Dell S6000 FTOS 9.0(2.0) Configuration Guide for the System - Page 384

www.dell.com | support.dell.com Fast Convergence after MSTP Topology Changes When a port transitions to the Forwarding state as a result of an STP or MSTP topology change, FTOS 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 You can designate an interface as a multicast router interface with the ip igmp snooping mrouter interface command. FTOS 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. Debugging IGMP Use any of the commands in EXEC Privilege mode to enable IGMP debugging. Command Syntax debug ip igmp [ip-address | fortyGigE | Gigabitethernet | port-channel | Tengigabitethernet | vlan] Command Mode Purpose EXEC Privilege View all information on IGMP, including query, report and leave. FTOS displays debug messages on the console. To view which debugging commands are enabled, use the show debugging command in EXEC Privilege mode. Use the keyword no followed by the debug command To disable a specific debug command. For example, to disable debugging of IGMP updates, enter no debug ip igmp command. Use no debug ip igmp to disable all IGMP debugging. Use undebug all to disable all debugging. 362 | Internet Group Management Protocol (IGMP)