mld-snooping querier enable

Function

The mld-snooping querier enable command enables the MLD snooping querier in a VLAN.

The undo mld-snooping querier enable command disables the MLD snooping querier in a VLAN.

By default, the MLD snooping querier is disabled in a VLAN.

Format

mld-snooping querier enable

undo mld-snooping querier enable

Parameters

None.

Views

VLAN view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

On an MLD-capable network, a Layer 3 multicast device functions as the querier to send MLD Query messages and maintain group memberships on the local network segment. If the Layer 3 multicast device does not run MLD or it uses only static multicast forwarding entries, it cannot function as a querier. You can enable MLD snooping querier on the downstream Layer 2 device so that the device can act as a querier to send MLD Query messages.

On a Layer 2 network that has no Layer 3 devices, multicast sources are connected to Layer 2 devices. MLD snooping querier needs to be enabled on the Layer 2 devices so that they can maintain multicast group memberships.

Prerequisites

MLD snooping has been enabled globally using the mld-snooping enable command.

Follow-up Procedure

Perform the following operations as required on your network:

Set the interval at which the MLD snooping querier sends General Query messages using the mld-snooping query-interval command.
Set the interval at which the MLD snooping querier sends Multicast-Address-Specific Query messages using the mld-snooping last-listener-query-interval command.
Set the query count using the mld-snooping robust-count command.

Configuration Impact

The MLD snooping querier does not participate in MLD querier election. However, the MLD snooping querier on an MLD-capable multicast network may affect the election result, because the Query messages sent by the MLD snooping querier may have a smaller source IP address than the Query messages sent by other devices. Therefore, the MLD snooping querier function is not recommended on an MLD-enabled multicast network.

Precautions

The configuration takes effect only after you run the mld-snooping_enable command to enable MLD snooping in the VLAN.
The MLD snooping querier function cannot be enabled in a VLAN if the corresponding VLANIF interface has IPv6 Layer 3 multicast function (such as MLD and IPv6 PIM) enabled.
The MLD snooping querier function and MLD snooping proxy cannot be enabled in the same VLAN.
If multicast VLAN replication is configured, the MLD snooping querier function cannot be enabled in user VLANs.

Example

# Enable the MLD snooping querier in VLAN 3.

<HUAWEI> system-view
[HUAWEI] mld-snooping enable
[HUAWEI] vlan 3
[HUAWEI-vlan3] mld-snooping enable
[HUAWEI-vlan3] mld-snooping querier enable