Users Guide

• Reports and Leaves are flooded by default to the uplink LAG irrespective of whether it is an mrouter
port or not.
Disabling Multicast Flooding
If the switch receives a multicast packet that has an IP address of a group it has not learned (unregistered
frame), the switch floods that packet out of all ports on the VLAN. To disable multicast flooding on all
VLAN ports, enter the
no ip igmp snooping flood command in global configuration mode.
When multicast flooding is disabled, unregistered multicast data traffic is forwarded to only multicast
router ports on all VLANs. If there is no multicast router port in a VLAN, unregistered multicast data traffic
is dropped.
Displaying IGMP Information
Use the show commands from the below table, to display information on IGMP. If you specify a group
address or interface:
• Enter a group address in dotted decimal format; for example, 225.0.0.0.
• Enter an interface in one of the following formats: tengigabitethernet slot/port, port-
channel port-channel-number, or vlan vlan-number.
Displaying IGMP Information
Command Output
show ip igmp snooping groups [group-
address [detail] | detail | interface [group-
address [detail]]
Displays information on IGMP groups.
show ip igmp snooping interface [interface] Displays IGMP information on IGMP-enabled interfaces.
show ip igmp snooping mrouter [vlan vlan-
number]
Displays information on IGMP-enabled multicast router
(mrouter) interfaces.
clear ip igmp snooping groups [group-
address | interface]
Clears IGMP information for group addresses and IGMP-
enabled interfaces.
show ip igmp snooping groups Command Example
Dell# show ip igmp snooping groups
Total Number of Groups: 2
IGMP Connected Group Membership
Group Address Interface Mode Uptime Expires
Last Reporter
226.0.0.1 Vlan 1500 INCLUDE 00:00:19 Never
1.1.1.2
226.0.0.1 Vlan 1600 INCLUDE 00:00:02 Never
1.1.1.2
Dell#show ip igmp snooping groups detail
Interface Vlan 1500
Group 226.0.0.1
100
Internet Group Management Protocol (IGMP)