H3C Technologies H3C S12500 Series Switches - Manual (Page 316)

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NOTE:
•
After you enable dropping unknown IPv6 multicast data, the switch does not drop the unknown IPv6
multicast data with the multicast MAC address of 3333-0000-00xx or 3333-FFxx-xxxx (where x
represents a hexadecimal number from 0 to F). Instead, the switch floods the IPv6 multicast data in the
VLAN to which they belong.
• After you enable dropping unknown IPv6 multicast data, the switch still forwards unknown IPv6
multicast data to other router ports in the VLAN.
Enabling MLD report suppression
When a Layer 2 switch receives an MLD report from an IPv6 multicast group member, the Layer 2 switch
forwards the message to the Layer 3 device that directly connects to the Layer 2 switch. When multiple
members of an IPv6 multicast group are attached to the Layer 2 switch, the Layer 3 device might receive
duplicate MLD reports for the IPv6 multicast group from these members.
With the MLD report suppression function enabled, within a query interval, the Layer 2 switch forwards
only the first MLD report for the IPv6 multicast group to the Layer 3 device. It does not forward subsequent
MLD reports for the same IPv6 multicast group to the Layer 3 device. This helps reduce the number of
packets being transmitted over the network.
IMPORTANT:
On an MLD snooping proxy, MLD membership reports are suppressed if the entries for the corresponding
groups exist in the forwarding table, no matter the suppression function is enabled or not.
To enable MLD report suppression:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter MLD-snooping view. mld-snooping N/A
3. Enable MLD report
suppression.
report-aggregation Enabled by default.
Setting the maximum number of multicast groups that a port can
join
You can set the maximum number of IPv6 multicast groups that a port can join to regulate the traffic on
the port.
When you configure this maximum number, if the number of IPv6 multicast groups the port has joined
exceeds the configured maximum value, the system deletes all the forwarding entries for the port from the
MLD snooping forwarding table, and the hosts on this port join IPv6 multicast groups again until the
number of IPv6 multicast groups that the port joins reaches the maximum value. When the port joins an
IPv6 multicast group, if the port has been configured as a static member port, the system applies the
configurations to the port again. If you have configured simulated joining on the port, the system creates
corresponding forwarding entry for the port after receiving a report from the simulated member host.
To set the maximum number of IPv6 multicast groups that a port can join: