onstituted by data and both high-speed data and telephone have to be delivered almost to every user. Evolving the network in pace with traffic evolution without changing the architecture would be a SO CAPEX-intensive operation that carriers have been driven toward a com- plete network redesign. At the base, there is the most natural consequence of data traffic domination: a tele- phone network carrying also data has to be transformed into a data network carrying also telephone. From an equipment point of view, this means eliminating the separation between data and telephone networks and deploying a unique network whose nodes are based on packet switching. From a transmission point of view, TDM systems are substituted by powerful WDM systems. This is a technically complex and very CAPEX-intensive operation, lasting several years and still undergoing for many carriers. As far as the equipment is concerned, the final tar- get is to deploy a network architecture that fulfills two main requirements: 1. Scaling with the increase of traffic with minimum CAPEX 2. Relevant OPEX reduction mainly due to the following expectations The power consumption of the packet machines is smaller for a given network traffic load with respect to the equivalent TDM machines. Packet machines are more compact, due to the concentration in a single machine of all the logical functionalities that where performed by a plethora of machines in the old network. However, the traditional telephone has to be delivered maintaining all the related services in such a way that the end user does not perceive the difference due to the network para- digm change. This causes the introduction of a new class of equipment whose role is to manage the telephone service exactly like other services (e.g., IP TV, network storage, etc.), through dedicated network equipment. This equipment relies essentially on a specific software to emulate the hardware perfor- mances of a traditional telephone switch and is called soft-switch [33]. Up to now, the requirements of ne