UMN:CLI
User Manual
V8102
500
TCN Flooding Suppression
When TCN is received, the switch where an IGMP snooping is running will flood multicast
traffic to all ports until receiving two general queries, or during two general query intervals
by default. You can also configure the switch to stop multicast flooding according to a
specified query count or query interval.
To specify a query count to stop multicast flooding, use the following command.
Command
Mode
Description
ip igmp snooping tcn flood que-
ry count
<1-10>
Global
Specifies a query count to stop multicast flooding.
1-10: query count value (default: 2)
no ip igmp snooping tcn flood
query count
Deletes a specified query count to stop multicast flood-
ing.
To specify a query interval to stop multicast flooding, use the following command.
Command
Mode
Description
ip igmp snooping tcn flood que-
ry interval
<1-1800>
Global
Specifies a query interval to stop multicast flooding in
the unit of second. An actual stop-flooding interval is
calculated by (query count) x (query interval).
1-1800: query interval value (default: 125)
no ip igmp snooping tcn flood
query interval
Deletes a specified query interval to stop multicast
flooding.
TCN Flooding Query Solicitation
Typically, if a network topology change occurs, the spanning tree root switch issues a
query solicitation which is actually a global leave message with the group address 0.0.0.0.
When a multicast router receives this solicitation, it immediately sends out IGMP general
queries to hosts, allowing the fast convergence. You can direct the switch where an IGMP
snooping is running to send a query solicitation when TCN is received.
To enable the switch to send a query solicitation when TCN is received, use the following
command.
Command
Mode
Description
ip igmp snooping tcn query
solicit
[
address
A.B.C.D
]
Global
Enables the switch to send a query solicitation when
TCN is received.
address: source IP address for query solicitation
To disable the switch to send a query solicitation when TCN is received, use the following
command.
Command
Mode
Description
no ip igmp snooping tcn query
solicit
[
address
]
Global
Disables the switch to send a query solicitation when
TCN is received.