In this paper, we propose a novel architecture for optical transport networks and its operation scheme guaranteeing the QoS requirements based on real-time traffic measurement. The key concept of the proposed architecture, which we call hybrid optical transport network (HOTNET), is to adopt both optical circuit switching and optical message switching in an optical network. To implement two different switching technologies in a single network, we modify the optical burst switching scheme and merge it into a TDM wavelength routed network. Then, we propose a control framework and an architecture of a switching node for this hybrid switching paradigm. We also discuss a real-time bandwidth provisioning scheme which utilizes the advantages of two respective switching schemes for traffic engineering. Finally, we evaluate the performance of the proposed scheme via computer simulation and the results show that it can guarantee the traffic QoS requirements while maintaining high channel utilization.

In this paper, we investigate the performance characteristics of parallel switching architectures constructed by a stack of multistage switching networks. We first find that the performances of the previously proposed parallel switching architectures are much worse than the expected ones from analytic models which are based on the assumption that traffic is uniformly distributed at each stage of a switching network. We show that this phenomenon is closely related to a traffic-distribution capability of a parallel switching system and has a large influence on the performance. From these results, we then propose an architectural solution based on the Generalized Shuffle Network (GSN) and analyze its performance by proposing a new iterative analysis method. The proposed architecture uses self-routing and deflection routing, and inherently has a traffic-distribution capability to improve switch performances such as cell loss and delay in a cost-effective manner. From the comparison of simulation and analysis results, it is shown that the developed models are quite accurate in predicting the performance of a new parallel switching system.