Reference Guide

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 oods
that packet out of all ports on the VLAN. To disable multicast ooding on all VLAN ports, enter the
no ip igmp snooping ood
command in global conguration mode.
When multicast ooding is disabled, unregistered multicast data trac is forwarded to only multicast router ports on all VLANs. If
there is no multicast router port in a VLAN, unregistered multicast data trac 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
Uptime 00:00:21
Expires Never
Router mode INCLUDE
Last reporter 1.1.1.2
Last reporter mode INCLUDE
Last report received IS_INCL
Group source list
Source address Uptime Expires
1.1.1.2 00:00:21 00:01:48
Member Ports: Po 1
Interface Vlan 1600
Group 226.0.0.1
Uptime 00:00:04
Expires Never
Router mode INCLUDE
Last reporter 1.1.1.2
Last reporter mode INCLUDE
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Internet Group Management Protocol (IGMP)