基于决策图贝叶斯的多目标QoS组播路由算法

随着实时组播通信需求的不断增长，要求网络能够提供更加严格高效的QoS(Quality of Service)路由保证，需要设计一个能够同时满足不同QoS约束的高效组播路由算法。此问题可归结为图论中的NP(Non-Polymenital)问题，一般方法是把多个QoS参数加权合并为一单目标函数进行优化。提出了一种基于决策图贝叶斯的多目标QoS组播路由算法，算法在不需做预处理的情况下可对多个不同的QoS参数同时进行优化。仿真结果表明，所提出的算法能够快速收敛于一组满足不同QoS约束的非支配解。     

Optimizing on multiple constrained QoS multicast routing algorithms based on GA

With the rapid development of Internet, mobile networks and high-performance networking technology,multiple constrained QoS multicast routing optimization in networks with uncertain parameters has become a very important research issue in the areas of networks and distributed systems. It is also a challenging and hard problem to the next generation Internet and high-performance networks, and has attracted the interests of many people. This paper discusses the multiple constrained QoS multicast routing problem, which may deal with the delay, delay jitter,bandwidth and packet loss metrics, and describes a network model for researching the routing problem. The paper mainly presents multiple constrained QoS multicast routing algorithm (MCQMRA), a QoS multicast routing policy for Internet,mobile network or other high-performance networks, which is based on the genetic algorithm (GA) and can provide QoS-sensitive paths in a scalable and flexible wayin the network environment with uncertain parameters. The MCQMRA can also optimize the network resources such as bandwidth, delay, packet loss metrics and can converge to the optimal or near-optimal solution within few iterations, even for the network environment with uncertain parameters. Simulation results show that MCQMRA is an available approach to QoS multicast routing decision.     

Multiple constraints-based QoS multicast routing: model and algorithms

1.INTRODUCTION Multicastserviceshavebeenusedbyvariouscontinu ousmediaapplications.Forexample,themulticast backbone(Mbone)oftheInternethasbeenusedto transportrealtimeaudio/videofornews,entertain ment,videoconferencing,anddistancelearning.The provisionofQoSguaranteesisofutmostimportance forthedevelopmentofthemulticastservices.Multi castroutinghascontinuedtobeaveryimportantre searchissueintheareasofnetworksanddistributed systems[1～4].Itattractstheinterestsofmanypeo ple. Afrequently…     

基于遗传算法与模糊选择的多播路由优化

遗传算法在优化计算特别是在多播路由问题中得到了广泛应用,但在进行大规模优化时,遗传算法存在着爬山能力差以及不成熟收敛等缺点。为此,提出基于启发式遗传算法和模糊选择机制的新型多播树计算方法,本算法采用树型结构编码和高效的遗传操作,同时优化时延、丢包率和带宽利用率等多个参数。仿真实验表明,这种算法用于多播路由多目标优化问题时,可以克服采用遗传算法进行多目标优化的缺陷。     

Multicast routing algorithm of multiple QoS based on widest-bandwidth

1 .INTRODUCTIONA mobile Ad hoc network refers to a temporal multi-hop autonomy system,whichis constituted by a groupof mobile nodes containing wireless send-receive equip-ments[1].It possesses manycharacteristics-fast-deploy-able,self-organized,acentric , movable and of multi-hop.It can be wildly applied to many fields ,such asnational defense,emergency and disaster ,scientificin-vestigation and exploration etc .,and uponthat ,it hasgreat prospects[1 ,3 6]. With the wide spread of mo-bile…     

QoS-aware multicast routing protocol for Ad hoc networks

1 .INTRODUCTIONA mobile ad hoc network ( MANET) is a multi-hopwireless network formed by a collection of mobilenodes without the intervention of fixedinfrastructure.Because an Ad hoc network is infrastructure-less andself-organized,it is used to provide i mpromptu com-munication facilities in harsh environments . Typicalapplication areas of mobile ad hoc networkinclude bat-tlefields ,emergency search,rescue sites and data ac-quisitionin remote areas . A mobile Ad hoc networkisalso usef…     

