Ip Igmp Max-Groups - Cisco Catalyst 3750 Command Reference Manual

Chapter 2 Catalyst 3750 Switch Cisco IOS Commands

ip igmp max-groups

Use the ip igmp max-groups interface configuration command on the switch stack or on a standalone
switch 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
12.1(11)AX
12.1(19)EA1
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 routed ports, switch virtual interfaces (SVIs), or ports that
belong to an EtherChannel group.
Follow these guidelines when configuring the IGMP throttling action:
•
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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,
remove an randomly-selected entry in the forwarding table and add an entry for the next
IGMP group.
Modification
This command was introduced.
The action {deny | replace} keywords were added.
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.
Catalyst 3750 Switch Command Reference
ip igmp max-groups
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