Ip Igmp Snooping Tcn Flood - Cisco Catalyst 3550 Command Reference Manual

Multilayer switch

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ip igmp snooping tcn flood

Use the ip igmp snooping tcn flood interface configuration command to specify multicast flooding as

the Internet Group Management Protocol (IGMP) snooping spanning-tree Topology Change

Notification (TCN) behavior. Use the no form of this command to disable the multicast flooding.

Syntax Description

This command has no arguments or keywords.

Multicast flooding is enabled on an interface during a spanning-tree TCN event.

Command Modes

Interface configuration

Command History

Usage Guidelines

When the switch receives a TCN, multicast traffic is flooded to all the ports until two general queries

are received. If the switch has many ports with attached hosts that are subscribed to different multicast

groups, 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 count

global configuration command.

This example shows how to disable the multicast flooding on an interface:

Switch(config)# interface gigabitethernet0/2

Switch(config-if)# no ip igmp snooping tcn flood

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

ip igmp snooping

ip igmp snooping tcn

show ip igmp snooping

Catalyst 3550 Multilayer Switch Command Reference

ip igmp snooping tcn flood

no ip igmp snooping tcn flood

Modification

This command was introduced.

Enables IGMP snooping on the switch or on a VLAN.

Configures the IGMP TCN behavior on the switch.

Displays the IGMP snooping configuration of the switch or the VLAN.

Catalyst 3550 Switch Cisco IOS Commands

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