Communication and optimal hierarchical networks

We study a general and simple model for communication processes. In the mod el, agents in a network (in particular, an organization) interchange inform ation packets following simple rules that take into account the limited cap ability of the agents to deal with packets and the cost associated with the existence of open communication channels. Due to the limitation in the cap ability, the network collapses under certain conditions. We focus on when t he collapse occurs for hierarchical networks and also on the influence of t he flatness or steepness of the structure. We find that the need for hierar chy is related to the existence of costly connections. (C) 2001 Elsevier Sc ience B.V. All rights reserved.