timer query (IGMP)

Usage Scenario

An IGMP querier checks whether a local network segment has group members by sending IGMP General Query messages at an interval, known as the general query interval. You can set the general query interval based on needs of your network. The general query interval affects the following processes:

• When the querier starts, it sends General Query messages a certain number of 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.

• After the startup process is complete, the querier sends General Query messages at intervals to maintain the group memberships on the interface.

Prerequisites

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

Precautions

• The querier is more sensitive when it sends General Query messages at a shorter interval. However, more bandwidth and switch resources are consumed in this case.
• 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.