I am working on a project on survivable multicasting.I want to propose a hybrid scheme(protection and restoration) for that purpose.Can anyone help me with an approach to decide protection points in a multicast tree??(The protection points will be those points upto which there will be an alternate path from the multicast source(protection) and from protection point to the multicast destination the path will be dynamically restored.).Pls suggest an approach to find the protection points.I found an approach name caterpillar tree which assigns the nodes on the spine of caterpillar tree as protection points.Is there any other such approach..?