Cisco Catalyst 4500 Series - Displaying IGMP Snooping Information

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 28 Configuring IGMP Snooping and Filtering, and MVR
Displaying IGMP Snooping Information
To establish an IGMP query threshold, perform this task:
This example shows how to modify the switch to stop flooding multicast traffic after four queries:
Switch(config)# ip igmp snooping tcn flood query count 4
Switch(config)# end
Switch#
When a spanning tree root switch receives a topology change in an IGMP snooping-enabled VLAN, the
switch issues a query solicitation that causes an Cisco IOS router to send out one or more general
queries. The new command ip igmp snooping tcn query solicit causes the switch to send the query
solicitation whenever it notices a topology change, even if that switch is not the spanning tree root.
This command operates at the global configuration level.
By default, query solicitation is disabled unless the switch is the spanning tree root. The default keyword
restores the default behavior.
To direct a switch to send a query solicitation, perform this task:
This example shows how to configure the switch to send a query solicitation upon detecting a TCN:
Switch(config)# ip igmp snooping tcn query solicit
Switch(config)# end
Switch#
Displaying IGMP Snooping Information
The following sections show how to display IGMP snooping information:
• Displaying Querier Information, page 28-15
• Displaying IGMP Host Membership Information, page 28-15
• Displaying Group Information, page 28-16
• Displaying Multicast Router Interfaces, page 28-17
Command Purpose
Step 1
Switch(config)#
ip igmp snooping tcn flood query count <n>
Modifies the number of IGMP queries the switch waits
for before it stops flooding multicast traffic.
To return the switch to the default number of IGMP
queries, enter this command:
default ip igmp snooping tcn flood query count.
Step 2
Switch(config)# end
Exits configuration mode.
Command Purpose
Step 1
Switch(config)# ip igmp snooping tcn query
solicit
Configures the switch to send a query solicitation when
a TCN is detected.
To stop the switch from sending a query solicitation (if
it is not a spanning tree root switch), enter the
no ip igmp snooping tcn query solicit command.
Step 2
Switch(config)# end
Exits configuration mode.