Implementation of hybrid void filling algorithm in optical burst switching network

Abstract

Optical burst switching is a type of switching technology that is capable of harnessing the enormous bandwidth potential of the wavelength division multiplexing optical fiber to transport huge amounts of data from the data source to its destination efficiently. The optical burst switched network is made up of core and edge nodes that perform specific functions in the network. Burst scheduling and contention resolution are the two main functions of the core node. Two important design criteria for the core nodes inside this type of network is their ability to process control packets as quickly as possible and be able to utilize voids efficiently. These criteria are difficult to obtain in existing scheduling algorithms because there is always a trade-off between control packet processing speed and efficient bandwidth utilization. In this study, a hybrid scheduling algorithm that attempts to balance this trade-off is proposed and its goal is to improve the overall throughput of the optical burst switched network. The proposed algorithm works by utilizing the inherent good features of the First-Fit Unscheduled Channel with Void Filling algorithm and the On-Demand Burst Rescheduling algorithm. These algorithms are then coupled with burst segmentation. The addition of the segmentation technique is in order to further reduce the burst drop ratio to a minimum. The study was carried out through extensive computer simulation using the NCTUns 6.0 network simulator. It was shown that, with the availability of many wavelengths the proposed algorithm has the ability to reduce the burst loss ratio in the network by approximately 20% when compared with the other scheduling techniques. But as the number of wavelengths reduce; its performance resembles the base scheduling technique used to build it.