igmp robust-count

Function

The igmp robust-count command sets a robustness variable for an IGMP querier on an interface.

The undo igmp robust-count command restores the default setting.

By default, the robustness variable of an IGMP querier is 2.

Format

igmp robust-count robust-value

undo igmp robust-count

Parameters

Parameter	Description	Value
robust-value	Specifies the robustness variable for an IGMP querier. It is the number of attempts to retransmit messages to compensate for packet loss.	The value is an integer ranging from 2 to 5.

Parameter

Description

Value

robust-value

Specifies the robustness variable for an IGMP querier. It is the number of attempts to retransmit messages to compensate for packet loss.

The value is an integer ranging from 2 to 5.

Views

100ge sub-interface view, 100GE interface view, 10GE sub-interface view, 10GE interface view, 200GE sub-interface view, 25GE sub-interface view, 25GE interface view, 400GE sub-interface view, 400GE interface view, 40GE sub-interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk sub-interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE sub-interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, Loopback interface view, PW-VE sub-interface view, Tunnel interface view, VBDIF interface view, VE sub-interface view, VLANIF interface view, Virtual template view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
igmp	write

Usage Guidelines

Usage Scenario

On a shared network segment where user hosts reside, the querier is responsible for maintaining IGMP group memberships. The robustness variable affects the timeout period of group memberships. The timeout period of a group membership is calculated by using the formula: Timeout period of a group membership = Interval for sending general IGMP query messages x Robustness variable + Maximum response time. The robustness variable defines the following values:

Number of times for sending general query messages when the querier starts
When the querier starts, it sends general query messages for the number of "robustness variable" times to query the multicast groups that have members on the attached network segment. The sending interval is 1/4 of the interval for sending general query messages. The interval for sending general query messages can be set by using the igmp timer query command or the timer query command.
Number of times for sending IGMPv2 or IGMPv3 group-specific query messages when the querier receives a Leave message
After receiving a Leave message for a group, the querier sends group-specific query messages continuously for the number of "robustness variable" times to check whether any other member of this group exists. The interval for sending group-specific query messages can be set by using the igmp lastmember-queryinterval command or the lastmember-queryinterval command.
Number of times for a querier to send group/source-specific query messages after receiving an IGMPv3 (S, G) Report message
After receiving a Report message for a multicast group corresponding to a source list, the querier sends group/source-specific query messages for the "robustness variable" times. The interval for sending group/source-specific query messages can be set by using the igmp lastmember-queryinterval command or the lastmember-queryinterval command.
The function of the igmp robust-count command is the same as the function of the robust-count command in the IGMP view. The configuration in the IGMP view is effective for all interfaces, whereas the configuration in the interface view is effective 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 the configuration in the interface view is not available.

Example

# On GE 0/1/0, set the robustness variable of an IGMP querier to 3.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] undo portswitch
[*HUAWEI-GigabitEthernet0/1/0] igmp robust-count 3