Pairwise cooperations in selfish ring routing for minimax linear latency

This paper studies the selfish routing game in ring networks with a load-dependent linear latency on each link. We adopt the asymmetric atomic routing model. Each player selfishly chooses a route to connect his source-destination pair, aiming at the lowest latency of his route, while the system objective is to minimize the maximum latency among all routes of players. The effectiveness of these routing games is often measured by the price of anarchy (PoA), the worst-case ratio between the maximum latencies in a Nash equilibrium (NE) and in a system optimum, where NE refers to a “stable state” among all players, from which no player has the incentive to deviate unilaterally. In classical setting, no cooperation is allowed and 16 stands as the current best upper bound on the PoA of such selfish ring routing. In this paper we show that the PoA is at most 10.16 provided cooperations within pairs of players are allowed, where any two players could change their routes simultaneously if neither would experience a longer latency and at least one would experience a shorter latency.