ass. Costs deriving from failures: on one side, repairing costs like spare management and field interventions and, on the other side, penalties due to SLA violation when this event happens. Costs for authentication, authorization, and accounting (AAA). Costs for planning, optimization, and all the running activities for the continuous network upgrade both from a hardware and a software point of view. Costs related to commercial activities, including new commercial offerings and the launch of new services. From the list given earlier, it becomes evident that it is difficult to carry out an abstract evaluation of OPEX unless a completely defined specific situation is referred to. Telecommunication Networks OPEX depends heavily on factors like the kind of equipment the carrier deploys in its network, what equipment is of the most recent generation, what is legacy equipment, and if the control is integrated over all the network or if different parts of the network (e.g., areas where different technologies are deployed) have different control software. The organizational structure of the carrier also impacts the OPEX, and even the local laws regulating work contracts have their own influence. Nevertheless, analyzing the carrier balance sheets and working out carrier OPEX evalu- ation models [32], it becomes clear that OPEX is the main expenditure of a carrier that has an established network. For example, a good approximation of the OPEX expenditure related to network oper- ations for U.S. carriers is about 70% of the overall company expenditure and a similar situation also exists in Europe. As far as Far East carriers are concerned, two elements contribute to creating a different situation: on one side, the CAPEX is higher (relative to the overall carrier business) due to the need of developing the network in areas in which either it uses old technologies or it is practically not present; on the other side, the impact of the labor cost is smaller. However, analyzing the results of China Telecom, for example, OPEX redu