1-21z For devices that support both drop-unknown and igmp-snooping drop-unknown commands atthe same time, the configuration made in IGMP snooping view and the configuration made in VLANview are mutually exclusive. Namely, after this function is enabled in IGMP snooping view, it cannotbe enabled or disabled in VLAN view, and vice versa.z Configurations made in IGMP snooping view are effective for all VLANs, while configurations madein VLAN view are effective only for ports belonging to the current VLAN.z If the function of dropping multicast packets is globally enabled in IGMP snooping view, multicastpackets sent to IGMP snooping-enabled VLANs are all dropped. The multicast packets mentionedhere include both multicast data packets and protocol packets, such as PIM, OSPF, and VRRPmessages.z After the function of dropping unknown multicast data packets is enabled in VLAN view, the switchforwards unknown multicast data packets to its router ports, if any, instead of flooding them in theVLAN. Otherwise, if no router ports exist, the switch drops these multicast data packets. Currently,the S7900E supports processing unknown multicast data packets destined for up to 2000 unknownmulticast addresses at a time. The switch floods excessive unknown multicast data packetsdirectly.z The S7900E supports the function of dropping unknown multicast data packets configuring in up to500 VLANs.Configuring IGMP Report SuppressionWhen a Layer 2 device receives an IGMP report from a multicast group member, the device forwardsthe message to the Layer 3 device directly connected with it. Thus, when multiple members of amulticast group are attached to the Layer 2 device, the Layer 3 device directly connected with it willreceive duplicate IGMP reports from these members.With the IGMP report suppression function enabled, within each query cycle, the Layer 2 deviceforwards only the first IGMP report per multicast group to the Layer 3 device and will not forward thesubsequent IGMP reports from the same multicast group to the Layer 3 device. This helps reduce thenumber of packets being transmitted over the network.Follow these steps to configure IGMP report suppression:To do... Use the command... RemarksEnter system view system-view —Enter IGMP snooping view igmp-snooping —Enable IGMP reportsuppression report-aggregation OptionalEnabled by default
