Configuration Example

Cisco router: determine amount of memory/flash

René Jorissen on January 22, 2010 2 Comments • Tags: #cisco #determine #dram #flash #memory #retrieve #router

Somebody asked me how he could determine the amount of DRAM and flash memory on a Cisco router. I always thought that everybody would know how to determine this information, but since this isn’t matter, I will tell you how you can determine the values.

You use the show version command to retrieve the requested information. Below you see an example output of the command on a Cisco 876 router.

Router#show version
Cisco IOS Software, C870 Software (C870-ADVIPSERVICESK9-M), Version 12.4(15)T6, RELEASE SOFTWARE (fc2)
If you require further assistance please contact us by sending email to

Cisco 876 (MPC8272) processor (revision 0x200) with 118784K/12288K bytes of memory.
Processor board ID FCZ121160T5
MPC8272 CPU Rev: Part Number 0xC, Mask Number 0x10
4 FastEthernet interfaces
1 ISDN Basic Rate interface
1 ATM interface
128K bytes of non-volatile configuration memory.
24576K bytes of processor board System flash (Intel Strataflash)

Configuration register is 0x2102

The first highlighted line tells you how much Dynamic RAM (DRAM) and Packet memory are installed in your router. Some platforms use a fraction of their DRAM as Packet memory. The memory requirements take this into account, so you have to add both numbers to find the amount of DRAM available on your router (from a memory requirement point of view).

Some types of routers have separate DRAM and Packet memory, so you only need to look at the first number. Other routers use a fraction of DRAM as Packet memory, so you need to add both numbers to find out the real amount of DRAM.

The second highlighted line tells you how much flash memory is installed in your router. This amount can also be determined by using the command show flash:.

Router#show flash:
24576K bytes of processor board System flash (Intel Strataflash)

Directory of flash:/

2  -rwx    18934284   Mar 1 2002 01:33:35 +01:00  c870-advipservicesk9-mz.124-15.T6.bin

23482368 bytes total (4542464 bytes free)

Maybe I can imagine why somebody doesn’t know where to look, because a show version actually gives you a lot of information. So I hope this posts helps all of you who don’t know where to look.

The following two tabs change content below.

René Jorissen

Co-owner and Solution Specialist at 4IP Solutions
René Jorissen works as Solution Specialist for 4IP in the Netherlands. Network Infrastructures are the primary focus. René works with equipment of multiple vendors, like Cisco, Aruba Networks, FortiNet, HP Networking, Juniper Networks, RSA SecurID, AeroHive, Microsoft and many more. René is Aruba Certified Edge Expert (ACEX #26), Aruba Certified Mobility Expert (ACMX #438), Aruba Certified ClearPass Expert (ACCX #725), Aruba Certified Design Expert (ACDX #760), CCNP R&S, FCNSP and Certified Ethical Hacker (CEF) certified. You can follow René on Twitter and LinkedIn.

Latest posts by René Jorissen (see all)

  1. Claudio says:

    The articule is very usefull, but I have some doubts about it: how can you know the available flash memory?
    What means “non-volatile configuration memory” and where is storaged?

Leave a comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.