1-17z When the number of IPv6 multicast groups that can be joined on a port reaches the maximumnumber configured, the system deletes all the forwarding entries persistent to that port from theMLD Snooping forwarding table, and the hosts on this port need to join IPv6 multicast groupsagain.z If you have configured static or simulated joining on a port, however, when the number of IPv6multicast groups on the port exceeds the configured threshold, the system deletes all theforwarding entries persistent to that port from the MLD Snooping forwarding table and applies thestatic or simulated joining again, until the number of IPv6 multicast groups joined by the port comesback within the configured threshold.Configuring IPv6 Multicast Group ReplacementFor some special reasons, the number of IPv6 multicast groups passing through a switch or port mayexceed the number configured for the switch or the port. In addition, in some specific applications, anIPv6 multicast group newly joined on the switch needs to replace an existing IPv6 multicast groupautomatically. A typical example is “channel switching”, namely, by joining the new multicast group, auser automatically switches from the current IPv6 multicast group to the new one.To address this situation, you can enable the IPv6 multicast group replacement function on the switch orcertain ports. When the number of IPv6 multicast groups a switch or a port has joined exceeds the limit.z If the IPv6 multicast group replacement is enabled, the newly joined IPv6 multicast groupautomatically replaces an existing IPv6 multicast group with the lowest IPv6 address.z If the IPv6 multicast group replacement is not enabled, new MLD reports will be automaticallydiscarded.Configuring IPv6 multicast group replacement globallyFollow these steps to configure IPv6 multicast group replacement globally:To do... Use the command... RemarksEnter system view system-view —Enter MLD Snooping view mld-snooping —Enable IPv6 multicast groupreplacementoverflow-replace [ vlanvlan-list ]RequiredDisabled by default
