From Network Planning to Traffic Engineering for Optical VPN and Multi-Granular Random Demands

In this paper, we investigate the routing problem for dynamic traffic demands providing differentiated types of service across the network. Two classes of traffic are considered: QoS traffic and best-effort traffic. We propose a comprehensive offline/online routing solution that enables service providers to satisfy the demands of customer traffic flows while respecting the traffic priority. As a first step, an offline global optimization tool is used for network dimensioning. It aims to minimize the number of optical and electrical ports required in the network in order to satisfy a given set of high priority demands. Once the network's nodes are dimensioned, the network can be over-dimensioned to carry additional best-effort traffic requests. The latter set of traffic is routed by means of an online sequential optimization tool. Low priority traffic are divided into two subsets according to the requested capacity of the demands. This capacity may correspond either to an optical channel data rate (lightpath demands) or to a fraction of that rate (electrical demands). Our sequential optimization tool proceeds automatically to the grooming of the electrical demands into grooming demands. The network performance is expressed as the ratio of the number of rejected/blocked requests to the total number of requests