BigIron RX Series Configuration Guide 105353-1001810-01Enabling IP multicast traffic reduction 41When the device starts up, it forwards all multicast groups even though multicast traffic filters areconfigured. This process continues until the device receives a group membership report. Once thegroup membership report is received, the device drops all multicast packets for groups other thanthe ones for which the device has received the group membership report.To enable IP multicast filtering, enter the following command.BigIron RX(config)# ip multicast filterSyntax: [no] ip multicast filterConfiguring IGMP snooping tracking per VLAN instanceWhen IGMP Snooping Tracking is enabled, the BigIron RX immediately removes any IGMP host portfrom the IP multicast group entry when it detects an IGMP-leave message on the specified hostport without first sending out group-specific queries to the interface. By default, IGMP SnoopingTracking is disabled.The ip multicast tracking command may be enabled globally as well as per VLAN basis. To enableIGMP Snooping Tracking globally, enter a command such as the following.BigIron RX(config)# multicast trackingSyntax: [no] ip multicast trackingThe no form of this command disables the tracking process globally.To enable IGMP Snooping Tracking per VLAN, enter commands such as the following.BigIron RX(config)# vlan 100BigIron RX(config-vlan-100)# multicast trackingSyntax: [no] multicast trackingThe no form of this command disables the tracking process per VLAN.For IGMPv3, the above command also internally tracks all the IGMPv3 hosts behind a given port.The port is not removed from the IP multicast group entry in the forwarding table until all the hostsbehind that port have left that multicast group. When the last IGMPv3 host sends a IGMPv3 leavemessage, the port is removed from the IP multicast group entry in the forwarding table immediatelywithout first sending out group_source_specific query to the interfaceSyntax: [no] multicast trackingStatic IGMP membershipWhen configuring a static IGMP membership, you have two options.The multicast static-group uplink command which sends the traffic to the router, and saves a port.The multicast static-group <group-address> <port-list> command is for downstream traffic anduses a port.
