Tuning for input and output drops

SPD and Input-queue tuning for input drops and flushes
http://www.cisco.com/en/US/products/hw/routers/ps167/products_tech_note09186a008012fb87.shtml
http://www.cisco.com/web/about/security/intelligence/spd.html

Queue-limit tuning for output drops

http://www.cisco.com/en/US/products/hw/routers/ps341/products_tech_note09186a0080af893d.shtml
http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/12simql.html