s LinkSummary and LinkSummaryAck or LinkSummaryNack (if the peer does not agree on some parameters). In this case a new LinkSummary message is sent after LinkSummaryNack. 8.3.2.7.4 Fault Management Since LMP is the tool that GMPLS control plane uses to manage the single point-to-point link, the procedure to localize a failure and to issue a notification message to the GLSR on Convergent Network Management and Control Plane the other side of the failed link starts, if it is the case, the restoration mechanism is located within the functionalities of LMP. To locate a fault up to a particular link between adjacent nodes, a downstream node (in terms of data flow) that detects data link failures will send a ChannelStatus message to notify its upstream peer. 8.4 Design and Optimization of ASON/GMPLS Networks The introduction of the ASON/GMPLS control plane is a real revolution in the carriers network, a new paradigm that substitutes the idea of centrally controlled network that was the strong point of the introduction of SDH/SONET. This evolution is strictly related to the gradual change in the service bundles that carriers offer to customers and consequently in the characteristics of the traffic routed through the network [4,5]. In particular the traffic is getting more dynamic and the operation of setting up a connec- tion or reroute a connection is no more a rare event. Moreover, and probably more important, it is much more difficult to foresee the evolution of future traffic. In the telephone era, when incumbent carriers were monopolist almost everywhere in the world, the traffic was strictly related to the population and to the well-known statistical characteristics of the telephone call. With the dominant role of data services and the mobility of the customers due to the competition of different carriers and to the variety of service offering, there is no more a known statistical distribution that helps carrier planners to forecast the traffic behavior. As a consequence, the network design has to be adapted to th