基于阈值检测的光突发交换偏射路由算法

光突发交换是适合在当前技术条件下的新交换技术,它比电路交换灵活,带宽利用率高,又比光分组交换易于实现,将成为下一代光IP骨干网的核心技术。在光突发交换网络中,偏射路由算法是有效解决突发竞争、提高网络性能的一种重要措施。首先分析了发送端控制的偏射路由技术,在此基础上提出了一种基于阈值检测的偏射路由的改进算法。该算法通过跳数来控制无效偏射路由并通过有条件地丢弃偏射突发来保证正常突发的丢包率,从而减少偏射路由对网络负荷的影响,使整个网络的丢包率得到一定提高,改善网络性能。     

在OBS网络中有限制偏射路由的研究

利用带有偏射检测功能的偏射路由和节点重发机制来减少突发包丢失率和提高网络的性能.仿真表明它能很好的控制偏射路由上突发包的丢失率.     

基于竞争控制的光突发交换条件偏射路由算法

光突发交换(OBS)网络中,偏射路由算法是有效地解决突发竞争、提高网络性能的一种重要措施,但通过分析发现,它可能会导致偏射路由上正常(非偏射)突发的丢失率上升.提出了一种基于竞争控制的条件偏射路由算法,根据定义的偏射条件检测函数,有条件的偏射或丢弃竞争突发来保证偏射路由上正常突发的QoS.仿真表明该算法可以很好地控制偏射突发对网络偏射路由上正常流量的影响.     

一种基于门限的光突发交换受限偏射路由算法

提出了一种基于突发丢失门限的条件偏射路由算法（LDFD），该算法采用丢弃少量偏射的高优先级突发来保证偏射路由上较低优先级非偏射突发的服务质量（QoS）。当偏射的高优先级突发到达核心节点而该节点没有空闲数据信道时，就启用定义的偏射条件检测函数来判断是丢弃该突发还是允许其抢占非偏射的低优先级突发的资源，从而减少偏射突发与偏射路由上原有突发的竞争。仿真表明，该算法可以很好地控制偏射突发对偏射路由上正常流量的影响，并有效地提高整个网络的突发丢失性能。     

基于链路负载的光突发交换混合路由算法

偏射路由和丢弃重传都能够有效解决光突发交换(OBS)网络中的突发竞争问题.结合偏射路由和丢弃重传的优点,提出了一种基于链路负载的偏射和重传混合的路由算法(LHDR).它根据网络链路的流量负载来计算和存储偏射路由,同时通过链路的平均负载率和节点跳数来确定对竞争突发的偏射或重传.仿真结果表明,LHDR在网络流量负载很高的情况下,能获得很好的突发丢失和端到端延时性能.     

规则全光分组网络中偏射路由算法的分析

就在ShuffleNet和Manhattan Street Network两种规则网络中使用偏射路由算法后的网络性能以及允许一个时隙插入多个数据包对该算法的影响进行了分析。结果说明，偏射路由算法不仅能使网络得到较高的性能，而且发挥了网状网具有迂回路由的能力。当采用允许插入多个数据包的策略时，网络的吞吐量和平均跳转次数都有小幅度的增加。     

OBS网络中基于拥塞避免的提前偏射路由研究

突发竞争是OBS(光突发交换)网络需要解决的关键问题,偏射路由作为一种有效的竞争解决方案而被广泛研究。文章提出了一种基于拥塞避免的提前偏射路由算法,利用周期性反馈的网络拥塞信息按一定概率提前偏射部分突发包。与传统的最短偏射路由算法相比,本算法达到了避免拥塞以及均衡网络负载的目的。仿真结果表明:文章所提算法在突发丢失率、吞吐量以及平均链路利用率方面性能都有所提高。     

OBS网络中偏射路由的研究

目前光突发交换（OBS）技术作为下一代光互联骨干网最有前途的交换方式受到广泛关注。偏射路由是一种有效的竞争解决方案。根据已有的研究,首先介绍了偏射路由的概念;然后探讨了偏射路由解决方案的关键问题,如偏射路由时间、控制分组的格式、节点的功能模块和实现算法;最后将偏射路由与其他竞争解决方案进行了比较。     

OBS中基于优先级与负载均衡的偏射路由算法

为了解决偏射算法在偏射控制七的问题,提出了一种基于优先级与负载均衡的偏射路由算法.当冲突发生时,分割优先级低的突发数据包;将冲突部分的突发包偏射到空闲的链路上,并在空闲的链路中选择若干条"当前最大剩余跳数小于源-目的节点的最大跳数"的路由作为候选路由;最后,在这些候选路由中选择一条可以使网络中各链路使用波长数的统计方差...     

