Saturday, April 3, 2010


File management on Cisco devices revolves around the copy command. There are three primary components in a Cisco device:
RAM - Runs very fast! The running-config, packet queues and so on are stored in the RAM. The RAM is volatile and will be wiped when power goes out.

NVRAM - Very small and slow. It is typically used to store the startup-config. NVRAM is typically just large enough to store a configuration and some certificates.

Flash - This is large. Typically the flash is used for storing the IOS. During boot, the IOS is decompressed and stored in the RAM.

Files are transferred in and out of the device typically through the TFTP protocol. TFTP stands for Trivial File Transfer Protocol. TFTP operates on UDP 69. You can set up a TFTP server using a program like TFTPD32.

Typically we save the configuration by typing:
copy running-config startup-config

The copy command follows the syntax:

You can actually copy a configuration to a TFTP server like this:
copy running-config tftp:// should be the address of your TFTP server. We can also copy an IOS in and out of a router through:
copy flash:c2801-adventerprisek9-mz.124-4.XC.bin tftp://

To copy an IOS back into the flash, use:
copy tftp:// flash:c2801-adventerprisek9-mz.124-4.XC.bin

When copying things into the running-configuration, it MERGES and replaces direct conflicts. It does not clear out commands that doesn't exist in the startup-config.

Your router can actually boot up from a TFTP server for testing before actually replacing the IOS. To do this, type:
boot system tftp://

Once we know that an IOS works, we can then replace the IOS with the one in the router.

No comments :

Post a Comment