Cisco Catalyst 2960 Series, Configuration Manual

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action permits access to the multicast group, the IGMP report from the port is forwarded for normal processing.
You can also set the maximum number of IGMP groups that a Layer 2 interface can join.
IGMP filtering controls only group-specific query and membership reports, including join and leave reports.
It does not control general IGMP queries. IGMP filtering has no relationship with the function that directs
the forwarding of IP multicast traffic. The filtering feature operates in the same manner whether CGMP or
MVR is used to forward the multicast traffic.
IGMP filtering applies only to the dynamic learning of IP multicast group addresses, not static configuration.
With the IGMP throttling feature, you can set the maximum number of IGMP groups that a Layer 2 interface
can join. If the maximum number of IGMP groups is set, the IGMP snooping 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 replace the randomly selected multicast entry with the received IGMP report.
IGMPv3 join and leave messages are not supported on switches running IGMP filtering. Note
Related Topics
Configuring IGMP Profiles , on page 151
Applying IGMP Profiles , on page 154
Setting the Maximum Number of IGMP Groups , on page 155
Configuring the IGMP Throttling Action , on page 157
Restrictions for IGMP Snooping, on page 116
Default IGMP Filtering and Throttling Configuration
This table displays the default IGMP filtering and throttling configuration for the switch.
Table 17: Default IGMP Filtering Configuration
Default Setting Feature
None applied. IGMP filters
No maximum set.
When the maximum number of groups is in the
forwarding table, the default IGMP throttling action
is to deny the IGMP report.
Note
IGMP maximum number of IGMP groups
None defined. IGMP profiles
Deny the range addresses. IGMP profile action
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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Information About IGMP Snooping and MVR