17z One port can belong to only one multicast VLAN.z The port connected to a user terminal must be a hybrid port.z The multicast member ports must be in the same VLAN with the router port. Otherwise, themulticast member port cannot receive multicast packets.z If a router port is in a multicast VLAN, the router port must be configured as a trunk port or a hybridport that allows tagged packets to pass for the multicast VLAN. Otherwise, all the multicastmember ports in this multicast VLAN cannot receive multicast packets.z The multicast VLAN function and the VLAN mapping function cannot be configured at the sametime.Displaying and Maintaining IGMP SnoopingTo do... Use the command… RemarksDisplay the current IGMPSnooping configurationdisplay igmp-snoopingconfiguration Available in any viewDisplay IGMP Snoopingmessage statisticsdisplay igmp-snoopingstatistics Available in any viewDisplay the information aboutIP and MAC multicast groups inone or all VLANsdisplay igmp-snoopinggroup [ vlan vlan-id ] Available in any viewClear IGMP Snooping statistics reset igmp-snoopingstatistics Available in user viewIGMP Snooping Configuration ExamplesConfiguring IGMP SnoopingNetwork requirementsTo prevent multicast traffic from being flooded at Layer 2, enable IGMP snooping on Layer 2 switches.z As shown in Figure 6-3, Router A connects to a multicast source (Source) through Ethernet 1/0/2,and to Switch A through Ethernet 1/0/1.z Run PIM-DM and IGMP on Router A. Run IGMP snooping on Switch A. Router A acts as the IGMPquerier.z The multicast source sends multicast data to the multicast group 224.1.1.1. Host A and Host B arereceivers of the multicast group 224.1.1.1.
