Multiperiod Planning for Optical Networks - Approaches Based on Cost Optimization and Limited Budget

Multiperiod network planning is, especially for cost intensive and long term operated core networks, a necessity to provide cost efficient long term solutions. In this paper we give an overview on commonly used multiperiod planning approaches and compare their cost allocations and dependencies on cost decreasing factors. Furthermore, we propose a new multiperiod approach, which aims at a complete new orientation: Instead of minimizing network costs, a restricted budget is used not only to satisfy occurring demand but also to purchase equipment for future demand requests. With this approach we obtain long term solutions for optical networks with a restricted budget. This Budget-Restricted approach has a strong relation to applications in industry and public authorities. We use for our studies an integer linear optimization model which takes cost optimal routing and also the wavelength assignment into account. Additionally we provide a detailed cost function with a special interest on node costs.