03-24-2010, 06:01 PM
IGMP runs on routers; IGMP snooping runs on layer 2 switches.
http://www.ciscosystems.com/en/US/docs/switches/lan/catalyst4500/12.1/8aew/configuration/guide/multi.pdf
http://www.ciscosystems.com/en/US/docs/switches/lan/catalyst4500/12.1/8aew/configuration/guide/multi.pdf