EDFA span is L km long and the EDFAs are all similar with a gain G = aL, where a is the fiber attenuation in dB/km. Finally, let us design the links with a bit of DGD under-compensation that is completely recovered by the EDC at the receiver. The SNo at the output of a wavelength path will be in the ideal condition in which the gains are exactly selected to compensate losses (the gain of the preamplifier to compensate the losses at the receiver) (all in dB) (10.30) where N is the noise power introduced by traversing the ith entity (link or cross-connect) along the path Gpre is the preamplifier gain that is a system parameter In order to consider the transmission impairments, it is possible to tag every link and node with the generated noise power N and consider it as a cost related to the traversing of the node or link. At this point, the first step of dimensioning can be carried out as follows: Every couple of nodes is considered. The shortest path is calculated between the couple of nodes. The final SN, is evaluated for the shortest path: If SNo is greater that the reference SNr (e.g., SNref=11 dB with standard FEC) - The path can be transmitted transparently. If SNo is smaller that the reference SNref - The path is a translucent path and the nodes candidate to be regeneration nodes have to be identified. For each translucent path The path is divided into transparent subpaths in all the possible ways that employ the minimum number of regenerators. For each candidate node, its candidate degree is evaluated, corresponding to the number of translucent paths traveling through it and asking for regeneration. Regenerators are placed in the candidate nodes starting with those with a higher degree. Telecommunication Networks For each placed regenerator, the affected translucent paths are transformed in par- tial paths by dividing them in two at the newly inserted regeneration point. When the new paths are created, they are classified transparent or translucent like for the original paths. When no more translucent paths