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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 20 Configuring IGMP Snooping and MVR
Configuring IGMP Filtering and Throttling
Beginning in privileged EXEC mode, follow these steps to set the maximum number of IGMP groups in
the forwarding table:
To remove the maximum group limitation and return to the default of no maximum, use the no ip igmp
max-groups interface configuration command.
This example shows how to limit to 25 the number of IGMP groups that an interface can join.
Switch(config)# interface fastethernet0/12
Switch(config-if)# ip igmp max-groups 25
Switch(config-if)# end
Switch# show running-config interface fastethernet0/12
Building configuration...
Current configuration : 123 bytes
!
interface FastEthernet0/12
no ip address
shutdown
snmp trap link-status
ip igmp max-groups 25
ip igmp filter 4
end
Configuring the IGMP Throttling Action
After you set the maximum number of IGMP groups that a Layer 2 interface can join, you can configure
an interface to remove a randomly selected multicast entry in the forwarding table and to add the next
IGMP group to it by using the ip igmp max-groups action replace interface configuration command.
Use the no form of this command to return to the default, which is to drop the IGMP join report.
Follow these guidelines when configuring the IGMP throttling action:
•
This restriction can be applied to Layer 2 ports only; you can use this command on a logical
EtherChannel interface but cannot use it on ports that belong to an EtherChannel port group.
•
When the maximum group limitation is set to the default (no maximum), entering the ip igmp
max-groups action {deny | replace} command has no effect.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and enter the physical interface to
configure, for example gigabitethernet0/1. The interface can be a
Layer 2 port that does not belong to an EtherChannel group or a
EtherChannel interface.
Step 3
ip igmp max-groups number
Set the maximum number of IGMP groups that the interface can join.
The range is from 0 to 4294967294. The default is to have no maximum
set.
Step 4
end
Return to privileged EXEC mode.
Step 5
show running-configuration interface
interface-id
Verify the configuration.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.