The gain and cost of multicast routing trees

The last several years we witness the proliferation of multimedia applications on Internet. One of the unavoidable techniques to support this type of communication is multicasting. However, even a decade after its initial proposal, multicast is not widely deployed. One reason lies in the lack of a business model. If the gain and the cost of multicast could be predicted, network operators might be encouraged to deploy multicast on a larger scale. We propose several analytical expressions that could be used to estimate the gain and cost of network-layer multicast. We show that the theoretical model we propose matches simulation and Internet measurement results remarkably well.