Sub-VLAN-based multicast VLAN
As shown in Figure 23:
Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.
On Switch B, VLAN 10 is a multicast VLAN. VLAN 2 through VLAN 4 are sub-VLANs of VLAN 10.
IGMP snooping is enabled for the multicast VLAN and its sub-VLANs.
Figure 23: Sub-VLAN-based multicast VLAN
IGMP snooping manages router ports in the multicast VLAN and member ports in each sub-VLAN. When Switch A receives multicast data from the multicast source, it sends only one copy of the multicast data to the multicast VLAN on Switch B. Then, Switch B sends a separate copy to each sub-VLAN in the multicast VLAN.