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Cisco 2811 router memory?


Hi to everybody,

We have 2 Cisco 2811 and we want to upgrade to the last IOS. The problem is these routers have 256MB  RAM and 64MB  flash.

Reading on 2811 router datasheet its said the the maximum allowed is :

Max DRAM: 768MB

Max FLASH: 256 MB

But on the new IOS information say that is recommended 1GBm RAM.

And the question is, We can really put 1GB RAM?


3 Replies 3

Alessio Andreoli

Hi Zamo,

the max DRAM will remain 768 MB and it is no use to install the 15.X IOS unless having very specific requirements like the full PFR features. I would like anyway to point out another issue you would face.. Your 2811 is a very nice well-built machine that is based on the previous generation of ISR hardware. The main memory on the 2900 series for example, is managed by a different set of hardware and you would not achieve the same result even if you could install 1GB of RAM on your 2811. At last let me give you two info more:

a) 12.4T(24) is a very brilliant rich-features IOS and i'd say you should consider it as a solution

b) I have many 2900 series working with even 15.2T and 512 MB RAM (NO BGP ON THEM!!!)

Take Care


If my understanding is correct, newer Call Manager releases can only be implemented in newer versions of IOS. CME8.6 or 9 for example which add a ton of new features.

I could be wrong, there is a lot of stuff you can pull off outside of what cisco recommends.

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

I've got some 2811 with 512 DRAM and they're loaded with15.1(1)T IOS since September 2010.  No problem.

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