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Desing a QoS Wan Router


I need design a edge wan router for QoS for the main office in which concentrate 30 remote sites,  the QoS polices are very specific, so whitch are the guide lines to choose this router?

Thanks in avance for your help

7 Replies 7

Rising star
Rising star

What is the aggregate bandwith inbound from all sites ?

How many physical links  will be supporting the aggregate inbound,

What kind of traffic flows are you anticipating?

Hi sorry for

There are 150 remote sites and limiting the bw per site whit QoS policies, one interface to LAN and the other to conect the mpls

So the problem is one 3825 taht concentrate all trafic and runs in 90 - 99% of cpu usage, cisco tac say the problem was the QoS policies (very especific), or the 3825 is small to support this traffic.

what can i do to choose the correct router that support all this trafic?

If you want y can send the show runn config,

Thanks a lot

The 38xx might be a bit small for that much processing. Take a look at the ASR1004 or 7200.

If your QOS configs are that complex, maybe there is a way to streamline them.

Do you have a desig guide or somethink to verfu that?

start here

I'm just basing my choice on the info provided. its less science and more art.

In your case, we already know there is a lot of QOS processing at the head end. that tells me you need a heavy duty

processor. You have 150 sites coming in over a wan. I don't know what transport you ar using, but If I assume traditional WAN

you need a device that is geared to that environment.

you also need to consider redundancy, life span of the device, all sorts of stuff thats specific to your envrornment.


It's a mpls wan and the router (3845) receive 80mbps and 160 remote sites (over mpls), without policies applied the process was 12% aprox  and when the policy map is applied to the wan interface, the proccess cpu is 50% to 60% but in 15 minutes or less the process is 97%.

The coustomer needs a document who explain why the actual 3845 is to small for the actual traffic described behind.

I'd pull the data sheets for the router, and potential replacements. the issue seems to be hitting the qos policy and getting process switched.

look at the forwarding rates, and any details on how fast they process swich.

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