Cisco IOS Boot System Image

[lagapidis (Lazarus Agapidis)]

Hello Hany.

I believe I answered that in the previous post. The quick answer is yes, Here is an excerpt of my previous answer.

@lagapidis

Switches follow a similar but not identical process. During bootup, switches will first search for an IOS image based on the BOOT environment variable which is set using the boot system global configuration mode command similar to routers. If this variable is not set, the switch only searches its own flash file system by performing a recursive, depth-first search throughout all of the directory structures found there. If an IOS is still not found, the switch will run a low level IOS stored in its ROM called Rom Monitor or ROMMON. It does not search a TFTP server for the IOS.

If however you want to force your switch to use an IOS image that is stored on a TFTP server on the network during bootup, you can configure the BOOT environment variable in order to do so. Specifically, you can configure the command boot system tftp filename [ip-address] so that at each bootup, the IOS image found there will be downloaded and loaded into RAM. More information about this command can be found under the command boot system at Cisco’s command reference.

Just to clarify, configuration registers do not play a role in this procedure.

I hope this has been helpful!

Laz