共查询到18条相似文献,搜索用时 78 毫秒
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一种高效的ASON安全光路建立协议 总被引:2,自引:0,他引:2
针对自动交换光网络光路建立过程中存在的安全威胁,提出了一种高效的安全光路建立协议.该协议使用综合的波长预留策略,通过数字签名和消息反馈等安全机制,对GMPLS RSVP-TE消息中的重要对象进行完整性保护,并可防止内部节点的恶意或自私行为.另外,考虑到自动交换光网络中路由模块和信令模块强耦合的特点,采用OSPF-TE的PKLSA消息分发光路建立协议中所需的节点公钥证书.经仿真实验及分析表明,该协议在保证光通路安全建立的同时,在连接阻塞率、光通路建立时间和消息负载方面都优于原有的RSVP-TE信令协议. 相似文献
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针对基于多协议标记交换的光突发交换网络在组网过程中存在传输性能劣化的问题,采用最坏值的方法,从典型光交叉节点的串扰特性入手,分析推导了网络中多个节点级联后同频串扰对传输性能的影响,并通过仿真进行验证.分析结果表明,核心节点级联产生的串扰累积是导致该网络传输性能劣化的重要因素. 相似文献
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组播业务的迅速增长对现有光网络的光路分配提出了更高的挑战.针对在大规模的光网络中,由于光组播路径中光信噪比过低导致传输层光链路无法正常工作,并由此带来"假性信令成功"的问题,提出了一种光信噪比受限的光组播路径分配机制.该机制充分利用光网络节点中光信噪比监测功能,在信令消息中携带光信噪比性能参量,并在光组播路径分配的信令过程中将光信噪比作为光波长分配的重要依据.通过该机制,控制平面在信令过程中充分考虑光信噪比因素,确保传输层的光组播路径得以顺利建立并正常工作.仿真结果表明,所提出的基于光信噪比感知的组播光路分配机制能够解决"假性信令成功"的问题,并有效降低光组播路径的阻塞率. 相似文献
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一种新的光突发交换网络信令协议与分析 总被引:1,自引:1,他引:0
提出了一种新的光突发交换网络信令协议,即DSH区分服务混合信令.根据实时(电路仿真)业务和非实时(数据)业务对QoS的不同要求分别采用TAW和JET信令控制协议,尤其是对TAW信令做了相应改进,使之更适合于OBS网络承载电路仿真业务.利用电路仿真业务发出的呼叫请求,在端到端的波长通道中建立虚通路,并在整个呼叫持续过程中保持虚通路的连接,这样可以保证电路仿真业务的端到端时延最小并避免信息丢失.通过理论分析和系统仿真,研究了DSH混合信令的性能及其对波长利用率和实时业务呼损率的影响. 相似文献
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为了节约网络成本和提高网络性能,将RSVP协议和OSPF协议进行扩展,提出了一个支持业务梳理的智能光网络组播协议,给出了消息类型,信令流程及状态机模型,并通过仿真验证协议性能.仿真表明,业务梳理可以一定程度降低组播业务阻塞率,但业务建立时延却大于不存在梳理的情况.梳理的存在使业务建立时延随着业务量的增大有一个由小变大再减小的过程. 相似文献
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用于WDM光突发交换网的改进JIT信令协议 总被引:1,自引:1,他引:0
提出了一种用WDM光突发交换网的良好时间通信协议(MJIT-SP)该协议结合了光线路交换和光分组交换的优点与用于光突发交换的其他信令协议相似,MJIT-SP的特点也是采用带外控制信号处理来排除核心节点处对光缓存器的需求然而,与其它协议如JIT-SP相比,它能最小化数据源端的建立时间和最大化交叉连接的带宽利用率而且,MJIT-SP还能支持光网络中无连接和面向连接的数据包传递并介绍了MJIT-SP的基本结构并从三个方面分析了它的基本性能,即建立时间、端到端延时和信道占用时间然后,对本协议与JIT-SP的性能进行了比较,结果显示:MJIT-SP不仅优于JIT-SP,而且还克服了JIT-SP的一个缺点,即过长的信道占用时间此外,还给出了MJIT-SP的信令信息,尤其是非常关键的信号与脉座电平差(SETUP)消息MJIT-SP中的SETUP与JIT-SP中的SETUP不同,它需要给出数据包路由和交换所需的信息,包括数据包长度、比特率、SETUP与数据包之间的偏置时间以及数据业务的质量控制系统(QoS)要求等最后讨论了MJIT-SP两种可能的变化并且分析了它们的优缺点. 相似文献
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《物理学报》2017,(5)
本文基于有向加权网络模型,构建了三个影响力矩阵,并利用层次分析法对其赋权求和,形成多重影响力矩阵,从而提出了一种基于该矩阵的节点重要性评价方法.该方法通过新定义的交叉强度指标,来表征节点的局部重要性;利用金网节点对待评估节点的重要性影响总值,来表征节点在全网中的相对重要性.在分析影响节点对待评估节点的影响比例时,既考虑到节点间的距离因素,又引入了最短路径条数因素;既考虑了该影响节点对网络中其他节点的影响关系,又考虑了网络中其他节点对该待评估节点的影响关系,使得评价方法更加全面.将算法运用于ARPA网络,结果表明,该方法能有效地区分各节点之间的差异,最后,对实验结果进疔连锁故障的仿真对比实验,进一步验证了方法的有效性. 相似文献
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Restoration approach in WDM optical networks 总被引:3,自引:1,他引:2
Critical applications require proactive-based survivability strategy which provides 100% degree of survivability, low blocking probability and very low restoration time. In this paper, we have proposed an efficient proactive restoration approach for WDM optical network that efficiently utilizes the resources and reduces blocking probability as compared to existing proactive restoration approach. It gives priority to primary lightpath as compared to backup lightpath because primary lightpath should not share resources with other lightpaths in critical applications but backup lightpaths can share the resources, i.e. backup multiplexing. 相似文献
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This article compares the performance of WDM lightpath protection and IP LSP protection schemes for IP-over-WDM networks. A mathematical formulation of the maximum throughput problem is presented and analytical expressions for recovery time are derived for both schemes. The throughputs and recovery times are analyzed and compared. Results show that the IP LSP protection scheme presents higher throughputs then WDM lightpath protection. The IP LSP protection scheme, providing individual IP LSP protection has, however, scalability problems. This scheme presents high recovery times when a failure affects many lightpaths and many hops are allowed for the primary routes of IP LSPs. 相似文献
