在3D-Mesh网络中的两种路由研究

在研究并行计算机系统容错时,路由算法是一个极为重要的研究课题。主要研究的是自适应路由算法和确定性路由算法在3D-Mesh网络上的性能。在每个结点具有独立的出错概率的模型下,提出的方法使得能够严格地推导出路由算法的成功概率,从而能够对算法进行分析和比较。研究结果表明,自适应路由算法具有明显的优势。一方面,自适应路由算法基于局部信息而变得高效;另一方面,自适应路由算法对于结点出错和网络规模具有更好的健壮性,而使其具有更高的成功概率。     

动态非探测式路由选择策略的设计与分析

本文研究了动态的、非探测式的路由选择策略提高了自适应路由算法的传输效率,由于避免使用网络状态探测包,减少了缓存面积开销和额外能耗,是一种适合于片上网络自适应路由算法的选择策略设计方法。     

大规模无线传感器网络自适应节能路由算法

在确保大规模无线传感器网络信息可靠传输的前提下,尽可能降低网络能量开销,提出了大规模无线传感器网络的自适应节能路由算法。针对长江三峡库区水质监测的具体应用环境,构建了网络模型,采用梯度型拓扑生成器生成网络拓扑,利用可以平衡负载的节能自适应算法进行最优路由选择,建立了应用于大规模无线传感器网络的自适应节能路由算法。在具有代表性的两种不同网络环境中,对该算法的节能效果进行测试,结果表明了算法的可行性和先进性;该算法能有效地将网络负载平均分配于整个网络中,减少网络的整体能量开销,延长整体网络的寿命。     

一种高效全自适路由算法的构造框架

路由算法在大规模并行处理机（ＭＰＰ）系统中对互连网络通信性能和系统性能的发挥起着关键作用,深入分析消息在网络中寻径特性,提出“最佳寻径网（ＢＮＲ）”概念,根据ＢＮＲ构造全自适应路由算法设计框架,并给出一类Ｍｅｓｈ网络基于ＢＮＲ的全自适应路由算法ＢＢＦＡＭ的设计,性能分析表明,ＢＢＦＡＭ是一类高效全自适应路由算法,从而证明ＢＮＲ构造框架对网络设计人员确能提供有效的路由算法设计指导。     

无线传感器网络自适应动态路由算法仿真

传统传感器路由算法存在信息传输能耗较高,且网络节点存活率偏低问题,提出无线传感器网络自适应动态路由算法,简称为HDAR算法.结合平面路由和层次路由构建新的无线传感器网络路由框架,在数据获取模块中选取层次路由,在数据传输模块中选取平面路由.调整节点非线性自适应权重,动态成簇自适应路由算法HDAR通过数据动态成簇来实现数据汇总,利用自适应路由选择算法将数据运转到Sink节点,最终实现HDAR算法设计.为验证所提算法的有效性,进行一次实验.实验结果表明:HDAR算法节能效果更好,且上述算法下节点存活数量更多,适用性较强,具有很好的应用前景.     

基于Bayes估计的WSN自适应路由算法

针对无线传感器网络中存在的路由请求域动态调整问题,提出一种基于Bayes估计的无线传感器网络自适应路由算法。该算法以圆柱形路由请求域的半径作为调整参数,利用Bayes估计对路由请求域进行自适应调整。仿真结果表明,该算法在数据包投递率、路由开销、数据包平均时延和网络剩余能量比率上的性能都优于AODVjr路由算法。     

基于多路径蚁群算法的无线传感器网络的路由

针对能量控制在无线传感器网络路由上的特殊要求,为了促使网络节点能量消耗相对均衡,将基本蚁群算法(ACS)应用于无线传感器网络的路由,提出一种基于多路径蚁群算法的无线传感器网络的路由(MACS).该算法利用蚁群的自组织、自适应和动态寻优能力,通过蚂蚁并行地寻找从源节点到达目的节点的最优路径和次优路径,使得网络中的节点不需要维护全局信息,形成多条传榆路径,延长了整个网络的生命期.仿真结果表明,该算法和定向扩散路由(DD)、基本蚁群算法及极大一极小蚁群算法(MMAS)相比,在路由代价和节能方面效果显著.     

