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Table 9 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-addre
ss-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 a matching entry:
•
If a match is found and the entry contains the receiving port as a dynamic member
port, the proxy restarts the aging timer for the port.
•
If a match is found but the entry 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 match is found, 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.
Protocols and standards
RFC 4541,
Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) Snooping Switches
MLD snooping configuration task list
For the configuration tasks in this section, the following rules apply:
•
The configurations made in MLD-snooping view are effective on all VLANs. The configurations
made in VLAN view are effective on only the current VLAN. For a given VLAN, a configuration
made in MLD-snooping view is effective only if you do not make the same configuration in
VLAN view.
•
The configurations made in MLD-snooping view are effective on all ports. The configurations
made in Layer 2 Ethernet interface view or Layer 2 aggregate interface view are effective on
only the current port. The configurations made in port group view are effective on only the ports
in the current port group. For a given port, a configuration made in MLD-snooping view is
effective only if you do not make the same configuration in Layer 2 Ethernet interface view,
Layer 2 aggregate interface view, or port group view.
•
The MLD snooping configurations made on Layer 2 aggregate interfaces do not interfere with
the configurations made on member ports. In addition, the configurations made on Layer 2
aggregate interfaces do not take part in aggregation calculations. A configuration made on a
member port of the aggregate group takes effect after the port leaves the aggregate group.
Task
Remarks
Configuring basic MLD
snooping functions
Required.
Specifying the version of MLD snooping
Optional.
