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1. The host sends an MLD done message to all IPv6 multicast routers on the local subnet. The
destination address is FF02::2.
2. After receiving the MLD done message, the querier sends a configurable number of multicast
address specific queries to the group that the host is leaving. The IPv6 multicast addresses queried
include both the destination address field and the group address field of the message.
3. One of the remaining members (if any on the subnet) of the group sends a report within the time
of the maximum response delay advertised in the query messages.
4. If the querier receives a report for the group within the maximum response delay time, it maintains
the memberships of the IPv6 multicast group. Otherwise, the querier assumes that no hosts on the
subnet are interested in IPv6 multicast traffic addressed to that group and stops maintaining the
memberships of the group.
MLDv2 enhancements
MLDv2 is based on and backwards-compatible with MLDv1. MLDv2 provides hosts with enhanced
control capabilities and enhances the MLD state.
Enhancements in control capability of hosts
MLDv2 has introduced IPv6 multicast source filtering modes (Include and Exclude). These modes allow
a host to join a designated IPv6 multicast group and to choose whether to receive or reject multicast data
from designated IPv6 multicast sources. When a host joins an IPv6 multicast group, one of the following
occurs:
• If the host expects IPv6 multicast data from specific IPv6 multicast sources like S1, S2, …, it sends a
report with Filter-Mode denoted as "Include Sources (S1, S2, …)."
• If the host does not expect IPv6 multicast data from specific IPv6 multicast sources like S1, S2, …,
it sends a report with Filter-Mode denoted as "Exclude Sources (S1, S2, …)."
As shown in Figure 8
3, the network has two IPv6 multicast sources, Source 1 (S1) and Source 2 (S2).
Both of the sources can send IPv6 multicast data to IPv6 multicast group G. Host B is interested only in the
IPv6 multicast data that Source 1 sends to G but not in the data from Source 2.
Figure 83 Flow paths of multicast address and source specific multicast traffic
In MLDv1, Host B cannot select IPv6 multicast sources when it joins IPv6 multicast group G. The IPv6
multicast streams from both Source 1 and Source 2 flow to Host B whether it needs them or not.
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