Which command reloads the router?

The reload command, when executed in privileged EXEC mode on a Cisco IOS device, initiates a system reboot. This command halts the operating system, performs a hardware self-test, and then loads the saved startup configuration from Non-Volatile RAM (NVRAM) into memory as the new running configuration. If unsaved changes exist in the current running configuration, the system will prompt the user to save them before proceeding. This is the standard and direct command to restart a Cisco router or switch.

B. copy run start: This command saves the active (running) configuration to the startup configuration file in NVRAM, making changes persistent across reboots; it does not reload the device.

C. show version: This is a verification command that displays critical system information, including the IOS version, uptime, hardware details, and the configuration register value.

D. exit: This command is used to move down one level in the command hierarchy or to terminate a management session (e.g., SSH, Telnet).

1. Cisco Systems, Cisco IOS Configuration Fundamentals Command Reference, "reload" Command.

Reference: Under the reload command description, the document states, "To reload the operating system, use the reload command in privileged EXEC mode." This source directly confirms the function of the command.

2. Cisco Systems, Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2, "Managing Configuration Files" chapter.

Reference: In the section "Copying a Configuration File," the guide explains that the copy running-config startup-config command is used to "save the running configuration to NVRAM." This distinguishes its function from reloading the device.

3. University of Kentucky, College of Engineering, Introduction to the Cisco Router IOS, Lab Manual.

Reference: In the "Basic IOS Commands" section (typically in introductory labs), the manual describes reload as the command to "Restart the router." It also defines copy running-config startup-config for saving and show version for displaying system information, clearly separating their functions.