  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.
