Multicast and unicast traffic share and compete for network resources. A cost-based approach to multicast pricing, based on accurate characterization of multicast scalability, will facilitate the efficient and equitable resource allocation between traffic types. Through the quantification of link usage, this paper establishes a multicast scaling relationship: the cost of a multicast distribution tree varies at the 0.8 power of the multicast group size. This result is validated with both real and generated networks, and is robust across topological styles and network sizes. Since multicast cost can be accurately predicted given the membership size, there is strong motivation to price multicast according to membership size. Furthermore, a price ceiling should be set to account for the effect of tree saturation. This tariff structure is superior to either a purely membership-based or a flat-rate pricing scheme, since it reflects the actual tree cost at all group membership levels. Keywords: multicast pricing, multicast scaling 1.

The growth of core Internet routing tables has been such that it is now viewed as an impediment to the continued expansion of the Internet. The main culprit is multi-homing that stems from sites’ desire for greater reliability and diversity in connectivity. These locally rational decisions have a global impact on the Internet, and there is currently no mechanism to effectively control them. A number of technical solutions are being pursued, but this paper explores the use of a “market mechanism. ” It formulates a model that accounts for sites ’ incentives and the impact their connectivity choices have on the size of routing tables, and introduces a pricing scheme that seeks to better reapportion the resulting costs. The model is solved for two configurations that capture different deployment realizations and stages. They demonstrate the scheme’s effectiveness in controlling the growth of Internet routing tables, while improving the welfare of sites and Internet Service Providers. 1.