Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
OL-8566-02
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
ip igmp max-groups
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 return to the default settings.
ip igmp max-groups {number | action {deny | replace}}
no ip igmp max-groups {number | action}
Syntax Description
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
Usage Guidelines You can use this command only on Layer 2 physical interfaces and on logical EtherChannel interfaces.
You cannot set IGMP maximum groups or configure the IGMP throttling action for routed ports, switch
virtual interfaces (SVIs), or ports that belong to an EtherChannel group.
Follow these guidelines when configuring the IGMP throttling action:
• 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 and 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.
number The maximum number of IGMP groups that an interface can join. The range is 0 to
4294967294. The default is no limit.
action deny When the maximum number of entries is in the IGMP snooping forwarding table, drop
the next IGMP join report. This is the default action.
action
replace
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.
Release Modification
12.1(8)EA1 This command was introduced.
12.1(19)EA1 The action {deny | replace} keywords were added.