igmp-snooping querier enable

Function

The igmp-snooping querier enable command enables the IGMP snooping querier function in a VLAN.

The undo igmp-snooping querier enable command disables the IGMP snooping querier function in a VLAN.

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

Format

igmp-snooping querier enable

undo igmp-snooping querier enable

Parameters

None

Views

VLAN view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

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

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

Prerequisites

IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.

Follow-up Procedure

Perform the following operations as required on your network:

Run the igmp-snooping query-interval command to set the interval at which General Query messages are sent.
Run the igmp-snooping lastmember-queryinterval command to set the interval at which Group-Specific Query messages are sent.
Run the igmp-snooping robust-count command to set the number of times Query messages are sent.

Configuration Impact

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

Precautions

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

Example

# Enable the querier function in VLAN 3.

<HUAWEI> system-view
[HUAWEI] igmp-snooping enable
[HUAWEI] vlan 3
[HUAWEI-vlan3] igmp-snooping enable
[HUAWEI-vlan3] igmp-snooping querier enable
Warning: Please confirm that no other querier is configured on the network, otherwise this command may cause querier re-election, continue? [Y/N]:y