QoS路由选择:问题与解决方法综述

保证服务质量的QoS路由(Quality of Service Routing)是网络中解决QoS问题的一项关键技术.QoS路由的主要目标是为接入的业务选择满足服务质量要求的传输路径,同时保证整个网络资源的有效利用.度量参数选择问题、寻路问题和路由信息不准确问题是QoS路由中的几个主要研究内容.本文围绕这三个方面,介绍了QoS路由中的主要问题及相关的解决办法,并探讨了今后QoS路由可能的研究方向.     

下—代网络中多约束路由算法述评

随着新业务的不断涌现，对网络QoS的需求也呈现出多样性，未来网络必然需要提供多约束的QoS路由能力。首先介绍了QoS路由及其路由策略和路由信息发布机制，并在对路由中特征值的选择和构成规则进行分析的基础上，着重讨论了当前多约束路由算法几种类型，分析了算法的性能和特点。最后，分析探讨多约束路由未来可能的研究方向。     

分布式服务质量路由预计算算法

服务质量路由作为下一代IP互联网提供服务质量(QoS)控制的一种重要方案,如何提高其可扩展性和路由性能是有待解决的难题.本文提出了基于聚类的分布式预计算算法,以具有多种QoS参数的路由表预计算为目标,引入了支持QoS参数的扩展距离向量,通过网络中各个节点的分布式协同计算,大大降低了单个路由器的计算复杂度.文章分析了优势路径及其选取策略,给出了路由计算中优势路径聚集的聚类方法,实现了QoS路由表的高效聚集压缩.实验结果进一步验证了该算法具有计算量小和QoS路由性能高的优点,在QoS度量维数和网络规模方面均具有良好的可扩展性,并对域间算法研究提供了重要依据.     

无线Mesh网络QoS路由度量研究

无线Mesh网络的研究非常活跃,针对网络路由选择已经提出了一些路由选择度量。本文对各种路由度量及优缺点进行了详细的分析,并在此基础上,给出了一种新的路由度量方式并展望无线Mesh网络QoS路由度量选择的发展方向。     

移动自组网模糊逻辑QoS动态源路由算法

该文提出了一种新的移动Ad hoc网络QoS路由算法:模糊逻辑QoS动态源路由算法。算法从模糊理论的思想出发,将业务的多个QoS参数进行综合评判产生一类以语言变量描述的请求,在修改动态源路由协议为多径路由算法的基础之上,对比各条路径综合模糊路由状态,选择出最适合业务请求的路径。仿真显示算法在支持QoS的同时对移动Ad hoc网络因拓扑动态变化而引起的信息不精确性有很好的适应度。     

下一代网络中多约束路由算法述评

随着新业务的不断涌现,对网络QoS的需求也呈现出多样性,未来网络必然需要提供多约束的QoS路由能力.首先介绍了QoS路由及其路由策略和路由信息发布机制,并在对路由中特征值的选择和构成规则进行分析的基础上,着重讨论了当前多约束路由算法几种类型,分析了算法的性能和特点.最后,分析探讨多约束路由未来可能的研究方向.     

基于K最优路径的QoS路由预计算新算法

针对下一代高速网络中的多约束服务质量路由问题,首先提出了一种精确链路状态信息条件下的路由预计算算法MKPPA.在此基础上根据网络状态信息的动态性,通过引入"警戒点"对MKPPA进行了改进,提出了一种基于警戒点的修正预计算算法M_-MKPPA,该算法能够适应网络链路信息的不精确性.最后通过理论分析表明MKPPA不仅能够解决加性度量参数受约束的QoS路由问题,而且能够解决加性与非加性度量参数混合受约束QoS路由问题,修正预计算算法M -MKPPA能够适应网络链路状态信息的动态特性.计算机仿真结果显示出MKPPA在求解QoS路由问题时,当计算次数不超过已有算法的计算次数时,不论是精确链路状态信息还是非精确链路状态信息条件下,均具有更高的路由计算成功率.     

