f networks, it is not possible to adopt them when network dimensioning is only a step of a complex procedure, for example, of a comparison between different network architectures or the study of the network sensitivity to a set of design variables. In this case, it could be necessary to repeat the dimensioning hundreds of times, which is quite hard using an ILP algorithm if the network is not particularly simple. Other times it is needed to have a first impression of the network deployment with a fast calculation, without resorting to the complexity of an ILP program. A plethora of heuristic network design algorithms have been proposed to be used in these cases, much less computation- ally hard than the ILP optimization. A class of design algorithms based on suboptimum design methods is those of the rout- ing-based design. These algorithms are inspired by the automatic configuration of the network and work as follows: A traffic matrix is individuated either through forecast of through statistical elaboration. A routing algorithm is also fixed for working capacity at all layers. Starting from the upper layer, connections are routed assuming the availability of infinite capacity in the network. At the end of the routing, the nodes and the links are inspected and the equipment required to sustain the performed routing is deployed. Every time that the dimensioning depends on the order in which the paths are routed, the dimensioning is performed in several cases and the cheaper solution is selected. Moreover the algorithm can be easily generalized to include design of survivability capacity both in cases of protection and restoration. For example, in case of 1 + 1 optical layer protection, the protection capacity is routed after the working one. In particular, the optical path protecting a link (i,j) is routed in the optical layer virtual topology where the link (i,j) has been eliminated and this procedure is repeated for all the links. Once the protection capacity has been provisioned it is consid- ered occupied exac