H3C Technologies H3C S12500 Series Switches - Manual (Page 304)

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Figure 80 Network diagram for MLD snooping proxying
As shown in Figure 80 , Switch A operates as an MLD snooping proxy. As a host from the perspective of
the querier Router A, Switch A represents its attached hosts to send their membership reports and done
messages to Router A.
Table 21 describes how an MLD snooping proxy processes MLD messages.
Table 21 MLD message processing on an MLD snooping proxy
MLD message Actions
General query
When receiving an MLD general query, the proxy forwards it to all ports but the port that
received the query. In addition, the proxy generates a report according to the group
memberships that it maintains and sends the report out of all router ports.
Multicast-addres
s-specific query
In response to the MLD group-specific query for a certain IPv6 multicast group, the proxy
sends the report to the group out of all router ports if the forwarding entry for the group still
contains a member port.
Report
When receiving a report for an IPv6 multicast group, the proxy looks up the multicast
forwarding table for the entry for the multicast group:
• If a forwarding entry matches the IPv6 multicast group, and contains the receiving port
as a dynamic member port, the proxy restarts the aging timer for the port.
• If a forwarding entry matches the IPv6 multicast group but does not contain the receiving
port, the proxy adds the port to the forwarding entry as a dynamic member port and
starts an aging timer for the port.
• If no forwarding entry matches the IPv6 multicast group, the proxy creates a forwarding
entry for the group, adds the receiving port to the forwarding entry as a dynamic
member port, and starts an aging timer for the port.
Then, the switch sends the report to the group out of all router ports.
Done
In response to a done message for an IPv6 multicast group, the proxy sends a
multicast-address-specific query for the group out of the receiving port. After making sure
that no member port is contained in the forwarding entry for the IPv6 multicast group, the
proxy sends a done message for the group out of all router ports.