Reconfiguration of virtual topology on wavelength-routed optical ring networks with dynamic traffic

In this paper we consider the problem of reconfiguration of virtual topology on wavelength-routed optical ring networks with dynamic changes in traffic. Unlike previous studies on this problem, we select the traffic needing rerouting and the most congested link load as our objectives. In addition, we consider the traffic with both rapid and slow changes. When the traffic changes slowly, we will select the routing strategy based on the shortest path, taking into account the cost caused by the reconfiguration and choose a heuristic similar to generalized least processing time (GLPT) as the wavelength assignment algorithm. Our consideration does make sense in that the strategies mentioned above enable the virtual topology to be updated to follow the change in traffic closely, while considering some certain cost of the reconfiguration. On the other hand, if the traffic changes dramatically, we choose the strategy of adding lightpaths or deleting lightpaths(LAD). It is clear that this strategy will result in a smaller change in the virtual topology. This implies the reconfiguration will lead to a lower cost. Numerical results show that our approach outperforms the previous ones and that we can set up a network with no change in our physical topology, which can sustain various patterns of traffic.