1-5Upon receiving the IGMP leave message from a host, the IGMP querier resolves the multicast groupaddress in the message and sends an IGMP group-specific query to that multicast group through theport that received the leave message. Upon receiving the IGMP group-specific query, the switchforwards it through all its router ports in the VLAN and all member ports for that multicast group, andperforms the following to the port on which it received the IGMP leave message:z If any IGMP report in response to the group-specific query is received on the port (suppose it is adynamic member port) before its aging timer expires, this means that some host attached to theport is receiving or expecting to receive multicast data for that multicast group. The switch resetsthe aging timer of the port.z If no IGMP report in response to the group-specific query is received on the port before its agingtimer expires, this means that no hosts attached to the port are still listening to that group address:the switch removes the port from the outgoing port list of the forwarding table entry for thatmulticast group when the aging timer expires.Protocols and StandardsIGMP Snooping is documented in:z RFC 4541: Considerations for Internet Group Management Protocol (IGMP) and Multicast ListenerDiscovery (MLD) Snooping SwitchesIGMP Snooping Configuration Task ListComplete these tasks to configure IGMP Snooping:Task RemarksEnabling IGMP Snooping RequiredConfiguring Basic Functionsof IGMP Snooping Configuring the Version of IGMP Snooping OptionalConfiguring Aging Timers for Dynamic Ports OptionalConfiguring Static Ports OptionalConfiguring Simulated Joining OptionalConfiguring IGMP SnoopingPort FunctionsConfiguring Fast Leave Processing OptionalEnabling IGMP Snooping Querier OptionalConfiguring IGMP Queries and Responses OptionalConfiguring IGMP SnoopingQuerierConfiguring Source IP Address of IGMP Queries OptionalConfiguring a Multicast Group Filter OptionalConfiguring Multicast Source Port Filtering OptionalConfiguring the Function of Dropping UnknownMulticast Data OptionalConfiguring IGMP Report Suppression OptionalConfiguring Maximum Multicast Groups that CanBe Joined on a Port OptionalConfiguring an IGMPSnooping PolicyConfiguring Multicast Group Replacement Optional
