IGMP Snooping Querier Configuration
As shown in
and Source 2 send multicast data to multicast groups 18.104.22.168 and 22.214.171.124 respectively, Host A
and Host C are receivers of multicast group 126.96.36.199, while Host B and Host D are receivers of
multicast group 188.8.131.52.
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.
To prevent flooding of unknown multicast traffic within the VLAN, it is required to configure all the
switches to drop unknown multicast data packets.
Because a switch does not enlist a port that has heard an IGMP query with a source IP address of
0.0.0.0 (default) as a dynamic router port, configure a non-all-zero IP address as the source IP
address of IGMP queries to ensure normal creation of Layer 2 multicast forwarding entries.
Figure 1-5 Network diagram for IGMP Snooping querier configuration
Configure switch A
# Enable IGMP Snooping globally.
# 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
1-5, in a Layer 2–only network environment, two multicast sources Source 1