The igmp lastmember-queryinterval command sets the interval for sending IGMP last member query messages when the IGMP querier on the interface receives a Leave message from a host.
The undo igmp lastmember-queryinterval command restores the default interval.
| Parameter | Description | Value |
|---|---|---|
| interval | Specifies the interval for the IGMP querier to send IGMP last member query messages. |
The value is an integer ranging from 1 to 5, in seconds. |
By default, the interval for sending IGMP last member query messages is 1 second.
IGMPv3 supports a last member query, also known as a group-specific query.
The shared network segment where the host resides may be connected to multiple multicast FWs. These multicast FWs automatically select a router to act as a querier. This querier is responsible for maintaining IGMP memberships on the interface.
When the querier receives a Leave message for a certain group, it continuously sends group-specific query messages to determine whether any other members of this group exist. The interval for sending group-specific query messages can be set using either the igmp lastmember-queryinterval command or the lastmember-queryinterval command. The number of times group-specific query messages can be sent, also known as robust-value, can be set using either the igmp robust-count command or the robust-count command.
If a member of this group exists on the network segment, the member is required to send a Report message during the maximum response time.
If the querier receives a Report message from the host within the period calculated by multiplying robust-value by robust-value, the querier continues to maintain memberships for this group. Otherwise, the querier thinks that no members of this group exist on the network segment and no longer maintains memberships for this group.
Except for the function range, the function of this command is the same as that of the lastmember-queryinterval command used in the IGMP view. The configuration in the IGMP view is globally valid in the instance, whereas the configuration in the interface view is valid only for the current interface. The system prefers the configuration in the interface view. The configuration in the IGMP view is used only when the configuration in the interface view is incomplete.
You must run the multicast routing-enable command to enable the multicast function before using the command.