lane, but are also different proposals on the table, partly complementary and partly alternative. Trying to make a synthesis, three different views emerge of the networking evolution, all representing a revolution more than an evolution. Naturally, each of these alternative views of the future networks has several different interpretations and depends in a different way on the technology evolution. 10.1.1 Digital Optical Network From the point of view of network management, the SDH/SONET remains the reference for all carriers. The strength of this standard is that the signal passes continuously through network elements that are capable of performing digital signal processing like regenera- tors, line terminals, ADM, and SO on. In this way, the network control is complete and detailed. In a wavelength division multiplexing (WDM) network, all-optical elements are on the contrary analog, as the amplifiers and the optical add drop multiplexers (OADMs). It much more difficult to implement monitoring and management functions through an ana- log equipment, and SO nodes containing analog optical elements are somehow function- ally poorer with respect to digital network elements. On the other hand, when WDM was introduced, there was SO huge a cost difference between the optical elements and the corresponding electrical one that there was no choice. However, with the great improvement in electronics, and with the possibility, at least on a III-V platform, of integrating optics and electronics components on the same chip, the situation could change. Carriers and equipment vendors pushing the digital optical network solution leverage on this evolution to propose a new physical layer architecture based not on analog optics but on digital electronics in order to be able to enrich signal processing and network man- agement functionalities. Telecommunication Networks In this view of the network, amplifiers are again substituted by monolithically integrated regenerators managing several wavelengths simultaneously and integrating 