Peering Versus Transit: A Game Theoretical Model for Autonomous Systems Connectivity

Abstract

We propose a model for network optimization in a non-cooperative game setting with specific reference to the Internet connectivity. The model describes the decisions taken by an Autonomous System (AS) when joining the Internet. We first define a realistic model for the interconnection costs incurred; then we use this cost model to perform a game theoretic analysis of the decisions related to link creation and traffic routing, keeping into account the peering/transit dichotomy. The proposed model doesn't fall into the standard category of routing games, hence we devise new tools to solve it by exploiting specific properties of our game. We prove analytically the existence of multiple equilibria 219 220 CHAPTER 14. PEERING VS TRANSIT for several scenarios, and provide an algorithm to compute the stable ones. Thanks to the use of simulations we covered those cases for which analytic results could not be obtained, thus analyzing a broad variety of general scenarios, both ad-hoc and realistic. The analysis of the model's outcome highlights the existence of a Price of Anarchy (PoA) and a Price of Stability (PoS), originated by the non-cooperative behavior of the ASes, which optimize their cost function in a selfish and decentralized manner. We further observe the presence of competition between the facilities providing either transit or peering connectivity, caused by the cost differences between these two interconnection strategies.