Operation Manual – MulticastH3C S5600 Series Ethernet Switches Chapter 6 IGMP Snooping Configuration6-5Upon receiving the IGMP leave message from a host, the IGMP querier resolves fromthe message the address of the multicast group that the host just left and sends anIGMP group-specific query to that multicast group through the port that received theleave message. Upon receiving the IGMP group-specific query, a switch forwards itthrough all the router ports in the VLAN and all member ports of that multicast group,and performs the following to the receiving port:z If any IGMP report in response to the group-specific query arrives to the memberport before its aging timer expires, this means that some other members of thatmulticast group still exist under that port: the switch resets the aging timer of themember port.z If no IGMP report in response to the group-specific query arrives to the memberport before its aging timer expires as a response to the IGMP group-specific query,this means that no members of that multicast group still exist under the port: theswitch deletes the forwarding entry corresponding to the port from the forwardingtable when the aging timer expires.Caution:After an Ethernet switch enables IGMP Snooping, when it receives the IGMP leavemessage sent by a host in a multicast group, it judges whether the multicast groupexists automatically. If the multicast group does not exist, the switch drops this IGMPleave message.6.2 Configuring IGMP SnoopingComplete the following tasks to configure IGMP Snooping:Task RemarksEnabling IGMP Snooping RequiredConfiguring the Version of IGMP Snooping OptionalConfiguring Timers OptionalConfiguring Fast Leave Processing OptionalConfiguring a Multicast Group Filter OptionalConfiguring the Maximum Number of Multicast Groups on a Port OptionalConfiguring IGMP Snooping Querier OptionalSuppressing Flooding of Unknown Multicast Traffic in a VLAN OptionalConfiguring Static Member Port for a Multicast Group Optional
