Performance evaluation of integrated OTN/WDM metropolitan networks in static and dynamic traffic scenarios

The introduction of optical transport network (OTN) switching technology in metropolitan networks enables efficient wavelength bandwidth utilization and reduces the number of wavelengths, leading to reduced network costs. It has been shown that the use of integrated OTN/WDM switch architecture is cost effective because it reduces the number of short-reach client interfaces and the rack space compared to an architecture that uses a re-configurable optical add-drop multiplexer and a separate standalone OTN switch or one that uses back-to-back muxponder connections to perform manual grooming. We have proposed an integrated OTN/WDM switch that allows for significantly lower complexity and cost at the price of relaxing the nonblocking ideal performance requirements normally applied to this kind of switch. In this paper we investigate the impact that the switch blocking has on the network performance in static and dynamic scenarios. We formulate the routing problem in the integrated OTN/WDM network as an integer linear problem and develop an efficient heuristic to evaluate the blocking performance in a static traffic scenario. We study the blocking degradation of the proposed switch in the case of some metropolitan networks, and we show how higher blocking occurs in networks having a larger average node degree. We also show that the degradation of two orders of magnitude in blocking probability occurring under a dynamic traffic scenario can be mitigated with the introduction of a spatial speedup equal to 1.5.