Channel scheduling is a key technology in Optical Burst Switch network. In conventional sense, BHP (burst header packet) is always processed at the core node once it is received. Compared with these immediate scheduling algorithms, BHP will be delayed to a time window in Group Channel-Schedule Algorithm before it is scheduled. As for the Group-Channel Schedule Algorithm, analysis was made to investigate the influence caused by the schedule time window ▵t on the performance of OBS network. Then comparison is made between the currently used immediate schedule algorithms and the group-schedule algorithm. Evaluation results show that the packet loss performance is improved.
Optical burst switching (OBS) provides a feasible paradigm for IP over DWDM. And one of key issues in OBS is the fast and efficient scheduling of bursts with different QoS demands. In this paper, we propose a novel window-based scheduling (WS) algorithm, in which all bursts arriving in the window are scheduled together based on priority BORA. Therefore batching scheduling can achieve an optimized BORA efficiency and then the number of contention in OBS can be reduced largely, and simultaneously priority scheduling in the window can efficiently enhance QoS. Simulation results show that the proposed WS algorithm with the optimal parameters such as window and max-delay, compared with BORA, can achieve more than one order blocking probability reduction for high priority bursts and approximately 3.5% improvement in bandwidth utilization at 0.8 load.
Contention resolution is one of the critical technologies in optical burst switch network, In this paper, we focused on this challenging issue, and introduce a novel scheme called batch channel-schedule. In a conventional OBS network, core node will process BHP(burst head packet)at once when it arrives, yet in our batch schedule mode, BHP is queued and then processed combining with a certain schedule algorithm at a batch schedule time. In this way, a much better decision can be made about a lot of bursts all-together. Through simulations, our algorithm is proved to improve performance and reduce burst loss probability.
High efficiency, long wavelengths InP/InGaAs resonant-cavity enhanced (RCE) Photodetector was fabricated. To circumvent the difficulty in achieving high reflective InP-based DBR, the Si/SiO2 DBR was evaporated as the bottom mirror of the cavity by using back illumination from the substrate. A quantum efficiency of 80% at 1.583um was achieved with an absorption layer thickness of only 0.2um. In addition, the Micro-pectinated Carrier-Collected Layer (MCCL) was fabricated by proton implantations, thus device capacitance can be reduced without decreasing of the illuminating area. The bandwidth was increased from 600MHz to 800MHz experimentally by formation of MCCL, without decreasing of the quantum efficiency.
As a promising switching paradigm, Optical Burst Switch (OBS) was proposed for optical networks showing more efficient and shorter delay than traditional circuit switching, and it is more feasible than optical packet switching. In OBS, burst assembly is one of the critical technologies, and will significantly affect the performance of networks. In this paper, we focus on the study of burst assembly mechanism, and propose a new burst assembly algorithm, which reduces the self-similarity of IP traffic, enhances the data burst utilization and avoids the bandwidth contention due to sending burst data synchronously at different ingress nodes.