2-25IGMP Snooping Querier ConfigurationNetwork requirementsz As shown in Figure 2-5, in a Layer 2–only network environment, two multicast sources Source 1and Source 2 send multicast data to multicast groups 224.1.1.1 and 225.1.1.1 respectively, Host Aand Host C are receivers of multicast group 224.1.1.1, while Host B and Host D are receivers ofmulticast group 225.1.1.1.z All the receivers are running IGMPv2, and all the switches need to run IGMP Snooping version 2.Switch A, which is close to the multicast sources, is chosen as the IGMP-Snooping querier.z To prevent flooding of unknown multicast traffic within the VLAN, it is required to configure all theswitches to drop unknown multicast data packets.z Because a switch does not enlist a port that has heard an IGMP query with a source IP address of0.0.0.0 (default) as a dynamic router port, configure a non-all-zero IP address as the source IPaddress of IGMP queries to ensure normal creation of Layer 2 multicast forwarding entries.Network diagramFigure 2-5 Network diagram for IGMP Snooping querier configurationConfiguration procedure1) Configure switch A# Enable IGMP Snooping globally. system-view[SwitchA] igmp-snooping[SwitchA-igmp-snooping] quit# Create VLAN 100 and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3 to the VLAN.[SwitchA] vlan 100[SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/3# Enable IGMP Snooping and the function of dropping unknown multicast traffic in VLAN 100.[SwitchA-vlan100] igmp-snooping enable[SwitchA-vlan100] igmp-snooping drop-unknown
