Cisco Catalyst 3750-X User Manual

26-6
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 26 Configuring IGMP Snooping and MVR
Configuring IGMP Snooping
IGMP Snooping and Switch Stacks
IGMP snooping functions across the switch stack; that is, IGMP control information from one switch is
distributed to all switches in the stack. (See Chapter 5, “Managing Switch Stacks,” for more information
about switch stacks.) Regardless of the stack member th
rough 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 the
content. These sections contain this configuration information:
• Default IGMP Snooping Configuration, page 26-6
• Enabling or Disabling IGMP Snooping, page 26-7
• Setting the Snooping Method, page 26-7
• Configuring a Multicast Router Port, page 26-8
• Configuring a Host Statically to Join a Group, page 26-9
• Enabling IGMP Immediate Leave, page 26-10
• Configuring the IGMP Leave Timer, page 26-10
• Configuring TCN-Related Commands, page 26-11
• Configuring the IGMP Snooping Querier, page 26-13
• Disabling IGMP Report Suppression, page 26-14
Default IGMP Snooping Configuration
Ta ble 26-3 Default IGMP Snooping Configuration
Feature Default Setting
IGMP snooping Enabled globally and per VLAN
Multicast routers None configured
Multicast router learning (snooping) method PIM-DVMRP
IGMP snooping Immediate Leave Disabled
Static groups None configured
TCN
1
flood query count
1. TCN = Topology Change Notification
2
TCN query solicitation Disabled
IGMP snooping querier Disabled
IGMP report suppression Enabled

Cisco Catalyst 3750-X Specifications

General

Brand	Cisco
Model	Catalyst 3750-X
Category	Switch
Language	English