Enhancement of the CBT multicast routing protocol

In this paper, we propose a simple practical scheme for many-to-many IP multicasting. The proposed scheme is based on the core based tree (CBT) protocol, and designed to enhance the CBT in the viewpoints of tree cost and traffic concentration. In the scheme, each group user is simply connected to the nearest core router in the network. Each core router forwards the source traffic to networks via the pre-configured backbone core trees spanning all the core routers in the network. To ensure that the backbone core tree keeps only the core routers with active group users, the core routers that have no downstream users are removed from backbone core tree. By experiments, we see that the proposed scheme significantly improves the existing CBT scheme in terms of tree cost and traffic concentration.