Segmented Burst Switching: Enhancement of Optical Burst Switching to Decrease Loss Rate and Support Quality of Service

With the growing demand of bandwidth and the development being made in the optical components technology, the IP over DWDM using optical burst switching seems to be the best solution to take advantage of the huge capacity of the fiber and accommodate high traffic of information. In this architecture the optical network is seen as an optical cloud with intelligent edges capable to interpret the IP address and store the information in electronic domains as well as checking and correcting errors. Optical burst switching [1,3] achieves better bandwidth exploitation because all the fiber wavelengths are shared among the bursts without resource pre-allocation and the whole wavelength capacity can be used by a burst. However with higher load, contention increases, and hence the number of dropped burst increases leading to a big lost of performance. Several methods can be used to lower the burst-dropping probability such as wavelength conversion [5] and the use of buffers [6], but these solutions are still not there due to the high cost and the immaturity of technology. In this paper we will propose another method where the burst is segmented into several parts of equal length and in case of contention only the parts at the beginning, causing the conflict, will be discarded. We will analyze and compare this method with other practical methods: delayed burst, deflection routing. The segments of burst can be used to carry different class of service since the dropping probability of each segment depends on its position in the burst. The parts at the end have the smallest probability to be dropped. We prove trough analysis and simulation that the segmented burst improves the performance and is more suitable for traffic with several class of service.