基于二维torus片上网络的间隙式流量控制及路由算法的研究

基于片上网络中常用的虚切通交换技术,提出了间隙式流量控制策略,为了改进片上网络路由机制的免死锁性和减少数据包的传输路径,根据二维Torus片上网络结构,又研究了与此相对应的间隙式自适应路由算法,并对该算法进行了免死锁证明.在NOXIM下仿真结果表明,此算法在数据包延迟和系统吞吐量方面明显优于X-Y,West-First,Odd-Even这些常规的路由算法.     

一种自适应动态缓存策略准入控制算法

针对片上网络的死锁问题,基于虚拟网络的自适应路由算法,设计了一个完全自适应片上路由器.重点介绍了路由算法及路由器的系统结构,设计实现了一个低代价、高效的完全自适应路由器,并在2DMesh拓扑结构下对其性能进行了模拟验证.实验结果表明,该路由器实现了无死锁的自适应路由,并提高了网络吞吐量,降低了平均网络延迟.     

一种完全自适应片上路由器的设计

针对片上网络的死锁问题,文中根据所提出的完全自适应路由思想—基于虚拟网络的自适应路由算法,设计了一个完全自适应片上路由器.重点介绍了路由算法及路由器的系统结构,最终设计实现了一个高效、低代价的完全自适应路由器,并在2D Mesh拓扑结构下对其性能进行了模拟验证.实验得出该路由器实现了无死锁的自适应路由,并降低了平均网络延迟,提高了网络吞吐量.     

一种片上网络自适应路由算法仿真与验证

针对片上网络的死锁问题,提出一种片上网络自适应路由算法--虚拟网络(VN)路由算法,该算法根据报文源地址和目的地址将网络分成4个虚拟网络.一旦报文在某个给定的虚拟网络中路由,所有属于最小路径的通道都可用于路由.但是,报文不能被传到另一个虚拟网络.显然,通道间没有环相关,从而避免了死锁.通过OPNET仿真,得出此算法吞吐量大、网络延迟小.     

基于保证QoS的片上网络路由算法

为了解决满足多个约束条件的片上网络服务质量,提出了一种基于区域的路由算法,该算法根据数据包所在的节点将整个网络按照X维分为两个部分,正面部分采用东最后路由,负面部分采用西优先路由.仿真结果表明,区域路由算法比传统的维序算法和奇偶转向模型能够很好地保证片上网络的服务质量.     

太比特路由器交换网络中路由算法的研究

太比特路由器在未来宽带网络建设中将发挥越来越重要的作用.作为其核心部件,大容量高性能交换网络是实现太比特路由器的关键技术之一,而交换网络中路由算法设计的优劣将直接影响交换网络的性能.本文从状态信息、路由策略、死锁活锁避免、服务质量路由和容错路由等五方面对交换网络路由算法设计进行了分析总结,最后展望了未来发展趋势.     

Torus网络中基于中心距离的完全自适应路由算法

Torus网络凭借其优越的结构特性,引起了工业界和学术界的广泛关注.高效、无死锁的路由算法设计是互连网络研究的一个重要方面.针对Torus网络实现自适应路由所需虚通道数目多的缺点,提出了自适应路由算法Gear,该算法基于中心距离的方法来限制虚通道的使用,在虚切通交换下仅需两条虚通道即可为Torus网络提供无死锁自适应路由.通过仿真对所提算法的有效性进行了验证,结果表明,在同等情况下算法Gear的性能较经典的维序路由和Duato协议具有非常明显的优势.     

