Patent ID: 8705403

Claim:
A method comprising: identifying a plurality of mappings of sources to a plurality of multicast groups, the plurality of mappings comprising a mapping for each combination of a particular source and a particular multicast group, each of the plurality of multicast groups having a set of members; generating a multicast distribution tree for each source-multicast group combination, a mapping associating a source with a multicast group, each multicast group having at least two multicast distribution trees; receiving, from a first source a frame destined for a first multicast group, the first multicast group having a first multicast distribution tree and a second multicast distribution tree; selecting the first multicast distribution tree but not the second multicast distribution tree for the frame; sending, via an outgoing interface, the frame over a path designated by the selected multicast distribution tree; in response to receiving a loopback packet from a destination within the first multicast group, determining that the loopback packet is received on an incoming interface that is the same as the outgoing interface; and in response to determining that the incoming interface is the same as the outgoing interface, forwarding the loopback packet to the first source.