The igmp-snooping lastmember-queryinterval command sets the last member query interval in a VLAN, that is, the interval at which Group-Specific Query messages are sent in the VLAN.
The undo igmp-snooping lastmember-queryinterval command restores the default last member query interval in a VLAN.
By default, Group-Specific Query messages are sent in a VLAN at intervals of 1 second.
igmp-snooping lastmember-queryinterval lastmember-queryinterval
undo igmp-snooping lastmember-queryinterval
Parameter |
Description |
Value |
|---|---|---|
lastmember-queryinterval |
Specifies the interval at which IGMP Group-Specific Query messages are sent. |
The value is an integer that ranges from 1 to 5, in seconds. |
Usage Scenario
By setting the last member query interval, you can:
Configure the switch to send IGMP Group-Specific Query messages at intervals when the querier function is enabled.
Change the aging time of multicast group member ports.
When the switch receives an IGMP Leave message from a host, the switch starts the aging timer for the corresponding member port. The aging time is calculated using the following formula: Aging time = Last member query interval x Last member query count. The igmp-snooping lastmember-queryinterval command sets the last member query interval. The last member query count is set by the igmp-snooping robust-count command.
If the switch (querier) receives Report messages from other hosts within the aging time, it continues to maintain memberships of the multicast group. If the switch does not receive any Report messages within the aging time, it stops maintaining memberships of the multicast group.
Prerequisites
IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.
Precautions
The switch sets the maximum response time field in the Group-Specific Query message to the configured last member query interval. Therefore, the maximum response time for Group-Specific Query messages is the same as the interval at which Group-Specific Query messages are sent.
IGMP snooping is enabled in the VLAN using the igmp-snooping enable (VLAN view) command.
The IGMP message version is set to v2 or v3 messages in the VLAN. (Hosts running IGMPv1 do not send Leave messages when they leave a multicast group.)