  We propose and study a model of traffic in communication networks. The
underlying network has a structure that is tunable between a scale-free growing
network with preferential attachments and a random growing network. To model
realistic situations where different nodes in a network may have different
capabilities, the message or packet creation and delivering rates at a node are
assumed to depend on the degree of the node. Noting that congestions are more
likely to take place at the nodes with high degrees in networks with scale-free
character, an efficient approach of selectively enhancing the
message-processing capability of a small fraction (e.g. 3%) of the nodes is
shown to perform just as good as enhancing the capability of all nodes. The
interplay between the creation rate and the delivering rate in determining
non-congested or congested traffic in a network is studied more numerically and
analytically.
