Igmp Snooping And Switch Stacks; Configuring Igmp Snooping - Cisco WS-C3750-48PS-S Software Configuration Manual

Configuring IGMP Snooping

IGMP Snooping and Switch Stacks

IGMP snooping functions across the switch stack; that is, IGMP control information obtained from one
switch is distributed to all switches in the stack. (See
information about switch stacks.) Regardless of the stack member through which IGMP multicast data
enters the stack, the data reaches the hosts that have registered for that group.
If a switch in the stack fails or is removed from the stack, only the members of the multicast group that
are on that switch will not receive the multicast data. All other members of a multicast group on other
switches in the stack continue to receive multicast data streams. However, multicast groups that are
common for both Layer 2 and Layer 3 (IP multicast routing) might take longer to converge if the stack
master is removed.
Configuring IGMP Snooping
IGMP snooping allows switches to examine IGMP packets and make forwarding decisions based on their
content.
These sections describe how to configure IGMP snooping:
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Default IGMP Snooping Configuration
Table 23-3
Table 23-3 Default IGMP Snooping Configuration
Feature
IGMP snooping
Multicast routers
Multicast router learning (snooping) method
IGMP snooping Immediate Leave
Static groups
IGMP report suppression
Catalyst 3750 Switch Software Configuration Guide
23-6
Default IGMP Snooping Configuration, page 23-6
Enabling or Disabling IGMP Snooping, page 23-7
Setting the Snooping Method, page 23-7
Configuring a Multicast Router Port, page 23-9
Configuring a Host Statically to Join a Group, page 23-10
Enabling IGMP Immediate Leave, page 23-11
Disabling IGMP Report Suppression, page 23-11
shows the default IGMP snooping configuration.
Chapter 23 Configuring IGMP Snooping and MVR
Chapter 5, "Managing Switch Stacks,"
Default Setting
Enabled globally and per VLAN
None configured
PIM-DVMRP
Disabled
None configured
Enabled
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