configuration for drop packets

hi All,

is there any way to configure explicit packet dropping in IOS ?
can drop packet by count ? (e.g. every 5 packet drop 2 etc)

e.g.
need to drop 20% of ICMP or any other type of packets going through router
interface ?

i have used QDISC based packet drooping using NETEM. This must be possible
with IOS.

thankx a lot

-- 
Nahskur Udniraht
Blogs and organic groups at http://www.ccie.net