Reference Guide

• IGMP snooping is not enabled by default on the switch.
• A maximum of 1800 groups and 600 VLAN are supported.
• IGMP snooping is not supported on a default VLAN interface.
• IGMP snooping is not supported over VLAN-Stack-enabled VLAN interfaces (you must disable IGMP
snooping on a VLAN interface before configuring VLAN-Stack-related commands).
• IGMP snooping does not react to Layer 2 topology changes triggered by spanning tree protocol (STP).
• IGMP snooping reacts to Layer 2 topology changes multiple spanning tree protocol (MSTP) triggers by
sending a general query on the interface that comes in the FWD state.
Important Points to Remember for IGMP Querier
• The IGMP snooping Querier supports version 2.
• You must configure an IP address to the VLAN interface for IGMP snooping Querier to begin. The
IGMP snooping Querier disables itself when a VLAN IP address is cleared, and then it restarts itself
when an IP address is reassigned to the VLAN interface.
• When enabled, IGMP snooping Querier does not start if there is a statically configured multicast
router interface in the VLAN.
• When enabled, IGMP snooping Querier starts after one query interval in case no IGMP general query
(with IP SA lower than its VLAN IP address) is received on any of its VLAN members.
• When enabled, IGMP snooping Querier periodically sends general queries with an IP source address
of the VLAN interface. If it receives a general query on any of its VLAN member, it checks the IP
source address of the incoming frame.
If the IP SA in the incoming IGMP general query frame is lower than the IP address of the VLAN
interface, the switch disables its IGMP snooping Querier functionality.
If the IP SA of the incoming IGMP general query is higher than the VLAN IP address, the switch
continues to work as an IGMP snooping Querier.
ip igmp snooping enable
Enable IGMP snooping on all or a single VLAN. This command is the master on/off switch to enable IGMP
snooping.
Syntax
ip igmp snooping enable
To disable IGMP snooping, use the no ip igmp snooping enable command.
Defaults Disabled.
Command
Modes
• CONFIGURATION
• INTERFACE VLAN
Command
History
This guide is platform-specific. For command information about other platforms,
refer to the relevant Dell Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version 9.5(0.0) Introduced on the Z9500.
772
Internet Group Management Protocol (IGMP)