Mesh跳步容错路由算法

随着芯片集成度的提高,基于片上系统[1]（SoC）的片上网络（NoC）已成为芯片设计的重点。随着IP核的增多,节点和链路的故障率大大增加,这就使得运用容错以提高系统的可靠性成为NoC的设计重点。本文在对传统NoC容错技术的基础上,基于2D-Mesh拓扑结构,提出一种基于转弯模型（Turn Model）的跳步容错算法（Hop-Fault-Tolerant,HFT）,并在OPNET仿真平台对其进行仿真和性能分析。     

基于报文检测的快速自适应NoC容错路由算法

传统的自适应片上网络(NoC)容错路由算法采用一步一比较的方式来确定最优端口, 未能有效降低传输延迟。根据数据包在2D Mesh NoC前若干连续的跳数内最优端口固定的特点, 提出了一种基于报文检测的快速(FPIB)自适应容错路由算法。算法采用跳步比较的方式来减少数据包的路由时间, 并使用模糊优先级策略来进行容错路由计算。实验结果表明, 与uLBDR容错路由算法相比, 该算法能有效地降低平均延迟, 且实现算法的硬件开销更低。     

片上网络容错路由算法研究

随着集成电路制造工艺的不断发展,集成在芯片上晶体管的数量也随之增多,已超过几十亿晶体管的规模,因此芯片上可以集成越来越多的IP核。随着芯片中IP核数量的增多,基于总线结构的片上系统(System-on-Chip,So C)已不能满足数据的通信要求,为了解决这个问题,片上网络(Network-on-Chip,No C)作为一种全新的互联结构被提出来。其核心是把网络设计的思想移植到芯片设计中,将片上资源互连起来,并将计算与通信分离。片上网络具有很好的空间可扩展性,采用的全局异步一局部同步的通信机制使并行通信效率更高。NOC带来了一种全新的片上通信方式,它的引入有利于提升可重用设计、解决通信瓶颈和全局同步等难题。本文在研究片上网络结构的基础上,针对片上网络多播通信的特点提出了一种多播容错路由算法。     

多优先级自适应片上网络路由算法设计

提出一种适用于二维网格结构的片上网络(NoC)路由算法,该算法具有自适应性与最短路径的特点.采用多种优先级对数据进行裁决并传输,能提高系统的吞吐量,降低网络延迟.通过采用NIRGAM仿真平台对算法进行仿真,在4×4网格结构下,与其他NoC路由算法进行性能对比,结果显示该算法在热点模式下具有优势.     

基于故障节点再利用的细粒度NoC容错路由算法

针对传统NoC容错算法中容错粒度过粗造成资源浪费的问题,提出了一种细粒度的自适应容错路由算法,对带有部分故障的节点重新利用。算法将各种故障映射为一种功能故障模型,结合新提出的路由端口优先级策略和嵌入的奇偶转向模型,实现数据包的无死锁容错路由。实验表明,随着负载和故障数目的增加,该算法具有更优越的容错性能,证明了算法的有效性。     

基于容错技术的优先级反转研究*

优先级反转是实时系统中出现最多的问题。为了防止这种现象的发生,目前经常采用的方法是优先级继承和优先级置顶。但是,它们在特定情况下也存在缺陷。容错技术是提高系统可靠性的重要保障,利用容错技术对优先级继承进行扩展,可以更好地解决优先级的反转问题,保障了系统的实时性能。     

基于2D-Mesh的容错路由算法

提出一种基于2D-Mesh只使用2条虚通道的容错路由算法,少于需要4条虚通道的Boppana算法,以及需要3条虚通道的Duan算法。算法基于块故障模型,故障块可以是f-ring,也可以是f-chain。无故障时算法用最短路径路由消息,当消息被故障块阻塞时使用绕道策略进行路由。在不重叠和重叠故障区情况下分别给出算法无死锁性的证明过程。     

容错优先级混合式分配搜索算法

在实时系统中,由于任务未能及时产生正确结果将导致灾难性后果,容错对于实时系统的有效性及可靠性至关重要.基于最坏响应时间计算的可调度性分析,提出了一种容错优先级混合式分配搜索算法.这种算法通过允许替代任务既能运行在高优先级别上,又可运行在低优先级别上,有效地提高了系统的容错能力.通过实验测试,与目前所知的同类算法相比,在提高系统容错能力方面更为有效.     

