H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 60)

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switched only at Layer-2 and no Layer 3 multicast devices are present, the Layer 2 device sends MLD
queries, so that multicast forwarding entries can be established and maintained at the data link layer.
To enable the MLD snooping querier:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter VLAN view. vlan vlan-id N/A
3. Enable the MLD snooping
querier.
mld-snooping querier Disabled by default
IMPORTANT:
It is meaningless to configure an MLD snooping querier in an IPv6 multicast network that runs MLD.
Although an MLD snooping querier does not participate in MLD querier elections, it might affect MLD
querier elections because it sends MLD general queries with a low source IPv6 address.
Configuring MLD queries and responses
You can set the MLD general query interval based on actual condition of the network.
After receiving an MLD query (general query or multicast-address-specific query), a host starts a timer for
each IPv6 multicast group it has joined. This timer is initialized to a random value in the range of 0 to the
maximum response time (the host obtains the value of the maximum response time from the Max
Response Time field in the MLD query it received). When the timer value comes down to 0, the host sends
an MLD report to the corresponding IPv6 multicast group.
An appropriate setting of the maximum response time for MLD queries allows hosts to respond to queries
quickly and avoids bursts of MLD traffic on the network caused by reports simultaneously sent by a large
number of hosts when the corresponding timers expire simultaneously.
• For MLD general queries, you can configure the maximum response time to fill the Max Response
time field.
• For MLD multicast-address-specific queries, you can configure the MLD last-member query interval
to fill the Max Response time field. Namely, for MLD multicast-address-specific queries, the
maximum response time equals to the MLD last-member query interval.
CAUTION:
Make sure that the MLD query interval is greater than the maximum response time for MLD general
queries. Otherwise, undesired deletion of IPv6 multicast members might occur.
Configuring MLD queries and responses globally
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter MLD-snooping view. mld-snooping N/A
3. Set the maximum response
time for MLD general queries. max-response-time interval
10 seconds by default
4. Set the MLD last-member
query interval.
last-listener-query-interval interval 1 second by default