What router should we consider as a next step up from a 3825?

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Jan 27th, 2009
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We currently have a 3825 that was used for a T3 connection to the Internet, and the 3825 did a fine job. We have since upgraded the Internet link to a tiered gigabit link, on which we have currently contract for 100Mb. During peak busy periods, we are receiving 80-90Mbps of traffic from the Internet and cpu goes to about 50% processing all this incoming traffic. We will be increasing the bandwidth on the gigabit Internet link, probably to 200 Mb, then 400, and possible up to 1Gb as our Internet demands increase and I'm pretty sure the 3825 won't work for us anymore. What router would be able to handle such high throughput requirements. Other features that we would need to use on the router are nbar, netflow, qos, and very large access lists.

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Leo Laohoo Tue, 01/27/2009 - 20:42
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You're probably looking at a 720X VXR or (if the pockets are deep enough) the new ASR 1000's.

If you want a quick information about the ASR, check this link out:


Note: The ASR's are very, very noisy.

Joseph W. Doherty Wed, 01/28/2009 - 05:35
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Agree with Leo, for the bandwidth you might upgrade to, the faster 7200VXRs or the ASR would be suitable platforms.

Other choices might be the 7300 series with a NSE, or a 6500/7600 with the right WAN card (not a LAN card).


At least on the 7200 platform, the later IOSs offer a new feature, complied ACLs, which is supposed to mitigate the performance impact of large ACLs.

CHRISTINE BERNS Thu, 01/29/2009 - 06:34
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Would a 7201 be suitable? Since we really only need 2 interfaces, one gigabit RJ45 to the inside, and one single mode fiber connection to the ISP, the 1RU size is attractive.

Joseph W. Doherty Thu, 01/29/2009 - 09:43
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It may since it also uses the fastest 7200 NPE engine, the G2.

Attached is a reference sheet which provides performance information for various Cisco routers. (While looking at the numbers, don't forget to allow for forwarding duplex traffic, additional CPU for other processing, and some CPU headroom.)


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