Managing Startup Files and IOS Images

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There are four areas to consider when managing the startup files.

There are two types of configuration files we need to pay attention in CCNA test: the running-config and the startup-config. The running-config file is stored in RAM. The startup-config file is stored in NVRAM. The running-config is used when the router is running, when the router is turned off, the running-config file is erased from the RAM. When the router boot up, the startup-config file is loaded from the NVRAM to the RAM as the running-config. The flash is where the IOS image is stored in a compress file, (.bin) and sometimes different IOS are stored on the flash.  A good reason for this is if you are running one version, and want to upgrade, keep the older one on there as well.  If you upgrade, and find that for some reason it don’t work, like being corrupted, then you can reload the older one.

There are a few commands used to show the contents of different router memory.

• show version -- displays the configuration of the system hardware and the software information


• show running-config -- show the contents in the RAM


• show startup-config -- show the contents in the NVRAM


• show flash -- show the contents in the flash memory


• copy running-config startup-config -- copy the running-config file from the RAM to the startup-config file in the NVRAM

The IOS image is stored in flash. Flash memory is saved even when the device is turned off. By default, this is the location the IOS image load from. However there are other locations the IOS image can be loaded from.

boot system flash

Specify flash memory as the boot location.

boot system tftp

Specify network server as the boot location.

boot system ROM

Specify the ROM as the boot location. This is a special IOS Image called MINI-IOS or RXBOOT, which is a smaller, scale down version of the actual IOS image file. MINI-ISO is used for upgrading the system, diagnostic and trouble-shooting purposes.

To backup the IOS Image located in the flash memory, use the command "copy flash tftp". The router will ask for the IP address of the tftp server and the file name of the file located in the flash, then copy the IOS Image from the flash to the tftp server.

To upgrade the IOS Image, use the command "copy tftp flash", the router will prompt you to input the IP address of the tftp server and the file name of the file located in the tftp server, then copy the IOS Image from the tftp server to the flash memory.