支持业务均衡的OBS网络分布式回退偏射路由算法

突发竞争是引起光突发交换(OBS)网络丢包的主要因素之一,而作为一种有效的突发竞争解决方法的偏射路由,因其对光缓存器的性能和数量要求较低而备受关注。然而,现有偏射路由算法忽略了偏射业务对偏射路径上原有业务的影响以及业务被偏射后自身的成功传输率,同时也忽略由偏射引起的偏置时间不够的问题,致使OBS网络整体丢包率较高。为此,本文提出了一种支持业务均衡的分布式回退偏射路由算法(DBDF-LB),基本思路在于:从全网业务均衡出发,根据网络状态信息分布式的为偏射业务选择一条丢包率最小、跳数最短的路径;然后通过回退机制,利用网络资源来缓存突发包,从而补偿由偏射引起的额外偏置时间。与典型的最短路径偏射算法(SPDF)相比,DBDF-LB能有效降低丢包率约23~50%,而成功传输突发包所经历的平均跳数增加不到1跳。     

A Limited Deflection Routing Algorithm Based on Burst Loss Threshold in OBS Networks

1 Introduction The increase in the demand of transport capacity duetothe explosive growth of the Internet IP-based traffichas fueled the development of high-speed transmissionsystems andthe emergence of Wavelength Division Mul-tiplexing ( WDM) technology[1].Soin the near future ,it will be possible to support hundreds of wavelengths ofseveral Gigabit/s each. A new approach called OpticalBurst Switching (OBS)[2]that combines the best of op-tical circuit switching and optical packet switch…     

Contention-Based Limited Deflection Routing Protocol in Optical Burst-Switched Networks

Optical burst switching (OBS) is a very promising switching technology for realization of an economical optical Internet. In OBS networks, when contention occurs at an intermediate switch, two or more bursts that are in contention can be lost because a forwarding path reservation is not made for a burst until a control message for the burst arrives. That is the reason why one of the critical design issues in OBS is finding ways to minimize burst dropping resulting from resource contention. In this paper, we propose and analyze a novel deflection routing protocol, which mitigates and resolves contention with significantly better performance as compared with techniques currently known in the literature. While several variants of the basic deflection routing scheme have been proposed before, they all lacked the ability to determine the alternate route based on clear performance objectives. In this paper, we present an on-demand deflection routing scheme, which sequentially performs the following: 1) based on certain performance criteria, dynamically determines if the burst should be deflection routed or retransmitted from source and 2) if the decision is to deflection route, then the same is done using a path that is based on minimization of a performance measure that combines distance and blocking due to contention. The proposed contention-based limited deflection routing scheme prevents injudicious deflection routing. Our simulation results show that the scheme proposed here has much superior performance both in terms of burst loss probability and increased network throughput. Through analytical and simulation modeling, a number of useful insights into the OBS network protocols and performance are provided.     

机会网络中基于社会属性的按需密钥管理方案

针对机会网络的间歇性连通、快速移动、自组织管理等特征,提出了基于社会属性的按需密钥管理方案。首先利用基于身份的门限签名方案,实现了节点社会属性的自认证。随后结合机会网络的路由特性,节点之间根据社会属性匹配度有选择地颁发身份证书,并建立可度量的信任网。算法在优化证书图的同时,避免了恶意节点可能导致的无效证书链路的生成。实验仿真表明,该方案可提供较高的证书链重构成功率与节点认证可达率,并有效地降低了密钥管理所需的网络开销。     

Bit-per-joule performance of power saving ad hoc networks with a mobile backbone

Energy efficient MAC protocols have been developed for wireless sensor and mobile ad hoc networks so that inactive nodes can transition into sleep state to conserve energy. It has been recognized that maintaining a continuously awake connected dominating set (CDS) serves to reduce the route setup latency. Under the mobile backbone network (MBN) architecture introduced by Rubin et al., a mobile backbone (Bnet) is dynamically constructed to provide a topological covering of the network. The MBN employs a hybrid routing algorithm under which flows that travel a distance longer than a threshold are directed along routes across the Bnet. In turn, a limited span network-wide global route discovery process is applied for routing shorter distance flows. In this paper, we introduce and analyze an MBN based power saving protocol (MBN-PS) that employs this hybrid routing scheme. Under the MBN-PS scheme, dynamically elected backbone nodes are kept awake, while inactive non-backbone nodes can reside in sleep state. We analytically show that, when the number of network flows is above a minimal level, the throughput per watt efficiency attained in an ad hoc network under complete backbone coverage is better than that achieved by a corresponding network that does not form a backbone. We present a model for the calculation of the bit-per-joule performance of the network as a function of the distance threshold. We confirm the validity of our analytical approach through simulations. Using our method, a network designer is able to choose the optimal distance threshold to be used by this scheme, based on traffic loading conditions.     

部分共享波长转换光网络动态路由的改进算法

提出了一种应用于部分共享波长转换（PWC）的波长路由光网络（WRON）中的基于节点阻塞的动态路由算法,它不需要共享复杂的波长转换信息,而是将各节点的阻塞特性考虑到路由过程中。为评价算法性能,在14节点的国家科学基金网（NSFNET）拓扑中进行了仿真。结果表明,新的路由算法显著改善了网络的阻塞性能和建路失败的概率,尤其是随着网络负载的降低,网络性能的改善更显著。     

Computing approximate blocking probabilities for a class ofall-optical networks

We study a class of all-optical networks using wavelength-division multiplexing (WDM) and wavelength routing, in which a connection between a pair of nodes in the network is assigned a path and a wavelength on that path. Moreover, on the links of that path no other connection can share the assigned wavelength. Using a generalized reduced load approximation scheme we calculate the blocking probabilities for the optical network model for two routing schemes: fixed routing and least loaded routing     

对等网的快速路由模型

在DHT基础上建立一种快速的自组织路由模型(FSRM),设计了该模型的路由查找方法,节点加入与离开机制。同时,针对扰动环境下临近节点选择问题,提出稳定性阈值度量的方法,保证了对等网的快速路由和快速收敛。并在仿真测试中对该模型的性能进行了分析,证明该模型在收敛时间,节点查询速度,和对扰动的适应性方面优于传统的模型。