My company has ~400 users. I use a 2801 router to route traffic between vlans ('cause we just have some layer 2 catalysts and this router) and nat for internet access. Our network model looks like this: IPS -> Router -> users. On subinterfaces, I've already used:
no ip redirects
no ip unreachables
no ip proxy-arp
But the cpu usage still goes high around 70~80%.
Do u have any ideas to reduce the cpu usage?
Is the 2801 being used for IP phones as well?
Have you turned off all debugging?
HTH, Please rate if so.