AppendixA Technical Specifications
Product Architecture
A-16
Cisco 12404 Internet Router Installation and Configuration Guide
OL-11636-01
NVRAM
The system configuration, software configuration register settings, and
environmental monitoring logs are contained in the 2 MB NVRAM, which is
backed up with built-in lithium batteries that retain the contents for a minimum of
five years. NVRAM is not able to be upgraded or configured
Caution Before you replace the PRP in the system, back up the running configuration to a
Trivial File Transfer Protocol (TFTP) file server or an installed Flash memory
card so you can retrieve it later.
If the configuration is not saved, the entire configuration will be lost inside the
NVRAM on the removed PRP and you will have to reenter the entire
configuration manually.
This procedure is not necessary if you are temporarily removing a PRP; lithium
batteries retain the configuration in memory until you replace the PRP in the
router.
Flash Memory
Both the onboard and PCMCIA card-based Flash memory allow you to remotely
load and store multiple Cisco IOS software and microcode images. You can
download a new image over the network or from a local server and then add the
new image to Flash memory or replace the existing files. You can then boot the
routers either manually or automatically from any of the stored images. Flash
memory also functions as a TFTP server to allow other servers to boot remotely
from stored images or to copy them into their own Flash memory.