Brocade FastIron Ethernet Switch IP Multicast Configuration Guide - Manual (Page 21)

Setting the maximum number of IGMP group addresses
The configured number of IGMP group addresses is the upper limit of an expandable database. Client
memberships exceeding the group limit are not processed. Configure the system-max igmp-snoop-
group-addr command to define the maximum number of IGMP group addresses.
Device(config)#system-max igmp-snoop-group-addr 1600
Syntax: [no] system-max igmp-snoop-group-addr num
The num variable is a value from 256 to 8192. The default for IGMP snooping group addresses is 4096,
except for ICX 6430 devices where the default is 1024.
Enabling IGMP snooping globally on the device
When you globally enable IGMP snooping, you can specify IGMP V2 or IGMP V3. The ip multicast
version command enables IGMP V3.
device(config)#ip multicast version 3
Syntax: [no] ip multicast version [2 | 3]
If you do not specify a version number, IGMP V2 is assumed.
Configuration notes for Layer 3 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 Brocade 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 Brocade 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
Setting the maximum number of IGMP group addresses
FastIron Ethernet Switch IP Multicast Configuration Guide 19
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