3Com Switch 4800G 24-Port Configuration Manual page 568

568 C 42: IGMP S
HAPTER
Configuring IGMP
Report Suppression
Configuring Maximum
Multicast Groups that
Can Be Joined on a Port
n
C
NOOPING ONFIGURATION
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:
To do...
Enter system view
Enter IGMP Snooping view
Enable IGMP report
suppression
By configuring the maximum number of multicast groups that can be joined on a
port, you can limit the number of multicast programs on-demand available to
users, thus to regulate traffic on the port.
Follow these steps to configure the maximum number of multicast groups that
can be joined on a port or ports:
To do...
Enter system view
Enter the
corresponding
view
Configure the maximum number of
multicast groups that can be joined on
the port(s)
When the number of multicast groups a port has joined reaches the maximum
■
number configured, the system deletes all the forwarding entries persistent to
that port from the IGMP Snooping forwarding table, and the hosts on this port
need to join the multicast groups again.
If you have configured static or simulated joins on a port, however, when the
■
number of multicast groups on the port exceeds the configured threshold, the
system deletes all the forwarding entries persistent to that port from the IGMP
Snooping forwarding table and applies the static or simulated joins again, until
the number of multicast groups joined by the port comes back within the
configured threshold.
Use the command...
system-view
igmp-snooping
report-aggregation
Use the command...
system-view
Enter Ethernet port interface interface-type
view interface-number
Enter port group port-group { manual
view port-group-name |
aggregation agg-id }
igmp-snooping
group-limit limit [ vlan
vlan-list ]
Remarks
-
-
Optional
Enabled by default
Remarks
-
Use either command
Optional
The default is 1024.