Operation Manual – MulticastH3C S3100-52P Ethernet Switch Chapter 3 IGMP Snooping Configuration3-163.2.12 Configuring a VLAN Tag for Query MessagesBy configuring the VLAN tag carried in IGMP general and group-specific queriesforwarded and sent by IGMP Snooping switches, you can enable multicast packetforwarding between different VLANs In a Layer-2 multicast network environment.Follow these steps to configure VLAN tag for query message:To do... Use the command... RemarksEnter system view system-view —Configure a VLAN tagfor query messagesigmp-snoopingvlan-mapping vlanvlan-idRequiredBy default, the VLAN tag inIGMP general andgroup-specific querymessages is not changed.Note:It is not recommended to configure this function while the multicast VLAN function is ineffect.3.2.13 Configuring Multicast VLANIn traditional multicast implementations, when users in different VLANs listen to thesame multicast group, the multicast data is copied on the multicast router for eachVLAN that contains receivers. This is a big waste of network bandwidth.In an IGMP Snooping environment, by configuring a multicast VLAN and adding portsto the multicast VLAN, you can allow users in different VLANs to share the samemulticast VLAN. This saves bandwidth because multicast streams are transmitted onlywithin the multicast VLAN. In addition, because the multicast VLAN is isolated fromuser VLANs, this method also enhances the information security.Multicast VLAN is mainly used in Layer 2 switching, but you must make thecorresponding configurations on the Layer 3 switch.Follow these steps to configure multicast VLAN on the Layer 3 switch:To do... Use the command... RemarksEnter system view system-view —Create a multicast VLANand enter VLAN view vlan vlan-id —Return to system view quit —
