基于蚁群优化算法的多QoS选播路由算法研究

提出一种基于蚁群优化算法的多QoS选播路由算法.算法设计了合理的路径评价方法,从平衡网络负载的角度出发,寻找适当的选播路由路径.通过对迭代最优解路径上的信息素的调整和算法重启的策略,算法有效地避免了陷入局部最优的缺陷,扩大了算法的搜索范围.实验结果表明,该算法能找到满足QoS约束的全局最优解,并在资源预留的基础上较好地满足用户对于带宽、时延的要求.     

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．     

一种基于改进蚁群算法的选播路由算法

为了在网络负载较大的情况下实现多目标多路径的选播路由,该文根据蚂蚁寻径与选播路由的相似性,提出了一种基于改进蚁群算法的选播路由算法。在运用数据包传输的历史信息来模拟路径信息素的基础上,增加了目标地址泛洪负载信息来模拟食物气味散发的过程,使得各个节点可以获得服务器和链路的最新信息。节点根据路径上的信息素、食物的气味以及链路的可见度等综合生成概率表,作为后继蚂蚁路径选择的依据。运用NS-2对该算法进行仿真,测试结果表明它可以减少传输时延,降低服务器负载的波动幅度,实现链路的负载均衡,增加网络的容量,提高选播服务的可扩展性。     

基于遗传算法提高网络资源利用率的选播QoS路由算法

选播通信提供了一种从一组具有相同选播地址的服务中选取最佳服务的机制。在研究选播通信服务模型的基础上利用改进的遗传算法实现了有QoS保证的选播路由,并进一步优化了网络的资源利用。仿真结果表明,这种算法是有效且可行的。     

一种基于遗传粒子群算法的选播路由算法

选播是IPv6中定义的一种新的通信模式.在分析选播通信服务基础上,提出一种基于遗传粒子群算法的选播路由算法,以求解多QoS约束的选播路由问题.算法将遗传算法和粒子群算法结合起来,通过设置一个更新算子,让路径之间相互学习,使得整个种群不断地趋干最优路径.仿真实验结果表明,该算法是可行和有效的,比单独基于遗传算法或粒子群算法的选播路由算法有一定的优越性.     

结合资源预留的分布式QoS组播路由算法

针对网络资源信息的动态变化对QoS组播路由算法的巨大影响,该文提出了一种与资源预留结合的分布式组播路由算法DQMTR。DQMTR通过在路径探索过程中进行资源预留克服网络信息变化对QoS路由算法的影响。DQMTR还通过记录预约资源的数量解决资源的过预约问题,并利用DiffServ体系下QoS路由算法的特点使算法能够适用于DiffServ网络。仿真实验表明,DQMTR提高了组成员加入的成功率,优化了平均路径代价值。     

基于多核单向共享树的选播路由算法的研究

为了更好地在应用层实现选播通信.在对已有选播路由算法PIA-SM和CBT的优缺点分析的基础上,提出了一种基于多核单向共享树的选播路由算法,并给出了核节点和选播组成员的选择策略,实验表明,本算法能有效平衡网络和服务器负载,并在网络负载较重的情况下,有效地降低数据包的传送时延.     

一种满足带宽和时延约束的选播QoS路由算法

建立一个满足带宽和时延约束的选播通信服务模型，提出相应的选播QoS路由算法。仿真实验结果表明：该算法是有效且切实可行的，它能同时满足带宽和时延的约束条件，较好地平衡网络负载．改善了网络服务质量。     

无线Mesh网络多网关选播QoS路由模型研究

无线Mesh网络中网关常常成为网络的瓶颈.为了解决网关的选取问题和提高QoS性能,根据多网关选取问题与选播路由的相似性,提出了一种基于选播机制的网关选取模型.该模型将所有网关节点抽象成一个选播组,带QoS约束的用户端通过有效的选播机制能够自适应地选择最优的网关节点为其服务,以保证无线Mesh网络良好的接入性能.仿真结果表明了该算法的正确性和有效性.     

一种基于粒子群优化的多QoS约束选播路由算法

提出一种基于粒子群优化算法的多QoS约束选播路由算法(RDO-PSO).算法使用特殊相加算子,使得路径之间能够相互进行学习,解决了较差路径向较好路径学习的问题;通过设计随机扰动算子,使算法在陷入局部最优时迅速跳出局部最优,保证了粒子的多样性.网络仿真结果表明,算法有效可行,收敛速度快.     

RSVP and integrated services in the Internet: a tutorial

The growing use of multimedia communication applications, with specific bandwidth and real-time delivery requirements has created the need for an integrated services Internet in which traditional best-effort datagram delivery can coexist with additional enhanced quality of service (QoS) delivery classes. Such classes provide data flows with QoS commitments with regard to bandwidth, packet loss, and delay through the reservation of network resources along the data path, which can be done using the Resource Reservation Protocol (RSVP). This article is a tutorial on how RSVP can be used by end applications to ensure that they receive the end-to-end QoS that they require     

QoS routing for anycast communications: motivation and anarchitecture for DiffServ networks

Much research in QoS routing has focused on the unicast communication paradigm. However, another communication paradigm - anycasting - has grown in importance. In the anycast paradigm, one endpoint is specified and the other is selected from a set of "equivalent" endpoints. An anycast service in a QoS-based network requires selection of both an endpoint and a path that satisfies a QoS constraint. This article provides background material on anycasting in both best-effort networks and QoS-based networks. We then focus on the differentiated services QoS model, and present the design of a QoS-based anycasting architecture consistent with that model. Via simulations, we explore the design options implied by the architecture, including signaling protocols, server selection/sorting algorithms, and resource reservation granularity. We conclude by highlighting open problems in the emerging area of QoS-based anycasting     

