IPS on 3640 router.

Just wanted to comfirm... I have 3 3640 routers and checked the cisco feature navigator to see if IPS is supported for my CCNA-S studies and couldn't find it. The closest thing I saw that I got was the 3660 router when searching with the feature "Intrusion Prevention System" Do I have to just resort to GNS for the IPS portion? Your input is appreciated.