Researches on the Architecture of Multi-Serviced Optical Networks which Enables the Quality of Service Provisioning

本研究的目的是研究超高速光网络的体系结构，重点研究通过公共网络平台提供不同质量等级服务的机制，并提出高效的光网络服务质量保证机制。为此，我们进行了两年的研究。在2004财政年度，也就是研究项目的第一年，我们研究了基于WDM的光突发交换网络中的服务区分机制，这是一种为下一代光网络提出的交换体系结构。我们已经提出了波长调度算法，该算法根据用户在一定时间段内的带宽使用情况来分配波长。在我们的算法中，服务区分是通过让较高类中的突发抢占较低类中的突发，或者通过丢弃过度使用资源的突发来实现的。仿真结果表明，我们的方案能够满足…的要求在突发丢失率方面提供了更有效的服务区分，而突发抢占机制的性能优于非抢占机制。在2005财年，我们发展了基于连续马尔可夫链模型的算法的分析方法。分析结果与仿真结果的比较表明，当突发长度服从泊松分布时，我们的模型是有效的。此外，我们还研究了提供绝对服务质量的机制，这是服务质量提供机制的另一个重要特征。我们提出了一种基于抢占的突发调度算法，该算法能够保证具有严格丢失率约束的类的突发丢失率。分析和仿真结果表明，该算法能有效地为较高等级提供丢包保证，同时抑制较低等级的不必要丢弃。本研究的主要贡献在于将服务质量提供的概念和机制引入了新的光交换模式。希望这项研究产生的成果将有助于在不久的将来研究和开发能够在高速光网络中提供服务质量的新的网络体系结构。较少

The purpose of this research is to study on the architecture of ultra high speed optical networks by focusing on the mechanisms that provide services with different quality levels through a common network platform, and propose efficient mechanisms for quality of service provisioning in optical networks. Towards this end, following studies have been carried out for two years.In Fiscal Year 2004, the first year of the research project, we have studied the mechanism for providing service differentiation in WDM based optical burst switching networks, which is a switching architecture proposed for the next generation optical networks. We have proposed wave-length scheduling algorithms that allocate wavelength to users based on their bandwidth usage during a certain period. In our algorithm, service differentiation is done by letting bursts in higher class preempt bursts in lower classes, or by dropping bursts which have over-usage of resources. Simulation results show that our schemes can p … More rovide efficient service differentiation in terms of burst loss rate, while burst preemption mechanism outperforms the non-preemptive one.In Fiscal Year 2005, we have developed the analytical methods for our proposed algorithms based on continuous Markov chain model. Comparison of the analytical results with simulations shows that our model is efficient when the burst length has Poisson distributions. Besides, we have studied on the mechanisms of providing absolute quality of service, which is another important feature for quality of service provisioning mechanisms. We proposed a preemption based burst scheduling algorithm that can guarantee the burst loss rate for classes with strict loss rate constraint. Our analytical and simulation results show that the proposed algorithm is efficient to provide loss guarantee for higher classes while suppress unnecessary drops for lower classes.The main contribution of this research is having adopted the quality of service provisioning notions and mechanisms into the new optical switching paradigm. Hopefully the outputs produced by this research will contribute as a part of the research and development of the new network architectures which enables the quality of service provisioning in high speed optical networks in the near future. Less