3Com S7906E - Switch, Configuration Manual

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1-6
MLD Snooping Proxying
You can configure the MLD snooping proxying function on an edge device to reduce the number of MLD
reports and done messages sent to its upstream device. The device configured with MLD snooping
proxying is called an MLD snooping proxy. It is a host from the perspective of its upstream device.
Even though an MLD Snooping proxy is a host from the perspective of its upstream device, the MLD
membership report suppression mechanism for hosts does not take effect on it. For the MLD report
suppression mechanism for hosts, refer to MLD Configuration in the IP Multicast volume .
Figure 1-3 Network diagram for MLD snooping proxying
As shown in Figure 1-3 , Switch A works 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 1-2 describes how an MLD Snooping proxy processes MLD messages.
Table 1-2 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
receiving port. In addition, the proxy generates a report according to the group
memberships it maintains and sends the report out all router ports.
Multicast-addr
ess-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 all router ports if the forwarding entry for
the group still contains a member port.