How Mldv2 Works - HP A5500 SI Switch Series Configuration Manual

At the same time, because Host A is interested in G2, it sends a report to the IPv6 multicast group
4.
address of G2.
Through the query/report process, the MLD routers discover that members of G1 and G2 are
5.
attached to the local subnet. The IPv6 multicast routing protocol (for example, IPv6 PIM) that is
running on the routers generates (*, G1) and (*, G2) multicast forwarding entries. These entries
will be the basis for subsequent IPv6 multicast forwarding, where * represents any IPv6 multicast
source.
When the IPv6 multicast data addressed to G1 or G2 reaches an MLD router, because the (*, G1)
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and (*, G2) multicast forwarding entries exist on the MLD router, the router forwards the IPv6
multicast data to the local subnet, and then the receivers on the subnet receive the data.
Leaving an IPv6 multicast group
When a host leaves a multicast group, the following process occurs:
The host sends an MLD done message to all IPv6 multicast routers on the local subnet. The
1.
destination address is FF02::2.
Upon receiving the MLD done message, the querier sends a configurable number of multicast-
2.
address-specific queries to the group that the host is leaving. The destination address field and
group address field of the message are both filled with the address of the IPv6 multicast group that
is being queried.
One of the remaining members (if any on the subnet) of the group that is being queried should
3.
send a report within the time of the maximum response delay set in the query messages.
If the querier receives a report for the group within the maximum response delay time, it will
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maintain the memberships of the IPv6 multicast group. Otherwise, the querier will assume that no
hosts on the subnet are still interested in IPv6 multicast traffic addressed to that group and will stop
maintaining the memberships of the group.

How MLDv2 works

Compared with MLDv1, MLDv2 provides the new features, IPv6 multicast group filtering, MLD state, and
receiver host state listening.
IPv6 multicast group filtering
MLDv2 has introduced IPv6 multicast source filtering modes—Include and Exclude, so that a host can
specify a list of IPv6 multicast sources that it expects or does not expect IPv6 multicast data from when it
joins an IPv6 multicast group:
If it expects IPv6 multicast data from specific IPv6 multicast sources like S1, S2, ..., it sends a report
•
with the Filter-Mode denoted as "Include Sources (S1, S2, ...)."
If it does not expect IPv6 multicast data from specific IPv6 multicast sources like S1, S2, ..., it sends
•
a report with the Filter-Mode denoted as "Exclude Sources (S1, S2, ...)."
As shown in
(S2), both of which 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 78, the network comprises two IPv6 multicast sources, Source 1 (S1) and Source 2
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