BigIron RX Series Configuration Guide 105153-1001810-01Enabling IP multicast traffic reduction 41To verify that IP Multicast Traffic Reduction is enabled, enter the following command at any level ofthe CLI.BigIron RX(config)# show ip multicastIP multicast is enabled - ActiveSyntax: show ip multicastChanging the IGMP modeWhen you enable IP Multicast Traffic Reduction on the device, IGMP also is enabled. The deviceuses IGMP to maintain a table of the Group Membership reports received by the device. You canuse active or passive IGMP mode. There is no default mode.The IGMP modes are as follows:• Active – When active IGMP mode is enabled, a Brocade device actively sends out IGMP queriesto identify IP multicast groups on the network and makes entries in the IGMP table based onthe Group Membership reports received from the network.NOTERouters in the network generally handle this operation. Use the active IGMP mode only whenthe device is in a stand-alone Layer 2 Switched network with no external IP multicast routerattachments. In this case, enable the active IGMP mode on only one of the devices and leavethe other devices configured for passive IGMP mode.• Passive – When passive IGMP mode is enabled, the device listens for IGMP GroupMembership reports but does not send IGMP queries. The passive mode is sometimes called“IGMP snooping”. Use this mode when another device in the network is actively sendingqueries.To enable active IGMP, enter the following command.BigIron RX(config)# ip multicast activeBigIron RX(config)# write memoryBigIron RX(config)# endBigIron RX# reloadSyntax: [no] ip multicast active | passiveTo enable passive IGMP, enter the following command.BigIron RX(config)# ip multicast passiveBigIron RX(config)# write memoryBigIron RX(config)# endBigIron RX# reloadConfiguring the IGMP mode per VLAN instanceIf the IP Multicast command is not applied globally as described in “Enabling IP multicast trafficreduction” on page 1050, you can apply it to individual VLANs instances within their configurations.In the following example, multicast traffic reduction is applied using IGMP snooping to VLAN 2.BigIron RX(config)# vlan 2BigIron RX(config-vlan-2)# multicast passiveTo remove multicast traffic reduction configurations in VLAN 2, and take the global multicast trafficreduction configuration, enter the following command.BigIron RX(config)# vlan 2BigIron RX(config-vlan-2)# no multicast
