Enhancements In Igmpv3 - H3C S5500-EI Configuration Manual

If the querier receives a membership report for the group within the maximum response time, it will
4.
maintain the memberships of the group. Otherwise, the querier will assume that no hosts on the
subnet are still interested in multicast traffic to that group and will stop maintaining the
memberships of the group.

Enhancements in IGMPv3

IGMPv3 is based on and is compatible with IGMPv1 and IGMPv2. It provides hosts with enhanced
control capabilities and provides enhancements of query and report messages.
Enhancements in control capability of hosts
IGMPv3 introduced two source filtering modes—Include and Exclude. These modes allow a host to join
a designated multicast group and to choose whether to receive or reject multicast data from designated
multicast sources. When a host joins a multicast group, one of the following situation occurs:
If it needs to receive multicast data from specific sources like S1, S2, ..., it sends a report with the
•
Filter-Mode denoted as "Include Sources (S1, S2, ...)."
If it needs to reject multicast data from specific sources like S1, S2, ..., it sends a report with the
•
Filter-Mode denoted as "Exclude Sources (S1, S2, ...)."
As shown in
both of which can send multicast data to multicast group G. Host B is only interested in the multicast data
that Source 1 sends to G but not in the data from Source 2.
Figure 34 Flow paths of source-and-group-specific multicast traffic
In the case of IGMPv1 or IGMPv2, Host B cannot select multicast sources when it joins multicast group G.
Therefore, multicast streams from both Source 1 and Source 2 will flow to Host B whether or not it needs
them.
When IGMPv3 is running between the hosts and routers, Host B can explicitly express that it needs to
receive the multicast data that Source 1 sends to multicast group G—denoted as (S1, G), rather than the
Figure 34, the network comprises two multicast sources, Source 1 (S1) and Source 2 (S2),
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