ip igmp snooping last-member-query-interval
Fast Convergence after MSTP Topology Changes
When a port transitions to the Forwarding state as a result of an STP or MSTP topology change, the
system sends a general query out of all ports except the multicast router ports. The host sends a
response to the general query and the forwarding database is updated without having to wait for the
query interval to expire.
When an IGMP snooping switch is not acting as a querier, it sends out the general query in response to
the MSTP triggered link-layer topology change, with the source IP address of 0.0.0.0 to avoid triggering
querier election.
Designating a Multicast Router Interface
To designate an interface as a multicast router interface, use the following command.
The system also has the capability of listening in on the incoming IGMP general queries and designate
those interfaces as the multicast router interface when the frames have a non-zero IP source address. All
IGMP control packets and IP multicast data traffic originating from receivers is forwarded to multicast
router interfaces.
• Designate an interface as a multicast router interface.
ip igmp snooping mrouter interface
396 Internet Group Management Protocol (IGMP)