Dell Force10 E300, Configuration Manual, Page: 407 / 1262

Internet Group Management Protocol | 407
Figure 19-4. IGMP Membership Reports: Joining and Filtering
Leaving and Staying in Groups
Figure 19-5 shows how multicast routers track and refresh state changes in response to group-and-specific
and general queries.
1. Host 1 sends a message indicating it is leaving group 224.1.1.1 and that the include filter for 10.11.1.1
and 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 host
is 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 state
information.
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 that
group.
1/1
Type: 0x22
Number of Group Records: 1
Record Type: 4
Number of Sources: 0
Multicast Address: 224.1.1.1
Interface Multicast Group Filter Source Source
Address Timer Mode Timer
1/1 224.1.1.1 GMI Exclude
None
1/1 224.1.1.1 Include
10.11.1.1 GMI
1/1 224.1.1.1 Include
10.11.1.1 GMI
10.11.1.2 GMI
IGMP Join message
Type: 0x22
Number of Group Records: 1
Record Type: 3
Number of Sources: 1
Multicast Address: 224.1.1.1
Source Address: 10.11.1.1
Change to Include
Type: 0x22
Number of Group Records: 1
Record Type: 5
Number of Sources: 1
Multicast Address: 224.1.1.1
Source Address: 10.11.1.2
Allow New
State-change reports retransmitted
Query Robustness Value-1 times at
Unsolicited Report Interval
Querier Non-Querier
Membership Reports: Joining and Filtering
1
2
4
Type: 0x11
Group Address: 244.1.1.1
Number of Sources: 1
Source Address: 10.11.1.1
IGMP Group-and-Source
Specific Query
3
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