical step involves checking the configuration register. The configuration register is a 16-bit value that controls the router's boot process and various behaviors, such as how the router accesses the configuration file and whether it boots from flash memory or another specified source. By checking the configuration register after POST, the router determines the appropriate actions for booting, based on the value stored within it. This value can indicate to the router whether to boot from a default IOS image, a specific IOS file, or even a different startup method, such as loading from a TFTP server. In summary, confirming the configuration register is essential, as it sets the conditions for the subsequent steps in the booting process, ensuring that the router knows where to look for its operating system and configuration files. This pivotal role distinguishes it as the step that directly follows the POST operation.