Maintaining Your Cisco Router Memory

Maintaining Your Cisco Router Memory

It is important that you know how to maintain and use the different types of router memory. In order to use the following advice, make sure your router is configured to allow you to interact with the system software. See the user guide for your specific platform on using the setup command facility and on using setup for first time startup. This is only meant to be a vague overview. You should also have a basic knowledge of the different types of router memory: DRAM, Flash, EPROM, and NVRAM.

One such function you should be acquainted with is how to relocate DRAM router memory on Cisco 3600 routers. This particular memory is organized as one address space divided between processor and I/O memory. There are cases when you’ll have to manually relocate the memory between the two. This process may be accomplished by utilizing the ‘memory size iomem’ command. Using this command, you can allocate 60 percent of the address space to processor memory, and 40 percent to I/O memory. You can use the ‘show version’ command in order to view the total amount of memory located on the server.

If you have a Flash B system, odds are you can partition banks of router memory into separate logical devices in order to maintain 2 or more software images. This will permit you to write to one portion of the flash memory while running software in another bank of flash memory. In order to do this you must have at least 2 sets of four chips available. There are many benefits to doing this. For example, it provides a simpler way of managing files, can download a new image into one Flash memory bank while an image is being executed from another, and because the partitioned system can support the same image twice, if one of the copies gets lost or destroyed you will still have another copy.

The last function to be discussed is how to Flash Load Helper to upgrade software. Flash Load Helper is a software option that allows you to upgrade software on run-from-Flash systems that only have a single bank of router memory. You can download a file using Flash Load Helper using the commands: ‘copy tftp: flash:,’ ‘copy rcp: flash:,’ and ‘copy ftp: flash:.’ Next to Monitor the Flash Load Helper, you can use the ‘more flh: logfile’ command. If you are using a remote Telnet device without a console connection, this method will allow you to output even when your Telnet device is disconnected.