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Compensation control study based on impairment-aware for Wavelength Switched Optical Networks (WSON) 总被引:1,自引:0,他引:1
In an optical network, the optical signal transmitted along the lightpath may need to travel through a number of cross connect switches (OXCs), optical amplifiers, and fiber segments. While the signal propagates toward its destination, the optical components would continuously degrade the signal quality by inducing impairments. When the signal degradation is so severe that the received bit-error rate (BER) becomes unacceptably high, the lightpath would not be able to provide good service quality to a connection request. Such a lightpath, which has poor signal quality due to transmission impairments in the physical layer, should not be used for connection provisioning in the network layer. This paper presents an adaptive PID controller based on the power compensation of BP neural network to restrict the influence of the impairment power for a networked control system (NCS) with the presence of controller time-delay and power compensation at amplifiers' node firstly. Control algorithms continuously adjust their channel powers in response to dynamic information from the network links. And the controller could achieve the on-line adaptive power compensation without changing the parameters of PID controller. The results of simulation show that the proposed controller could adjust better channel power at the transmitter sites and achieve channel optical signal-to-noise ratio (OSNR) optimization with controller's time-delay. 相似文献
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Abstract This article compares the performance of WDM lightpath protection and IP LSP protection schemes for IP-over-WDM networks. A mathematical formulation of the maximum throughput problem is presented and analytical expressions for recovery time are derived for both schemes. The throughputs and recovery times are analyzed and compared. Results show that the IP LSP protection scheme presents higher throughputs then WDM lightpath protection. The IP LSP protection scheme, providing individual IP LSP protection has, however, scalability problems. This scheme presents high recovery times when a failure affects many lightpaths and many hops are allowed for the primary routes of IP LSPs. 相似文献
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To improve the network performance after traffic demand changes , reconfiguring the logical topology is necessary. We present an ILP algorithm to find out the least lightpath changes needed with guaranteed network performance. 相似文献
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云纹干涉法面内位移测量的光栅补偿方法研究 总被引:2,自引:0,他引:2
分析导致云纹干涉法面内位移和应变测量的根本原因,给出对称入射光路云纹干涉法面内位移计量的基本公式,设计定量补偿面内位移和变形的非对称光栅补偿光路系统。最后证明基准光栅补偿方法的可行性和可靠性。 相似文献
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《Optics Communications》2004,229(1-6):233-239
Due to transmission impairments, optical regeneration is needed to extend the length of a lightpath beyond its transparent length. Spare transmitter (Tx) and receiver (Rx) modules in an optical network node can be used for optical regeneration. A Max-spare algorithm for locating the regeneration nodes for a lightpath is proposed and compared with a Greedy algorithm in conjunction with two routing algorithms, namely, wavelength weighted (WW) and length weighted (LW) routing algorithms. Through simulation we find that significant number of lightpaths that cannot be established due to the violation of transparent length can be established if the regeneration algorithm is used to select transit nodes that have spare Tx and Rx for 3R regeneration. The translucent optical network with limited number of transceivers can still perform close to a transparent optical network with full set of transceivers. We find that for the same routing algorithm, the Max-spare algorithm yields better results than the Greedy algorithm. In addition; for the same regeneration nodes selection algorithm, the WW algorithm has better performance than the LW algorithm. 相似文献