Configure MLD snooping Querier

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

Configuration Condition

Before configuring the basic functions of MLD snooping, first complete the following tasks:

• Enable global and VLAN MLD snooping function.

Enable MLD snooping Querier

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

Table 10-5 Enable the MLD snooping querier

Configure IPv6 Address of the Querier

The querier configured with IPv6 address takes part in the election of the MLD querier in VLAN and the querier fills the IPv6 address in the source IPv6 address field of the sent MLD group query packet.

Table 10-6 Configure the IPv6 address of the querier

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  When the querier IPv6 address is not configured, the default source IPv6 address of the querier is 0::0, but the querier does not send the MLD group query packet with source IPv6 address 0.0.0.0.

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Configure Query Interval of General Group

MLD querier periodically sends the query packets of the general group to maintain the group member relation. You can modify the interval of sending the MLD 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 MLD protocol packets in the network, avoiding the network congestion.

Table 10-7 Configure the query interval of the general group

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  In one VLAN, the configured query interval of the general group should be larger than the maximum response time. Otherwise, the configuration will fail.

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Configure Max. Response Time

The general group query packet sent by MLD querier contains the maximum response time field. The multicast receiver sends the member report packets within the maximum response interval. If the multicast receiver does not send the member report packets within the maximum response time, the device regards that the subnet does not have the receiver of the multicast group, and then, deletes the multicast group information at once.

Table 10-8 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 will fail.

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Configure Query Interval of Specified Group

When the MLD 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 “maximum response time”, delete the information of the multicast group.

Table 10-9 Configure the query interval of the 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 10-10 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 MLD 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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