timer other-querier-present (IGMP)
Function
The timer other-querier-present command sets the other querier present timer.
The undo timer other-querier-present command restores the default value of the other querier present timer.
The formula used to calculate the other querier present timer value is:
Other querier present timer = Robustness variable x Interval for sending IGMP General Query messages + 1/2 x Maximum response time for IGMP query messages
If the robustness variable, the interval for sending IGMP General Query messages, and the maximum response time for IGMP Query messages all use default values, the other querier present timer value is 125 seconds.
Parameters
| Parameter | Description | Value |
|---|---|---|
| interval | Specifies the other querier present timer value. | The value is an integer that ranges from 60 to 300, in seconds. |
Usage Guidelines
Usage Scenario
When a user network segment connects to multiple Layer 3 multicast devices, only one Layer 3 multicast device is elected as the IGMP querier to send Query messages to hosts on the network segment. If the querier fails to send Query messages, group memberships cannot be created or maintained. Non-queriers running IGMPv2 or IGMPv3 start the other querier present timer after they fail in the querier election. If the non-queriers do not receive Query messages from the querier before the timer times out, they consider the querier failed and start a new querier election.
Prerequisites
IP multicast routing has been enabled using the multicast routing-enable command.
Precautions
- This command applies only to IGMPv2 and IGMPv3.
- This command has the same function as the igmp timer other-querier-present 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 the configuration in the interface view is not done.
If the other querier present timer value is shorter than the interval for sending IGMP General Query messages, the querier election is triggered frequently.