Studies On The Performance Of Optical Burst Switching Network

With the rapid advance in wavelength division multiplexing (WDM) technologies,Optical Network has become the bone of Internet. Many researches have been done on the definition of the network architectures in order to realize the transmission and switch in the optical domain. Optical burst switching (OBS) networks have been receiving more and more attention. In this paper, we mainly discuss the contention resolution scheme and quality of service (QoS) in the OBS network.In chapter 1, the growth of architectures of optical network is reviewed. Then popular all-optical switching technologies, such as optical circuit switching (OCS), optical packet switching (OPS) and optical burst switching (OBS) are discussed, and their advantages and disadvantages are analyzed.In chapter 2, firstly the framework of OBS network is introduced. Then, key technologies of , such as protocol, resource reservation, assemble of bursts and contention resolutions, have been discussed and analyzed.In chapter 3, a novel contention resolution based on a Burst Dropping (BD) technique was proposed to be implemented for the OBS networks to support the quality of service (QoS). Based on the BD technique, we presented a wavelength resource reservation algorithm to guarantee a low packet loss rate for high priority burst by discarding the contention part of lower priority burst. By simulations, we evaluated the packet loss rate and end-to-end delay performance of the BD scheme and the traditional Just-Enough-Time (JET) scheme for comparison. Result shows that, the proposed scheme can provide a better QoS for high priority bursts with decreased end-to-end delay.In chapter 4, we proposed a new optical buffer configure unit (BCU) scheme, which based on Leaky-Bucket Traffic Model, to provide differentiated service for the OBS network. The new scheme could balance the weightiness of the blocking probability and the transmission delay very well and achieves a high resource utilization. Then the burst drop scheme and a buffer scheme were integrated to be a new OBS network switch node model. To evaluate its performance, we conduct some simulations and compare the scheme with a conventional QoS schemes used in the OBS network. A calculation result indicates that the new switch node model could provide better support for QoS and achieve higher utilization of the network resource.