Filter
Top Products
1-29
Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
OL-11497-03
Chapter 1 Product Overview
Route Processors
SDRAM
SDRAM stores routing tables, protocols, and network accounting applications,
and runs the Cisco IOS software. The default PRP configuration includes 512 MB
of error checking and correction (ECC) SDRAM. DIMM upgrades of 512 MB and
1 GB are available. You cannot mix memory sizes. If two DIMMS are installed,
they must be the same memory size.
Caution Cisco Systems strongly recommends that you use only Cisco-approved memory.
To prevent memory problems, SDRAM DIMMs must be +3.3 VDC,
PC133-compliant devices. Do not attempt to install other devices in the DIMM
sockets.
SRAM
SRAM provides 2 MB of parity-protected, secondary CPU cache memory. It acts
as a staging area for routing table updates and for information sent to and received
from line cards. SRAM is not user configurable and cannot be upgraded in the
field.
NVRAM
NVRAM provides 2 MB of memory for system configuration files, software
configuration register settings, and environmental monitoring logs. This
information is backed up with built-in lithium batteries that retain the contents for
a minimum of 5 years. NVRAM is not user configurable and cannot be upgraded
in the field.
Flash Memory
Flash memory allows 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 then can 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. The
onboard Flash memory (called bootflash) contains the Cisco IOS boot image, and