Choosing a router 2900 or 3900

[Mokhalil82]

I require 2 x Cisco router for a large office that currently is using cisco 2821's. We have no issues with the current routers but as we have budget and are upgrading the LAN, we can afford to replace the routers also

I am trying to see what the best replacement routers I can use.

I want to spec both routers for 3 x 1G links, and I was thinking of either choosing the 2911 or 2921 but more towards the 2921 as it offers SFP connectivity. I have seen Cisco now pushing the 4000 series and not sure if that is the way to go but assuming they will be pricey

Does anyone have any recommendations?

Thanks

[Karsten Iwen]

I would go for the 4k as they are the more recent models and will probably be supported much longer than the ISR G2 (2900, 3900).

[Mokhalil82]

So if I go for a 3451, which has a throughput rating of 400mbps. I plan to connect the router into a 1G point to point circuit. Does the router throughput rating have anything in common with the links I plan to connect the router to. 

For example will the bandwidth over the link be limited to 400mbps because of the router??

[Karsten Iwen]

Yes, they will be limited. But with the Performance-License, the limit can be lifted when your throughput needs grow.

Edit: Just realized for your mentioned 4351: 400 MBit is the throughput with performance-license. It's 200 MBit without.

[Mokhalil82]

Thankyou all for the useful information. Looking at the longer term I may opt for the 4351 with the performance license

[Joseph W. Doherty · Accepted solution]

Very much so!

As Karsten has noted, the 4Ks are licensed for performance.  Also unlike a 2900 or 3900 where maximum performance varies much based on your traffic mix and device configuration, the 4K license caps are set (often well) below the device's actual maximum performance.  This to try to insure the device can always meet its maximum performance regardless of the traffic mix or its configuration.

If you're looking to support a gig link, the 2900 or 3900 series aren't really suitable.  Before the ASRs and 4Ks, that kind of bandwidth was a 7200 or 7300 series router.

Even a maxed out 4351 might be boarder line.  The low end ASR 1Ks, though, are suitable for gig.  (Unfortunately if you were worried about 4K prices, the ASR 1K prices will be a bit of shock.)

[Karsten Iwen]

One more thing to be aware of: The 4k still doesn't support SSL/TLS-VPN with AnyConnect (unless it's added in the very newest image).

[Julio E. Moisa]

Hi

I prefer Cisco router 4000 series, but it depends of your requirements, costs, growth plan, etc, Also the following link can help you to take a decision:

http://3c3cc.com/c/dam/assets/prod/routers/cisco-router-selector/index.html

Hope it is useful. 

[Joseph W. Doherty]

In addition to what the other posters have noted, you might not find the new 4K series as pricey as you might assume, especially as with newer models you can often downsize the model to obtain similar performance.

Additionally, if the 29xx and 39xx series are not announced EoL, I wouldn't expect them to remain so for too much longer.

[Sam Smiley]

Here is an old performance comparison for the Cisco routers; this doesn't include the 4K series. This will at least give you something to compare in relation to your 2821s.

Cheers,
Sam