igmp fastlearn
The fast learn option allows fast convergence of multicast traffic after a topology change. This command is executed in the global config context.
Syntax:
no igmp fastlearn port-list
This command enabled fast learn on the specified ports. The form of the command disables the fast learn function on the specified ports.
Default: Disabled
To enable fastlearn on ports 5 and 6
switch(config)# igmp fastlearn 5-6