基于WDM技术的虚拟多环互连网络的自适应路由算法

自适应路由算法能够根据网络状态选择能回避阻塞或故障结点的路径，使得链路得到有效利用，均匀分布通信流量，减少平均传输延时，最大限度地提高网络的性能。该文针对一种结构简单、易于实现、性能较优的多跳虚拟环网结构DS－WDM Ring设计了三种自适应路由处算法。在PC机上设计并实现了路由算法模拟模型，对DS－WDM Ring上的自适应路由算法和静态路由算法进行了模拟，统计出了几种路由算法在不同的网络负载下的平均阻塞率、平均跳数、平均延时和结点端口的利用率，比较分析了几种路由的性能。     

BNR：最短路径无死锁全自适应路由算法的分析与设计工具

1 引言大规模并行计算机(MPP)系统性能的发挥极大程度上依赖于互连网络的通信性能,互连网络采用的路由算法决定了消息在网络中如何选取路径,其性能对网络效率的发挥起着重要作用,根据允许选择路径的不同,路由算法有最短路径和非最短路径以及确定性和自适应性之分,自适应又有部分自适应和完全     

片上网络路由算法的研究

路由算法作为片上网络研究的一项关键技术,负责将分组正确无误地发送到目的节点.片上网络路由算法可分为无关路由算法和自适应路由算法两种.无关路由算法简单易实现,但具有一定的盲目性,自适应路由算法能够灵活地选择路由路径,却需要复杂的控制逻辑和硬件电路.对目前已经出现的几种路由算法进行了分析、对比,并从所适用拓扑、是否防止死锁等方面对算法进行了评价,并提出了片上网络路由算法的研究方向.     

虚网叠加构造自适应路由算法的有效框架

大规模并行处理机系统中路由算法对互联网络通信性能和系统性起着重要作用。     

A framework for designing deadlock-free wormhole routing algorithms

This paper presents a framework to design fully-adaptive, deadlock-free wormhole algorithms for a variety of network topologies. The main theoretical contributions are: (a) design of new wormhole algorithms using store-and-forward algorithms, (b) a sufficient condition for deadlock free routing by the wormhole algorithms so designed, and (c) a sufficient condition for deadlock free routing by these wormhole algorithms with centralized flit buffers shared among multiple channels. To illustrate the theory, several wormhole algorithms based on store-and-forward hop schemes are designed. The hop-based wormhole algorithms can be applied to a variety of networks including torus, mesh, de Brujin, and a class of Cayley networks, with the best known bounds on virtual channels for minimal routing on the last two classes of networks. An analysis of the resource requirements and performances of a proposed algorithm, called negative-hop algorithm, with some of the previously proposed algorithms for torus and mesh networks is presented     

A survey of wormhole routing techniques in direct networks

Several research contributions and commercial ventures related to wormhole routing, a switching technique used in direct networks, are discussed. The properties of direct networks are reviewed, and the operation and characteristics of wormhole routing are discussed in detail. By its nature, wormhole routing is particularly susceptible to deadlock situations, in which two or more packets may block one another indefinitely. Several approaches to deadlock-free. routing, along with a technique that allows multiple virtual channels to share the same physical channel, are described. In addition, several open issues related to wormhole routing are discussed     

Collective communication in wormhole-routed massively parallelcomputers

Most MPC networks use wormhole routing to reduce the effect of path length on communication time. Researchers have exploited this by designing ingenious algorithms to speed collective communication. Many projects have addressed the design of efficient collective communication algorithms for wormhole-routed systems. By exploiting the relative distance-insensitivity of wormhole routing, these new algorithms often differ fundamentally from their store-and-forward counterparts. We examine software and hardware approaches to implementing collective communication operations. Although we emphasize methods in which the underlying architecture is a direct network, such as a hypercube or mesh, as opposed to an indirect switch-based network, several approaches apply to systems of either type. We illustrate several issues arising in this research area and describe the major classes of algorithms proposed to solve these problems     

