Resource allocation for dynamic routing in WDM networks

Dynamic routing in WDM (Wavelength Division Multiplexing) networks is achieving increasing interest due to the expected traffic growth for future optical networks. This contribution concentrates on network performance issues occurring for network operation under dynamic traffic load. In this context, routing strategies play a central role. We show that a new strategy achieves very good performance over a wide load range by making use of three beneficial components: providing multiple pre-calculated alternatives which are selected according to the network planning decisions, dynamic path search to search for routes in the cases where all pre-calculated alternatives are blocked, and an adaptive length limit to avoid on the one hand unnecessary restrictions for low traffic load, and on the other hand very long alternative routes for high traffic load. Moreover, specific effects for the influence of resource allocation strategies in photonic WDM networks are highlighted. This includes the dependence of a routing strategy on conversion degree and the influence of converter usage strategies in networks with partial conversion. The results show that an efficient routing strategy has to take into account various specific aspects of WDM networks to achieve good performance. Finally, we present how results from dynamic routing investigation can help to optimize the network planning process.