Dell PowerEdge FX2/FX2s - Manual (Page 86)

• The host’s third message indicates that it is only interested in traffic from sources 10.11.1.1 and
10.11.1.2. Because this request again prevents all other sources from reaching the subnet, the router
sends another group-and-source query so that it can satisfy all other hosts. There are no other
interested hosts, so the request is recorded.
Figure 13. IGMP Membership Reports: Joining and Filtering
Leaving and Staying in Groups
The below illustration shows how multicast routers track and refreshes the state change in response to
group-and-specific and general queries.
• Host 1 sends a message indicating it is leaving group 224.1.1.1 and that the included filter for 10.11.1.1
and 10.11.1.2 are no longer necessary.
• The querier, before making any state changes, sends a group-and-source query to see if any other
host is interested in these two sources; queries for state-changes are retransmitted multiple times. If
any are interested, they respond with their current state information and the querier refreshes the
relevant state information.
• Separately in the below figure, the querier sends a general query to 224.0.0.1.
• Host 2 responds to the periodic general query so the querier refreshes the state information for that
group.
86 IGMP Overview