A Tree Switching Protocol for Multicast State Reduction

In this paper, we propose a new Tree Switching Protocol (TSP) to reduce multicast routing states required for a forest of multicast trees. The protocol accomplishes this goal by selecting a base multicast tree and " switching '' other multicast trees to the base tree. This results in more overlapping among the multicast trees and a net reduction in multicast state. A further reduction in the state is possible by applying state aggregation to the overlapped tree branches. Simulation results show that the tree switching operation alone could result in a very significant state reduction. The TSP is a distributed protocol running on top of any protocol independent multicast routing protocols. It is also loop-free and very efJicient.