Techno-economical optimizations in optical backbone networks

When planning how to roll out a new network or extend an existing one, the operator has several possibilities for minimizing the costs. A first approach is to optimize the introduction time of new switching equipment (e.g. OXC) in the network, considering the estimated traffic-growth and evolution of the equipment-cost. We study the costs of a network-wide migration of introducing OXCs at a single point in time, as well as a so-called island-based migration in which the OXCs are introduced gradually. Another approach is to find the most economical way to realize the bandwidth in the network. There is the possibility to lease dark fiber on a per year basis or to acquire fiber via an IRU (Indefeasible Right of Use) for a longer period. We compare the total cost for dark fiber with the cost for leased wavelengths. In the case-studies, we use a planning period of multiple years.