Ip Igmp Max-Groups - Cisco Catalyst 3030 Command Reference Manual

Chapter 2 Cisco Catalyst Blade Switch 3030 Cisco IOS Commands

ip igmp max-groups

Use the ip igmp max-groups interface configuration command to set the maximum number of Internet
Group Management Protocol (IGMP) groups that a Layer 2 interface can join or to configure the IGMP
throttling action when the maximum number of entries is in the forwarding table. Use the no form of this
command to set the maximum back to the default, which is to have no maximum limit, or to return to the
default throttling action, which is to drop the report.
Syntax Description
number
action deny
action
replace
Defaults The default maximum number of groups is no limit.
After the switch learns the maximum number of IGMP group entries on an interface, the default
throttling action is to drop the next IGMP report that the interface receives and to not add an entry for
the IGMP group to the interface.
Command Modes Interface configuration
Command History Release
12.2(25)SEE
Usage Guidelines
You can use this command only on Layer 2 physical interfaces and on logical EtherChannel interfaces.
You cannot set IGMP maximum groups for ports that belong to an EtherChannel group.
Follow these guidelines when configuring the IGMP throttling action:
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•
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ip igmp max-groups {number | action {deny | replace}}
no ip igmp max-groups {number | action}
The maximum number of IGMP groups that an interface can join. The range is 0 to
4294967294. The default is no limit.
When the maximum number of entries is in the IGMP snooping forwarding table, drop
the next IGMP join report. This is the default action.
When the maximum number of entries is in the IGMP snooping forwarding table,
replace the existing group with the new group for which the IGMP report was received.
Modification
This command was introduced.
If you configure the throttling action as deny and set the maximum group limitation, the entries that
were previously in the forwarding table are not removed but are aged out. After these entries are
aged out, when the maximum number of entries is in the forwarding table, the switch drops the next
IGMP report received on the interface.
If you configure the throttling action as replace and set the maximum group limitation, the entries
that were previously in the forwarding table are removed. When the maximum number of entries is
in the forwarding table, the switch replaces a randomly selected multicast entry with the received
IGMP report.
When the maximum group limitation is set to the default (no maximum), entering the ip igmp
max-groups {deny | replace} command has no effect.
Cisco Catalyst Blade Switch 3030 Command Reference
ip igmp max-groups
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