Internet Group Management Protocol | 407Figure 19-4. IGMP Membership Reports: Joining and FilteringLeaving and Staying in GroupsFigure 19-5 shows how multicast routers track and refresh state changes in response to group-and-specificand general queries.1. Host 1 sends a message indicating it is leaving group 224.1.1.1 and that the include filter for 10.11.1.1and 10.11.1.2 are no longer necessary.2. The querier, before making any state changes, sends a group-and-source query to see if any other hostis interested in these two sources; queries for state-changes are retransmitted multiple times. If any are,they respond with their current state information and the querier refreshes the relevant stateinformation.3. Separately in Figure 19-5, the querier sends a general query to 224.0.0.1.4. Host 2 responds to the periodic general query so the querier refreshes the state information for thatgroup.1/1Type: 0x22Number of Group Records: 1Record Type: 4Number of Sources: 0Multicast Address: 224.1.1.1Interface Multicast Group Filter Source SourceAddress Timer Mode Timer1/1 224.1.1.1 GMI ExcludeNone1/1 224.1.1.1 Include10.11.1.1 GMI1/1 224.1.1.1 Include10.11.1.1 GMI10.11.1.2 GMIIGMP Join messageType: 0x22Number of Group Records: 1Record Type: 3Number of Sources: 1Multicast Address: 224.1.1.1Source Address: 10.11.1.1Change to IncludeType: 0x22Number of Group Records: 1Record Type: 5Number of Sources: 1Multicast Address: 224.1.1.1Source Address: 10.11.1.2Allow NewState-change reports retransmittedQuery Robustness Value-1 times atUnsolicited Report IntervalQuerier Non-QuerierMembership Reports: Joining and Filtering124Type: 0x11Group Address: 244.1.1.1Number of Sources: 1Source Address: 10.11.1.1IGMP Group-and-SourceSpecific Query3fnC0072mp
