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Evolution and Structure of the Internet

Romualdo Pastor-Satorras, Alessandro Vespignani

posted on 01 May 2004

reviewed by Ginestra Bianconi

The exponential booming of the Internet must have overcome the
expectations of the researchers that start working on it in the early
1960. Even more surprising is that this successful technological and
communication system has become the object of statistical physics
research in the last half decade.
What is the relevance of large-scale properties of the Internet and what
are the new results that the study of this system can bring to
statistical physics?
Now a new book of the world experts R. Pastor-Satorras and A. Vespignani
"Evolution and Structure of the Internet: a Statistical Physics
Approach" provides a diffuse and articulate answer to these questions.
The keywords in this field is "network structure and evolution". In fact
properties like the robustness of the Internet which is able to bypass
local breakdown of routers or every-day life phenomena like the long
life of computer viruses are routed in the network structure of the
system and while studying, probing and modeling the Internet one cannot
neglect its dynamical nature.

The reader of the book is introduced to a deep characterization of the
physical Internet and of the virtual network defined on it (the
World-Wide-Web for example but also the email network and the
peer-to-peer network). Sometimes this brings the author to present new
mechanisms like the so-called preferential attachment that drives the
dynamic of Internet sometimes this brings the authors to provide a full
comprehension of real phenomena of the Internet in the framework of
classical problems in statistical physics (robustness of the Internet
viewed like a percolation problem, spreading of computer viruses viewed
like an epidemic spreading). But the book contains also chapters on less
formalized problems as the search on the World-Wide-Web and traffic
problems in the Internet providing a stimulating point of view for
further research.
The book is very well written motivating deeply the results and deriving
analytical calculation in an exhaustive not redundant way, when needed
using the reference to useful appendixes.

The idea that the book promotes that is widely diffused in the physics
community and with whom we agree is that large-scale properties of the
Internet are preserved by the Internet evolution and are consequently
crucial characteristics that have to be considered and exploited to
validate and improve new technology.On the other hand from the
statistical point of view Internet is a prototype of a complex system
and its understanding is important also to compare its properties with
properties of other complex systems. Finally the study of its structure
suggests very abstract questions of graph theory.
We strongly recommend the reading of this important book to the wide
public of computer scientists, mathematicians and physicists.