clear choice is to exclude all forms of free space communication and related networking techniques. Radio bridges are no longer used as transmission trunks in the network, but only for particular situations, generally in the access area. Almost all the wireless segment of the network is constituted by the cellular infrastructure that is a rel- evant part of the access network. Even if a strong push by the market exists toward a services and techniques convergence of wireless and wired access networks, the cellular network has up to now evolved with its own standards and specific equipment. Even radio technology used in cellular equipment is not utilized in other telecommu- nication equipment, having, on the contrary, common elements with other applications of Telecommunication Networks the radio technology like radars, free space communications between moving platforms (like airplanes or ships), and similar systems. Therefore, in Chapter 2, wireless access is considered only to look at wireless services. Readers interested in the wireless technology are encouraged to access the rich technical bibliography. Also, software technology is considered only marginally in this book, even if its evolu- tion is instrumental in the present transformation of telecommunication engineering. This will result evident from the great attention devoted to the network control pro- cedures, whose evolution would be impossible without modern software development techniques. Considering the different areas in which the wireline telecommunication network is divided, the greater attention is reserved to the so-called core network: that part of the net- work covering geographical areas that are extended over a continent or a big country. Here optical transmission systems convey thousands of Gbit/s over distances of thousands of kilometers, and IP routers of the capacity of several Tbit/s carry out the basic operations of the Internet. Service sources, like video on demand, IP TV servers, soft switches for the IP phone, and SO on, are gene