User Guide

this case, enable the active IGMP mode on only one of the devices and leave the other devices
configured for passive IGMP mode.
• Passive - When passive IGMP mode is enabled, it forwards reports to the router ports which
receive queries. IGMP snooping in the passive mode does not send queries. However, it forwards
queries to the entire VLAN.
Configuring the global IGMP mode
To globally set the IGMP mode to active, enter the following command.
device(config)#ip multicast active
Syntax: [no] ip multicast [ active | passive ]
If you do not enter either active or passive, the passive mode is assumed.
Configuring the IGMP mode for a VLAN
If you specify an IGMP mode for a VLAN, it overrides the global setting.
To set the IGMP mode for VLAN 20 to active, enter the following commands.
device(config)#vlan 20
device(config-vlan-20)#multicast active
Syntax: [no] multicast [ active | passive]
Configuring the IGMP version
Use the procedures in this section to specify the IGMP version.
Configuring the global IGMP version
To globally specify IGMP V2 or IGMP V3, refer to Enabling IGMP snooping globally on the device on
page 19.
Configuring the IGMP version for a VLAN
You can specify the IGMP version for a VLAN. For example, the following commands configure VLAN
20 to use IGMP V3.
device(config)#vlan 20
device(config-vlan-20)#multicast version 3
Syntax: [no] multicast version [2 | 3 ]
If no IGMP version is specified, then the globally-configured IGMP version is used. If an IGMP version
is specified for individual ports, those ports use that version, instead of the VLAN version.
Configuring the global IGMP mode
20 FastIron Ethernet Switch IP Multicast Configuration Guide
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