The Research For Optical Burst Switching Networks With Providing Service Differentiation

IP over WDM technology with the advantages of enormous bandwidth and simplified configuration is the evolving trend of next generation optical internet. However, as the network capacity increases, electronic switching nodes seem unable to keep up. Optical burst switching technologies (OBS) have many virtues such as supporting bandwidth multiplexing, fine granularity and facilitating the better synergy of the mature electronic technologies and the advanced optical technologies. Meanwhile, it should be considered that providing QoS support for special applications.The focus of this dissertation is on the study of OBS network architecture supporting (QoS), at the same time, some schemes and algorithms which could provide service differentiation are proposed. Firstly, based on the characteristics of all kinds of applications and the analysis of QoS parameters in optical layer, a mapping model between applications and QoS parameters is built. It is show that providing QoS support in optical layer is necessary and important and OBS can support service differentiation. In edge routers, burst assemble scheme with time and length limit and advanced reserving resource scheme based on load differentiation to provide delay differentiation are proposed. Detailed flow charts and processes are also introduced. Finally, simulation results show that burst assemble scheme could provide delay differentiation for different applications, which burst assemble timer and burst length threshold is set to smaller value for delay-sensitive applications and vice versa. Applications which employ LD-ARR scheme also have less delay in edge routers than those use conventional reserving resource scheme. In core routers, a delay scheduling before deadline (DSBD) algorithm to provide jitter differentiation are proposed. The expressions for upper and lower bound of delay and the upper bound of delay jitter are also derived. Numerical results show that DSBD scheduling algorithm could strictly guarantee the requirements of delay jitter for jitter-sensitive applications, which can reduce delay jitter of about 40% comparing with that without using this algorithm. And DSBD scheduling algorithm could support jitter differentiation for different applications.