Recovering From Flood Mode (Cli) - Cisco Catalyst 3650 Configuration Manual

Configuring IGMP
Command or Action
Example:
Device> enable
Step 2
configure terminal
Example:
Device# configure terminal
Step 3 ip igmp snooping tcn flood query count count
Example:
Device(config)# ip igmp snooping tcn flood
query count 3
Step 4
end
Example:
Device(config)# end
Step 5
show ip igmp snooping
Example:
Device# show ip igmp snooping
Step 6 copy running-config startup-config
Example:
Device# copy running-config startup-config

Recovering from Flood Mode (CLI)

When a topology change occurs, the spanning-tree root sends a special IGMP leave message (also known as
global leave) with the group multicast address 0.0.0.0. However, when you enable the ip igmp snooping tcn
query solicit global configuration command, the device sends the global leave message whether or not it is
the spanning-tree root. When the router receives this special leave, it immediately sends general queries, which
expedite the process of recovering from the flood mode during the TCN event. Leaves are always sent if the
device is the spanning-tree root regardless of this configuration command. By default, query solicitation is
disabled.
OL-29890-01
Enters the global configuration mode.
Specifies the number of IGMP general queries for which the
multicast traffic is flooded. The range is 1 to 10. By default,
the flooding query count is 2.
Note
Returns to privileged EXEC mode.
Verifies the TCN settings.
(Optional) Saves your entries in the configuration file.
IP Multicast Routing Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3650 Switches)
How to Configure IGMP Snooping
Purpose
• Enter your password if prompted.
To return to the default flooding query count, use the
no ip igmp snooping tcn flood query count global
configuration command.
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