21-22
Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
78-11380-10
Chapter21 Configuring IGMP Snooping and MVR
Configuring IGMP Filtering and Thrott li ng
Note IGMPv3 join and leave messages are not supported on switches running IGMP filtering.
You can also set the maximum number of IGMP groups that a Layer 2 interface can join.
With the IGMP throttling feature, you can also set the maximum number of I GMP groups that a Layer 2
interface can join. If the maximum number of IGMP groups is set, the IGMP snoo ping forwarding table
contains the maximum number of entries, and the interface receives an IGMP join report, you can
configure an interface to drop the IGMP report or to remove a randomly selected multicast entry in the
forwarding table and then to add the IGMP group in t he rep ort to the tabl e.
These sections describe how to configure IGMP filtering and throttling:
•Default IGMP Filtering and Throttling Configuration, page 21-22
•Configuring IGMP Profiles, page 21-22 (optional)
•Applying IGMP Profiles, page 21-24 (optional)
•Setting the Maximum Number of IGMP Groups, page 21-25 (optional)
•Configuring the IGMP Throttling Action, page 21-25 (optional)
Default IGMP Filtering and Throttling Configuration
Table21-7 shows the default IGMP filtering configuration.
When the maximum number of groups is in forwarding table, the default IGMP throttling action is to
deny the IGMP report. For configuration guidelines, see the “Configu ring th e I GMP Th rottling Action”
section on page 21-25.
Configuring IGMP Profiles
To configure an IGMP profile, use the ip igmp profile global configuration command with a profile
number to create an IGMP profile and to enter IGMP profile configuration mode. From thi s mo de , you
can specify the parameters of the IGMP profile to be used for filtering IGMP join requests from a port.
When you are in IGMP profile configuration mode, you can create the profile by using these commands:
•deny: Specifies that matching addresses are denied; this is the default condition.
•exit: Exits from igmp-profile configuration mode.
•no: Negates a command or sets its defaults.
Table21-7 Default IGMP Filtering Configuration
Feature Default Setting
IGMP filters None applied
IGMP Maximum number of IGMP groups No maximum set
IGMP profiles None defined
IGMP profile action Deny the range addresses