H3C Technologies H3C S10500 Series Switches - Manual (Page 33)

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switch removes the port from the outgoing port list of the forwarding table entry for that multicast
group when the aging timer expires.
IGMP snooping proxying
You can configure the IGMP snooping proxying function on an edge device to reduce the number of
IGMP reports and leave messages sent to its upstream device. The device configured with IGMP
snooping proxying is called an IGMP snooping proxy. It is a host from the perspective of its upstream
device.
NOTE:
Even though an IGMP snooping proxy is a host from the perspective of its upstream device, the IGMP
membership report suppression mechanism for hosts does not take effect on it. For more information
about the IGMP report suppression mechanism for hosts, see the chapter “IGMP configuration.”
Figure 13 Network diagram for IGMP snooping proxying
As shown in Figure 13 , Switch A works as an IGMP snooping proxy. As a host from the perspective of the
querier Router A, Switch A represents its attached hosts to send membership reports and leave messages
to Router A.
Table 6 IGMP message processing on an IGMP snooping proxy
IGMP message Actions
General query
When receiving an IGMP 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.
Group-specific query
In response to the IGMP group-specific query for a certain 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.