Quality-of-service mechanisms in all-IP wireless access networks

In this paper, we focus on resource reservation protocol (RSVP)-based quality-of-service (QoS) provisioning schemes under Internet protocol (IP) micromobility. We consider QoS provisioning mechanisms for on-going RSVP flows during handoff. First, the rerouting of RSVP branch path at a crossover router (CR) at every handoff event can minimize resource reservation delays and signaling overheads, and in turn the handoff service degradation can be minimized. We show that RSVP branch path rerouting scheme could give a good tradeoff between the resource reservation cost and the link usage. Second, the new RSVP reservation can be made along the branch path toward the CR via a new base station in advance, while the existing reservation path is maintained, and in turn the on-going flow can be kept with the guaranteed QoS. We also show that seamless switching of RSVP branch path could provide the QoS guarantee by adaptively adjusting the pilot signal threshold values. Third, during RSVP resource reservation over wireless link, dynamic resource allocation scheme is used to give a statistical guarantee on the handoff success of on-going flows. We finally obtain the forced termination probability of guaranteed service flows, the average system time of best effort flows by using a transition rate matrix approach.     

Integration of Explicit Effective-Bandwidth-Based QoS Routing With Best-Effort Routing

This paper presents a methodology for protecting low-priority best-effort (BE) traffic in a network domain that provides both virtual-circuit routing with bandwidth reservation for QoS traffic and datagram routing for BE traffic. When a QoS virtual circuit is established, bandwidths amounting to the traffic's effective bandwidths are reserved along the links. We formulate a new QoS-virtual-circuit admission control and routing policy that sustains a minimum level of BE performance. In response to a QoS connection request, the policy executes a two-stage optimization. The first stage seeks a minimum-net-effective-bandwidth reservation path that satisfies a BE protecting constraint; the second stage is a tie-breaking rule, selecting from tied paths one that least disturbs BE traffic. Our novel policy implementation efficiently executes both optimization stages simultaneously by a single run of Dijkstra's algorithm. According to simulation results, within a practical operating range, the consideration that our proposed policy gives to the BE service does not increase the blocking probability of a QoS connection request.      

Efficient Resource Allocation for Policy-Based Wireless/Wireline Interworking

This paper proposes efficient resource allocation techniques for a policy-based wireless/wireline interworking architecture, where quality of service (QoS) provisioning and resource allocation is driven by the service level agreement (SLA). For end-to-end IP QoS delivery, each wireless access domain can independently choose its internal resource management policies to guarantee the customer access SLA (CASLA), while the border-crossing traffic is served by a core network following policy rules to meet the transit domain SLA (TRSLA). Particularly, we propose an engineered priority resource sharing scheme for a voice/data integrated wireless domain, where the policy rules allow cellular-only access or cellular/WLAN interworked access. By such a resource sharing scheme, the CASLA for each service class is met with efficient resource utilization, and the interdomain TRSLA bandwidth requirement can be easily determined. In the transit domain, the traffic load fluctuation from upstream access domains is tackled by an inter-TRSLA resource sharing technique, where the spare capacity from underloaded TRSLAs can be exploited by the overloaded TRSLAs to improve resource utilization. Advantages of the inter-SLA resource sharing technique are that the core network service provider can freely design the policy rules that define underload and overload status, determine the bandwidth reservation, and distribute the spare resources among bandwidth borrowers, while all the policies are supported by a common set of resource allocation techniques.     

The integrated services in the Internet: state of the art

This paper is about the evolution of the Internet from a simple data network into a true multiservice network that can support the emerging multimedia applications and their protocols with appropriate performance and costs. The real-time delivery and specific bandwidth requirements of these multimedia applications have created a need for an integrated services Internet in which traditional best effort datagram delivery can coexist with additional enhanced quality of service delivery classes. The integrated services Internet will be able to commit to meet bandwidth, packet loss, and delay specifications for individual data flows by using the resource reservation protocol together with appropriate packet forward scheduling policies     

Dynamic-Grouping bandwidth reservation scheme for multimedia wireless networks

In wireless networks carrying multimedia traffic (voice, video, data, and image), it becomes necessary to provide a quality-of-service(QoS) guarantee for multimedia traffic connections supported by the network. In order to provide mobile hosts with high QoS in the next-generation wireless networks, efficient and better bandwidth reservation schemes must be designed. This paper presents a novel dynamic-grouping bandwidth reservation scheme as a solution to support QoS guarantees in the next-generation wireless networks. The proposed scheme is based on the probabilistic resource estimation to provide QoS guarantees for multimedia traffic in wireless cellular networks. We establish several reservation time sections, called groups, according to the mobility information of mobile hosts of each base station. The amount of reserved bandwidth for each base station is dynamically adjusted for each reservation group. We use the dynamic-grouping bandwidth reservation scheme to reduce the connection blocking rate and connection dropping rate, while increasing the bandwidth utilization. The simulation results show that the dynamic-grouping bandwidth reservation scheme provides less connection-blocking rate and less connection-dropping rate and achieves high bandwidth utilization.     

一种基于QoS的选播路由算法研究

随着计算机和网络技术的迅猛发展,对网络服务质量的要求越来越高,因此选播成为了IPv6中的一种标准通信模型。在提出了一种新的解决多种限制条件下QoS路由问题的启发式算法,在该算法中,综合考虑了时延、带宽和费用的限制条件,主要采用了网络链路信息预先处理和改进的宽度优先搜索等方法。实验结果表明,该算法具有良好的性能指标,能够有效解决多种限制条件下的QoS路由问题,并且较好的平衡网络负载和服务器负载。