This paper is concerned with the characterization of the relationship between
topology and traffic dynamics. We use a model of network generation that allows
the transition from random to scale free networks. Specifically, we consider
three different topological types of network: random, scale-free with \gamma =
3, scale-free with \gamma = 2. By using a novel LRD traffic generator, we
observe best performance, in terms of transmission rates and delivered packets,
in the case of random networks. We show that, even if scale-free networks are
characterized by shorter characteristic-path- length (the lower the exponent,
the lower the path-length), they show worst performances in terms of
communication. We conjecture this could be explained in terms of changes in the
load distribution, defined here as the number of shortest paths going through a
given vertex. In fact, that distribu- tion is characterized by (i) a decreasing
mean (ii) an increas- ing standard deviation, as the networks becomes
scale-free (especially scale-free networks with low exponents). The use of a
degree-independent server also discriminates against a scale-free structure. As
a result, since the model is un- controlled, most packets will go through the
same vertices, favoring the onset of congestion.Comment: 4 pages, 4 figures, included in conference proceedings ISCAS 2005,
Kobe Japa
