G.988-201210: 9.3.27 Multicast operations profile, Attribute: Upstream IGMP tag control. This attribute controls the upstream IGMP TCI attribute. If this attribute is not pass-through, a possible extended VLAN tagging operation ME is ignored for upstream frames containing IGMP/MLD packets. Value Meaning 1 G.988 Value 0. Pass upstream IGMP/MLD traffic transparently, neither adding, stripping nor modifying tags that may be present. 2 G.988 Value 1. Add a VLAN tag (including P bits) to upstream IGMP/MLD traffic. The tag is specified by the upstream IGMP TCI attribute. 3 G.988 Value 2. Replace the entire TCI (VLAN ID plus P bits) on upstream IGMP/MLD traffic. The new tag is specified by the upstream IGMP/MLD TCI attribute. If the received IGMP/MLD traffic is untagged, an add operation is performed. 4 G.988 Value 3. Replace only the VLAN ID on upstream IGMP/MLD traffic, retaining the original DEI and P bits. The new VLAN ID is specified by the VLAN ID field of the upstream IGMP TCI attribute. If the received IGMP/MLD traffic is untagged, an add operation is performed, with DEI and P bits also taken from the upstream IGMP TCI attribute.