The question about sinkhole routing

[skytosky]

Hi, there.

I'm Alex. I have a question about sinkhole routing.

When I implement sinkhole routing using null interface, Does device's CPU utilization increase?

If yes, why does it increase?

Best Regards,

From R.O.K

Thank you~

[Richard Burts · Accepted solution]

When you talk about sinkhold routing I assume that you mean creating a route that will send undesirable traffic to the null interface.

If that is what you mean, then we need to understand your question about whether router CPU will increase as relative to what? To the extent that the router is making routing decisions there will be some CPU usage to make the routing decision. So, in absolute terms, yes the router CPU will go up if you configure sinkhold routing. But if we compare that to some other alternative such as creating an access list to discard the undesirable traffic it takes less CPU to make a routing desicion than it does to match against an access list.

So while sinkhold routing takes some CPU, it takes less CPU than most of the alternatives.

HTH

Rick