Any positive and negative effect on the 3640 with the ip cef enabled?

[taolei]

Hello!

Would somebody tell me if enabling ip cef could lower CPU utilization on a 3640?

I f yes,what's the cost?

Thanks a lot !

[j.vanrooyen]

CEF will lower the util dependant on the actions of the router i.e . if you are running policy routing it forces the router to process switch and cef will have no effect. If however you are running straight forward routing i.e. Static or routing protocol it will lower the CPU util substantially. , for an example I have a 3640 routing ip as well as 12 channel digital voice and the util was touching on 70% without CEF.Once I enabled CEF it dropped to 15 % on a 5 minute average.

The availability of CEF is dependant on the IOS version . The command to enable is : ip cef