title: Congestion phenomena on complex networks.
abstract: We define a minimal model of traffic flows in complex networks in order to study the trade-off between topological-based and traffic-based routing strategies. The resulting collective behavior is obtained analytically for an ensemble of uncorrelated networks and summarized in a rich phase diagram presenting second-order as well as first-order phase transitions between a free-flow phase and a congested phase. We find that traffic control improves global performance, enlarging the free-flow region in parameter space only in heterogeneous networks. Traffic control introduces nonlinear effects and, beyond a critical strength, may trigger the appearance of a congested phase in a discontinuous manner. The model also reproduces the crossover in the scaling of traffic fluctuations empirically observed on the Internet.
authors.affiliation: International School for Advanced Studies SISSA and INFN, via Beirut 2-4, 34014 Trieste, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: De Martino
authors.forename: Luca
authors.initials: L
authors.lastname: Dall'asta
authors.forename: Ginestra
authors.initials: G
authors.lastname: Bianconi
authors.forename: Matteo
authors.initials: M
authors.lastname: Marsili