Mld Snooping Proxying - HP A5500 SI Switch Series Configuration Manual

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.
NOTE:
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 more information
about the MLD report suppression mechanism, see the chapter "MLD configuration."
Figure 65 Network diagram for MLD snooping proxying
As shown in
the querier Router A, Switch A represents its attached hosts to send their membership reports and done
messages to Router A.
Table 9 MLD message processing on an MLD snooping proxy
MLD message
General query
Multicast-
address-specific
query
Report
Figure 65, Switch A works as an MLD snooping proxy. As a host from the perspective of
Actions
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.
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.
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 the forwarding entry is found
with the receiving port contained as a dynamic port in the outgoing port list, the proxy
resets the aging timer for the entry. If the forwarding entry is found but the outgoing port
list does not include the receiving port, the proxy adds the port to the outgoing port list
as a dynamic member port and starts an aging timer for it. If no forwarding entry is
found, the proxy creates the entry, adds the receiving port to the outgoing port list as a
dynamic member port and starts an aging timer for the port. Then, it sends a report to
the group out all router ports.
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