Excluding braess’s paradox in nonatomic selfish routing

Abstract

Braess’s paradox exposes a counterintuitive phenomenon that when travelers selfishly choose their routes in a network, removing links can improve overall network performance. Under the model of nonatomic selfish routing, we characterize the topologies of k-commodity undirected and directed networks in which Braess’s paradox never occurs. Our results generalize Milchtaich’s series-parallel characterization for the single-commodity undirected case.