| With the explosive increase in network traffic and the emergence of high performance optical network devices, such as optical cross-connect (OXC) and optical add/drop multiplexer (OADM), wavelength division multiplexing (WDM) technology becomes the core technology of next generation networks. Because traffics are uncertain and unpredictable, optical networks are required to rapidly provide high-quality multi-granularity bandwidth services and applications to users. However, the dominant backbone networks are based on wavelength routing technology. As is well known, the minimum granularity used in the wavelength routing technology is a wavelength. And this leads to low utilization efficiency for the titantic bandwidth provided by the WDM technology. At the same time, optical packet switching (OPS) technology is falled into dilima due to lacking of available optical random access memory and to the difficulty in synchronization. To overcome these problems, optical burst switching (OBS) is proposed in the literature. The basic ideas underlying the OBS are two aspecs: the burstification (i.e. assemble multiple IP packets into a larger data burst) and the separation of transimmison and control. The OBS technology not only can combine the advantages of the wavelength routing technology and the optical packet switching technology, but also can overcome their disadvantages. From the comparison made in chapter 3, one can see that the OBS technology outperforms the wavelength routing technology in supporting packet traffic and is easier than the OPS technology in reasilization.The reaserch in this thesis comes from the hi-tech Research and Development Program of China under contract NO.2002AA122021. The focus in this thesis is on the realization of the OBS network edge node and correlant critical technologies such burstification queue manner, burstification queue management. Firstly, This thesis briefly reviews the ongoing project related to the optical technology and the history of switching technology in chapter 1. And chapter 2 briefly reviews the various aspecs of OBS networks, especially on the charater of OBS technology, on the control mechanism of the OBS network and on the critical technologies telated to the core node of OBS networks.Chapter 3 describes the architecture of an OBS edge node and the realization scheme in detail. Some related technologes are also presented in this chapter.Since there is no research on the burstification manner, which refers how to switch the incoming traffic from the line cards equipped at the OBS edge node to the burstification queues, chapter 4 proposes three burstification queue manners: centralized burstification queue manner, individual burstification queue manner and hybrid burstification manner. The performance of the three burstification queue manner is extensively studied by analysis and simulation. Results from analysis and simulations demonstrate that the centralized burstification queue manner is the best among them.Chapter 5 studies the burstification queue management problem, which refers to how many burstification queues we should set at each OBS ingress edge node and how to manage these burstification queues efficiently. This thesis proposes thress burstification queue management policies: static burstification queue management policy, quasi-static burstification queue management policy and dynamic burstification queue management policy. The performance of the three burstification queue management policies is studied in this thesis. Besides the analysis, extensive simulations are also made. Results from analysis and simulations demonstrate that the dynamic burstification queue management policy outperforms the other two burstification queue management policies since it employs less buffer and has better scalability than the other two burstification queue management policies.Since it's difficult to support Quality-of-Service (QoS) in optical burst switching networks, in our project, we take a hybrid network architecture. That is, we combine the wavelen... |
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