Clearing IGMP counters on VLANs

To clear IGMP snooping on error and traffic counters for all VLANs, enter the clear ip multicast
counters command.
device#clear ip multicast counters
Syntax: clear ip multicast counters
Disabling the flooding of unregistered IPv4 multicast frames in anIGMP-snooping-enabled VLAN
NOTE
Disabling the flooding of unregistered IPv4 multicast frames in an IGMP-snooping-enabled VLAN is
supported only on ICX 6650 devices.
To disable the flooding of unregistered IPv4 multicast frames in an IGMP-snooping-enabled VLAN,
use the ip multicast disable-flooding command in global configuration mode.
The following example shows the disabling of flooding of unregistered IPv4
multicast frames.
Brocade(config)# ip multicast disable-flooding
PIM SM traffic snooping overview
When multiple PIM sparse routers connect through a snooping-enabled device, the Brocade device
always forwards multicast traffic to these routers. For example, PIM sparse routers R1, R2, and R3
connect through a device. Assume R2 needs traffic, and R1 sends it to the device, which forwards it to
both R2 and R3, even though R3 does not need it. A PIM SM snooping-enabled device listens to join
and prune messages exchanged by PIM sparse routers, and stops traffic to the router that sends prune
messages. This allows the device to forward the data stream to R2 only.
PIM SM traffic snooping requires IGMP snooping to be enabled on the device. IGMP snooping
configures the device to listen for IGMP messages. PIM SM traffic snooping provides a finer level of
multicast traffic control by configuring the device to listen specifically for PIM SM join and prune
messages sent from one PIM SM router to another through the device.

Application examples of PIM SM traffic snooping

Figure 1 shows an example application of the PIM SM traffic snooping feature. In this example, a device
is connected through an IP router to a PIM SM group source that is sending traffic for two PIM SM
groups. The device also is connected to a receiver for each of the groups.
When PIM SM traffic snooping is enabled, the device starts listening for PIM SM join and prune
messages and IGMP group membership reports. Until the device receives a PIM SM join message or
an IGMP group membership report, the device forwards IP multicast traffic out all ports. Once the

Clearing IGMP counters on VLANs

FastIron Ethernet Switch IP Multicast Configuration Guide 35
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