Evaluation of burst loss rate of an optical burst switching network with wavelength conversion capability

Abstract

An analytical expression for the burst loss rate is proposed on the basis of a one-way protocol in a slotted optical burst-switching network with wavelength conversion capability. In this protocol; a wavelength is reserved" (in a core node) for a burst immediately after the arrival of the corresponding control packet. In our analysis, a slotted timing model is used in which the entire time period of a burst is divided; each of divided duration is called slot time. Burst loss rate is related with different network design parameters such as wavelength conversion capability, burst arrival" probability, network traffic, number of slots per burst and number of wavelengths. Further, analytical expression for burst loss rate is also extended which shows the relationship of burst loss rates between two different service classes. Each service class has a fixed number of reserved wavelengths. If the transmitted" burst of one service class is smaller than the number of reserved wavelengths, the excess reserved wavelengths of that service class are used to carry burstS of dIe other service class. In this situation, an algorithm is developed to calculate the number of wavelengths for each service classes. The burst loss rates between two service classes is differentiated'where one service class has increasing number of reserved wavelengths and the other service class has decreasing number of reserved wavelengths in an OBS network with constant number of wavelengths. Performance results are evalilated in terms of burst loss rate (BLR) for wavelength conversion capability, burst arrival probability, network traffic, number of slots per burst and number of wavelengths. Results show that system performance improves with the increasing of wavelength conversion capability and number of wavelengths but the system performance degrades whli the increasing of burst arrival probability and number of slots per burst or network traffic. The model results are found to be satisfactory agreement with the expected results. The anlll)-iicalresults of this thesis wi/Hind application in design of a WDM system in a slotted optical burst switching network with wavelength conversion capability.