To configure an MLD querier, you can configure the MLD prompt leave function and set the following parameters: interval at which general query messages are sent, robustness variable, maximum response time of Query messages, keepalive time of other MLD queriers, and interval MLD last-listener query messages are sent.
Usage Scenario
Interfaces that connect multicast devices to the same user network segment must have the same MLD parameter configurations; otherwise, these multicast devices fail to communicate.
An MLD querier is responsible for periodically sending MLD Query messages on a shared network segment to update group memberships. You can configure parameters of an MLD querier either globally or on an interface.
- Global configuration: takes effect on all interfaces.
- Interface-specific configuration: takes precedence over the global configuration. If an interface-specific configuration is not available, the interface uses the global configuration.
During the configuration, ensure that the interval for sending general query messages is greater than the maximum response time of Query messages but smaller than the keepalive time of other MLD queriers.
Pre-configuration Tasks
Before configuring an MLD querier, complete the following tasks:
Procedure
- Configure an MLD querier globally.
- Run system-view
The system view is displayed.
- Run mld
The MLD view is displayed.
- Run timer query interval
The interval at which the device sends general query messages is set.
- Run robust-count robust-value
An MLD robustness variable is set.
When the router starts, the router sends general query messages for the number of robust-value times. The sending interval is 1/4 of the interval for sending MLD general query messages.
After receiving a Done message, the router sends last-listener query messages for the number of robust-value times. The sending interval is set by using the lastlistener-query interval command.
- Run max-response-time interval
The maximum response time of MLD Query messages is set.
- Run timer other-querier-present interval
The keepalive time of other MLD queriers is set.
- Run lastlistener-queryinterval interval
The interval at which the device sends MLD last-listener query messages is set.
- Run commit
The configuration is committed.
- Configure an MLD querier on an interface.
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The interface view is displayed.
- Run mld timer query interval
The interval at which the interface sends general query messages is set.
- Run mld max-response-time interval
The maximum response time of MLD Query messages is set.
- Run mld timer other-querier-present interval
The keepalive time of other MLD queriers is set.
- Run mld robust-count robust-value
An MLD robustness variable is set.
- Run mld lastlistener-queryinterval interval
The interval at which the interface sends MLD last-listener query messages is set.
- Run mld prompt-leave [ group-policy { basic-acl6-number | acl6-name acl6-name } ]
The MLD prompt leave function is configured on the interface.
- Run commit
The configuration is committed.