The Internet is comprised of a large number of private and public networks,
which function as autonomous systems within the overall network. The netwo
rk structure of an individual network, which may have grown by acquisition,
has an impact on its efficiency. Using graph theory, this paper examines t
he network structure of ten "backbone" provider networks in the USA. The ne
tworks exhibit very different structures, which affect both the competitive
positions of the firms as providers of Internet service to their customers
and the nature of integration of other networks. (C) 2000 Elsevier Science
Ltd. All rights reserved.