网络多播路由的改进编码软件设计与实现

传统网络多播路由编码方法采用多播分布树进行编码,但链路容量遭遇瓶颈,致使编码节点较多,导致浪费带宽资源的问题。在此提出基于Koetter指数时间的网络多播路由改进编码算法对编码软件进行设计,分析多播路由的总体设计,通过数据包编码转发模块在多播拓扑不相交路径上进行编码和转发多播数据包,利用输入模块实现网络多播路由和上游节点的信息交换,通过开关仲裁模块判断能够向特定输出端口传输信息的输入端口,利用死锁控制模块对出现死锁现象的路由节点进行检测,一段时间后使多播路由恢复正常的数据交换,通过输出模块对数据的输出进行管理。以降低带宽资源为目的,采用Koetter指数时间算法实现网络多播路由编码,并给出编码的详细代码。实验结果表明,所提方法不仅节省网络资源,而且显著降低多播路由时延,增强网络吞吐量。     

基于NoC的容错路由算法

各种各样的软件和硬件上的错误都会破坏网络的数据传输,因此研究No C网络的容错算法是非常必要的。在基于XY路由算法的基础上提出了改进的容错路由算法,当链路或者传输节点之间发生错误时,可通过重新设置路由规则来获取一条有效的路由路径。在FPGA上进行路由容错算法的仿真,并和目前常用的几种路由算法在所适用拓扑、是否防止死锁等方面进行对比。仿真结果显示改进的路由容错算法性能优越,是可行的。     

三维片上网络内核测试

片上网络是一种新兴的大规模集成电路的设计方法.片上网络的测试包括对内核、路由器和通信通道的测试.本文主要提出了一种新的片上网络内核测试方法.该方法通过重用片上网络通信结构,采用基于单播的多播数据传递方式,以及一种无死锁的完全自适应路由方法来传递测试数据,显著地提高了通信效率,提升了测试的并行性,降低了测试成本.     

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。     

服务质量选路的研究

支章围绕网络状态信息管理和服务质晕选路算法两个方面对服务质质量选路技术的研究进行了综述，对服务质量选路方面需要进一步研究的问题进行了讨论。     

Improved ant colony-based multi-constrained QoS energy-saving routing and throughput optimization in wireless Ad-hoc networks简

In order to establish a route supporting multi-constrained quality of service（QoS）, increase network throughput and reduce network energy consumption, an improved ant colony-based multi-constrained QoS energy-saving routing algorithm（IAMQER） is proposed. The ant colony algorithm, as one of the available heuristic algorithms, is used to find the optimal route from source node to destination node. The proposed IAMQER algorithm, which is based on the analysis of local node information such as node queue length, node forwarding number of data packets and node residual energy, balances the relationship between the network throughput and the energy consumption, thus improving the performance of network in multi-constrained QoS routing. Simulation results show that this IAMQER algorithm can find the QoS route that reduce average energy consumption and improves network packet delivery ratio under the end-to-end delay and packet loss ratio constraints.     

非精确网络状态信息下基于Bellman-Ford的QoS路由算法

及时传输有服务质量(QoS，Quality of Service)要求的多媒体信息对于集成服务的宽带网络发展提出了新的挑战。QoS路由算法的优劣直接影响网络服务质量，而由于链路信息的不及时更新必将造成网络链路信息的非精确性。本文提出了一种在非精确网络状态信息下基于改进的Bellman—Ford算法的随机QoS路由算法Random_link_SONO，该算法采用随机策略来平衡网络负载和改善网络性能。通过网络模拟器的测试，该算法具有良好的性能指标，同时减少了处理和协议的额外开销。     

A new delay‐constrained algorithm for multicast routing tree construction

New multimedia applications provide guaranteed end‐to‐end quality of service (QoS) and have stringent constraints on delay, delay‐jitter, bandwidth, cost, etc. The main task of QoS routing is to find a route in the network, with sufficient resources to satisfy the constraints. Most multicast routing algorithms are not fast enough for large‐scale networks and where the source node uses global cost information to construct a multicast tree. We propose a fast and simple heuristic algorithm (EPDT) for delay‐constrained routing problem for multicast tree construction. This algorithm uses a greedy strategy based on shortest‐path and minimal spanning trees. It combines the minimum cost and the minimum radius objectives by combining respectively optimal Prim's and Dijkstra's algorithms. It biases routes through destinations. Besides, it uses cost information only from neighbouring nodes as it proceeds, which makes it more practical, from an implementation point of view. Copyright © 2004 John Wiley & Sons, Ltd.     

