We propose a novel static primary routing algorithm, called ALB Dijkstra (Adaptive Load Balancing Dijkstra), which introduces new concepts and methods into the traditional Dijkstra algorithm to improve its performance with respect to burst drop probability in optical burst switching networks. This new algorithm has a basic version and an extended version, which are applicable to networks with and without wavelength converters, respectively. By introducing two new concepts of virtual link cost and virtual link-wavelength cost, the new algorithm is able to take account of the influence of actual topology and traffic load distribution in its adaptive searching procedure. ALB Dijkstra offers a fast approach to optimized path selection so that link resources can be utilized efficiently. Numerical simulations show that the overall network performance is significantly improved over the ordinary shortest-path routing strategy.
Considering the economic and technical aspects of wavelength converters, full wavelength conversion capability will not be available throughout optical networks in the foreseeable future. This letter investigates the wavelength assignment problem in wavelength-continuous optical burst switching (OBS) networks. First, we develop a novel static approach, termed balanced static wavelength assignment (BSWA), which outperforms all other static strategies, and achieves almost the same performance as dynamic strategies with the advantage that no extra dynamic information is needed. Then, we apply BSWA to a dynamic approach to accelerate network convergence and reduce the initial burst loss. Numerical results show that our approaches make significant improvements in the burst loss probability in OBS networks.
To reduce burst drop probability is a key issue in optical burst switching networks for it was connected strongly with the
network's overall performance. In this paper, we propose a novel O/E/O conversion and electronic storage based
strategy to resolve burst contention. Unlike traditional FDLs based contention resolution which is only able to provide
discrete buffering time, O/E/O storage based strategy can offer unlimited buffering time. We propose an intermediate
node architecture and corresponding scheduling algorithm called Nearest Available Void (NAV). Simulations show that
our novel burst contention resolution enjoys high contention resolution capability and only introduce extremely low
extra delay time compared to FDLs based mechanism. The maximum electronic RAM demand is also studied, and the
result shows that the demand is comparatively small, which implies the cost of this strategy can be economic.
Optical Burst Switching (OBS) is supposed to be a promising switching technology in the future WDM networks,
which is suitable to support burst traffic. A problem with OBS network is that bursts with longer routing lengths are
more likely to be dropped before arriving at the destination router. In this paper, we propose two approaches using offset
time differentiation (OTD) and burst length differentiation (BLD) to solve the burst loss differentiation (BLP) unfairness
problem in OBS networks. Simulations show that BLP fairness in OBS is greatly enhanced with our approaches,
especially with the OTD approach. Besides, we also investigate the BLP unfairness problem in offset time based QoS