Since I am planning certain network I am wondering if following case would work regarding multicast and Q-in-Q: There are 3rd party access devices which perform Q-in-Q on end user traffic. Traffic is further aggregated to Cisco Metro Ethernet network. All traffic will be double taged except multicast. Double taged traffic will have S-VLAN ethertype 0x88a8 and C-VLAN ethertype 0x8100. The question is if Cisco devices like ME6524, 6500 or at least ES20 can perform IGMP and IGMP snooping on single VLAN traffic that has only S-VLAN ethertype 0x88a8 tag. There is NO C-VLAN of 0x8100.