HP 6125XLG R2306-HP 6125XLG Blade Switch IP Multicast Configuration Guide - Page 109

report message, the switch resolves the IPv6 multicast group address in the report and looks up the ACL. If a match is found to permit the port that received the report to join the IPv6 multicast group, the switch creates an MLD snooping forwarding entry for the IPv6 multicast group and adds the port to the forwarding entry. Otherwise, the switch drops this report message, in which case, the IPv6 multicast data for the IPv6 multicast group is not sent to this port, and the user cannot retrieve the program. A switch does not forward an MLD report through a non-router port. If the switch forwards a report through a member port, the MLD report suppression mechanism causes all attached hosts that monitor the reported IPv6 multicast group address to suppress their own reports. In this case, the switch cannot determine whether the reported IPv6 multicast group still has active members attached to that port. For more information about the MLD report suppression mechanism, see "Configuring MLD." Done message When a host leaves an IPv6 multicast group, the host sends an MLD done message to the multicast routers. When the switch receives the MLD done message on a dynamic member port, the switch first examines whether a forwarding entry matches the IPv6 multicast group address in the message, and, if a match is found, determines whether the forwarding entry contains the dynamic member port. • If no forwarding entry matches the IPv6 multicast group address, or if the forwarding entry does not contain the port, the switch directly discards the MLD done message. • If a forwarding entry matches the IPv6 multicast group address and contains the port, the switch forwards the done message to all router ports in the VLAN. Because the switch does not know whether any other hosts attached to the port are still listening to that IPv6 multicast group address, the switch does not immediately remove the port from the forwarding entry for that group. Instead, it restarts the aging timer for the port. After receiving the MLD done message, the MLD querier resolves the IPv6 multicast group address in the message and sends an MLD multicast-address-specific query to the IPv6 multicast group through the port that received the done message. After receiving the MLD multicast-address-specific query, the switch forwards it through all its router ports in the VLAN and all member ports of the IPv6 multicast group. The switch also performs the following action for the port that received the MLD done message: • If the port (assuming that it is a dynamic member port) receives an MLD report in response to the MLD multicast-address-specific query before its aging timer expires, it means that some host attached to the port is receiving or expecting to receive IPv6 multicast data for that IPv6 multicast group. The switch adjusts the aging timer for the port. • If the port receives no MLD report in response to the MLD multicast-address-specific query before its aging timer expires, it means that no hosts attached to the port are still monitoring that IPv6 multicast group address. The switch removes the port from the forwarding entry for the IPv6 multicast group after the aging timer for the port expires. Protocols and standards RFC 4541, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches 102