  We study navigation with limited information in networks and demonstrate that
many real-world networks have a structure which can be described as favoring
communication at short distance at the cost of constraining communication at
long distance. This feature, which is robust and more evident with limited than
with complete information, reflects both topological and possibly functional
design characteristics. For example, the characteristics of the networks
studied derived from a city and from the Internet are manifested through
modular network designs. We also observe that directed navigation in typical
networks requires remarkably little information on the level of individual
nodes. By studying navigation, or specific signaling, we take a complementary
approach to the common studies of information transfer devoted to broadcasting
of information in studies of virus spreading and the like.
