This is important in case the brain of the router (the IOS software image) becomes corrupted or accidentally erased.

One of those maintenance operations that will use a filesystem is the backing up, restore and upgrades of IOS images. Flash is flash: and TFTP is tftp: The directory location and file names are also conventions and standards on their IFS. So NVRAM is called nvram: RAM can be referenced using the system keyword. So when copying files from RAM, for example, the running configuration into NVRAM or flash or even backing them up in a TFTP server, you will be able to reference them using URL prefixes that are common and consistent. This includes the use of the same type of URLs to reference and copy to and from the various locations. The good thing about IOS is that it uses the Cisco IFS feature or IOS filesystem to provide a single consistent interface to all the filesystems that the Cisco router uses. You may do it extensively if you are using the network heavily for centralizing your configuration files and IOS images. In managing your Cisco device, you will be transporting and copying files from location to location. We will learn how to use commands like copy to change the location of those components and also use troubleshooting commands like show and debug to monitor and verify the process.

Cisco tftp server commands