针对目前IP over WDM网络中的路由算法在负载均衡方面存在的问题,提出了一种考虑负载均衡的新型联合路由算法——负载均衡算法(LBA).该算法在链路(包括逻辑链路和物理链路)权值分配过程中考虑了节点负载的影响,并且在目标函数的选取中...针对目前IP over WDM网络中的路由算法在负载均衡方面存在的问题,提出了一种考虑负载均衡的新型联合路由算法——负载均衡算法(LBA).该算法在链路(包括逻辑链路和物理链路)权值分配过程中考虑了节点负载的影响,并且在目标函数的选取中充分考虑了链路资源的利用情况.通过对节点负载分布的方差和业务阻塞率的仿真分析,验证了该算法在负载均衡和网络资源优化利用及降低端到端时延等方面的优越性.展开更多
Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will con...Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will consume considerable time(compared with ground networks)derived from long ISL delay and flooding between hundreds or even thousands of satellites.During the network convergence/update stage,the lack of up-to-date forwarding information may cause severe packet loss.Considering the fact that ISL handovers for close-to-earth constellation are predictable and all the ISL handover information could be stored in each satellite during the network initialization,we propose a self-update routing scheme based on open shortest path first(OSPF-SUR)to address the slow route convergence problem caused by frequent ISL handovers.First,for predictable ISL handovers,forwarding tables are updated according to locally stored ISL handover information without link state advertisement(LSA)flooding.Second,for unexpected ISL failures,flooding could be triggered to complete route convergence.In this manner,network convergence time is radically descended by avoiding unnecessary LSA flooding for predictable ISL handovers.Simulation results show that the average packet loss rate caused by ISL handovers is reduced by 90.5%and 61.3%compared with standard OSPF(with three Hello packets confirmation)and OSPF based on interface state(without three Hello packets confirmation),respectively,during a period of topology handover.And the average endto-end delay is also decreased by 47.6%,9.6%,respectively.The packet loss rate of the proposed OSPF-SUR does not change along with the increase of the frequency of topology handovers.展开更多
In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiple...In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiplexing(WDM)networks,waveband conversion has been proposed to solve spectral contention in EONs.In this paper,we discuss the design of node architectures for an EON with waveband conversion.Four node architectures with shared Tuneable Waveband Converters(TWBCs)are proposed,and their blocking performances are evaluated by simulation.Simulation results show that the blocking probability of a node is significantly improved by waveband conversion.The sharing efficiency of waveband converters is also investigated.Simulation results show that at the same blocking rate,the node architecture with converters shared per node can save more than 20% waveband converters compared with that of the one with converters shared per link.展开更多
文摘针对目前IP over WDM网络中的路由算法在负载均衡方面存在的问题,提出了一种考虑负载均衡的新型联合路由算法——负载均衡算法(LBA).该算法在链路(包括逻辑链路和物理链路)权值分配过程中考虑了节点负载的影响,并且在目标函数的选取中充分考虑了链路资源的利用情况.通过对节点负载分布的方差和业务阻塞率的仿真分析,验证了该算法在负载均衡和网络资源优化利用及降低端到端时延等方面的优越性.
基金The National Key Basic Research and Development Program of China(Nos.2010CB328201,2010CB328202)the National Natural Science Foundation of China(Nos.60907030,60736003,61205058)+1 种基金the National High Technology Research and Development Program of China(No.2011AA01A106)the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)
基金the National Natural Science Foundations of China(Nos.61771074,62171059)。
文摘Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will consume considerable time(compared with ground networks)derived from long ISL delay and flooding between hundreds or even thousands of satellites.During the network convergence/update stage,the lack of up-to-date forwarding information may cause severe packet loss.Considering the fact that ISL handovers for close-to-earth constellation are predictable and all the ISL handover information could be stored in each satellite during the network initialization,we propose a self-update routing scheme based on open shortest path first(OSPF-SUR)to address the slow route convergence problem caused by frequent ISL handovers.First,for predictable ISL handovers,forwarding tables are updated according to locally stored ISL handover information without link state advertisement(LSA)flooding.Second,for unexpected ISL failures,flooding could be triggered to complete route convergence.In this manner,network convergence time is radically descended by avoiding unnecessary LSA flooding for predictable ISL handovers.Simulation results show that the average packet loss rate caused by ISL handovers is reduced by 90.5%and 61.3%compared with standard OSPF(with three Hello packets confirmation)and OSPF based on interface state(without three Hello packets confirmation),respectively,during a period of topology handover.And the average endto-end delay is also decreased by 47.6%,9.6%,respectively.The packet loss rate of the proposed OSPF-SUR does not change along with the increase of the frequency of topology handovers.
基金supported by the National Key Basic Research Program of China (973 Program) under Grants No. 2010CB328201,No.2010CB328202the National Natural Science Foundation of China under Grants No. 60907030,No. 61275071,No. 60736003,No. 60931160439the National High Technical Research and Development Program of China (863 Program)under Grant No. 2011AA01A106
文摘In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiplexing(WDM)networks,waveband conversion has been proposed to solve spectral contention in EONs.In this paper,we discuss the design of node architectures for an EON with waveband conversion.Four node architectures with shared Tuneable Waveband Converters(TWBCs)are proposed,and their blocking performances are evaluated by simulation.Simulation results show that the blocking probability of a node is significantly improved by waveband conversion.The sharing efficiency of waveband converters is also investigated.Simulation results show that at the same blocking rate,the node architecture with converters shared per node can save more than 20% waveband converters compared with that of the one with converters shared per link.
