mld-snooping robust-count

Function

The mld-snooping robust-count command sets the MLD robustness variable in a VLAN.

The undo mld-snooping robust-count command restores the default MLD robustness variable in a VLAN.

By default, the MLD robustness variable in a VLAN is 2.

mld-snooping robust-count robust-count

undo mld-snooping robust-count

Parameter	Description	Value
robust-count	Specifies the MLD robustness variable.	The value is an integer that ranges from 2 to 5.

VLAN view

2: Configuration level

Usage Scenario

Setting MLD snooping parameters helps improve the multicast forwarding performance. By setting the MLD robustness variable, you can:

Set the last listener query count for the querier to prevent packet loss.

When receiving an MLD Done message of a multicast group, the querier sends Multicast-Address-Specific Query messages a certain number of times specified by the robustness variable to check whether the multicast has members. If the quality of transmission links is low, increase the MLD robustness variable.
Change the aging time of member ports.

When receiving an MLD Report message from a host, the switch starts the aging timer for the corresponding member port. The aging time is calculated using the following formula: Aging time = MLD robustness variable x General query interval + Maximum response time for General Query messages. The mld-snooping robust-count command sets the MLD robustness variable.

Prerequisites

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

Follow-up Procedure

Perform the following operations to optimize multicast service performance:

Run the mld-snooping query-interval command to set the interval at which General Query messages are sent.
Run the mld-snooping max-response-time command to set the maximum response time for General Query messages.
Run the mld-snooping last-listener-query-interval command to set the interval at which Multicast-Address-Specific Query messages are sent.

Precautions

The configuration takes effect only after you run the mld-snooping_enable command to enable MLD snooping in the VLAN.

# Set the robustness variable to 5 in VLAN 3.

<HUAWEI> system-view
[HUAWEI] mld-snooping enable
[HUAWEI] vlan 3
[HUAWEI-vlan3] mld-snooping enable
[HUAWEI-vlan3] mld-snooping robust-count 5