H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – Multicast
H3C S7500E Series Ethernet Switches Chapter 2 IGMP Snooping Configuration
2-20
To do... Use the command... Remarks
Enter system view
system-view
—
Enter IGMP Snooping
view
igmp-snooping
—
Enable the function of
dropping unknown
multicast data
drop-unknown
Required
Disabled by default
II. Configuring the function of dropping unknown multicast data in a VLAN
Follow these steps to configure the function of dropping unknown multicast data in a
VLAN:
To do... Use the command... Remarks
Enter system view
system-view
—
Enter VLAN view
vlan vlan-id
—
Enable the function of
dropping unknown
multicast data
igmp-snooping
drop-unknown
Required
Disabled by default
 Note:
z After the function of dropping unknown multicast data is enabled in IGMP Snooping
view, it cannot be enabled or disabled in VLAN view, and vice versa.
z When the S7500E series Ethernet switches are enabled to drop unknown multicast
data, they still forward unknown multicast data to other router ports in the VLAN.
2.6.5 Configuring IGMP Report Suppression
When a Layer 2 device receives an IGMP report from a multicast group member, the
device forwards the message to the Layer 3 device directly connected with it. Thus,
when multiple members of a multicast group are attached to the Layer 2 device, the
Layer 3 device directly connected with it will receive duplicate IGMP reports from these
members.
With the IGMP report suppression function enabled, within each query cycle, the Layer
2 device forwards only the first IGMP report per multicast group to the Layer 3 device
and will not forward the subsequent IGMP 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 IGMP report suppression: