Users Guide

Layer 2 Switching Commands 526
multicast packets received in the VLAN. This behavior can be used to ensure
that IGMP snooping will selectively forward IPv4 multicast data traffic in a
VLAN even if no dynamically discovered IPv4 multicast router has been
discovered.
Multicast data plane traffic from multicast sources in a VLAN is always
forwarded to the mrouter ports in the VLAN. Multicast control plane packets
(those addressed to the reserved 224.0.0.X address) are always flooded to all
ports in the VLAN, regardless of whether an mrouter port is defined or not.
Example
console(config)#ip igmp snooping vlan 10 mrouter interface Gi1/0/2