Multi-Period Network Design of Optical Transmission Networks

In this paper we study the multi-period network design problem (MPND), and focus on a special case, called multi-period network design with incremental routing (MPNDI). We optimize simultaneously the network architecture and the link dimensioning under discrete cost functions in order to route all traffic demands in line with traffic growth over a discrete time horizon. We are interested here in incremental routing, that is, routing paths used at a given period to route some traffic demands have to be preserved over subsequent periods. We present here some new valid inequalities related to multi-period incremental routing, in addition to some previous results already presented in [13]. Finally, some computational results for a range of instances with eight and ten nodes for two and three periods are given. They provide a comparison of the classical MPND problem and the MPNDI problem in terms of overall costs and CPU time.