Logical topology optimisation for dynamic multilayer recovery schemes

This paper summary includes an overview description and first results of ongoing work on a logical topology optimisation problem. The problem is to find an optimal IP topology that routes a given IP demand matrix and makes it resilient against single router failures. The functionality of an underlying ASON is used to ensure survivability against single router failures, leading to what is called a dynamic multilayer resilience strategy. The routing in the IP layer is chosen to be OSPF in order to limit operational complexity. The recovery mechanisms in the optical layer make it survivable against cable cuts or optical node failures. The objective is to minimise the total cost of the needed resources, like IP router interfaces and WDM line system equipment. New in this optimisation problem is the possibility, as a result of the ASON, to reuse resources over the failure free and the failure scenarios.