Brocade TurboIron 24X Series Configuration Guide - Manual (Page 809)

Brocade TurboIron 24X Series Configuration Guide 775
53-1003053-01
Configuring IGMP snooping
Setting the maximum number of IGMP group addresses
When IGMP snooping is enabled, by default, devices support up to 4K of IGMP group addresses by
default, and the configurable range is from 4096 to 8192. The configured number is the upper
limit of an expandable database. Client memberships exceeding the group limit are not processed.
Enter a command such as the following to define the maximum number of IGMP group addresses.
TurboIron(config)#system-max igmp-max-group-addr 1600
Syntax: [no] system-max igmp-max-group-addr <num>
<num> is a value between 4096 and 8192 and the default is 4096.
Enabling IGMP snooping globally on the device
Use the procedures in this section to enable IGMP snooping on a global basis.
Configuration notes for layer devices
• If Layer 3 multicast routing is enabled on your system, do not attempt to enable Layer 2 IGMP
snooping. Layer 2 IGMP snooping is automatically enabled with Layer 3 multicast routing.
• If the "route-only" feature is enabled on the Layer 3 Switch, then IP multicast traffic reduction
will not be supported.
• IGMP snooping is not supported on the default VLAN of Layer 3 Switches.
Configuring the IGMP mode
You can configure active or passive IGMP modes on the device. The default mode is passive. If you
specify an IGMP mode for a VLAN, it overrides the global setting.
• Active - When active IGMP mode is enabled, a device actively sends out IGMP queries to
identify multicast groups on the network, and makes entries in the IGMP table based on the
group membership reports it receives.
NOTE
Routers in the network generally handle this operation. Use the active IGMP mode only when
the device is in a stand-alone Layer 2 Switched network with no external IP multicast router
attachments. In 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.
TurboIron(config)#ip multicast active
Syntax: [no] ip multicast [active | passive]
If you do not enter either active or passive, the passive mode is assumed.