A Model of Interdomain Network Formation, Economics and Routing

Abstract

The Internet at the interdomain level is highly dynamic, as autonomous networks change their connectivity to optimize either monetary cost, profit and/or performance. Internet Service Providers (ISPs), for example, are mainly concerned with maximizing their profits, and they attempt to do so by changing their set of providers or peers. It is not well understood, however, what the properties of the resulting internetwork are, in terms of topology, economics and performance. In this paper, we propose ITER, a first-principles model of interdomain network formation that incorporates the effects of economics, interdomain traffic flow, geography, pricing/cost structures and interdomain routing policies. We use an agent-based computational method (treating networks as selfish agents) to find the equilibrium that results as each network uses a certain provider and peer selection strategy (such as “peer by traffic ratios” or “peer by necessity”). We study the properties of this equilibrium in terms of topology, traffic flow and economics. We also investigate the effect of factors such as the interdomain traffic matrix, geography, and customer preferences on the properties of the equilibrium network.