  We study network traffic dynamics in a two dimensional communication network
with regular nodes and hubs. If the network experiences heavy message traffic,
congestion occurs due to finite capacity of the nodes. We discuss strategies to
manipulate hub capacity and hub connections to relieve hub congestion. We find
that the betweenness centrality (BC) criterion is useful for identifying hubs
which are most likely to cause congestion, and that the addition of assortative
connections to hubs of high BC relieves congestion most efficiently.
