Configuring the Querier Function
The querier function enables a device to send Query messages for its upstream device and respond to Multicast Listener Discovery (MLD) messages sent from downstream devices.
Context
There is an MLD-capable Layer 3 multicast device acting as a querier on a multicast network. The querier sends MLD Query messages to create and maintain multicast forwarding entries for normal multicast data forwarding.
- MLD messages sent from the Layer 3 device cannot reach a downstream Layer 2 device.
- Multicast forwarding entries on the Layer 3 device are statically configured and do not need to be dynamically learned.
To solve these issues, configure the querier function on the Layer 2 device so that it can create and maintain multicast forwarding entries at the data link layer, ensuring normal multicast data forwarding. The querier parameters can be set as required.
Procedure
- Run system-view
The system view is displayed.
- Perform either of the following operations based on the
VLAN or VPLS networking scenario:
- Run the vlan vlan-id command to enter the VLAN view.
- Run the vsi vsi-name [ static ] command to enter the VSI view.
- Run mld-snooping enable
MLD snooping is enabled for the VLAN or VSI.
- Run mld-snooping querier enable
The querier function is enabled.
- (Optional) Run mld-snooping querier-election
The querier election function is enabled, so that the device can participate in querier election.
If the querier function is enabled on multiple devices in a VSI or VLAN, querier election needs to be enabled. The elected querier is used to send Query messages to user hosts.
- (Optional) Set querier parameters.
Run mld-snooping query-interval query-interval
The interval at which a querier sends general Query messages is set.
Run mld-snooping robust-count robust-count
The number of group-specific Query messages to be sent is set.
Run mld-snooping max-response-time max-response-time
The maximum time for a querier to wait for responses from downstream hosts is set.
The maximum wait time must be shorter than the interval at which general Query messages are sent.
Run mld-snooping lastmember-queryinterval lastmember-queryinterval
The interval at which a querier sends group-specific Query messages or source-and group-specific Query messages is set.
- Run commit
The configuration is committed.
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