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Configuring the Switch
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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 multcast
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 and Throttling
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
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Console(config)#exit
Console#show mac-address-table multicast vlan 1
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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#