timer query (IGMP)
Function
The timer query command sets a global interval for sending IGMP General Query messages.
The undo timer query command restores the default interval for sending IGMP General Query messages.
By default, the interval for sending IGMP General Query messages is 60 seconds.
Parameters
Parameter | Description | Value |
---|---|---|
interval | Specifies the interval for sending IGMP General Query messages | The value is an integer that ranges from 1 to 18000, in seconds. |
Usage Guidelines
Usage Scenario
A user network segment may be connected to multiple multicast devices. The multicast devices elect a querier to maintain group memberships on interfaces. The timeout interval of group memberships is calculated using the following formula:
Timeout interval of group memberships = Interval for sending IGMP General Query messages x Robustness variable + Maximum response time
When the querier starts, it sends General Query messages certain times specified by the robustness variable to query members of multicast groups. The message sending interval during this process is 1/4 of the interval for sending General Query messages. The robustness variable is configured using the igmp robust-count or robust-count command.
The querier then sends General Query messages at configured intervals to maintain the memberships on interfaces.
Prerequisites
Multicast routing has been enabled using the multicast routing-enable command.
Configuration Impact
The querier is more sensitive when it sends General Query messages at a shorter interval. However, more bandwidth and wireless access controller resources are consumed in this case.
Precautions
This command has the same function as the igmp timer query 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.