移动自组网基于动态蜂窝的QoS路由协议

本文为移动自组网提出了一个基于动态蜂窝的QoS路由协议，它利用移动跟踪技术实现了一个分布式动态蜂窝生成协议；采用一个多Qos路由探测算法选择一条能够最大满足QoS要求的路由，并在这条路由上建立端．端主动资源预留；使用移动预测和被动资源预留技术预测源结点和目的结点可能进入的蜂窝集合，并在这些蜂窝集合与目的结点和源结点之间提前进行端．端被动资源预留；融合蜂窝动态检测技术与QoS路由修补技术自动发现和修补断裂的QoS路由．由于该路由协议模仿了固定蜂窝网络中的操作，所以，大大改善了QoS路由的性能．仿真结果表明：在满足QoS条件下，它明显提高了包传输率，减轻了路由负载．     

Ad hoc网络的QoS路由综述

Ad hoc网络与传统的有线网络和无线局域网不同,具有其独特的特点,传统的路由选择不适合Ad hoc网络。为了适应Ad hoc网络的特殊性,研究人员结合服务质量提出了基于Ad hoc网络的多种QoS路由。本文介绍了不同的QoS路由算法以及QoS路由算法的优化。     

基于蚁群算法的自适应QoS路由优化

Internet网络规模的迅速增长和网络技术的不断完善，使得如何在满足QoS（quality of service）要求下进行路由选择成为路由算法研究的重要方向。提出了一种多约束条件下的自适应蚁群算法，该算法基于目标函数的信息素分配策略来自适应地调整蚂蚁的搜索行为，使多约束QoS路由优化问题得到了很好的解决。     

MPLS网络中保证服务质量的多径路由选择策略

本文提出了一种在多协议标签交换(MPLS, Multiple Protocol Label Switching) 网络中保证服务质量 (QoS,Quality-of-Service) 的多径路由选择策略,其核心思想是引入多路径分散业务量机制,在保证用户服务质量要求的同时达到增加网络呼叫接受率和平衡网络负载的目的.文中着重讨论了用户端对端服务质量要求的多路分解和分配问题,在此基础上提出了多径路由的分支路径选择策略,并研究了策略中的关键参数K对该策略性能的影响.数值结果显示出多路径分散业务量在网络负载均衡方面的重要意义,并且表明用户的要求相对网络资源越高使用多径传输的优势越明显.     

Multipath Cognitive Routing in Integrated Multicast Satellite-HAP System Structures

A new multilayered inter satellite-high altitude platform(HAP)system routing algorithm is proposed,which is mainly based on multipath routing to ensure the network reliability.The proposed multipath routing scheme principally relies on splitting the traffic between different paths to make the best utilization of multiple routes.Linear programming is the main method used for multipath selection.The major constraints to the quality of service(QoS)(delay and link utilization)have been taken into account to meet the criteria of the advanced multimedia applications.Due to the effect of link utilization,the system encounters traffic flow oscillation between paths over time,which affects the system performance.Hence,to fix this issue,we propose a cognitive routing algorithm which reacts to the long-term changes of the traffic loads rather than short-term ones.The performance of the proposed routing techniques has been evaluated using appropriate simulation models and implemented by Matlab.     

基于被动测量的网络故障诊断

A new passive method for automatic discovery and location of network failure is proposed. This method employs a passive measurement to collect information and events from network traffic, and employs a model-based reasoning system to detect and locate network faults.Measurement points are deployed in a backbone network to capture the traffic and then evaluate the Quality of Service (QoS) metrics of end-to-end IP conversations. A routing model is also established for the observed network to simulate the attributes and activities of routers and links. This routing model also deduces the routing path for each IP conversation, and thus the QoS metrics of IP conversations are mapped into the metrics of paths. With the information of shared links of overlapping paths and network tomography technique, the QoS metrics of links can also be estimated, and the poorly rated links are picked out as failure points. This method is implemented in a tool named Fault-Man, which is deployed in a campus network. Test results have shown its availability in middle-scale networks.     

MPLS流量工程中的约束路由技术

传统的IP路由协议采用最短路径算法(SPF),极易造成网络的拥塞.流量工程是目前网络中实现负载均衡和提高网络性能的一个重要技术.文中简要介绍了MPLS流量工程,重点分析了MPLS流量工程中所使用的路由协议约束路由,给出了约束的计算方法以及路由度量选择的准则.     

