H3C Technologies H3C S7500E Series Switches - Manual (Page 279)

9-23
To do... Use the command... Remarks
Enable dropping unknown IPv6
multicast data packets
mld-snooping drop-unknown
Required
Disabled by default
z For devices that support both drop-unknown and mld-snooping drop-unknown
commands at the same time, the configuration made in MLD snooping view and the
configuration made in VLAN view are mutually exclusive. Namely, after this function is
enabled in MLD snooping view, it cannot be enabled or disabled in VLAN view, and vice
versa.
z Configurations made in MLD snooping view are effective for all VLANs, while
configurations made in VLAN view are effective only for ports belonging to the current
VLAN.
z If the function of dropping IPv6 multicast packets is globally enabled in MLD snooping view,
IPv6 multicast packets sent to MLD snooping-enabled VLANs are all dropped. The IPv6
multicast packets mentioned here include both IPv6 multicast data packets and protocol
packets, such as IPv6 PIM, OSPFv3, and IPv6 VRRP messages.
z After the function of dropping unknown IPv6 multicast data packets is enabled in VLAN
view, the switch forwards unknown IPv6 multicast data packets to its router ports, if any,
instead of flooding them in the VLAN. Otherwise, if no router ports exist, the switch drops
these IPv6 multicast data packets. Currently, the S7500E supports processing unknown
IPv6 multicast data packets destined for up to 1000 IPv6 unknown multicast addresses at a
time. The switch floods excessive unknown IPv6 multicast data packets directly.
z The S7500E supports the function of dropping unknown IPv6 multicast data packets
configuring in up to 500 VLANs.
Configuring MLD Report Suppression
When a Layer 2 device receives an MLD report from an IPv6 multicast group member, the Layer
2 device forwards the message to the Layer 3 device directly connected with it. Thus, when
multiple members belonging to an IPv6 multicast group exist on the Layer 2 device, the Layer 3
device directly connected with it will receive duplicate MLD reports from these members.
With the MLD report suppression function enabled, within a query interval, the Layer 2 device
forwards only the first MLD report of an IPv6 group to the Layer 3 device and will not forward
the subsequent MLD reports from the same multicast group to the Layer 3 device. This helps
reduce the number of packets being transmitted over the network.
Follow these steps to configure MLD report suppression:
To do... Use the command... Remarks
Enter system view system-view —