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Cisco Systems Intelligent Gigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide
24R9746
Chapter 14 Configuring IGMP Snooping and MVR
Configuring IGMP Filtering and Throttling
profile denying access to a multicast group is applied to a switch port, the IGMP join report requesting
the stream of IP multicast traffic is dropped, and the port is not allowed to receive IP multicast traffic
from that group. If the filtering action permits access to the multicast group, the IGMP report from the
port is forwarded for normal processing.
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.
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 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 describe how to configure IGMP filtering and throttling:
• Default IGMP Filtering and Throttling Configuration, page 14-22
• Configuring IGMP Profiles, page 14-23 (optional)
• Applying IGMP Profiles, page 14-24 (optional)
• Setting the Maximum Number of IGMP Groups, page 14-25 (optional)
• Configuring the IGMP Throttling Action, page 14-25 (optional)
Default IGMP Filtering and Throttling Configuration
Table 14-7 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 14-25.
Table 14-7 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