Installation manual
3-252
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CLI – This example assigns a multicast address to VLAN 1, and then displays all the
known multicast services supported on VLAN 1.
IGMP Filtering and Throttling
In certain switch applications, the administrator may want to control the multicast services
that are available to end users. For example, an IP/TV service based on a specific
subscription plan. The IGMP filtering feature fulfills this requirement by restricting access
to specified multicast services on a switch port, and IGMP throttling limits the number of
simultaneous multicast groups a port can join.
IGMP filtering enables you to assign a profile to a switch port that specifies multicast
groups that are permitted or denied on the port. An IGMP filter profile can contain one or
more, or a range of multicast addresses; but only one profile can be assigned to a port.
When enabled, IGMP join reports received on the port are checked against the filter
profile. If a requested multicast group is permitted, the IGMP join report is forwarded as
normal. If a requested multicast group is denied, the IGMP join report is dropped.
IGMP throttling sets a maximum number of multicast groups that a port can join at the
same time. When the maximum number of groups is reached on a port, the switch can
take one of two actions; either “deny” or “replace”. If the action is set to deny, any new
IGMP join reports will be dropped. If the action is set to replace, the switch randomly
removes an existing group and replaces it with the new multicast group.
Note:
IGMP filtering and throttling only applies to dynamically learned multicast groups. It
does not apply to statically configured groups.
Enabling IGMP Filtering
To implement IGMP filtering and throttling on the switch, you must first enable the feature
globally and create IGMP profile numbers.
Command Attributes
• IGMP Filter – Enables IGMP filtering and throttling globally for the switch.
(Default: Disabled)
• IGMP Profile – Creates IGMP profile numbers. (Range: 1-4294967295)
Console(config)#ip igmp snooping vlan 1 static 224.1.1.12
ethernet 1/12 4-314
Console(config)#exit
Console#show mac-address-table multicast vlan 1 4-317
VLAN M'cast IP addr. Member ports Type
---- --------------- ------------ -------
1 224.1.1.12 Eth1/12 USER
1 224.1.2.3 Eth1/12 IGMP
Console#