6
Overview of Cisco 2800 Series Routers
OL-5783-01
Hardware Features
Memory
Cisco 2800 series routers contain the following types of memory:
•DRAM—Stores the running configuration and routing tables and is used for packet buffering by the
network interfaces. Cisco IOS software executes from DRAM memory.
•Boot/NVRAM—Internal flash memory. Stores the bootstrap program (ROM monitor), the
configuration register, and the startup configuration.
•Flash memory—External flash memory. Stores the operating system software image.
Table 3 summarizes the memory options for Cisco 2800 series routers. The default memory numbers for
RAM represent the minimum usable memory. You can install additional RAM in multiples of the default
amount, up to the maximum amount.
Table3 Router Memory Specifications
Router
Platform DRAM Boot/NVRAM Flash Memory
Cisco 2801 Type—SDRAM DIMM
DIMM sizes—64 MB, 128 MB, 256 MB
DIMM expansion slots—11
Default onboard memory—128 MB
Maximum memory—384 MB
1. Cisco 2801 routers have 128 MB of SDRAM soldered onto the system board. You can install a DIMM into the expansion slot
to increase memory to the maximum of 384 MB.
Internal 4-MB
flash memory
External CompactFlash
memory cards of the
following optional
sizes:
•64 MB (default)
•128 MB
Cisco 2811 Type—ECC DDR (error-correcting code,
double data rate) SDRAM DIMM
DIMM sizes—256 MB, 512 MB
DIMM slots—2
Default onboard memory— none
Default memory—256 MB
Maximum memory—768 MB2
2. Cisco 2811 routers can accept one 256 MB and one 512 MB DIMM to provide 768 MB of usable memory.
Internal 2-MB
flash memory
External CompactFlash
memory cards of the
following optional
sizes:
•64 MB (default)
•128 MB
•256 MB
Cisco 2821 Type—ECC DDR (error-correcting code,
double data rate) DRAM DIMM
DIMM sizes—256 MB, 512 MB
DIMM slots—2
Default onboard memory— none
Default memory—256 MB
Maximum memory—1024 MB3
3. Cisco 2851 routers can accept two 512 MB DIMMs to provide 1024 MB of usable memory.
Cisco 2851