03-18-2009 06:59 AM - edited 03-04-2019 03:59 AM
All,
I have a 20mb DS3 that's getting installed at a remote branch. We have a 20mb DS3 circuit here as well, and we don't want the remote branch being able to suck down all of our bandwidth.
I can shape the traffic on the outside interface for the remote branch, but if I shaped it from 20mb to 3mb, would that take a major hit on the routers cpu? It's a DR site, and the only time we want them to be able to use 20mb is if we had to go over there because of a DR situation. The router is a 3745, and there are about 100 users at this location.
Thanks,
John
03-18-2009 07:33 AM
That should not impact the CPU that much to be honest.
HTH>
03-18-2009 08:56 AM
John
Shaping does incur extra CPU overhead but it is really quite minimal and if adding shaping to the router has a major impact on CPU then you probably need a better router anyway.
With what you have you should be fine.
Jon
03-18-2009 09:04 AM
Thanks :)
03-18-2009 09:55 AM
Which exact type of circuit is that? If p-t-p DS3 you can use dsu commands to limit bandwidth.
03-18-2009 10:11 AM
As the others have noted, yes you could and CPU is (usually) minimal. (re: usually, I've noticed on the later 12.4T versions, the default Tc now appears to be 4ms and I've seen such a minimal value impact the CPU. [If it does, increasing Tc appears to reduce CPU impact.])
PS:
As an alternative, instead of always limiting the bandwidth to the remote site, you could also consider using something like CBWFQ with a 15% bandwidth setting. This should also provide 3 Mbps but will allow more if not otherwise being used.
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