无虚拟通道的3D NoC ZoneDefense容错路由算法*

3D片上网络能有效解决片上系统的通信问题。本文针对3D Mesh NoC中的节点故障,提出了一种无虚拟通道容错路由算法,称为3D ZoneDefense容错路由算法(3D-ZDFT)。该算法建立在3D防御区域基础之上,3D防御区域能够提供故障体的位置信息。根据防御区域提供的故障体位置信息,3D-ZDFT可提前发现故障位置并改变转发端口,实现容错的同时避免引入死锁。实验结果表明,与HamFA相比,3D-ZDFT有较低的网络延迟和更高的可靠性。面积开销分析显示,3D-ZDFT比HamFA的面积开销高约3.1%。     

基于前缀的片上网络容错源路由算法

为克服片上网络链路永久性错误带来的路由问题,提出一种基于前缀的片上网络容错源路由算法PFTSR。该算法适用于二维mesh片上网络,采用预测路径并根据反馈信息调整路径的方法进行路由探测。在仿真平台NIRGAM上进行仿真,实验结果表明,与传统片上网络容错源路由算法SRN相比,PFTSR极大降低了片上系统的功耗,并且在大多数情况下能减少探测到第一条路径的时间。     

Origin-based fault-tolerant routing in the mesh

The ability to tolerate faults is critical in multicomputer employing large numbers of processors. This paper describes a class of fault-tolerant routing algorithms for n-dimensional meshes that can tolerate large numbers of faults without using virtual channels. We show that these routing algorithms prevent livelock and deadlock while remaining highly adaptive.     

改进的WPAN mesh路由协议

为实现网状（mesh）网在无线个人区域网（WPAN）中的应用,设计了一种基于WPAN mesh网络的二层路由协议算法。该算法引入“次优路由”和“二层路由”路由优化策略,进一步给出报文格式、路由协议模型及其模拟实现,并对协议进行性能分析比较。实验结果表明,该算法有效减小了路由的端到端跳数,较好地提高了报文发送比率和端到端通信效率。     

A heuristic fault-tolerant routing algorithm in mesh using rectilinear-monotone polygonal fault blocks

A new, rectilinear-monotone polygonally shaped fault block model, called Minimal-Connected-Component (MCC), was proposed in [D. Wang, A rectilinear-monotone polygonal fault block model for fault-tolerant minimal routing in mesh, IEEE Trans. Comput. 52 (3) (2003) 310–320] for minimal adaptive routing in mesh-connected multiprocessor systems. This model refines the widely used rectangular model by including fewer non-faulty nodes in fault blocks. The positions of source/destination nodes relative to faulty nodes are taken into consideration when constructing fault blocks. Adaptive routing algorithm was given in Wang (2003), that constructs a minimal “Manhattan” route avoiding all fault blocks, should such routes exist. However, if there are no minimal routes, we still need to find a route, preferably as short as possible. In this paper, we propose a heuristic algorithm that takes a greedy approach, and can compute a nearly shortest route without much overhead. The significance of this algorithm lies in the fact that routing is a frequently performed task, and messages need to get to their destinations as soon as possible. Therefore one would prefer to have a fast answer about which route to take (and then take it), rather than spend too much time working out an absolutely shortest route.     

