The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article pres...The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.展开更多
The deflection routing protocol is an effective contention resolution in Optical Burst Switching network, However, it can worsen loss performance of non-deflected burst on the deflection route. To improve the burst lo...The deflection routing protocol is an effective contention resolution in Optical Burst Switching network, However, it can worsen loss performance of non-deflected burst on the deflection route. To improve the burst loss performance, a limited deflection routing scheme based on burst loss threshold is proposed to prevent injudicious deflection routing. By using threshold check function, it restrainedly allows the deflected burst to preemptive network resource, consequently, improve the QoS performance of non-deflected burst. Simulation results show that the scheme can efficiently prevent deflected burst contending with non-deflected burst on deflection route, and effectively improve the burst loss performance of entire networks.展开更多
Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is no...Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as 'mixture' of WR and OBS. We believe the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, efficiency and etc. simultaneously. However, many related problems still need to be further researched.展开更多
模拟了基于曼哈顿网络模型的光突发交换。网络结构采用4×4的曼哈顿网络,偏折路由和JIT(Just In Time)信令协议;数据源选用具有自相似性的突发性数据源。分别对带波长转换器与不带波长转换器的网络的性能进行了模拟,并对结果进行了...模拟了基于曼哈顿网络模型的光突发交换。网络结构采用4×4的曼哈顿网络,偏折路由和JIT(Just In Time)信令协议;数据源选用具有自相似性的突发性数据源。分别对带波长转换器与不带波长转换器的网络的性能进行了模拟,并对结果进行了分析。结果表明,当网络负载达到0.3时网络的丢包率明显增大,而平均时延开始减小。本次模拟主要为下一步建立突发交换实验网提供有益的指导。展开更多
文摘The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.
基金This workis supported by project of National Science Foundation of China (No.90304004) , National"863"Project Plan (No.2005AA122310) , Keyproject of Science and Technology of National Education Department (No.204125) , project of Science Foundation of Chongqing Science and Technology Commission(No.2005BB2062) , Youth Science and Technology Grant of CQUPT(No.A2005-28) .
文摘The deflection routing protocol is an effective contention resolution in Optical Burst Switching network, However, it can worsen loss performance of non-deflected burst on the deflection route. To improve the burst loss performance, a limited deflection routing scheme based on burst loss threshold is proposed to prevent injudicious deflection routing. By using threshold check function, it restrainedly allows the deflected burst to preemptive network resource, consequently, improve the QoS performance of non-deflected burst. Simulation results show that the scheme can efficiently prevent deflected burst contending with non-deflected burst on deflection route, and effectively improve the burst loss performance of entire networks.
文摘Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as 'mixture' of WR and OBS. We believe the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, efficiency and etc. simultaneously. However, many related problems still need to be further researched.
基金The Young Junior Faculties Programme of Education Department of Henan Province(No.2011GGJS-081)the Project in Natural Science Research Foundation of Education Department of Henan Province(No.2010A510002)
文摘模拟了基于曼哈顿网络模型的光突发交换。网络结构采用4×4的曼哈顿网络,偏折路由和JIT(Just In Time)信令协议;数据源选用具有自相似性的突发性数据源。分别对带波长转换器与不带波长转换器的网络的性能进行了模拟,并对结果进行了分析。结果表明,当网络负载达到0.3时网络的丢包率明显增大,而平均时延开始减小。本次模拟主要为下一步建立突发交换实验网提供有益的指导。
