1721 flash memory question

[Russell Starr]

I was wondering what the difference was between the 1720 and the 1721, but I quickly found this answer after some research. The problem is that I found some conflicting information.

According to this following document,

http://www.cisco.com/application/pdf/en/us/guest/products/ps223/c1079/ccmigration_09186a0080147795.pdf

... the max you can have for flash memory on your 1721 is 16M. I have a 1721 that reports 32M of flash memory. Am I correct to assume that the reason behind this is because the 1721 uses "Dual Bank Flash Memory" as desribed in the following page:

http://www.cisco.com/application/pdf/en/us/guest/products/ps223/c1079/ccmigration_09186a0080147795.pdf

I guess it has double, but only half is usable because the other half is for redundancy?

Please clarify.

[thomas.chen]

The Cisco 1721 is a modular router. Whereas 1720 is a fixed one. What this means is that you can add new hardware to the slots that are available on a modular router. Thats the reason you are seeing 32M of flash. Its not for redundancy but that 16M was upgraded to 32M because it is a modular router.