无线网状网络的多路径路由与调度算法

提出了一种保障服务质量的多路径路由算法,数据分组可通过多条不同的路径进行传输,以提升网络总吞吐量性能.进一步提出了一种多路径调度策略.通过使用调度策略,基于当前可用带宽信息和路径所引入的时延信息,数据分组在传输前可被分成多段并通过不同的路径发送,根据路径时延调整优化调度策略,从而使得数据可通过在不同的路径上进行更高效地传输.仿真实验进一步验证了本文提出的路由机制和调度策略在不同网络负载下的优越性.     

基于遗传算法的无线网状网QoS路由算法*

对基于遗传算法的多QoS约束路由算法进行了研究,实验结果表明,该算法在无线网状网中是一种高效的路由算法.     

A quality based routing protocol for wireless mesh networks

Wireless mesh networks can provide low-cost solutions for extending the reach of wireless access points by using multi-hop routing over a set of stationary wireless routers. The routing protocol for these networks may need to address quality considerations to meet the requirements of the user. In this paper, we present a quality based routing protocol for wireless mesh networks that tries to maximize the probability of successful transmissions while minimizing the end-to-end delay. The proposed routing protocol uses reactive route discoveries to collect key parameters from candidate routes to estimate the probability of success and delay of data packets transmitted over them. To achieve accurate route quality assessments, a new route quality metric is proposed that uses performance models of data packet transmissions as opposed to estimating route quality from the transmission of control packets, which have different transmission characteristics. These models are developed after careful evaluations of multi-hop wireless transmissions and validated by computer simulations. Relevant parameters that can be used to assess the route quality metric using these models are explained. Extensive performance evaluations of the proposed quality based routing protocol are presented and its benefits in comparison to some other known routing protocols are discussed.     

A survey of routing algorithm for mesh Network-on-Chip

With the rapid development of semiconductor industry, the number of cores integrated on chip increases quickly, which brings tough challenges such as bandwidth, scalability and power into on-chip interconnection. Under such background, Network-on-Chip (NoC) is proposed and gradually replacing the traditional on-chip interconnections such as sharing bus and crossbar. For the convenience of physical layout, mesh is the most used topology in NoC design. Routing algorithm, which decides the paths of packets, has significant impact on the latency and throughput of network. Thus routing algorithm plays a vital role in a wellperformed network. This study mainly focuses on the routing algorithms of mesh NoC. By whether taking network information into consideration in routing decision, routing algorithms of NoC can be roughly classified into oblivious routing and adaptive routing. Oblivious routing costs less without adaptiveness while adaptive routing is on the contrary. To combine the advantages of oblivious and adaptive routing algorithm, half-adaptive algorithms were proposed. In this paper, the concepts, taxonomy and features of routing algorithms of NoC are introduced. Then the importance of routing algorithms in mesh NoC is highlighted, and representative routing algorithms with respective features are reviewed and summarized. Finally, we try to shed light upon the future work of NoC routing algorithms.     

无线Mesh网络中多信道生成树路由算法

无线Mesh网络是一种特殊的AdHoc网络。它易于部署、安装,能有效地构建无线骨干网,通常被用作宽带Internet接入和扩展无线LAN的覆盖范围。针对无线Mesh网络的特点,提出了一种不同于一般MANET路由协议的路由算法。该算法基于网络拓扑生成树,使用多个无重叠信道;在解决信道分配问题的同时,兼顾信道多样性和信道重用,更好地利用无线频谱资源,支持链路并行传输。     

IP Mesh网络的多约束QoS选路研究

多约束QoS路由算法一直是研究重点和难点,是一个有待解决的NP完全问题。针对IP Mesh网络的特点,设计出相应的完全图,并且推出了n个节点的完全图路径总数目公式。提出了一种CBFS_MCP算法,首先用Dijsktra最短路径算法对节点和边进行删减,将完全图简化,再在简化图上用类BFS算法通过“约束条件夹逼”和不断剪枝,寻找一条从起点s到终点t的符合两个约束条件的可行路径。实验结果表明CBFS_MCP算法有着良好的算法性能。