IPv6 MLD Traffic and Data Forwarding

MLD traffic is forwarded as follows.

• MLD general queries received on a multicast-router interface are forwarded to all other interfaces in the VLAN or bridge domain.
• MLD group-specific queries received on a multicast-router interface are forwarded to only those interfaces in the VLAN or bridge domain that are members of the group.
• MLD reports received on a host interface are forwarded to multicast-router interfaces in the same VLAN or bridge domain, but not to the other host interfaces in the VLAN or bridge domain.
• All unrecognized multicast packets must be flooded on to all (STP) unblocked member ports of the VLAN or bridge domain to ensure that no data traffic is dropped.
• MLD reports with an EXCLUDE source list are not supported. Traffic are flooded for the source lists in EXCLUDE mode

Data forwarding rules ensure that the multicast traffic received at the switch is forwarded to all interested downstream port members. Forwarding rules are based on the Layer 3 multicast destination IP address.

• If a switch is already in a learned multicast group, multicast packets are forwarded only to those host interfaces in the VLAN or bridge domain that are members of the multicast group and to all multicast-router interfaces in the VLAN or bridge domain.
• If a switch is not in a learned multicast group (a group that has no current members), multicast packets are flooded to all member ports of the VLAN or bridge domain and to all multicast-router interfaces in the VLAN or bridge domain.