ity. Telecommunication Networks As far as some restoration types are concerned, the following algorithm is used For each link construct the network topology without that link. Determine the paths affected by the link elimination. Reroute the affected path with the Dijstra algorithm on the new topology (where the failed link is eliminated) adding, where needed, new equipment. Analyze the new paths from the transmission point of view. If a path is not acceptable, either the notification is done SO that the corresponding working path cannot be restored if the considered link fails or an electrical regenerator is added to the OXC at half the path to regain transmission quality. The choice depends on the flag set at the beginning of the algorithm.. Construct a table associating the link failure with a restoration path for all the affected wavelength paths in case the restoration strategy requests preassignment. After the determination of the backup path for all the working paths, reconsider the whole network (working and restoration capacity). For the new network, repeat the procedure of creating new topologies cutting one link. For all affected restoration paths, try to find another route with a smaller cost. If this path exists, there is the possibility of rerouting. The rerouted path is analyzed from the transmission point of view. If it is not acceptable, either it is not rerouted (if regenerators are not selected as possible net- work elements) or two solutions are considered from a cost point of view: in the first the path is not rerouted, in the second a regenerator is added along the path. As always, the less costly solution is adopted. Shared protection is planned in a similar manner. 10.3.5.2 No Wavelength Conversion Cyclic Algorithm If no wavelength conversion is available, the algorithm that we have described in the pre- vious section is not enough. However, it is a possible starting point. As a matter of fact, the algorithm for the case in which wavelength conversion is not present works this way: Route w