Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 447
53-1002269-02
Configuring IGMP snooping
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Setting the maximum number of IGMP group addresses
When IGMP snooping is enabled, by default, PowerConnect B-Series TI24X 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.
PowerConnect(config)# system-max igmp-max-group-addr 1600
Syntax: [no] system-max igmp-max-group-addr <num>
On PowerConnect B-Series TI24X devices, <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.
PowerConnect(config)# ip multicast active
Syntax: [no] ip multicast [active | passive]