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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 21 Configuring IGMP Snooping and MVR
Configuring IGMP Filtering and Throttling
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 IGMP or MVR is used to forward the multicast traffic.
IGMP filtering is applicable 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.
Note IGMPv3 join and leave messages are not supported on switches running IGMP filtering.
These sections contain this configuration information:
• Default IGMP Filtering and Throttling Configuration, page 21-24
• Configuring IGMP Profiles, page 21-25 (optional)
• Applying IGMP Profiles, page 21-26 (optional)
• Setting the Maximum Number of IGMP Groups, page 21-26 (optional)
• Configuring the IGMP Throttling Action, page 21-27 (optional)
Default IGMP Filtering and Throttling Configuration
Table 21-7 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 “Configuring the IGMP Throttling Action”
section on page 21-27.
Tab le 21-7 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