Cisco 2900 series routers, memory

[roncro]

Hello,

I don't know if this is the right place to ask; but let's see.

I have a Cisco 2911 router (and a 2951) and was wondering if adding memory would do any "good", as in higher performance?  

Also what type of memory modules does it take/use are they Cisco specific ones, or like with server/PCs  is there some sort of generic type?  (also, assuming memory is not limited in a license,  like what Oracle does with CPUs ?)

thanks,

Ron

[balaji.bandi]

what kind of performance issue you have. - what is the bandwidth you have on 2911.

you need to look the license also.

so please provide the below information :

show version

show license

the bandwidth you expect to support on this kit ?

[roncro]

Oh I don't have any performance issues, I wa more thinking like "why not".

So does the amount of memory one can use in a router, depend on the license? (How can I see that?)

The bandwidth is fine, I think, for what I use it for, at home.

Ron

[Joseph W. Doherty]

Generally, but not always, a small Cisco router's performance limited by the "speed" of its CPU.

When additional memory is of benefit, it's more as a resource to support features that require lots of RAM, one example, containing the full Internet route table, or multiple peer instances of it.  In these cases though, whatever feature(s) require large amounts of RAM also often require more CPU processing, so in that respect, overall performance might be actually "slowed".

[roncro]

Ok, I can see that.  I was more thinking in terms of maybe "caching"  traffic and tables, not that I expect there to be a lot.

Since, in general, prices of memory, nowadays are pretty low I figured, maybe it just helps.  (btw:  in Cisco terms it might be small, but works a heck of a lot better than wht one gets from providers for residential use.)

[Joseph W. Doherty]

Again, no, extra memory isn't going to help unless you're using a feature in a way that you're running out of memory.  That said, it's possible that additional RAM, to full capacity, might work like some PCs in that such RAM can be interleaved, but even on PCs, because of CPU caching, there's only minor benefit to overall performance.

Also keep in mind, generic memory is low cost, but if you find you need Cisco specific RAM, price might not be so low.

[Leo Laohoo]

Look at the license enabled on the router.  

sh license feature

Is the router ONLY doing routing? 

Is the router doing other "stuff" such as firewall or collaboration, like CUE? 

If the answer to the 2nd question are both "no", then extra DRAM will not many any difference.