QoS multicast routing algorithm based on GA

1 .INTRODUCTIONTheprovisionofquality of service (QoS) guaranteesisofutmostimportanceforthedevelopmentofthemulticastservices .Multicastroutinghascontinuedtobeaveryimportantresearchissueintheareasofnet worksanddistributedsystems.Ithasattractedtheinterestsof…     

Distributed QoS multicast routing protocol in ad hoc networks

1 .INTRODUCTIONMobile ad hoc networks ( MANET) , also calledthe infrastructureless mobile network or self-or-ganized network,consists of a collection of mobilenodes sharing a wireless channel without any cen-tralized control or established communication back-bone .ad hoc networks have no fixed routers ;allnodes are capable of movement and can be connect-ed dynamically in an arbitrary manner . Usually ,these nodes act as both end systems and routers atthe same ti me . Nodes of these netwo…     

基于线性能量函数的组播路由算法性能评价策略

作为下一代高速网络的核心技术之一,多约束服务质量组播路由成为了当前网络研究的重点,但对算法性能进行合理的评价仍是一个开放性问题。提出了一种基于线性能量函数的组播路由算法性能综合评价策略——IESMR。算法通过线性能量函数将待评价组播算法的各项QoS性能转化为单一度量值,考察其距极限最优能量值的偏差半径作为算法性能综合度量指标。     

Distributed QoS multicast routing in networks with imprecise state information

1.INTRODUCTION WiththerapiddevelopmentofInternet,mobilenet worksandhigh performancenetworkingtechnology,itbringsoutextensiveinterestsofpeopleinproviding multimediaandreal timeservicessuchasvideoconfer ence,distanceeducation,entertainmentandsoon.Theseservicesrequirecertainquality of service(QoS)fromthenetworks.Thatis,thereshouldbe guaranteesastobandwidth,delay,delay jitter,ratio ofpacket lossandlowcostduringthedatatransmis sion.Meanwhile,multicastserviceshavebeenused invariousmultimediaap…     

一种基于改进蚁群算法的多点路由算法

蚁群算法是一种新型的随机优化算法,蚁群算法与其它随机优化算法同样存在收敛速度慢易于限于局部最小点等缺陷.提出一种改进的蚁群算法,并将其与启发式方法相结合以解决多点路由问题.仿真证明,基于改进蚁群算法的多点路由算法模型可以稳定地获得优于现有启发式算法的解,是一种有效的多点路由算法,同时该算法也适用于并行执行和应用.     

非线性约束最短路问题的启发式算法

多约束QoS路由优化是当前网络研究中的一个重要课题,而受限最短路问题(RSP)是QoS路由的一个基本问题。它是NP-完全的,并有许多具有多项式时间和伪多项式时间的启发式求解算法。然而这些方法只能求解一些带有线性约束的RSP。对一些非线性的约束(比如丢失率约束)大都用数学方法转化成线性约束来求解,这增加了问题的复杂性。本文提出了一种新的具有伪多项式时间的启发式算法来求解这类带非线性约束的RSP。主要思想是将非线性约束作为检验条件来使用。当每得到一个解时,检查解是否满足非线性约束。如满足,则得到最终解;否则在原问题中添加一个线性约束。该新约束将去除已经找到的解,从而使原问题的解空间进一步缩小,直到得到最终解。仿真算例说明了算法的有效性。     

A multicast routing algorithm with multiple trees

1.INTRODUCTION Qualityofservice(QoS)multicastroutinghascon tinuedtobeaveryimportantresearchtopicintheIn ternet.Multicastisacommunicationservicethatal lowssimultaneoustransmissionofthesamemessage fromonesourcetoagroupofdestinationnodes.To carryoutdifferentmulticastsessions,anetworkmust minimizethesessions’resourceconsumption,while meetingtheirrequirements.Efficientallocationof networkresourcestosatisfyQoSrequirementsisthe primarygoalofmulticastrouting.Howevertheinter dependencyandconfli…     

Multi-constraint quality of service routing algorithm for dynamic topology networks

An adaptive multi-QoS routing algorithm called AMQRA is proposed for dynamic topology networks, such as satellite networks and Ad-hoc networks. The AMQRA is a distributed and mobile-agents-based routing algorithm, which combines ant quantity system （AQS） with ant colony optimization （ACO） that is used in AntNet routing algorithm. In dynamic topology networks, the AMQRA achieves timely optimization for concave metric QoS constraint and fast convergence. The proposed routing algorithm is simulated in Iridium satellite constellation on OPNET. The results show that AMQRA not only outperforms the AntNet in convergence rate in dynamic topology networks but also can optimize concave metric QoS constraint and reasonably allot bandwidth to the load to avoid networks congestion.     

