Internet Group Management Protocol (IGMP) 331By default, a router joins no multicast group.Limiting Multicast Groups An Interface Can AccessA multicast router learns whether there are members of a multicast group on thenetwork via the received IGMP membership message. A filter can be set on aninterface so as to limit the range of allowed multicast groups.Perform the following configuration in Interface view.By default, no filter is configured, that is, all multicast groups are allowed on theinterface.Configuring the Interval to Send IGMP Query MessageMulticast routers send IGMP query messages to discover which multicast groups arepresent on attached networks. Multicast routers send query messages periodically torefresh their knowledge of members present on their networks.Perform the following configuration in Interface view.When there are multiple multicast routers on a network segment, the querier isresponsible for sending IGMP query messages to all hosts on the LAN.By default, the interval is 60 seconds.Table 334 Configuring a router to join specified multicast groupOperation CommandConfigure a router to joinspecified multicast group(VLAN Interface View)igmp host-join group_address port { interface_typeinterface_ num | interface_name } [ to {interface_type interface_ num | interface_name } ]Quit from specifiedmulticast group (VLANInterface View)undo igmp host-join group-address port {interface_type interface_ num | interface_name } [to { interface_type interface_ num |interface_name } ]Configure a router to joinspecified multicast group(Ethernet Port View)igmp host-join group-address vlan vlanidQuit from specifiedmulticast group (EthernetPort View)undo igmp host-join group-address vlan vlanidTable 335 Limiting multicast groups an interface can accessOperation CommandLimit the range of allowedmulticast groups oncurrent interface (InterfaceView)igmp group-policy acl_number [ 1 | 2 | port {interface_type interface_ num | interface_name }[ to { interface_type interface_ num |interface_name } ] ]Remove the filter set onthe interface (InterfaceView)undo igmp group-policy [ port { interface_typeinterface_ num | interface_name } [ to {interface_type interface_ num | interface_name }] ]Table 336 Configuring the interval to send IGMP query messageOperation CommandConfigure the interval to send IGMP query message igmp timer query secondsRestore the default value undo igmp timer query
