Edge-Core ECS4120-28F, Reference Manual, Page: 646 / 938

Chapter 24
| Multicast Filtering Commands
IGMP Snooping
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The proxy query and unsolicited MRD request are flooded to all VLAN ports
except for the receiving port when the switch receives such packets.
Example
The following example enables TCN flooding.
Console(config)#ip igmp snooping tcn-flood
Console(config)#
ip igmp snooping
tcn-query-solicit
This command instructs the switch to send out an IGMP general query solicitation
when a spanning tree topology change notification (TCN) occurs. Use the
no form
to disable this feature.
Syntax
[ no ] ip igmp snooping tcn-query-solicit
Default Setting
Disabled
Command Mode
Global Configuration
Command Usage
◆
When the root bridge in a spanning tree receives a topology change
notification for a VLAN where IGMP snooping is enabled, it issues a global IGMP
leave message (query solicitation). When a switch receives this solicitation, it
floods it to all ports in the VLAN where the spanning tree change occurred.
When an upstream multicast router receives this solicitation, it will also
immediately issues an IGMP general query.
◆
The ip igmp snooping tcn query-solicit command can be used to send a
query solicitation whenever it notices a topology change, even if the switch is
not the root bridge in the spanning tree.
Example
The following example instructs the switch to issue an IGMP general query
whenever it receives a spanning tree topology change notification.
Console(config)#ip igmp snooping tcn query-solicit
Console(config)#