G.988-201210: 9.3.27 Multicast operations profile, Attribute: Downstream IGMP and multicast TCI(first byte). This attribute controls the downstream tagging of both the IGMP/MLD and multicast frames. If this attribute is not 1, a possible extended VLAN tagging operation ME is ignored for downstream IGMP/MLD and multicast frames. Value Meaning 1 G.988 Value 0 Pass the downstream IGMP/MLD and multicast traffic transparently, neither stripping nor modifying tags that may be present. 2 G.988 Value 1 Strip the outer VLAN tag (including P bits) from the downstream IGMP/MLD and multicast traffic. 3 G.988 Value 2 Add a tag onto the downstream IGMP/MLD and multicast traffic. The new tag is specified by gponOnuIgmpDownstreamTagControl. 4 G.988 Value 3 Replace the tag on the downstream IGMP/MLD and multicast traffic. The new tag is specified by gponOnuIgmpDownstreamTagControl. 5 G.988 Value 4 Replace only the VLAN ID on the downstream IGMP/MLD and multicast traffic, retaining the original DEI and P bits. The new VLAN ID is specified by gponOnuIgmpDownstreamTagControl.