Why is flash memory erased prior to upgrading the IOS image from the TFTP server?
A. The router cannot verify that the Cisco IOS image currently in flash is valid. B. Flash memory on Cisco routers can contain only a single IOS image. C. Erasing current flash content is requested during the copy dialog. D. In order for the router to use the new image as the default, it must be the only IOS image in flash.
Correct Answer: C
During the copy process, the router asked “Erasing flash before copying? [confirm]” and the administrator confirmed (by pressing Enter) so the flash was deleted.
A Cisco router is booting and has just completed the POST process. It is now ready to find and load an IOS image. What function does the router perform next?
A. It checks the configuration register. B. It attempts to boot from a TFTP server. C. It loads the first image file in flash memory. D. It inspects the configuration file in NVRAM for boot instructions.
Correct Answer: A
Default (normal) Boot Sequence
Power on Router – Router does POST – Bootstrap starts IOS load – Check configuration register to see what mode the router should boot up in (usually 0x2102 to read startupconfig in NVRAM / or 0x2142 to start in “setup-mode”) – check the startup-config file in NVRAM for boot-system commands – load IOS from Flash.