Understanding incentives for prefix aggregation in BGP

Abstract

Over the last few years, a significant amount of the effort of the Future Internet architecture is devoted in order to improve the scalability of the next generation routing architecture. In this paper, we study providers' incentives to perform prefix aggregation or deaggregation of non-customers routes. This is essentially a trade-off between reduced router memory and reduced capacity of attracting customer traffic. We study the case where two ISPs compete for attracting traffic, by using game theory. In particular, we propose a game-theoretic model and we analyze the properties of the equilibrium. In a symmetric case, if a single Autonomous System (AS) is found to be deaggregating a given prefix, then all others will have the incentive to do the same, even if they end up with lower benefits. We find that pure equilibria do not always exist and we derive the conditions based on two model parameters. These findings suggest that BGP instability can be a common problem in a competitive scenario.