IP/ MPLS over WDM网中考虑QoS的VPN业务设计

本文研究了在IP／MPLS over WDM网络中支持不同QoS要求的VPN业务的逻辑拓扑设计问题。对于给定的网络物理拓扑和业务需求矩阵，本文提出，基于不同时延要求的VPN业务逻辑拓扑设计可以运用两种方法加以解决。一为基于迭代的线性规划方法，适合于规模较小的网络。另一个为启发式算法，可运用于网络规模较大的环境。对比仿真结果表明，启发式算法不但较好地解决了不同QoS要求的VPN业务的选路和波长分配问题，还较好地降低了链路的最大负载。     

基于智能业务识别的可信路由研究

本文研究并提出了基于智能业务识别与控制的可信路由架构.该架构根据动态配置的安全/Qos策略,在智能业务分类与识别的基础上,标记数据包,执行业务流量自适应调节与控制,并采用队列管理和调度管理,实现可信Qos路由.此外,本文综合了端口匹配法的简单、快速、复杂度低和灵活性好,净荷分析法的精确有效,以及流量特征分析法可扩展性好等特点,提出并建立了实时智能网络业务分类系统.该系统具有较高精度、低计算复杂度、良好的可扩展性、早期检测和鲁棒等优点,是高速链路可信路由的前提和保障.     

对新型网络路由机制的思考

路由是网络的结构基石,新型网络路由机制是构建新型网络体系的必需。目前网际层的路由本质上是所谓的"单下一跳路由"机制,解决网络传输拥塞问题的一个根本措施在于改变当前网络单下一跳的选路模式,允许多条路径的并行传输。边界网关协议(BGP)是目前Internet唯一采用的域间路由协议,针对当前域间路由系统面临的规模可扩展性问题,文章提出了一个规模可扩展的新型分层域间路由架构(s-idra)。除了可扩展性以外,路由体系还面临其他挑战,比如安全性、服务质量(QoS)、组播、移动、动态网络拓扑等等。路由协议尤其是未来新型信息网络体系结构的路由协议的研究任重而道远。     

Q-MOHRA: QoS Assured Multi-objective Hybrid Routing Algorithm for Heterogeneous WSN

Quality of Service (QoS) assurance in Wireless Sensor Network (WSN) is a tough task, and it is more exciting due to the scarcity of resources. The requirement of different WSN applications running over has different constraints. In QoS, routing protocol the network has to balance the traffic. This paper presents a novel heuristic routing algorithm known as QoS assured Multi-objective Hybrid Routing Algorithm (Q-MOHRA) for Heterogeneous WSN. Q-MOHRA takes into account the link (energy, hop count, link quality indicator etc.) and path (jitter) metrics for optimal path selection. The performance of Q-MOHRA is evaluated through intensive simulation and equated with Simple Hybrid Routing Protocol (SHRP) and Dynamic Multi-objective Routing Algorithm (DyMORA). The metrics such as average energy consumption, residual energy, packet delivery ratio, jitter, and normalized routing load are used for comparison. The performance of Q-MOHRA has been observed to outclass SHRP and DyMORA. It improves the packet delivery ratio by 24.31% as compared to SHRP and 11.86% as compared to DyMORA. Q-MOHRA outperforms DyMORA in terms of average energy consumption by a factor of 8.27%.     

A Dynamic Alternate Path QoS Enabled Routing Scheme in Mobile Ad hoc Networks

A mobile ad hoc network (MANET) is a collection of self-organized mobile nodes that are capable of communicating with each other without the aid of any established infrastructure or centralized administration. Routing algorithm has been a challenge task in the wireless ad hoc network for a long time due to the dynamic nature of network topology. A recent trend in ad hoc network routing is the reactive on-demand philosophy where routes are established only when required. The on-demand routing protocol for ad hoc network is appealing because of its low routing overhead and its effectiveness when the frequency of route re-establishment and the demand of route queries are not high. However, considering the increasing demand of Quality-of-Service (QoS) requirements in many applications, the current on-demand routing protocols used for ad-hoc network should be adapted appropriately to effectively meet the stringent QoS requirements of specific multimedia traffic. We thus propose a routing protocol which tries its best to satisfy QoS requirements of specific multimedia traffic in the volatile environments of a MANET. The results of a series of simulations exhibit the practicability and feasibility of our approaches. This research was partially supported by National Science Council under grant NSC 93-2213-E-026-001