Configure IGMP snooping Querier

If there is no L3 multicast device in the network, it cannot realize the related functions of the IGMP querier. To solve the problem, you can configure the IGMP snooping querier on the L2 multicast device to realize the IGMP querier function so that L2 multicast device can set up and maintain multicast forwarding entry, so as to forward multicast service packets normally.

Configuration Condition

Before configuring the basic functions of IGMP snooping querier, first complete the following task:

• Enable global and VLAN IGMP snooping function

Enable IGMP snooping Querier

You should first enable the IGMP snooping querier function so that the configuration of the other features of the querier can take effect.

Table 2-5 Enable IGMP snooping querier

Configure Querier IP Address

The querier configured with IP address takes part in the election of the IGMP querier in VLAN and the querier fills the IP address in the source IP address field of the sent IGMP group query packet.

Table 2-6 Configure querier IP address

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  When the querier IP address is not configured, the default source IP address of the querier is 0.0.0.0, but the querier does not send the IGMP group query packet with source IP address 0.0.0.0.

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Configure Query Interval of General Group

IGMP querier periodically sends the query packets of the general group to maintain the group member relation. You can modify the interval of sending the IGMP general group query packets according to the actuality of the network. For example, if the configured general group query interval is long, it can reduce the number of the IGMP protocol packets in the network, avoiding the network congestion.

Table 2-7 Configure query interval of general group

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  In the same VLAN, the configured query interval of the general group should be larger than the maximum response time. Otherwise, the configuration cannot succeed.

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Configure Max. Response Time

The general group query packet sent by IGMPv2 querier contains the maximum response time field. The multicast receiver sends the member report packets within the maximum response interval.

Table 2-8 Configure the maximum response time

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  In one VLAN, the configured maximum response time should be smaller than the query interval of the general group. Otherwise, the configuration cannot succeed.

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Configure Query Interval of Specified Group

When the IGMP querier receives the leave packet of one multicast group, it sends the query packet of the specified group to query the segment for the multicast group, so as to know whether the subnet has the member of the multicast group. If not receiving the member report packet of the multicast group after waiting for “last life period”, delete the information of the multicast group.

Table 2-9 Configure query interval of specified group

Configure Fast Leave

If the device receives the leave packet of one multicast group after configuring fast leave, the device does not send the query packet of the specified group to the port any more and the information of the multicast group is deleted at once.

Table 2-10 Configure fast leave

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  There are multiple receivers of the same multicast group in the device port at the same time. When the port receives the IGMP leave packet of the multicast group sent by one receiver and if fast leave is configured in the VLAN of the device port, the multicast services of the other receivers are interrupted.

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