Joining And Filtering Groups And Sources - Dell PowerEdge M IO Aggregator Command Reference Manual

Joining and Filtering Groups and Sources

Figure 9-4
reports.
1. The first unsolicited report from the host indicates that it wants to receive traffic for group 224.1.1.1.
2. The host's second report indicates that it is only interested in traffic from group 224.1.1.1, source
10.11.1.1. Include messages prevent traffic from all other sources in the group from reaching the
subnet, so before recording this request, the querier sends a group-and-source query to verify that there
are no hosts interested in any other sources. The multicast router must satisfy all hosts if they have
conflicting requests. For example, if another host on the subnet is interested in traffic from 10.11.1.3,
the router cannot record the include request. There are no other interested hosts, so the request is
recorded. At this point, the multicast routing protocol prunes the tree to all but the specified sources.
3. 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 9-4. IGMP Membership Reports: Joining and Filtering
Interface Multicast Group Filter Source Source
Address Timer Mode
1/1 224.1.1.1 GMI
1/1 224.1.1.1
1/1 224.1.1.1
2 Change to Include
State-change reports retransmitted
Query Robustness Value-1 times at
Unsolicited Report Interval
112 | Internet Group Management Protocol (IGMP)
shows how multicast routers maintain the group and source information from unsolicited
Membership Reports: Joining and Filtering
Querier
Timer
Exclude
None
Include
10.11.1.1 GMI
Include
1/1
10.11.1.1 GMI
10.11.1.2 GMI
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
IGMP Group-and-Source
3
Specific Query
Type: 0x11
Group Address: 244.1.1.1
Number of Sources: 1
Source Address: 10.11.1.1
Type: 0x22
Number of Group Records: 1
Record Type: 4
Number of Sources: 0
Multicast Address: 224.1.1.1
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
Non-Querier
IGMP Join message
1
Allow New
4
fnC0072mp