Bandwidth constrained QoS routing scheme for MPLS traffic engineering

Traffic engineering has been essential to optimize the utilization of network resource and to provide for QoS,QoS routing is a basic component of traffic engineering in MPLS networks. Aiming at some shortages of certain existing routing algorithms, we propose an efficient bandwidth constrained QoS routing scheme with additional traffic engineering objectives. The objectives of traffic engineering considered in our algorithm are to reduce the blocking probability of requests and to evenly distribute the traffic load. Accordingly, the algorithm avoids using critical links as far as possible by assigning large weights to them as a function of their criticality. The critical links can be specified according to max-flow reduction weight, a new link weight introduced by the algorithm. Then, a new defined additive metric, path saturation,is used to select optimal path. Extensive simulations are carried out to evaluate the performance of the proposed algorithm in terms of call blocking probability and link resource utilization. Compared to other several routing algorithms, the simulation results show the new algorithm performs well.     

基于配队蚁群算法的QoS组播路由方法

QoS组播路由是网络信息传输的一项关键技术,提出了一种配队蚁群算法对该问题进行求解。算法以满足约束条件下的组播分解、策略控制下的组播树生成为基本思想;定义了扩展组播树,并改进了蚁群算法的信息素更新策略,使之更适合于组播问题的求解。仿真实验表明,该算法能快速搜索并收敛到全局(近似)最优解,且随着网络规模的增大算法保持了良好的特性。     

QoS路由仿真器的设计与实现

随着QoS路由技术的发展，研究人员不断地提出新的QoS路由算法以满足多媒体业务的服务质量需求。实用的QoS路由算法在应用之前除了严密的理论分析之外，还需要足够的实验来进行实际验证。在没有实际的路由实验环境下，有必要设计性能良好的QoS路由仿真平台进行仿真实验。设计并实现了一个通用的、简单的、开放性强的QoS路由仿真器QRSIM，为QoS路由算法的性能测试构建出真实、准确的仿真平台。对随机网络拓扑生成算法进行了研究，重点分析了QRSIM的总体框架和各功能模块的实现，并给出仿真实例验证了QRSIM的可靠性和有效性。     

基于SDN的卫星网络多QoS目标优化路由算法

针对传统卫星网络中业务类型多样化导致的网络配置复杂和业务服务质量(quality of service, QoS)无法得到有效保障的问题,研究了基于软件定义网络(software-defined networking, SDN)的卫星网络架构,提出了一种能够满足多种QoS需求的自适应路由算法。首先,建立了软件定义卫星网络多约束条件路由选择优化模型;然后,使用拉格朗日松弛法对模型进行松弛处理;最后,使用梯度法进行迭代求解,搜索出满足带宽、时延、丢包率等多种QoS的最优路径。研究结果表明,该优化算法在QoS满意度方面相比近地轨道卫星路由算法提高了64%,在时延满意度和丢包率满意度方面相比软件定义路由算法提高了28%。     

质量水平涨落函数与动态质量路由算法

实数区间适于表示用户质量需求和网络资源的动态变化。提出质量涨落函数这一新概念,揭示了质量因素的变化与质量水平涨落之间的内在联系。在约束质量水平涨落的前提下,推广了源路由算法、基于距离向量协议和链接状态协议的质量路由算法,使之成为与用户需求和网络变化特性相适应的、体现网络服务供需平衡与适度优化思想的动态质量路由算法。最后,给出判定路由路径质量水平涨落幅度的定理及其证明。     

基于禁忌搜索的负载均衡组播路由算法

提出了一种基于禁忌搜索策略的能实现网络负载均衡的QoS组播路由优化算法。该算法在满足业务带宽和时延的基本要求下,将网络费用和负载均衡分布作为目标函数进行优化,达到网络费用较小和负载均衡分布的目的。仿真结果表明,该算法是一个有效、可行的算法。