Patent ID: 7953027

Claim:
A method comprising: detecting an imminent topology change; identifying a new multicast distribution tree for a multicast group, in response to detection of the imminent topology change; sending a join message towards a root of the new multicast distribution tree; maintaining forwarding information subsequent to sending the join message, wherein the forwarding information identifies a current multicast distribution tree instead of the new multicast distribution tree; continuing to forward multicast traffic addressed to the multicast group via the current multicast distribution tree, subsequent to sending the join message; receiving a multicast packet addressed to the multicast group via the new multicast distribution tree, subsequent to sending the join message; dropping the multicast packet in response to the forwarding information corresponding to the multicast group not identifying the new multicast distribution tree, subsequent to sending the join message; and updating the forwarding information corresponding to the multicast group to identify the new multicast distribution tree, in response to the receiving; wherein the detecting, the identifying, the sending, the maintaining, the continuing to forward, the receiving, the dropping, and the updating are performed by a network device.