ABSTRACT
Telecommunication networks in all their various shapes are indispensable to bring information quickly
anywhere and anytime, which is a vital need of our modern global society. Since the invention of the
electrical telegraph by Samuel Morse in 1837, the variety of telecommunication services has grown at an
increasing pace, as illustrated in figure C1.2.1. In addition, the services are becoming ever more
individualized, and along with the penetration of video-based services (‘a picture says more than a
thousand words’) the request for information transport capacity has exploded and is continuing to do
so. Since the early 1990s, the introduction of the worldwide Internet has drastically promoted this
information transport explosion. The number of Internet hosts is still increasing exponentially; from
January 1992 to January 1997 to January 2002, it has grown from 727 thousand to 19.5 million to 147
million worldwide. This is causing data traffic to take an ever-larger share of the telecommunication
network capacity; since a few years, it has surpassed the volume of the traditional voice traffic (but not
yet its revenues). Wireless mobile telecommunication is attracting ever more users, and enables a fast
roll-out of services to the end users without the need to install extensive first-mile customer access
networks. The telecommunication market liberalization has provided ample opportunities to the entry
of more operators and service providers, and the resulting national and international competition is
pressing for very efficient high-capacity telecommunication networks.
