2-236Cisco Catalyst Blade Switch 3130 and 3032 for Dell Command ReferenceOL-13271-03Chapter 2 Cisco Catalyst Blade Switch 3130 and 3032 for Dell Cisco IOS Commandsip igmp snooping tcn floodip igmp snooping tcn floodUse the ip igmp snooping tcn flood interface configuration command on the switch stack or on astandalone switch to specify multicast flooding as the Internet Group Management Protocol (IGMP)snooping spanning-tree Topology Change Notification (TCN) behavior. Use the no form of thiscommand to disable the multicast flooding.ip igmp snooping tcn floodno ip igmp snooping tcn floodSyntax Description This command has no arguments or keywords.Defaults Multicast flooding is enabled on an interface during a spanning-tree TCN event.Command Modes Interface configurationCommand HistoryUsage Guidelines When the switch receives a TCN, multicast traffic is flooded to all the ports until two general queries arereceived. If the switch has many ports with attached hosts that are subscribed to different multicastgroups, the flooding might exceed the capacity of the link and cause packet loss.You can change the flooding query count by using the ip igmp snooping tcn flood query count countglobal configuration command.Examples This example shows how to disable the multicast flooding on an interface:Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# no ip igmp snooping tcn floodYou can verify your settings by entering the show ip igmp snooping privileged EXEC command.Related CommandsRelease Modification12.2(40)EX1 This command was introduced.Command Descriptionip igmp snooping Enables IGMP snooping on the switch or on a VLAN.ip igmp snooping tcn Configures the IGMP TCN behavior on the switch.show ip igmp snooping Displays the IGMP snooping configuration of the switch or the VLAN.
