Modern telecommunication networks are structured hierarchically. In the core network, the highest level, many flows from subnetworks are aggregated, resulting in high bandwidth traffic which has to be handled carefully. If optical transmission technology is applied, such networks are called optical transport networks.

Data flows in optical transport networks are transported along so-called lightpaths, ongoing optical connections between pairs of nodes. For their realization, many technical and operational restrictions must be taken into account. Among these, survivability of the connections is of special importance in the core network. Altogether, the planning of appropriate static lightpath configurations states a sophistical task for which we develop mathematical models and solution methods.