Wormhole Routing—大规模并行处理系统中的一项关键技术

本文详细介绍了基于直接网络的大规模并行计算机的ＷｏｒｍｈｏｌｅＲｏｕｔｉｎｇ的原理。Ｗｏｒｍｈｏｌｅ寻径算法以及其它与通信性能有关的技术问题。     

不规则网络中基于拐弯模型的路由算法的设计

由虫孔路由交换器连接而成的不规则拓扑网络，越来越多地用于构建工作站机群系统（NOWs），以实现高性能价格比的并行处理．采用虫孔路由技术，网络中容易发生死锁．交换器之间连接的不规则性，使路由避免死锁问题变得更加复杂．本文给出了在不规则网络中，设计基于拐弯模型的无死锁路由算法的一般方法，并采用扩展链路方向的方法得到多种路由策略，确定了up-first与down-last两种性能较优的路由算法．最后通过模拟实验，评价了算法的性能．     

A theory of deadlock-free adaptive multicast routing in wormholenetworks

A theory for the design of deadlock-free adaptive routing algorithms for wormhole networks, proposed by the author (1991, 1993), supplies sufficient conditions for an adaptive routing algorithm to be deadlock-free, even when there are cyclic dependencies between channels. Also, two design methodologies were proposed. Multicast communication refers to the delivery of the same message from one source node to an arbitrary number of destination nodes. A tree-like routing scheme is not suitable for hardware-supported multicast in wormhole networks because it produces many headers for each message, drastically increasing the probability of a message being blocked. A path-based multicast routing model was proposed by Lin and Ni (1991) for multicomputers with 2D-mesh and hypercube topologies. In this model, messages are not replicated at intermediate nodes. This paper develops the theoretical background for the design of deadlock-free adaptive multicast routing algorithms. This theory is valid for wormhole networks using the path-based routing model. It is also valid when messages with a single destination and multiple destinations are mixed together. The new channel dependencies produced by messages with several destinations are studied. Also, two theorems are proposed, developing conditions to verify that an adaptive multicast routing algorithm is deadlock-free, even when there are cyclic dependencies between channels. As an example, the multicast routing algorithms of Lin and Ni are extended, so that they can take advantage of the alternative paths offered by the network     

A necessary and sufficient condition for deadlock-free routing incut-through and store-and-forward networks

This paper develops the theoretical background for the design of deadlock-free adaptive routing algorithms for virtual cut-through and store-and-forward switching. This theory is valid for networks using either central buffers or edge buffers. Some basic definitions and three theorems are proposed, developing conditions to verify that an adaptive algorithm is deadlock-free, even when there are cyclic dependencies between routing resources. Moreover, we propose a necessary and sufficient condition for deadlock-free routing. Also, a design methodology is proposed. It supplies fully adaptive, minimal and non-minimal routing algorithms, guaranteeing that they are deadlock-free. The theory proposed in this paper extends the necessary and sufficient condition for wormhole switching previously proposed by us. The resulting routing algorithms are more flexible than the ones for wormhole switching. Also, the design methodology is much easier to apply because it automatically supplies deadlock-free routing algorithms     

Efficient and Scalable Routing Algorithms for Collective Communication Operations on 2D All-Port Torus Networks

Collective Communication Algorithms for 2D torus networks have been investigated quite extensively in the literature and two broad approaches, namely direct methods and indirect (message combining) methods are recognized in the field. While direct methods minimize the volume of data, the indirect methods reduce the number of message start-ups. Consequently, either a suite of algorithms must be employed for efficiency over a wide range of message lengths and communication operations or algorithms should be able to adapt themselves to the current case, possibly by switching between direct and indirect routing modes as appropriate. In this paper, we propose adaptive routing algorithms for all-port, wormhole routed, synchronous, 2D torus networks optimized for one-to-all broadcast,  gossiping and complete exchange collective communication operations. The proposed algorithms employ completely-connected subnetworks where complete exchange amongst the nodes in the subnetwork can be accomplished in one step only. Combined with suitable 2D plane tiling techniques, the proposed algorithms share the same set of primitive operations and yield superior performance compared to previously proposed methods, either pure or hybridized.     

Fault-tolerant wormhole routing for hypercube networks

We present an adaptive fault-tolerant wormhole routing algorithm for hypercubes by using 3 virtual networks. The routing algorithm can tolerate at least n−1 faulty nodes and can route a message via a path of length no more than the shortest path plus four. Previous algorithms which achieve the same fault tolerant ability need 5 virtual networks. Simulation results are also given in this paper.