How does an IGMP-enabled S series switch determine whether a member host exists in the multicast group

In IGMPv1 on S series switches, hosts leave their multicast groups without sending Leave messages. The device uses IGMP group entries timer to determine the whether all multicast group members in the network segment have left.
In IGMPv2 and IGMPv3, hosts send Leave messages when leaving their group. After receiving the Done message, the querier sends a Group-Specific or a Source-Specific Query message to the network segment. The destination address of the Query message is the address of the multicast group and the group address in the message is also filled in with the address of the multicast group.
If other members of the group exist on the network segment, they respond with Report messages.
If no response is received when the timeout period ends, the querier considers that no member of the group exists on the network segment and cancels forwarding multicast data to the group.

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