3Com 10014298 manual By default, the interval is 1 second, Igmp lastmember-queryinterval, Seconds

Configuring IGMP 119

Configuring the Interval for Sending the IGMP Group-Specific Query Packet

In the shared network, where the same network segment includes multiple hosts and multicast routers, the query router is responsible for maintaining the IGMP group membership on the interface.

When the IGMP v2 host leaves a group, it sends an IGMP Group Leave message. When the IGMP query router receives the IGMP Leave message, it must send the IGMP group query message for the specified number of times ( the robust-valueparameter in the igmp robust-countcommand, with a default value of 2) in a specified time interval (the seconds parameter in the igmp lastmember-queryintervalcommand, with a default value of 1 second).

If other hosts, which are interested in the specified group, receive the IGMP query message from the IGMP query router, they send back the IGMP Membership Report message within the specified maximum response time interval. If the IGMP query router receives the IGMP Membership Report message within the defined period (equal to robust-valueseconds), it continues to maintain the membership of this group. When the IGMP query router receives no IGMP Membership Report messages from any host within the defined period, it perceives a timeout and stops membership maintenance for the group.

Perform the following configuration in VLAN interface view.

Table 123 Configure The Interval of Sending IGMP Group-Specific Query Packet

Operation	Command
Configure the interval of sending IGMP	igmp lastmember-queryinterval
Group-Specific Query packet	seconds
Restore the interval of sending IGMP	undo igmp
Group-Specific Query packet to the default	lastmember-queryinterval
value

By default, the interval is 1 second.

This command is only available on the IGMP query router running IGMP v2. For the host running IGMP v1, this command cannot take effect, because the host may not send the IGMP Leave message when it leaves a group.

Configuring the Interval for Sending IGMP Group-Specific Query Packet

In a shared network where the same network segment including multiple hosts and multicast routers, the query router is responsible for maintaining the IGMP group membership on the interface.

When the IGMP v2 host leaves a group, it sends a IGMP Leave message. When receiving the IGMP Leave message, IGMP query router must send the IGMP group query message for specified times (by the robust-value parameter in the igmp robust-count command, with default value as 2) in a specified time interval (by the seconds parameter in the igmp lastmember-queryinterval command, with default value as 1 second).

If other hosts, which are interested in the specified group, receive the IGMP query message from the IGMP query router, they will send back the IGMP Membership Report message within the specified maximum response time interval. If the IGMP