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Setting the IGMP last member query interval
A receiver host starts a report delay timer for a multicast group when it receives an IGMP
group-specific query for the group. This timer is set to a random value in the range of 0 to the
maximum response time advertised in the query. When the timer value decreases to 0, the host
sends an IGMP report to the group.
The IGMP last member query interval defines the maximum response time advertised in IGMP
group-specific queries. Set an appropriate value for the IGMP last member query interval to speed
up hosts' responses to IGMP group-specific queries and avoid IGMP report traffic bursts.
Configuration restrictions and guidelines
When you set the IGMP last member query interval, follow these restrictions and guidelines:
•
The Layer 2 device does not send an IGMP group-specific query if it receives an IGMP leave
message from a port enabled with fast-leave processing.
•
You can set the IGMP last member query interval globally for all VLANs in IGMP-snooping view
or for a VLAN in VLAN view. For a VLAN, the VLAN-specific configuration takes priority over the
global configuration.
Setting the IGMP last member query interval globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IGMP-snooping view.
igmp-snooping
N/A
3.
Set the IGMP last member
query interval globally.
last-member-query-interval
interval
The default setting is 1
second.
Setting the IGMP last member query interval in a VLAN
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter VLAN view.
vlan vlan-id
N/A
3.
Set the IGMP last member
query interval for the VLAN.
igmp-snooping
last-member-query-interval
interval
The default setting is 1
second.
Configuring IGMP snooping port features
Before you configure IGMP snooping port features, complete the following tasks:
•
Enable IGMP snooping for the VLAN.
•
Determine the aging timer for dynamic router ports.
•
Determine the aging timer for dynamic member ports.
•
Determine the addresses of the multicast group and multicast source.
Setting aging timers for dynamic ports
When you set aging timers for dynamic ports, follow these restrictions and guidelines:
•
If the memberships of multicast groups frequently change, you can set a relatively small value
for the aging timer of the dynamic member ports. If the memberships of multicast groups rarely
change, you can set a relatively large value.