Research On Conflict Resolution Algorithm Based On Burst Segmentation In Optical Burst Switching Networks

With the great development of communication technology and new business emerges in endlessly, more and more user access and use networks. It strongly promotes the transmission bandwidth and the exchange rate of optical network to develop a higher level. The matures and commercial of dense wavelength division multiplexing (DWDM) technology provides the optical network approximate unlimited bandwidth and transmission capacity, and it will become the core transmission technology of backbone network. In order to overcome the electronic bottleneck, an optical burst switching (OBS) technology is proposed. Optical burst switching is considered as core switching technology of optical networks, achieving internet protocol-over-wavelength division multiplexing (IP-over-WDM), because of it has many advantages such us moderate exchange of size, all-optical transparently transmission, much more efficient of wavelength resource reservation protocol, higher bandwidth utilization and so on.In the OBS network, when two or more bursts request to reserve resources at the same time and on the same wavelength of the same output port, it will cause burst competition, thus reducing network bandwidth utilization efficiency. Therefore, reducing burst loss probability is the existing prominent problem in OBS network and one of key of whether the OBS network can move toward practicality. Firstly, the OBS network architecture and function of core node are studied in this paper. The basic operating principle and the three core technologies of which are summarized, and the core algorithms adopted by each item of technology are sketched. Then on this base, the operating principle and relative merits of several traditional conflict resolution methods in OBS network are analyzed.Secondly, in order to resolve the limitation of signal conflict resolution methods in dealing with the question of bust conflict, a conflict resolution algorithm which is based on burst segmentation and wavelength conversion in OBS networks is proposed. The idea of the algorithm is first segmented and then wavelength converted. Via setting the wavelength converter at the core node, the conflict parts of segmentation burst is converted to the free wavelength channels transmit. When a collision occurs, the low priority burst is first segmented. The collision free parts are handled directly in the reserved output data channel. The collision parts are converted to free wavelength channel by the wavelength converter. The result of the simulation shows that the algorithm is able to guarantee the transfer integrity of burst. What’s more, it can reduce the network burst packet loss rate. So the scheme efficiently improves the performance of OBS networks.Finally, three conflict resolution algorithms which are based on segmentation and wavelength conversion, segmentation and optical buffer, segmentation and deflection routing are carried out mathematical modeling and theoretical derivation. On the base, this paper makes a comparison between the conflict resolution algorithms which based on bust segmentation and wavelength conversion and the conflict resolution algorithms which based on bust segmentation and optical buffer. The result of comparison shows:When the network load is higher, the conflict resolution algorithms which based on bust segmentation and optical buffer can efficiently reduce the burst loss probability. When the network load is lower, the conflict resolution algorithms which based on bust segmentation and wavelength conversion can efficiently reduce the burst loss probability.