一种基于时延信息的多QoS快速自适应路由算法

本文在分析现有自适应蚁群算法局限性的基础上，提出了一种基于时延的自适应多QoS路由算法，它在满足带宽和时延波动约束条件下，直接利用前一周期的时延信息来更新路由表，以作为当前寻找路径的依据。仿真和分析结果表明，该算法具有快速准确的特点，能够及时协调网络拥塞和资源有效利用两者间的矛盾。     

Evaluating the impact of stale link state on quality-of-servicerouting

Quality-of-service (QoS) routing satisfies application performance requirements and optimizes network resource usage by selecting paths based on connection traffic parameters and link load information. However, distributing link state imposes significant bandwidth and processing overhead on the network. This paper investigates the performance tradeoff between protocol overhead and the quality of the routing decisions in the context of the source-directed link state routing protocols proposed for IP and ATM networks. We construct a detailed model of QoS routing that parameterizes the path-selection algorithm, link-cost function, and link state update policy. Through extensive simulation experiments with several network topologies and traffic patterns, we uncover the effects of stale link state information and random fluctuations in traffic load on the routing and setup overheads. We then investigate how inaccuracy of link state information interacts with the size and connectivity of the underlying topology. Finally, we show that tuning the coarseness of the link-cost metric to the inaccuracy of underlying link state information reduces the computational complexity of the path-selection algorithm without significantly degrading performance. This work confirms and extends earlier studies, and offers new insights for designing efficient quality-of-service routing policies in large networks     

基于蚁群系统的QoS单播路由算法

针对QoS路由算法中的QoS要求、资源的优化利用和负载均衡3方面问题,对原有的算法模型进行了改进,提出了相应的启发式信息和链路代价计算公式。对基本算法中的步骤进行改进,使算法能准确、迅速地找到全局最优解。实验结果表明,算法能在整网性能,尤其是网络负载均衡方面大幅优化了传统QoS单播路由算法。     

A hierarchical multilayer QoS routing system with dynamic SLAmanagement

This paper proposes a hierarchical multilayer QoS routing system with dynamic SLA management for large-scale IP networks. Previously, the promising approach to provide QoS in large-scale IP networks using a mixture of DiffServ-based QoS management and MPLS-based traffic engineering has been actively discussed. However, the introduction of QoS exacerbates the already existing scalability problems of the standard IP routing protocols. In order to address this issue, we propose a new scalable routing framework based on hierarchical QoS-aware path computation. We augment the existing OSPF and CR-LDP protocols to support hierarchical QoS routing, QoS aggregation, and QoS reservation in our MPLS-DiffServ-based hierarchical routing network. In order to provide additional flexibility and cost-efficiency, we augment the network with a policy server which is capable of dynamically handling SLAs between the networks and providing load balancing management within the network. We implement a prototype of the proposed framework and study its performance with a virtual network simulator and specially designed QoS routing algorithm simulator. In our simulations, we evaluate both the implementation complexity and algorithms performance; the results demonstrate the efficiency of the framework and its advantages over the existing proposals     

Adaptive proportional routing: a localized QoS routing approach

Most of the QoS routing schemes proposed so far require periodic exchange of QoS state information among routers, imposing both communication overhead on the network and processing overhead on core routers. Furthermore, stale QoS state information causes the performance of these QoS routing schemes to degrade drastically. In order to circumvent these problems, we focus on localized QoS routing schemes where the edge routers make routing decisions using only local information and thus reducing the overhead at core routers. We first describe virtual capacity based routing (vcr), a theoretical scheme based on the notion of virtual capacity of a route. We then propose proportional sticky routing, an easily realizable approximation of vcr and analyze its performance. We demonstrate through extensive simulations that adaptive proportional routing is indeed a viable alternative to the global QoS routing approach.