lastmember-queryinterval (IGMP)

Function

The lastmember-queryinterval command configures interval at which an IGMP querier sends IGMP Group-Specific Query messages or IGMP Group-and-Source-Specific Query messages after receiving IGMP Leave messages from hosts.

The undo lastmember-queryinterval command restores the default value.

By default, the interval at which an IGMP querier sends IGMP Group-Specific Query messages or IGMP Group-and-Source-Specific Query messages is 1 second.

Format

lastmember-queryinterval interval

undo lastmember-queryinterval

Parameters

Parameter	Description	Value
interval	Specifies the interval for sending IGMP Group-Specific Query messages or IGMP Group-and-Source-Specific Query messages.	The value is an integer that ranges from 1 to 5, in seconds.

Views

IGMP view of the public network instance, IGMP view of a VPN instance

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

When the querier receives a Leave message that a host sends to leave a multicast group, the querier periodically sends IGMP Group-Specific Query messages or IGMP Group-and-Source-Specific Query messages to check for other members in the multicast group. The lastmember-queryinterval command sets the interval at which the querier sends Last Member Query messages. The querier stops forwarding multicast data to the group if it receives no Report message from the group within the period specified by interval x robust-value. Here, robust-value is the robustness variable configured using the igmp robust-count or robust-count command.

If the querier does not receive any Report message within the specified period, it considers that the last member has left the group and no longer maintains the membership of this group.

Prerequisites

IP multicast routing has been enabled using the multicast routing-enable command.

Precautions

The igmp lastmember-queryinterval command is valid only when the IGMP querier runs IGMPv2 or IGMPv3.
This command has the same function as the igmp lastmember-queryinterval command used in the interface view. The configuration in the IGMP view is globally valid, whereas the configuration in the interface view takes effect only for the specified interface. The configuration in the interface view takes precedence over the configuration in the IGMP view. The configuration in the IGMP view is used only when no configuration is performed in the interface view.

Example

# In the IGMP view, set the interval for sending IGMP Group-Specific Query messages or IGMP Group-and-Source-Specific Query messages to 3 seconds.

<HUAWEI> system-view
[HUAWEI] multicast routing-enable
[HUAWEI] igmp
[HUAWEI-igmp] lastmember-queryinterval 3