, are still there. Nevertheless, the forecasted revolution of transparent optics did not happen and while the time goes on seems less and less probable. Several elements contribute to this apparently surprising result, and we will try to ana- lyze them. The first point is, for sure, the great CAPEX that would be needed to completely change the network core technology, at a time when the access network is also rapidly evolving. From the bubble end (see Chapter 2), carriers have greatly reduced the CAPEX to focus on the exploitation of the installed equipment. The transparent revolution would be clearly in the opposite direction. Telecommunication Networks Moreover, the new technology seems weak from a management point of view. Implementing T-OTN would require a complete change in the way the network is moni- tored, both as definition and as transport of monitoring variables and of management commands. The OPEX is strongly related to the management effectiveness of the network, and there is the risk that a solution built with the intention of reducing the OPEX, in the long run, will increase them in the early operational years due both to lack of instruc- tion about the new procedures and the lack of experience on the part of equipment vendors. On top of these elements, there is a possibility that if transparent networking is adopted, transmission trunks cannot be designed according to the required specifics, thereby losing the optimized design that today's systems have. In addition, 100 Gbit/s is clearly quite difficult to manage without a specifically designed link, and there is a diffused opinion that 100 Gbit/s is difficult to install in LH links in a transparent network. As far as bit rate and format transparency is concerned, pure transparent networks, for sure, can have this property, but as soon as a few regenerators have to be deployed to cope with long distances or huge OXCs, the full transparency is immediately lost. On the other side, standardization works very well in the core network allowing the limi