VLAN multicast problem

[marco-chen]

I create a VLAN interface in Layer-3 Switch and configure multicast traffic over this VLAN. But the multicast traffic is always duplicated after passing the Layer-3 Switch. I checked the throughput among devices and found that the layer3 switch receives traffic from a upstream router, and sends a copy back to the router. Then it sends double traffic to downstream device. Does anyone know why the traffic is doubled? How to figure it out? Thank you!

[owillins]

Reason may be RPF failure . RPF failures may occur when there are multiple paths between devices that forward multicast traffic from a source to receivers, and the unicast routing topology is not congruent or the same as the data distribution tree of multicast topology.