We study the information traffic in Barab\'asi-Albert scale free networks wherein each node has finite queue length to store the packets. It is found that in the case of shortest path routing strategy the networks undergo a first order phase transition i.e., from a free flow state to full congestion sate, with the increasing of the packet generation rate. We also incorporate random effect (namely random selection of a neighbor to deliver packets) as well as a control method (namely the packet-dropping strategy of the congested nodes after some delay time T) into the routing protocol to test the traffic capacity of the heterogeneous networks. It is shown that there exists optimal value of T for the networks to achieve the best handling ability, and the presence of appropriate random effect also attributes to the performance of the networks.
@article{arxiv.0711.1655,
title = {Congestion diffusion and decongestion strategy in networked traffic},
author = {Zhi-Xi Wu and Wen-Xu Wang and Kai-Hau Yeung},
journal= {arXiv preprint arXiv:0711.1655},
year = {2009}
}