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Scheduling in a node plays an important role in improving the efficiency of exploiting the bandwidth of optical burst switched networks. This article focuses on analyzing the role of FDL buffer in scheduling and evaluating its performances basing on the simulation results on NS2. | JOURNAL OF SCIENCE, Hue University, Vol. 69, No. 6, 2011 THE ROLE OF FDLS IN SCHEDULING IN OBS NETWORKS Vo Viet Minh Nhat1 and Nguyen Hong Quoc2 1 Faculty of Hospitality and Tourism, Hue University 2 College of Pedagogy, Hue University Abstract. Scheduling in a node plays an important role in improving the efficiency of exploiting the bandwidth of optical burst switched networks. However, a burst cannot be scheduled and will be dropped if resources, including a wavelength channel and a position of scheduling an arriving burst on the channel, are not available. A solution to this problem is to use an FDL buffer to delay the appearance of the arriving burst at output, by changing the position of scheduling the arriving burst on the selected available wavelength channel, hopefully there exists an available resource at the delayed output time. This article focuses on analyzing the role of FDL buffer in scheduling and evaluating its performances basing on the simulation results on NS2. Keywords: OBS, Scheduling, FDL buffer. 1 Introduction To satisfy the increasing demands for bandwidth in backbone networks such as the Internet, many models of optical network have been studied and proposed. In these models, wavelength routing (WR) networks are relatively easy to be installed, but difficult to handle on variable increment flows and frequently changed-status links. Optical packet switching (OPS) networks are obviously the next choice to overcome the above disadvantages, but they require more advanced technologies such as optical buffer and optical packet switching fabric which are currently unavailable. A new approach is the model of optical burst switching (OBS) which combines the advantages of wavelength routing and optical packet switching networks. Fig. 1. The offset time is calculated at least equal to the total of processing and transmission time from source to destination 75 From the first proposal of C. Qiao and M. Yoo [1][2], OBS models quickly get much
