120Configuring multicast forwarding on a downstream interfaceOnly queriers can forward multicast traffic but non-queriers have no multicast forwarding capabilities.This design helps avoid duplicate multicast flows. It is the same on IGMP proxy switches. Only thedownstream interfaces acting as a querier can forward multicast traffic to downstream hosts.However, when a downstream interface of a proxy switch fails to win the querier election, you mustenable multicast forwarding on this interface.On a multi-access network with more than one IGMP proxy switch, you cannot enable multicastforwarding on any other non-querier downstream interface after one of the downstream interfaces ofthese IGMP proxy switches has been elected as the querier. Otherwise, duplicate multicast flows mightbe received on the multi-access network.To enable multicast forwarding on a downstream interface:Step Command Remarks1. Enter system view. system-view N/A2. Enter interface view. interface interface-typeinterface-number N/A3. Enable multicast forwarding ona non-querier downstreaminterface.igmp proxying forwarding Disabled by defaultDisplaying and maintaining IGMPCAUTION:The reset igmp group command might cause multicast data transmission failures.To display and maintain IGMP:Task CommandDisplay IGMP group information.display igmp [ all-instance |vpn-instance vpn-instance-name ]group [ group-address | interfaceinterface-type interface-number ][ static | verbose ] [ | { begin |exclude | include }regular-expression ]Available in any view.Display the Layer 2 portinformation of IGMP groups.display igmp group port-info [ vlanvlan-id ] [ slot slot-number ][ verbose ] [ | { begin | exclude |include } regular-expression ]Available in any view.
