  We numerically investigate jamming transitions in complex heterogeneous
networks. Inspired by Internet routing protocols, we study a general model that
incorporates local traffic information through a tunable parameter. The results
show that whether the transition from a low-traffic regime to a congested phase
is of first or second order type is determined by the protocol at work. The
microscopic dynamics reveals that these two radically different behaviors are
due to the way in which traffic jams propagate through the network. Our results
are discussed in the context of Internet dynamics and other transport processes
that take place on complex networks and provide insights for the design of
routing policies based on traffic awareness in communication systems.
