H3C Technologies H3C S12500-X Series Switches - Manual (Page 36)

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Step Command Remarks
2. Enter VLAN view. vlan vlan-id N/A
3. Enable dropping unknown
multicast data for the VLAN.
igmp-snooping drop-unknown
By default, this function is disabled.
Unknown multicast data is flooded.
Enabling IGMP report suppression
After receiving an IGMP report from a multicast group member, a Layer 2 switch forwards the IGMP
report to the directly connected Layer 3 device. If multiple members of a multicast group are attached to
the Layer 2 switch, the Layer 3 device will receive multiple membership reports for the same multicast
group.
To reduce the multicast traffic, you can enable the IGMP report suppression function on the Layer 2 switch.
In this way, the Layer 2 switch forwards only the first IGMP report for the multicast group to the upstream
Layer 3 device during one query interval.
To enable IGMP report suppression:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter IGMP-snooping view. igmp-snooping N/A
3. Enable IGMP report
suppression.
report-aggregation
By default, IGMP report suppression is
disabled.
Setting the maximum number of multicast groups on a port
You can set the maximum number of multicast groups on a port to regulate the port traffic.
When you set the maximum number of multicast groups on a port, follow these guidelines:
• This configuration is effective for the multicast groups that a port dynamically joins. If you configure
the port as a static member port for a multicast group, this configuration is not effective for the
multicast group.
• If the number of multicast groups on a port exceeds the limit, the system removes all the forwarding
entries related to that port from the IGMP snooping forwarding table. The receiver hosts attached to
that port can join multicast groups again before the number of multicast groups on the port reaches
the limit.
To set the maximum number of multicast groups on a port:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface interface-type
interface-number
N/A
3. Set the maximum number of
multicast groups on a port.
igmp-snooping group-limit limit
[ vlan vlan-list ] The default setting is
4294967295.