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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter21 Configuring IGMP Snooping and M VR Displaying IGMP Snooping Information
To disable the aging of the forwarding table entries, enter the ip igmp snooping source-only-learning
age-timer 0 global configuration command.
If you disable source-only learning by using the no ip igmp snooping source-only learning global
configuration command and the aging time is enabled, it has no effect on the switch.
Displaying IGMP Snooping Information
You can display IGMP snooping information for dynamically learned and statically c on figured rou ter
ports and VLAN interfaces. You can also display MA C address multi cast entries for a VLAN conf igured
for IGMP snooping.
To display IGMP snooping information, use one or more of the privileged EXEC c omman ds in
Table21-4.
For more information about the keywords and options in these commands, refer to the command
reference for this release. For examples of output from t he c omm ands i n Ta ble 21 -4, refer to the
command reference for this release.
Table21-4 Commands for Displaying IGMP Snooping Information
Command Purpose
show ip igmp snooping [vlan vlan-id] Display the snooping configuration information for all VLANs on the
switch or for a specified VLAN.
(Optional) Enter vlan vlan-id to display information for a single VLAN.
show ip igmp snooping group [vlan vlan-id] Display information about the IGMP multicast groups, the compatibility
mode, and the ports that are associated with each group.
(Optional) Enter vlan vlan-id to display information for a single VLAN.
show ip igmp snooping mrouter [vlan vlan-id] Display information on dynamically learned and manually configured
multicast router interfaces.
Note When you enable IGMP snooping, the switch automatically
learns the interface to which a multicast router is connected.
These are dynamically learned interfaces.
(Optional) Enter vlan vlan-id to display information for a single VLAN.
show ip igmp snooping querier [vlan vlad-id] Display information about the IGMP version that an interface supports.
(Optional) Enter vlan vlan-id to display information for a single VLAN.
show mac address-table multicast [vlan vlan-id]
[user | igmp-snooping] [count]Display the Layer 2 MAC address table entries for a VLAN. The
keywords are all optional and limit the display as shown:
•vlan vlan-id—Displays only the specified multicast group VLAN.
•user—Displays only the user-configured multicast entries.
•igmp-snooping—Displays only entries learned t hrough IG MP
snooping.
•count—Displays only the total number of entries for the selected
criteria, not the actual entries.